< draft-shirey-secgloss-v2-00.txt   draft-shirey-secgloss-v2-01.txt >
INTERNET-DRAFT R. W. Shirey INTERNET-DRAFT R. W. Shirey
Obsoletes: RFC 2828 (if approved) BBN Technologies Obsoletes: RFC 2828, FYI 36 BBN Technologies
Expiration Date: 20 February 2004 20 August 2004 Expiration Date: 9 September 2005 9 March 2005
Internet Security Glossary, Version 2 Internet Security Glossary, Version 2
<draft-shirey-secgloss-v2-00.txt> <draft-shirey-secgloss-v2-01.txt>
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed, patent or other IPR claims of which I am aware have been disclosed,
or will be disclosed, and any of which I become aware will be or will be disclosed, and any of which I become aware will be
disclosed, in accordance with RFC 3668. disclosed, in accordance with RFC 3668.
This document may not be modified, and derivative works of it may This document may not be modified, and derivative works of it may
not be created, except to publish it as an RFC and to translate it not be created, except to publish it as an RFC and to translate it
into languages other than English. into languages other than English.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that other
other groups may also distribute working documents as Internet- groups may also distribute working documents as Internet-Drafts.
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than a "work in progress." material or to cite them other than a "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html" http://www.ietf.org/shadow.html"
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2005). All Rights Reserved.
Abstract Abstract
This Glossary has 1,500 entries that give definitions, abbreviations, This Glossary provides definitions, abbreviations, and explanations
and explanations for terminology concerning information system of terminology for information system security. The 288 pages of
security. It makes recommendations to improve the clarity of Internet listings offer recommendations to improve the clarity of Internet
Standards documents (ISDs) and the ease with which international Standards documents (ISDs) and to make them more easily understood by
readers can understand ISDs. Its follow the principles that ISDs international readers. The recommendations follow the principles that
should (a) use the same term or definition whenever the same concept ISDs should (a) use the same term or definition whenever the same
is mentioned; (b) use terms in their plainest, dictionary sense; (c) concept is mentioned; (b) use terms in their plainest, dictionary
use terms that are already well-established in open publications; and sense; (c) use terms that are already well-established in open
(d) avoid terms that are proprietary, favor a particular vendor, or publications; and (d) avoid terms that are proprietary, favor a
create a bias toward a particular technology or mechanism versus particular vendor, or create a bias toward a particular technology or
other, competing techniques that already exist or might be developed. mechanism versus other, competing techniques that already exist or
might be developed.
Table of Contents Table of Contents
Section Page Section Page
------- ---- ------- ----
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Format of Entries . . . . . . . . . . . . . . . . . . . . . . 4 2. Format of Entries . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Presentation Order . . . . . . . . . . . . . . . . . . . . 4 2.1 Presentation Order . . . . . . . . . . . . . . . . . . . . 4
2.2 Capitalization and Abbreviation . . . . . . . . . . . . . 4 2.2 Capitalization and Abbreviation . . . . . . . . . . . . . 4
2.3 Support for Automated Searching . . . . . . . . . . . . . 5 2.3 Support for Automated Searching . . . . . . . . . . . . . 5
2.4 Definition Type and Context . . . . . . . . . . . . . . . 5 2.4 Definition Type and Context . . . . . . . . . . . . . . . 5
2.5 Explanatory Notes . . . . . . . . . . . . . . . . . . . . 5 2.5 Explanatory Notes . . . . . . . . . . . . . . . . . . . . 5
2.6 Cross-References . . . . . . . . . . . . . . . . . . . . . 5 2.6 Cross-References . . . . . . . . . . . . . . . . . . . . . 5
2.7 Trademarks . . . . . . . . . . . . . . . . . . . . . . . . 6 2.7 Trademarks . . . . . . . . . . . . . . . . . . . . . . . . 6
2.8 The New Punctuation . . . . . . . . . . . . . . . . . . . 6 2.8 The New Punctuation . . . . . . . . . . . . . . . . . . . 6
3. Types of Definitions . . . . . . . . . . . . . . . . . . . . . 6 3. Types of Entries . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 Type "I": Recommended Definition with Internet Basis . . . 6 3.1 Type "I": Recommended Definitions of Internet Origin . . . 6
3.2 Type "N": Recommended Definition with Non-Internet Basis . 7 3.2 Type "N": Recommended Definitions of Non-Internet Origin . 7
3.3 Type "O": Other Definitions. . . . . . . . . . . . . . . . 7 3.3 Type "O": Other Terms and Definitions to be Noted . . . . 7
2.4 Type "D": Deprecated Definitions . . . . . . . . . . . . . 7 3.4 Type "D": Deprecated Terms and Definitions . . . . . . . . 7
2.5 Definition Substitutions . . . . . . . . . . . . . . . . . 7 3.5 Definition Substitutions . . . . . . . . . . . . . . . . . 7
4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 9 4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Informative References . . . . . . . . . . . . . . . . . . . 276 5. Informative References . . . . . . . . . . . . . . . . . . . . 297
6. Security Considerations . . . . . . . . . . . . . . . . . . . 293 6. Security Considerations . . . . . . . . . . . . . . . . . . . 315
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 293 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 315
8. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 293 8. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 315
9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 293 9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 315
1. Introduction 1. Introduction
This Glossary provides an internally consistent and self-contained This Glossary provides an internally consistent and self-contained
set of terms, abbreviations, and definitions -- supported by set of terms, abbreviations, and definitions -- supported by
explanations, recommendations, and references -- for terminology that explanations, recommendations, and references -- for terminology that
concerns information system security. The intent of this Glossary is concerns information system security. The intent of this Glossary is
to improve the comprehensibility of Internet Standards documents to improve the comprehensibility of Internet Standards documents
(ISDs) -- i.e., RFCs, Internet-Drafts, and other material produced as (ISDs) -- i.e., RFCs, Internet-Drafts, and other material produced as
part of the Internet Standards Process [R2026] -- and of all other part of the Internet Standards Process (RFC 2026) -- and other
Internet-related material, too. A few non-security, networking terms Internet-related discourse. A few non-security, networking terms are
are included to make the Glossary self-contained, but more complete included to make the Glossary self-contained, but more complete
glossaries of networking terms are available elsewhere [A1523, F1037, glossaries of networking terms are available elsewhere [A1523, F1037,
R1208, R1983]. R1208, R1983].
This Glossary supports the goals of the Internet Standards Process: This Glossary supports the goals of the Internet Standards Process:
o Clear, Concise, Easily Understood Documentation o Clear, Concise, Easily Understood Documentation
This Glossary seeks to improve comprehensibility of security- This Glossary seeks to improve comprehensibility of security-
related content of ISDs. That requires wording to be clear and related content of ISDs. That requires wording to be clear and
understandable, and requires the set of security-related terms and understandable, and requires the set of security-related terms and
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Just as Internet Standard (STD) protocols should operate Just as Internet Standard (STD) protocols should operate
effectively, ISDs should use terminology accurately, precisely, effectively, ISDs should use terminology accurately, precisely,
and unambiguously to enable standards to be implemented correctly. and unambiguously to enable standards to be implemented correctly.
o Prior Implementation and Testing o Prior Implementation and Testing
Just as STD protocols require demonstrated experience and Just as STD protocols require demonstrated experience and
stability before adoption, ISDs need to use well-established stability before adoption, ISDs need to use well-established
language. Using terms in their plainest, dictionary sense (when language. Using terms in their plainest, dictionary sense (when
appropriate) helps to ensure international understanding. ISDs appropriate) helps to ensure international understanding. ISDs
need to avoid using private, made-up terms in place of generally- need to avoid using private, made-up terms in place of generally
accepted terms from open publications. ISDs need to avoid accepted terms from open publications. ISDs need to avoid
substituting new definitions that conflict with established ones. substituting new definitions that conflict with established ones.
ISDs need to avoid using "cute" synonyms (e.g., see: Green Book), ISDs need to avoid using "cute" synonyms (e.g., see: Green Book),
because no matter how popular a nickname may be in one community, because no matter how popular a nickname may be in one community,
it is likely to cause confusion in another. it is likely to cause confusion in another.
o Openness, Fairness, and Timeliness o Openness, Fairness, and Timeliness
ISDs need to avoid terms that are proprietary or otherwise favor a ISDs need to avoid terms that are proprietary or otherwise favor a
particular vendor, or that create a bias toward a particular particular vendor, or that create a bias toward a particular
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Each entry is preceded by a dollar sign ($) and a space. This Each entry is preceded by a dollar sign ($) and a space. This
makes it possible to find the defining entry for an item "X" by makes it possible to find the defining entry for an item "X" by
searching for the character string "$ X", without stopping at searching for the character string "$ X", without stopping at
entries in which "X" is used in explanations. entries in which "X" is used in explanations.
2.4 Definition Type and Context 2.4 Definition Type and Context
Each entry is preceded by a character -- I, N, O, or D -- enclosed Each entry is preceded by a character -- I, N, O, or D -- enclosed
in parentheses, to indicate the type of definition (as is in parentheses, to indicate the type of definition (as is
explained further in Section 3): explained further in Section 3):
- "I" for a RECOMMENDED term or definition of Internet origin. - "I" for a RECOMMENDED term or definition of Internet origin.
- "N" if RECOMMENDED but not of Internet origin. - "N" if RECOMMENDED but not of Internet origin.
- "O" for a term or definition that is NOT recommended for use in - "O" for a term or definition that is NOT recommended for use in
ISDs but is something that authors of Internet documents need ISDs but is something that authors of Internet documents should
to know about. know about.
- "D" for a term or definition that is deprecated and SHOULD NOT - "D" for a term or definition that is deprecated and SHOULD NOT
be used in Internet documents. be used in Internet documents.
If a definition is valid only in a specific context (e.g., If a definition is valid only in a specific context (e.g.,
"baggage"), that context is shown immediately following the "baggage"), that context is shown immediately following the
definition type and is enclosed by a pair of slash symbols (/). If definition type and is enclosed by a pair of slash symbols (/). If
the definition is valid only for specific parts of speech, that is the definition is valid only for specific parts of speech, that is
shown in the same way (e.g., "archive). shown in the same way (e.g., "archive).
2.5 Explanatory Notes 2.5 Explanatory Notes
Some entries have explanatory text that is introduced by one or Some entries have explanatory text that is introduced by one or
more of the following keywords: more of the following keywords:
- Deprecated Abbreviation (e.g., "EE", "H field", "W3") - Deprecated Abbreviation (e.g., "EE", "H field", "W3")
- Deprecated Definition (e.g., "digital certification") - Deprecated Definition (e.g., "digital certification")
- Deprecated Usage (e.g., "authenticate") - Deprecated Usage (e.g., "authenticate")
- Deprecated Term (e.g., "certificate authority") - Deprecated Term (e.g., "certificate authority")
- Pronunciation (e.g., "*-property") - Pronunciation (e.g., "*-property")
- Derivation (e.g., "discretionary access control") - Derivation (e.g., "discretionary access control")
- Tutorial (e.g., "accreditation") - Tutorial (e.g., "accreditation")
- Example (e.g., "back door") - Example (e.g., "back door")
- Usage (e.g., "access") - Usage (e.g., "access")
Explanatory text in this Glossary MAY be reused in other ISDs. Explanatory text in this Glossary MAY be reused in other ISDs.
However, such text is not intended to authoritatively supersede However, such text is not intended to authoritatively supersede
text of an ISD in which the Glossary entry is already used. text of an ISD in which the Glossary entry is already used.
2.6 Cross-References 2.6 Cross-References
Some entries contain a parenthetical remark of the form "(See: Some entries contain a parenthetical remark of the form "(See:
X)", where X is a list one of more related Glossary entries. Some X.)", where X is a list one of more related Glossary entries. Some
entries contain a remark of the form "(Compare: X)", where X is a entries contain a remark of the form "(Compare: X)", where X is a
list of other entries that either are antonyms or differ in some list of other entries that either are antonyms or differ in some
other manner worth observing. other manner worth noting.
2.7 Trademarks 2.7 Trademarks
All servicemarks and trademarks that appear in this Glossary are All servicemarks and trademarks that appear in this Glossary are
used in an editorial fashion and to the benefit of the mark owner, used in an editorial fashion and to the benefit of the mark owner,
without any intention of infringement. without any intention of infringement.
2.8 The New Punctuation 2.8 The New Punctuation
This Glossary uses the "new" or "logical" punctuation style that This Glossary uses the "new" or "logical" punctuation style
is favored by computer programmers, as described in [Raym]: favored by computer programmers, as described by Raymond [Raym]:
Programmers use pairs of quotation marks the same way they use Programmers use pairs of quotation marks the same way they use
pairs of parentheses, i.e., as balanced delimiters. For example, pairs of parentheses, i.e., as balanced delimiters. For example,
if " Alice sends" is a phrase, and so are "Bill receives" and "Eve if "Alice sends" is a phrase, and so are "Bill receives" and "Eve
listens", then a programmer would write the following sentence: listens", then a programmer would write the following sentence:
"Alice sends", "Bill receives", and "Eve listens". "Alice sends", "Bill receives", and "Eve listens".
According to standard American usage, the punctuation in that According to standard American usage, the punctuation in that
sentence is incorrect; the continuation commas and the final sentence is incorrect; the continuation commas and the final
period should go inside the string quotes, like this: period should go inside the string quotes, like this:
"Alice sends," "Bill receives," and "Eve listens." "Alice sends," "Bill receives," and "Eve listens."
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Then delete one line from the file by typing "dd." Then delete one line from the file by typing "dd."
However, in the vi language, the dot character repeats the last However, in the vi language, the dot character repeats the last
command accepted. So, if a reader entered "dd.", two lines would command accepted. So, if a reader entered "dd.", two lines would
be deleted instead of one. be deleted instead of one.
Similarly, use of standard American punctuation might cause Similarly, use of standard American punctuation might cause
misunderstanding in entries in this Glossary. Thus, the new misunderstanding in entries in this Glossary. Thus, the new
punctuation is used here, and we recommend it for ISDs. punctuation is used here, and we recommend it for ISDs.
3. Types of Definition 3. Types of Entries
Each entry in this Glossary is marked as type I, N, O, or D: Each entry in this Glossary is marked as type I, N, O, or D:
3.1 Type "I": Recommended Term or Definition with Internet Basis 3.1 Type "I": Recommended Definitions of Internet Origin
The marking "I" indicates two things: The marking "I" indicates two things:
- Origin: "I" (as opposed to "N") means either that the Internet - Origin: "I" (as opposed to "N") means either that the Internet
Standards Process or Internet community is authoritative for Standards Process or Internet community is authoritative for
the definition *or* that the term is sufficiently generic that the definition *or* that the term is sufficiently generic that
this Glossary can freely state a definition without this Glossary can freely state a definition without
contradicting a non-Internet authority (e.g., "attack"). contradicting a non-Internet authority (e.g., "attack").
- Recommendation: "I" (as opposed to "O") means that the term and - Recommendation: "I" (as opposed to "O") means that the term and
definition are RECOMMENDED for use in ISDs. However, some "I" definition are RECOMMENDED for use in ISDs. However, some "I"
entries may be accompanied by a "Usage" note that states a entries may be accompanied by a "Usage" note that states a
limitation (e.g., "certification"), and ISDs SHOULD NOT use the limitation (e.g., "certification"), and ISDs SHOULD NOT use the
defined term outside that limited context. defined term outside that limited context.
Many "I" entries are proper nouns (e.g., "Internet Protocol") for Many "I" entries are proper nouns (e.g., "Internet Protocol") for
which the definition is intended only to provide basic which the definition is intended only to provide basic
information; i.e., the authoritative definition of such terms is information; i.e., the authoritative definition of such terms is
found elsewhere. For a proper noun described as an "Internet found elsewhere. For a proper noun described as an "Internet
protocol", please refer to the current edition of "Internet protocol", please refer to the current edition of "Internet
Official Protocol Standards" (STD 1) for the standardization Official Protocol Standards" (Standard 1) for the standardization
status of the protocol. status of the protocol.
3.2 Type "N": Recommended Term or Definition with Non-Internet Basis 3.2 Type "N": Recommended Definitions of Non-Internet Origin
The marking "N" indicates two things: The marking "N" indicates two things:
- Origin: "N" (as opposed to "I") means that the entry has a non- - Origin: "N" (as opposed to "I") means that the entry has a non-
Internet basis or origin. Internet basis or origin.
- Recommendation: "N" (as opposed to "O") means that the term and - Recommendation: "N" (as opposed to "O") means that the term and
definition are RECOMMENDED for use in ISDs, if they are needed definition are RECOMMENDED for use in ISDs, if they are needed
at all in ISDs. Many of these entries are accompanied by a at all in ISDs. Many of these entries are accompanied by a
label that states a context (e.g., "package") or a note that label that states a context (e.g., "package") or a note that
states a limitation (e.g., "data integrity"), and ISDs SHOULD states a limitation (e.g., "data integrity"), and ISDs SHOULD
NOT use the defined term outside that context or limit. Some of NOT use the defined term outside that context or limit. Some of
the contexts are rarely if ever expected to occur in an ISD the contexts are rarely if ever expected to occur in an ISD
(e.g., see: baggage). In those cases, the listing exists to (e.g., see: baggage). In those cases, the listing exists to
make Internet authors aware of the non-Internet usage so that make Internet authors aware of the non-Internet usage so that
they can avoid conflicts with non-Internet documents. they can avoid conflicts with non-Internet documents.
3.3 Type "O": Other Terms and Definitions To Be Noted 3.3 Type "O": Other Terms and Definitions To Be Noted
The marking "O" means that the definition has a non-Internet basis The marking "O" means that the definition is of non-Internet
and SHOULD NOT be used in ISDs *except* in cases where the term is origin and SHOULD NOT be used in ISDs *except* in cases where the
specifically identified as non-Internet. term is specifically identified as non-Internet.
For example, an ISD might mention "BCA" (see: brand certification For example, an ISD might mention "BCA" (see: brand certification
authority) or "baggage" as an example of some concept; in that authority) or "baggage" as an example of some concept; in that
case, the document should specifically say "SET(trademark) BCA" or case, the document should specifically say "SET(trademark) BCA" or
"SET(trademark) baggage" and include the definition of the term. "SET(trademark) baggage" and include the definition of the term.
3.4 Type "D": Deprecated Terms and Definitions 3.4 Type "D": Deprecated Terms and Definitions
If this Glossary recommends that an term or definition SHOULD NOT If this Glossary recommends that a term or definition SHOULD NOT
be used in ISDs, then the entry is marked as type "D", and a be used in ISDs, then the entry is marked as type "D", and a
"Deprecated Term", "Deprecated Definition", or "Deprecated Usage" "Deprecated Term", "Deprecated Definition", or "Deprecated Usage"
explanatory note is provided. explanatory note is provided.
3.5 Definition Substitutions 3.5 Definition Substitutions
Some terms have a definition published by a non-Internet authority Some terms have a definition published by a non-Internet authority
-- government (e.g., "object reuse"), industry (e.g., "Secure Data -- government (e.g., "object reuse"), industry (e.g., "Secure Data
Exchange"), national authority (e.g., "Data Encryption Standard"), Exchange"), national authority (e.g., "Data Encryption Standard"),
or international body (e.g., "data confidentiality") -- that is or international body (e.g., "data confidentiality") -- that is
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exchange") or explanations, using other terms that are defined in exchange") or explanations, using other terms that are defined in
this Glossary. In those cases, this Glossary marks the entry "O", this Glossary. In those cases, this Glossary marks the entry "O",
and provides an "I" or "N" entry that precedes, and is intended to and provides an "I" or "N" entry that precedes, and is intended to
supersede, the "O" entry. supersede, the "O" entry.
In some cases where this Glossary provides a definition to In some cases where this Glossary provides a definition to
supersede an "O" definition, the substitute is intended to subsume supersede an "O" definition, the substitute is intended to subsume
the meaning of the "O" entry and not conflict with it. For the the meaning of the "O" entry and not conflict with it. For the
term "security service", for example, the "O" definition deals term "security service", for example, the "O" definition deals
narrowly with only communication services provided by layers in narrowly with only communication services provided by layers in
the OSI model and is inadequate for the full range of ISD usage, the OSIRM and is inadequate for the full range of ISD usage, while
while the new "I" definition provided by this Glossary can be used the new "I" definition provided by this Glossary can be used in
in more situations and for more kinds of service. However, the "O" more situations and for more kinds of service. However, the "O"
definition is also listed so that ISD authors will be aware of the definition is also listed so that ISD authors will be aware of the
context in which the term is used more narrowly. context in which the term is used more narrowly.
When making substitutions, this Glossary attempts to avoid When making substitutions, this Glossary attempts to avoid
contradicting any non-Internet authority. Still, terminology contradicting any non-Internet authority. Still, terminology
differs between the standards of the American Bar Association, differs between authorities such as the American Bar Association,
OSI, SET, the U.S. DoD, and other authorities; and this Glossary OSI, SET, the U.S. DoD, and other authorities; and this Glossary
probably is not exactly aligned with any of them. probably is not exactly aligned with any of them.
4. Definitions 4. Definitions
$ *-property $ *-property
(N) Synonym for "confinement property" in the context of the Bell- (N) Synonym for "confinement property" in the context of the Bell-
LaPadula model. Pronunciation: star property. LaPadula model. Pronunciation: star property.
$ 3DES $ 3DES
See: Triple Data Encryption Algorithm. (N) See: Triple Data Encryption Algorithm.
$ A1 computer system $ A1 computer system
(O) See: TCSEC. (O) /TCSEC/ See: Tutorial under "Trusted Computer System
Evaluation Criteria".
$ AA $ AA
See: attribute authority. See: attribute authority.
$ ABA Guidelines $ ABA Guidelines
(N) "American Bar Association (ABA) Digital Signature Guidelines" (N) "American Bar Association (ABA) Digital Signature Guidelines"
[ABA], a framework of legal principles for using digital [ABA], a framework of legal principles for using digital
signatures and digital certificates in electronic commerce. signatures and digital certificates in electronic commerce.
$ Abstract Syntax Notation One (ASN.1) $ Abstract Syntax Notation One (ASN.1)
(N) A standard for describing data objects. [Larm, X680] (See: (N) A standard for describing data objects. [Larm, X680] (See:
CMS.) CMS.)
Usage: This term is often incorrectly used to refer to BER. Deprecated Usage: The term "ASN.1" can be used narrowly to
describe the notation or language called "Abstract
Syntax Notation One", or can be used more broadly to
encompass the notation, its associated encoding rules
(see: BER), and software tools that assist in its use.
Tutorial: OSIRM defines computer network functionality in layers. Tutorial: OSIRM defines computer network functionality in layers.
Protocols and data objects at higher layers are abstractly defined Protocols and data objects at higher layers are abstractly defined
to be implemented using protocols and data objects from lower to be implemented using protocols and data objects from lower
layers. A higher layer may define transfers of abstract objects layers. A higher layer may define transfers of abstract objects
between computers, and a lower layer may define those transfers between computers, and a lower layer may define those transfers
concretely as strings of bits. Syntax is needed to specify data concretely as strings of bits. Syntax is needed to specify data
formats of abstract objects, and encoding rules are needed to formats of abstract objects, and encoding rules are needed to
transform abstract objects into bit strings at lower layers. OSI transform abstract objects into bit strings at lower layers. OSI
standards use ASN.1 for those specifications and use various standards use ASN.1 for those specifications and use various
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In ASN.1, formal names are written without spaces, and separate In ASN.1, formal names are written without spaces, and separate
words in a name are indicated by capitalizing the first letter of words in a name are indicated by capitalizing the first letter of
each word except the first word. For example, the name of a CRL is each word except the first word. For example, the name of a CRL is
"certificateRevocationList". "certificateRevocationList".
$ ACC $ ACC
(I) See: access control center. (I) See: access control center.
$ acceptable risk $ acceptable risk
(I) A risk that is understood and tolerated by a system's (I) A risk that is understood and tolerated by a system's user,
accreditor, usually because the cost or difficulty of implementing operator, owner, or accreditor, usually because the cost or
an effective countermeasure for the associated vulnerability difficulty of implementing an effective countermeasure for the
exceeds the expectation of loss. (See: adequate security, (second associated vulnerability exceeds the expectation of loss. (See:
law under) Courtney's laws.) adequate security, "second law" under "Courtney's laws".)
$ access $ access
1. (I) The ability and means to communicate with or otherwise 1. (I) The ability and means to communicate with or otherwise
interact with a system to use system resources either to handle interact with a system to use system resources either to handle
information or to gain knowledge of the information the system information or to gain knowledge of the information the system
contains. (Compare: handle.) contains. (Compare: handle.)
Usage: The definition is intended to include all types of Usage: The definition is intended to include all types of
communication with a system, including one-way communication in communication with a system, including one-way communication in
either direction. In actual practice, however, entities that are either direction. In actual practice, however, passive users might
outside a security perimeter and can receive output from the be treated as not having "access" and, therefore, be exempt from
system but cannot provide input or otherwise directly interact most requirements of the system's security policy. (See: "passive
with the system, might be treated as not having "access" (and, user" under "user".)
therefore, be exempt from security policy requirements, such as
the need for a security clearance).
2. (O) /formal model/ "A specific type of interaction between a 2. (O) /formal model/ "A specific type of interaction between a
subject and an object that results in the flow of information from subject and an object that results in the flow of information from
one to the other." [NCS04] one to the other." [NCS04]
$ Access Certificate for Electronic Services (ACES) $ Access Certificate for Electronic Services (ACES)
(O) A PKI operated by the U.S. Government's General Services (O) A PKI operated by the U.S. Government's General Services
Administration in cooperation with industry partners. (See: CAM.) Administration in cooperation with industry partners. (See: CAM.)
$ access control $ access control
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human controls to identify or admit personnel with properly human controls to identify or admit personnel with properly
authorized access to a SCIF. authorized access to a SCIF.
$ access control center (ACC) $ access control center (ACC)
(I) A computer that maintains a database (possibly in the form of (I) A computer that maintains a database (possibly in the form of
an access control matrix) defining the security policy for an an access control matrix) defining the security policy for an
access control service, and that acts as a server for clients access control service, and that acts as a server for clients
requesting access control decisions. requesting access control decisions.
Tutorial: An ACC is sometimes used in conjunction with a key Tutorial: An ACC is sometimes used in conjunction with a key
center to implement access control in a key distribution system center to implement access control in a key-distribution system
for symmetric cryptography. (See: BLACKER, Kerberos.) for symmetric cryptography. (See: BLACKER, Kerberos.)
$ access control list (ACL) $ access control list (ACL)
(I) /information system/ A mechanism that implements access (I) /information system/ A mechanism that implements access
control for a system resource by enumerating the system entities control for a system resource by enumerating the system entities
that are permitted to access the resource and, either implicitly that are permitted to access the resource and stating, either
or explicitly, the types of access granted to each. (Compare: implicitly or explicitly, the access modes granted to each entity.
access control matrix, access list, access profile, capability.) (Compare: access control matrix, access list, access profile,
capability list.)
$ access control matrix $ access control matrix
(I) A rectangular array of cells, with one row per subject and one (I) A rectangular array of cells, with one row per subject and one
column per object. The entry in a cell -- that is, the entry for a column per object. The entry in a cell -- that is, the entry for a
particular subject-object pair -- indicates the access mode that particular subject-object pair -- indicates the access mode that
the subject is permitted to exercise on the object. Each column is the subject is permitted to exercise on the object. Each column is
equivalent to an "access control list" for the object; and each equivalent to an "access control list" for the object; and each
row is equivalent to an "access profile" for the subject. row is equivalent to an "access profile" for the subject.
$ access control service $ access control service
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Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts
in a potentially misleading way. Access control may be based on in a potentially misleading way. Access control may be based on
attributes other than classification level. attributes other than classification level.
$ access list $ access list
(I) /physical security/ Roster of persons who are authorized to (I) /physical security/ Roster of persons who are authorized to
enter a controlled area. (Compare: access control list.) enter a controlled area. (Compare: access control list.)
$ access mode $ access mode
(I) A distinct type of data processing operation -- e.g., read, (I) A distinct type of data processing operation -- e.g., read,
write, append, or execute -- that a subject can potentially write, append, or execute, or a combination of operations -- that
perform on an object in an information system. [Huff] a subject can potentially perform on an object in an information
system. [Huff]
$ access policy $ access policy
(I) A kind of "security policy". (See: access, access control.) (I) A kind of "security policy". (See: access, access control.)
$ access profile $ access profile
(O) /information system/ A mechanism that implements access (O) A synonym for "capability list".
control for a system entity by enumerating the system resources
that the entity is authorized to access and, either implicitly or
explicitly, the types of access granted to each. (Compare: access
control matrix, access control list, access list, capability.)
Usage: The definition is not widely known; therefore, ISDs that Usage: ISDs that use this term SHOULD state a definition for it
use this term SHOULD state a definition for it. because the definition is not widely known.
$ access right $ access right
(I) Synonym for "authorization"; emphasizes the possession of the (I) Synonym for "authorization"; emphasizes the possession of the
authorization by a system entity. authorization by a system entity.
$ accountability $ accountability
(I) The property of a system or system resource that ensures that (I) The property of a system or system resource that ensures that
the actions of a system entity may be traced uniquely to that the actions of a system entity may be traced uniquely to that
entity, which can then be held responsible for its actions. [Huff] entity, which can then be held responsible for its actions. [Huff]
(See: audit service.) (See: audit service.)
Tutorial: Accountability (also known as "individual Tutorial: Accountability (a.k.a. "individual accountability")
accountability") typically involves a system capability to typically requires a system ability to positively associate the
positively associate the identity of a user with the time, method, identity of a user with the time, method, and mode of the user's
and mode of the user's access to the system. This capability access to the system. This ability supports detection and
supports detection and subsequent investigation of security subsequent investigation of security breaches. Individual persons
breaches. Individual persons who are system users are held who are system users are held accountable for their actions after
accountable for their actions after being notified of the rules of being notified of the rules of behavior for using the system and
behavior for using the system and the penalties associated with the penalties associated with violating those rules.
violating those rules.
$ accounting $ accounting
See: COMSEC accounting. See: COMSEC accounting.
$ accounting legend code (ALC) $ accounting legend code (ALC)
(O) /U.S. Government/ Numeric system used to indicate the minimum (O) /U.S. Government/ Numeric system used to indicate the minimum
accounting controls required for items of COMSEC material within accounting controls required for items of COMSEC material within
the CMCS. [C4009] (See: COMSEC accounting.) the CMCS. [C4009] (See: COMSEC accounting.)
$ accreditation $ accreditation
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2. (O) /SET/ "The institution (or its agent) that acquires from 2. (O) /SET/ "The institution (or its agent) that acquires from
the card acceptor the financial data relating to the transaction the card acceptor the financial data relating to the transaction
and initiates that data into an interchange system." [SET2] and initiates that data into an interchange system." [SET2]
$ activation data $ activation data
(N) Secret data, other than keys, that is required to access a (N) Secret data, other than keys, that is required to access a
cryptographic module. cryptographic module.
$ active attack $ active attack
(I) See: (secondary definition under) attack. (I) See: secondary definition under "attack".
$ active content $ active content
(O) "Electronic documents that can carry out or trigger actions (O) "Electronic documents that can carry out or trigger actions
automatically on a computer platform without the intervention of a automatically on a computer platform without the intervention of a
user. [This technology enables] mobile code associated with a user. [This technology enables] mobile code associated with a
document to execute as the document is rendered." [SP28] document to execute as the document is rendered." [SP28] (See:
mobile code.)
$ active user
(I) See: secondary definition under "attack".
$ active wiretapping $ active wiretapping
(I) A wiretapping attack that attempts to alter data being (I) A wiretapping attack that attempts to alter data being
communicated or otherwise affect data flow. (See: wiretapping. communicated or otherwise affect data flow. (See: wiretapping.
Compare: active attack, passive wiretapping.) Compare: active attack, passive wiretapping.)
$ add-on security $ add-on security
(N) The retrofitting of protection mechanisms, implemented by (N) The retrofitting of protection mechanisms, implemented by
hardware or software, in an information system after the system hardware or software, in an information system after the system
has become operational. [FP039] (Compare: baked-in security.) has become operational. [FP039] (Compare: baked-in security.)
$ adequate security $ adequate security
(O) /U.S. DoD/ "Security commensurate with the risk and magnitude (O) /U.S. DoD/ "Security commensurate with the risk and magnitude
of harm resulting from the loss, misuse, or unauthorized access to of harm resulting from the loss, misuse, or unauthorized access to
or modification of information." (See: acceptable risk, residual or modification of information." (See: acceptable risk, residual
risk.) risk.)
$ administrative security $ administrative security
1. (I) Management procedures and constraints to prevent 1. (I) Management procedures and constraints to prevent
unauthorized access to a system. (See: (third law under) unauthorized access to a system. (See: "third law" under
Courtney's laws, operational security, procedural security, "Courtney's laws", operational security, procedural security,
security architecture. Compare: technical security.) security architecture. Compare: technical security.)
Examples: Clear delineation and separation of duties; Examples: Clear delineation and separation of duties;
configuration control. configuration control.
Usage: Administrative security is usually understood to consist of Usage: Administrative security is usually understood to consist of
methods and mechanisms that are implemented and executed primarily methods and mechanisms that are implemented and executed primarily
by people, rather than by automated systems. by people, rather than by automated systems.
2. (O) "The management constraints, operational procedures, 2. (O) "The management constraints, operational procedures,
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$ administrator $ administrator
1. (O) /Common Criteria/ A person that is responsible for 1. (O) /Common Criteria/ A person that is responsible for
configuring, maintaining, and administering the TOE in a correct configuring, maintaining, and administering the TOE in a correct
manner for maximum security. (See: administrative security.) manner for maximum security. (See: administrative security.)
2. (O) /ITSEC/ A person in contact with the TOE, who is 2. (O) /ITSEC/ A person in contact with the TOE, who is
responsible for maintaining its operational capability. responsible for maintaining its operational capability.
$ Advanced Encryption Standard (AES) $ Advanced Encryption Standard (AES)
(N) A U.S. Government standard [FP197] (the successor to DES) that (N) A U.S. Government standard [FP197] (the successor to DES) that
(a) specifies the "the AES algorithm", which is a symmetric block (a) specifies "the AES algorithm", which is a symmetric block
cipher that is based on Rijndael and uses key sizes of 128, 192, cipher that is based on Rijndael and uses key sizes of 128, 192,
or 256 bits to operate on a 128-bit block, and (b) states policy or 256 bits to operate on a 128-bit block, and (b) states policy
for using that algorithm to protect unclassified, sensitive data. for using that algorithm to protect unclassified, sensitive data.
Tutorial: Rijndael was designed to handle additional block sizes Tutorial: Rijndael was designed to handle additional block sizes
and key lengths that were not adopted in the AES. Rijndael was and key lengths that were not adopted in the AES. Rijndael was
selected by NIST through a public competition that was held to selected by NIST through a public competition that was held to
find a successor to the DEA; the other finalists were MARS, RC6, find a successor to the DEA; the other finalists were MARS, RC6,
Serpent, and Twofish. Serpent, and Twofish.
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$ Affirm $ Affirm
(O) A formal methodology, language, and integrated set of software (O) A formal methodology, language, and integrated set of software
tools developed at the University of Southern California's tools developed at the University of Southern California's
Information Sciences Institute for specifying, coding, and Information Sciences Institute for specifying, coding, and
verifying software to produce correct and reliable programs. verifying software to produce correct and reliable programs.
[Cheh] [Cheh]
$ aggregation $ aggregation
(I) A circumstance in which a collection of information items is (I) A circumstance in which a collection of information items is
required to be classified at a higher security level than any of required to be classified at a higher security level than any of
the items is classified individually. the items is classified individually. (See: classification.)
$ AH $ AH
(I) See: Authentication Header (I) See: Authentication Header
$ air gap $ air gap
(I) An interface between two systems at which (a) they are not (I) An interface between two systems at which (a) they are not
connected physically and (b) any logical connection is not connected physically and (b) any logical connection is not
automated (i.e., data is transferred through the interface only automated (i.e., data is transferred through the interface only
manually, under human control). (See: sneaker net.) manually, under human control). (See: sneaker net. Compare:
gateway.)
Example: Computer A and computer B are on opposite sides of a Example: Computer A and computer B are on opposite sides of a
room. To move data from A to B, a person carries a floppy disk room. To move data from A to B, a person carries a floppy disk
across the room. If A and B operate in different security domains, across the room. If A and B operate in different security domains,
than moving data across the air gap may involve an upgrade or than moving data across the air gap may involve an upgrade or
downgrade operation. downgrade operation.
$ ALC $ ALC
(O) See: accounting legend code. (O) See: accounting legend code.
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$ American National Standards Institute (ANSI) $ American National Standards Institute (ANSI)
(N) A private, not-for-profit association that administers U.S. (N) A private, not-for-profit association that administers U.S.
private sector voluntary standards. private sector voluntary standards.
Tutorial: ANSI has approximately 1,000 member organizations, Tutorial: ANSI has approximately 1,000 member organizations,
including equipment users, manufacturers, and others. These including equipment users, manufacturers, and others. These
include commercial firms, government agencies, and other include commercial firms, government agencies, and other
institutions and international entities. institutions and international entities.
ANSI is the sole U.S. representative to the two major non-treaty ANSI is the sole U.S. representative to (1) ISO and (2) (via the
international standards organizations, ISO and, via the U.S. U.S. National Committee) the International Electrotechnical
Commission (IEC), which are the two major, non-treaty,
National Committee (USNC), the International Electrotechnical international standards organizations.
Commission (IEC).
ANSI provides a forum for ANSI-accredited standards development ANSI provides a forum for ANSI-accredited standards development
groups. Among those groups, the following are especially relevant groups. Among those groups, the following are especially relevant
to Internet security: to Internet security:
- International Committee for Information Technology - International Committee for Information Technology
Standardization (INCITS) (formerly X3): Primary U.S. focus of Standardization (INCITS) (formerly X3): Primary U.S. focus of
standardization in information and communications technologies, standardization in information and communications technologies,
encompassing storage, processing, transfer, display, encompassing storage, processing, transfer, display,
management, organization, and retrieval of information. management, organization, and retrieval of information.
Example: [A3092]. Example: [A3092].
- Accredited Standards Committee X9: Develops, establishes, - Accredited Standards Committee X9: Develops, establishes,
maintains, and promotes standards for the financial services maintains, and promotes standards for the financial services
industry. Example: [A9009]. industry. Example: [A9009].
- Alliance for Telecommunications Industry Solutions (ATIS): - Alliance for Telecommunications Industry Solutions (ATIS):
Develops standards, specifications, guidelines, requirements, Develops standards, specifications, guidelines, requirements,
technical reports, industry processes, and verification tests technical reports, industry processes, and verification tests
for interoperability and reliability of telecommunications for interoperability and reliability of telecommunications
networks, equipment, and software. Example: [A1523]. networks, equipment, and software. Example: [A1523].
$ American Standard Code for Information Interchange (ASCII)
(N) A scheme that encodes 128 specified characters -- the numbers
0-9, the letters a-z and A-Z, some basic punctuation symbols, some
control codes that originated with Teletype machines, and a blank
space -- into the 7-bit binary numbers. Forms the basis of the
character set representations used in most computers and many
Internet standards. [FP001] (See: code.)
$ Anderson report $ Anderson report
(O) A 1972 study of computer security that was written by James P. (O) A 1972 study of computer security that was written by James P.
Anderson for the U.S. Air Force [Ande]. Anderson for the U.S. Air Force [Ande].
Tutorial: Anderson collaborated with a panel of experts to study Tutorial: Anderson collaborated with a panel of experts to study
Air Force requirements for multilevel security. The study Air Force requirements for multilevel security. The study
recommended research and development that was urgently needed to recommended research and development that was urgently needed to
provide secure information processing for command and control provide secure information processing for command and control
systems and support systems. The report introduced the reference systems and support systems. The report introduced the reference
monitor concept and provided development impetus for computer and monitor concept and provided development impetus for computer and
network security technology. However, many of the security network security technology. However, many of the security
problems that the 1972 report called "current" still plague problems that the 1972 report called "current" still plague
information systems today. information systems today.
$ anomaly detection $ anomaly detection
(I) A intrusion detection method that searches for activity that (I) A intrusion detection method that searches for activity that
is different from the normal behavior of system entities and is different from the normal behavior of system entities and
system resources. (Compare: misuse detection. See: IDS.) system resources. (See: IDS. Compare: misuse detection.)
$ anonymity $ anonymity
(I) The condition of having a name that is unknown or concealed. (I) The condition of having a name that is unknown or concealed.
(Compare: privacy. See: alias, anonymizer, anonymous credential, (See: alias, anonymizer, anonymous credential, anonymous login,
anonymous login, persona certificate.) onion routing, persona certificate. Compare: privacy.)
Tutorial: An application may require security services that Tutorial: An application may require security services that
maintain anonymity of users or other system entities, perhaps to maintain anonymity of users or other system entities, perhaps to
preserve their privacy or hide them from attack. To hide an preserve their privacy or hide them from attack. To hide an
entity's real name, an alias may be used. For example, a financial entity's real name, an alias may be used. For example, a financial
institution may assign an account number. Parties to a transaction institution may assign an account number. Parties to a transaction
can thus remain relatively anonymous, but can also accept the can thus remain relatively anonymous, but can also accept the
transaction as legitimate. Real names of the parties cannot be transaction as legitimate. Real names of the parties cannot be
easily determined by observers of the transaction, but an easily determined by observers of the transaction, but an
authorized third party may be able to map an alias to a real name, authorized third party may be able to map an alias to a real name,
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$ anonymizer $ anonymizer
(I) A internetwork service, usually provided via a proxy server, (I) A internetwork service, usually provided via a proxy server,
that provides anonymity and privacy for clients. That is, the that provides anonymity and privacy for clients. That is, the
service enables a client to access servers without allowing the service enables a client to access servers without allowing the
anyone to gather information about which servers the client anyone to gather information about which servers the client
accesses and without allowing the accessed servers to gather accesses and without allowing the accessed servers to gather
information about the client, such as its IP address. information about the client, such as its IP address.
$ anonymous credential $ anonymous credential
(D) /U.S. Government/ An credential that (a) can be used to (D) /U.S. Government/ A credential that (a) can be used to
authenticate a person as having a specific attribute or being a authenticate a person as having a specific attribute or being a
member of a specific group (e.g., military veterans or U.S. member of a specific group (e.g., military veterans or U.S.
citizens) but (b) does not reveal the individual identity of the citizens) but (b) does not reveal the individual identity of the
person that presents the credential. [M0404] person that presents the credential. [M0404] (See: anonymity.)
Deprecated term: ISDs SHOULD NOT use this term; it mixes concepts Deprecated term: ISDs SHOULD NOT use this term; it mixes concepts
in a potentially misleading way. For example, when the credential in a potentially misleading way. For example, when the credential
is an X.509 certificate, the term could be misunderstood to mean is an X.509 certificate, the term could be misunderstood to mean
that the certificate was signed by a CA that has a persona that the certificate was signed by a CA that has a persona
certificate. Instead, use "attribute certificate", "organizational certificate. Instead, use "attribute certificate", "organizational
certificate", or "persona" certificate" depending on what is certificate", or "persona certificate" depending on what is meant,
meant, with additional explanations as needed. and provide additional explanations as needed.
$ anonymous login $ anonymous login
(I) An access control feature (actually, an access control (I) An access control feature (actually, an access control
vulnerability) in many Internet hosts that enables users to gain vulnerability) in many Internet hosts that enables users to gain
access to general-purpose or public services and resources of a access to general-purpose or public services and resources of a
host (such as allowing any user to transfer data using File host (such as allowing any user to transfer data using File
Transfer Protocol) without having a pre-established, identity- Transfer Protocol) without having a pre-established, identity-
specific account (i.e., user name and password). specific account (i.e., user name and password). (See: anonymity.)
Tutorial: This feature exposes a system to more threats than when Tutorial: This feature exposes a system to more threats than when
all the users are known, pre-registered entities that are all the users are known, pre-registered entities that are
individually accountable for their actions. A user logs in using a individually accountable for their actions. A user logs in using a
special, publicly known user name (e.g., "anonymous", "guest", or special, publicly known user name (e.g., "anonymous", "guest", or
"ftp"). To use the public login name, the user is not required to "ftp"). To use the public login name, the user is not required to
know a secret password and may not be required to input anything know a secret password and may not be required to input anything
at all except the name. In other cases, to complete the normal at all except the name. In other cases, to complete the normal
sequence of steps in a login protocol, the system may require the sequence of steps in a login protocol, the system may require the
user to input a matching, publicly known password (such as user to input a matching, publicly known password (such as
"anonymous") or may ask the user for an e-mail address or some "anonymous") or may ask the user for an e-mail address or some
other arbitrary character string. other arbitrary character string.
$ ANSI $ ANSI
(I) See: American National Standards Institute. (N) See: American National Standards Institute.
$ anti-jam $ anti-jam
(N) "Measures ensuring that transmitted information can be (N) "Measures ensuring that transmitted information can be
received despite deliberate jamming attempts." [C4009] (See: received despite deliberate jamming attempts." [C4009] (See:
electronic security, frequency hopping, jam, spread spectrum.) electronic security, frequency hopping, jam, spread spectrum.)
$ apex trust anchor
(N) The trust anchor that is superior to all other trust anchors
in a particular system or context. (See: trust anchor, top CA.)
$ API $ API
(I) See: application programming interface. (I) See: application programming interface.
$ APOP $ APOP
(I) See: POP3 APOP. (I) See: POP3 APOP.
$ application layer $ Application Layer
(I) See: Open Systems Interconnection Reference Model (OSIRM). See: Internet Protocol Suite, OSIRM.
$ application program $ application program
(I) A computer program that performs a specific function directly (I) A computer program that performs a specific function directly
for a user (as opposed to a program that is part of a computer for a user (as opposed to a program that is part of a computer
operating system and exists to perform functions in support of operating system and exists to perform functions in support of
application programs). application programs).
$ archive $ archive
1a. (I) /noun/ A collection of data that is stored for a 1a. (I) /noun/ A collection of data that is stored for a
relatively long period of time for historical and other purposes, relatively long period of time for historical and other purposes,
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archive. (Compare: back up.) archive. (Compare: back up.)
Tutorial: A digital signature may need to be verified many years Tutorial: A digital signature may need to be verified many years
after the signing occurs. The CA -- the one that issued the after the signing occurs. The CA -- the one that issued the
certificate containing the public key needed to verify that certificate containing the public key needed to verify that
signature -- may not stay in operation that long. So every CA signature -- may not stay in operation that long. So every CA
needs to provide for long-term storage of the information needed needs to provide for long-term storage of the information needed
to verify the signatures of those to whom it issues certificates. to verify the signatures of those to whom it issues certificates.
$ ARPANET $ ARPANET
(N) Advanced Research Projects Agency (ARPA) Network, a pioneer (I) Advanced Research Projects Agency (ARPA) Network, a pioneer
packet-switched network that was designed, implemented, operated, packet-switched network that (a) was designed, implemented,
and maintained by BBN from January 1969 until July 1975 under operated, and maintained by BBN from January 1969 until July 1975
contract to the U.S. Government; led to the development of today's under contract to the U.S. Government; (b) led to the development
Internet; and was decommissioned in June 1990. [B4799, Hafn] of today's Internet; and (c) was decommissioned in June 1990.
[B4799, Hafn]
$ ASCII $ ASCII
(I) American Standard Code for Information Interchange, a scheme (N) See: American Standard Code for Information Interchange.
that encodes 128 specified characters -- the numbers 0-9, the
letters a-z and A-Z, some basic punctuation symbols, some control
codes that originated with Teletype machines, and a blank space --
into the 7-bit binary numbers. Forms the basis of the character
set representations used in most computers and many Internet
standards. (See: code.)
$ ASN.1 $ ASN.1
(I) See: Abstract Syntax Notation One. (N) See: Abstract Syntax Notation One.
$ asset $ asset
(I) A system resource that is (a) required to be protected by an (I) A system resource that is (a) required to be protected by an
information system's security policy, (b) intended to be protected information system's security policy, (b) intended to be protected
by a countermeasure, or (c) required for a system's mission. by a countermeasure, or (c) required for a system's mission.
$ association $ association
(I) A cooperative relationship between system entities, usually (I) A cooperative relationship between system entities, usually
for the purpose of transferring information between them. (See: for the purpose of transferring information between them. (See:
security association.) security association.)
$ assurance $ assurance
See: security assurance. See: security assurance.
$ assurance level $ assurance level
(I) A rank on a hierarchical scale of confidence that a TOE (N) A rank on a hierarchical scale that judges the confidence
adequately fulfills stated security requirements. (See: assurance, someone can have that a TOE adequately fulfills stated security
certificate policy, EAL, TCSEC.) requirements. (See: assurance, certificate policy, EAL, TCSEC.)
Example: U.S. Government guidance [M0404] describes four assurance Example: U.S. Government guidance [M0404] describes four assurance
levels for identity authentication, where each level "describes levels for identity authentication, where each level "describes
the [Government] agency~Os degree of certainty that the user has the [Government] agency's degree of certainty that the user has
presented [a credential] that refers to [the user's] identity." In presented [a credential] that refers to [the user's] identity." In
that guidance, "assurance is defined as (a) "the degree of that guidance, "assurance is defined as (a) "the degree of
confidence in the vetting process used to establish the identity confidence in the vetting process used to establish the identity
of the individual to whom the credential was issued" and (b) "the of the individual to whom the credential was issued" and (b) "the
degree of confidence that the individual who uses the credential degree of confidence that the individual who uses the credential
is the individual to whom the credential was issued." The four is the individual to whom the credential was issued."
levels are described as follows:
- Level 1: Little or no confidence in the asserted identity. The four levels are described as follows:
- Level 2: Some confidence in the asserted identity. - Level 1: Little or no confidence in the asserted identity.
- Level 3: High confidence in the asserted identity. - Level 2: Some confidence in the asserted identity.
- Level 4: Very high confidence in the asserted identity. - Level 3: High confidence in the asserted identity.
- Level 4: Very high confidence in the asserted identity.
Standards for determining these levels are provided in a NIST Standards for determining these levels are provided in a NIST
publication [SP12]. However, as noted there, an assurance level is publication [SP12]. However, as noted there, an assurance level is
"a degree of confidence, not a true measure of how secure the "a degree of confidence, not a true measure of how secure the
system actually is. This distinction is necessary because it is system actually is. This distinction is necessary because it is
extremely difficult -- and in many cases virtually impossible -- extremely difficult -- and in many cases virtually impossible --
to know exactly how secure a system is." to know exactly how secure a system is."
$ asymmetric cryptography $ asymmetric cryptography
(I) A modern branch of cryptography (popularly known as "public- (I) A modern branch of cryptography (popularly known as "public-
skipping to change at page 20, line 8 skipping to change at page 20, line 20
public key and a private key) and use a different component of the public key and a private key) and use a different component of the
pair for each of two counterpart cryptographic operations (e.g., pair for each of two counterpart cryptographic operations (e.g.,
encryption and decryption, or signature creation and signature encryption and decryption, or signature creation and signature
verification). (See: key pair, symmetric cryptography.) verification). (See: key pair, symmetric cryptography.)
Tutorial: Asymmetric algorithms have key management advantages Tutorial: Asymmetric algorithms have key management advantages
over equivalently strong symmetric ones. First, one key of the over equivalently strong symmetric ones. First, one key of the
pair need not be known by anyone but its owner; so it can more pair need not be known by anyone but its owner; so it can more
easily be kept secret. Second, although the other key is shared by easily be kept secret. Second, although the other key is shared by
all entities that use the algorithm, that key need not be kept all entities that use the algorithm, that key need not be kept
secret from other, non-using entities; thus, the key distribution secret from other, non-using entities; thus, the key-distribution
part of key management can be done more easily. part of key management can be done more easily.
Asymmetric cryptography can be used to create algorithms for Asymmetric cryptography can be used to create algorithms for
encryption, digital signature, and key agreement: encryption, digital signature, and key agreement:
- In an asymmetric encryption algorithm (e.g., see: RSA), when - In an asymmetric encryption algorithm (e.g., see: RSA), when
Alice wants to ensure confidentiality for data she sends to Alice wants to ensure confidentiality for data she sends to
Bob, she encrypts the data with a public key provided by Bob. Bob, she encrypts the data with a public key provided by Bob.
Only Bob has the matching private key that is needed to decrypt Only Bob has the matching private key that is needed to decrypt
the data. (Compare: seal.) the data. (Compare: seal.)
- In an asymmetric digital signature algorithm (e.g., see: DSA), - In an asymmetric digital signature algorithm (e.g., see: DSA),
when Alice wants to ensure data integrity or provide when Alice wants to ensure data integrity or provide
authentication for data she sends to Bob, she uses her private authentication for data she sends to Bob, she uses her private
key to sign the data (i.e., create a digital signature based on key to sign the data (i.e., create a digital signature based on
the data). To verify the signature, Bob uses the matching the data). To verify the signature, Bob uses the matching
public key that Alice has provided. public key that Alice has provided.
- In an asymmetric key agreement algorithm (e.g., see: Diffie- - In an asymmetric key-agreement algorithm (e.g., see: Diffie-
Hellman), Alice and Bob each send their own public key to the Hellman), Alice and Bob each send their own public key to the
other party. Then each uses their own private key and the other party. Then each uses their own private key and the
other's public key to compute the new key value. other's public key to compute the new key value.
$ asymmetric key
(I) A cryptographic key that is used in an asymmetric
cryptographic algorithm. (See: asymmetric cryptography, private
key, public key.)
$ ATIS $ ATIS
(N) See: (Alliance for Telecommunications Industry Solutions (N) See: "Alliance for Telecommunications Industry Solutions"
under) ANSI. under "ANSI".
$ attack $ attack
1. (I) An intentional act by which an entity attempts to evade 1. (I) An intentional act by which an entity attempts to evade
security services and violate the security policy of a system. security services and violate the security policy of a system.
That is, an actual assault on system security that derives from an That is, an actual assault on system security that derives from an
intelligent threat. (See: penetration, violation, vulnerability.) intelligent threat. (See: penetration, violation, vulnerability.)
2. (I) A method or technique used in an assault (e.g., 2. (I) A method or technique used in an assault (e.g.,
masquerade). (See: distributed attack.) masquerade). (See: distributed attack.)
Tutorial: Attacks can be characterized according to intent: Tutorial: Attacks can be characterized according to intent:
- An "active attack" attempts to alter system resources or affect - An "active attack" attempts to alter system resources or affect
their operation. their operation.
- A "passive attack" attempts to learn or make use of information - A "passive attack" attempts to learn or make use of information
from the system but does not affect system resources. (E.g., from the system but does not affect system resources. (E.g.,
see: wiretapping.) see: wiretapping.)
The object of a passive attack might be to obtain data that is The object of a passive attack might be to obtain data that is
needed for an off-line attack. needed for an off-line attack.
- An "off-line attack" is one in which the attacker obtains data - An "off-line attack" is one in which the attacker obtains data
from the target system and then analyzes the data on a from the target system and then analyzes the data on a
different system of the attacker's own choosing, possibly in different system of the attacker's own choosing, possibly in
preparation for a second stage of attack on the target. preparation for a second stage of attack on the target.
Attacks can be characterized according to point of initiation: Attacks can be characterized according to point of initiation:
- An "inside attack" is one that is initiated by an entity inside - An "inside attack" is one that is initiated by an entity inside
the security perimeter (an "insider"), i.e., an entity that is the security perimeter (an "insider"), i.e., an entity that is
authorized to access system resources but uses them in a way authorized to access system resources but uses them in a way
not approved by those who granted the authorization. not approved by those who granted the authorization.
- An "outside attack" is initiated from outside the perimeter, by - An "outside attack" is initiated from outside the perimeter, by
an unauthorized or illegitimate user of the system (an an unauthorized or illegitimate user of the system (an
"outsider"). In the Internet, potential outside attackers range "outsider"). In the Internet, potential outside attackers range
from amateur pranksters to organized criminals, international from amateur pranksters to organized criminals, international
terrorists, and hostile governments. terrorists, and hostile governments.
The term "attack" relates to some other basic security terms as The term "attack" relates to some other basic security terms as
shown in the following diagram: shown in the following diagram:
+ - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+ + - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+
| An Attack: | |Counter- | | A System Resource: | | An Attack: | |Counter- | | A System Resource: |
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| | Attacker |<==================||<========= | | | | Attacker |<==================||<========= | |
| | i.e., | Passive | | | | | Vulnerability | | | | i.e., | Passive | | | | | Vulnerability | |
| | A Threat |<=================>||<========> | | | | A Threat |<=================>||<========> | |
| | Agent | or Active | | | | +-------|||-------+ | | | Agent | or Active | | | | +-------|||-------+ |
| +----------+ Attack | | | | VVV | | +----------+ Attack | | | | VVV |
| | | | | Threat Consequences | | | | | | Threat Consequences |
+ - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+ + - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+
$ attack potential $ attack potential
(I) The perceived likelihood of success should an attack be (I) The perceived likelihood of success should an attack be
launched, expressed in terms of the attacker's capability (i.e., launched, expressed in terms of the attacker's ability (i.e.,
expertise and resources) and motivation. (Compare: threat, risk.) expertise and resources) and motivation. (Compare: threat, risk.)
$ attack sensing, warning, and response $ attack sensing, warning, and response
(I) A set of security services that cooperate with audit service (I) A set of security services that cooperate with audit service
to detect and react to indications of threat actions, including to detect and react to indications of threat actions, including
both inside and outside attacks. (See: indicator.) both inside and outside attacks. (See: indicator.)
$ attack tree $ attack tree
(I) A branching, hierarchical data structure that represents a set (I) A branching, hierarchical data structure that represents a set
of potential approaches to achieving an event in which system of potential approaches to achieving an event in which system
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$ attribute $ attribute
1. (N) The information of a particular type concerning an 1. (N) The information of a particular type concerning an
identifiable system entity or object. An "attribute type" is the identifiable system entity or object. An "attribute type" is the
component of an attribute that indicates the class of information component of an attribute that indicates the class of information
given by the attribute; and an "attribute value" is a particular given by the attribute; and an "attribute value" is a particular
instance of the class of information indicated by an attribute instance of the class of information indicated by an attribute
type. (See: attribute certificate.) type. (See: attribute certificate.)
$ attribute authority (AA) $ attribute authority (AA)
1. (I) A CA that issues attribute certificates. 1. (N) A CA that issues attribute certificates.
2. (O) "An authority [that] assigns privileges by issuing 2. (O) "An authority [that] assigns privileges by issuing
attribute certificates." [X509] attribute certificates." [X509]
Usage: The abbreviation "AA" should not be used in an ISD unless Deprecated Abbreviation: The abbreviation "AA" SHOULD NOT be used
it is first defined in the ISD. in an ISD unless it is first defined in the ISD.
$ attribute certificate $ attribute certificate
1. (I) A digital certificate that binds a set of descriptive data 1. (I) A digital certificate that binds a set of descriptive data
items, other than a public key, either directly to a subject name items, other than a public key, either directly to a subject name
or to the identifier of another certificate that is a public-key or to the identifier of another certificate that is a public-key
certificate. certificate. (See: capability token.)
2. (N) "A data structure, digitally signed by an [a]ttribute 2. (O) "A data structure, digitally signed by an [a]ttribute
[a]uthority, that binds some attribute values with identification [a]uthority, that binds some attribute values with identification
information about its holder." [X509] information about its holder." [X509]
Tutorial: A public-key certificate binds a subject name to a Tutorial: A public-key certificate binds a subject name to a
public key value, along with information needed to perform certain public key value, along with information needed to perform certain
cryptographic functions. Other attributes of a subject, such as a cryptographic functions using that key. Other attributes of a
security clearance, may be certified in a separate kind of digital subject, such as a security clearance, may be certified in a
certificate, called an attribute certificate. A subject may have separate kind of digital certificate, called an attribute
multiple attribute certificates associated with its name or with certificate. A subject may have multiple attribute certificates
each of its public-key certificates. associated with its name or with each of its public-key
certificates.
An attribute certificate might be issued to a subject in the An attribute certificate might be issued to a subject in the
following situations: following situations:
- Different lifetimes: When the lifetime of an attribute binding - Different lifetimes: When the lifetime of an attribute binding
is shorter than that of the related public-key certificate, or is shorter than that of the related public-key certificate, or
when it is desirable not to need to revoke a subject's public when it is desirable not to need to revoke a subject's public
key just to revoke an attribute. key just to revoke an attribute.
- Different authorities: When the authority responsible for the - Different authorities: When the authority responsible for the
attributes is different than the one that issues the public-key attributes is different than the one that issues the public-key
certificate for the subject. (There is no requirement that an certificate for the subject. (There is no requirement that an
attribute certificate be issued by the same CA that issued the attribute certificate be issued by the same CA that issued the
associated public-key certificate.) associated public-key certificate.)
$ audit $ audit
See: security audit. See: security audit.
$ audit log $ audit log
(I) Synonym for "security audit trail". (I) Synonym for "security audit trail".
skipping to change at page 23, line 29 skipping to change at page 23, line 45
$ AUTH $ AUTH
(I) See: POP3 AUTH. (I) See: POP3 AUTH.
$ authentic signature $ authentic signature
(I) A signature (especially a digital signature) that can be (I) A signature (especially a digital signature) that can be
trusted because it can be verified. (See: validate vs. verify.) trusted because it can be verified. (See: validate vs. verify.)
$ authenticate $ authenticate
(I) Verify (i.e., establish the truth of) an identity claimed by (I) Verify (i.e., establish the truth of) an identity claimed by
or for a system entity. (See: authentication, validate vs. verify, or for a system entity. (See: authentication, validate vs. verify,
("relationship between data integrity service and authentication "relationship between data integrity service and authentication
services" under) data integrity service.).) services" under "data integrity service".)
Deprecated Usage: In general English usage, this term is used with Deprecated Usage: In general English usage, this term is used with
the meaning "to prove genuine" (e.g., an art expert authenticates the meaning "to prove genuine" (e.g., an art expert authenticates
a Michelangelo painting); but this Internet definition restricts a Michelangelo painting); but this Internet definition restricts
usage as follows: usage as follows:
- ISDs SHOULD NOT use this term to refer to proving or checking - ISDs SHOULD NOT use this term to refer to proving or checking
that data has not been changed, destroyed or lost in an that data has not been changed, destroyed or lost in an
unauthorized or accidental manner. Instead use "verify". unauthorized or accidental manner. Instead use "verify".
- ISDs SHOULD NOT use this term to refer to proving the truth or - ISDs SHOULD NOT use this term to refer to proving the truth or
accuracy of a fact or value such as a digital signature. accuracy of a fact or value such as a digital signature.
Instead, use "verify". Instead, use "verify".
- ISDs SHOULD NOT use this term to refer to establishing the - ISDs SHOULD NOT use this term to refer to establishing the
soundness or correctness of a construct, such as a digital soundness or correctness of a construct, such as a digital
certificate. Instead, use "validate". certificate. Instead, use "validate".
$ authentication $ authentication
(I) The process of verifying an identity claimed by or for a (I) The process of verifying an identity claimed by or for a
system entity. (See: authenticate, authentication exchange, system entity. (See: authenticate, authentication exchange,
authentication information, credential, data origin authentication information, credential, data origin
authentication, peer entity authentication, simple authentication, authentication, peer entity authentication, "relationship between
strong authentication, X.509. Also see: ("relationship between data integrity service and authentication services" under "data
data integrity service and authentication services" under) data integrity service", simple authentication, strong authentication,
integrity service.) X.509.)
Tutorial: An authentication process consists of two steps: Tutorial: An authentication process consists of two steps:
- Identification step: Presenting an identifier to the security - Identification step: Presenting an identifier to the security
system. (Identifiers should be assigned carefully, because system. (Identifiers should be assigned carefully, because
authenticated identities are the basis for other security authenticated identities are the basis for other security
services, such as access control service.) services, such as access control service.)
- Verification step: Presenting or generating authentication - Verification step: Presenting or generating authentication
information that acts as evidence to prove the binding between information that acts as evidence to prove the binding between
the claimant and the identifier. (See: verification.) the claimant and the identifier. (See: verification.)
$ authentication code $ authentication code
(D) Synonym for a checksum based on cryptography. (Compare: (D) Synonym for a checksum based on cryptography. (Compare:
Message Authentication Code.) Message Authentication Code.)
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
any form of checksum, cryptographic or not; the term mixes any form of checksum, cryptographic or not. Instead, use
concepts in a potentially misleading way. Instead, use "checksum", "checksum", "error detection code", "hash", "keyed hash", "Message
"error detection code", "hash", "keyed hash", "Message
Authentication Code", or "protected checksum", depending on what Authentication Code", or "protected checksum", depending on what
is meant. is meant.
The word "authentication" is misleading because the checksum may The term mixes concepts in a potentially misleading way. The word
be used to perform a data integrity function rather than a data "authentication" is misleading because the checksum may be used to
origin authentication function. The word "code" is misleading perform a data integrity function rather than a data origin
because it suggests either that encoding or encryption is involved authentication function. The word "code" is misleading because it
or that the term refers to computer software. suggests either that encoding or encryption is involved or that
the term refers to computer software.
$ authentication exchange $ authentication exchange
1. (I) A mechanism to verify the identity of an entity by means of 1. (I) A mechanism to verify the identity of an entity by means of
information exchange. information exchange.
2. (O) "A mechanism intended to ensure the identity of an entity 2. (O) "A mechanism intended to ensure the identity of an entity
by means of information exchange." [I7498 Part 2] by means of information exchange." [I7498 Part 2]
$ Authentication Header (AH) $ Authentication Header (AH)
(I) An Internet protocol [R2402] designed to provide (I) An Internet protocol [R2402] designed to provide
connectionless data integrity service and connectionless data connectionless data integrity service and connectionless data
origin authentication service for IP datagrams, and (optionally) origin authentication service for IP datagrams, and (optionally)
to provide partial sequence integrity and protection against to provide partial sequence integrity and protection against
replay attacks. (See: IPsec. Compare: ESP.) replay attacks. (See: IPsec. Compare: ESP.)
Tutorial: Replay protection may be selected by the receiver when a Tutorial: Replay protection may be selected by the receiver when a
security association is established. AH authenticates upper-layer security association is established. AH authenticates the upper-
protocol data units and as much of the IP header as possible. layer PDU that is carried as an IP SDU, and also authenticates as
However, some IP header fields may change in transit, and the much of the IP PCI (i.e., the IP header) as possible. However,
value of these fields, when the packet arrives at the receiver, some IP header fields may change in transit, and the value of
may not be predictable by the sender. Thus, the values of such these fields, when the packet arrives at the receiver, may not be
fields cannot be protected end-to-end by AH; protection of the IP predictable by the sender. Thus, the values of such fields cannot
header by AH is only partial when such fields are present. be protected end-to-end by AH; protection of the IP header by AH
is only partial when such fields are present.
AH may be used alone, or in combination with the ESP, or in a AH may be used alone, or in combination with the ESP, or in a
nested fashion with tunneling. Security services can be provided nested fashion with tunneling. Security services can be provided
between a pair of communicating hosts, between a pair of between a pair of communicating hosts, between a pair of
communicating security gateways, or between a host and a gateway. communicating security gateways, or between a host and a gateway.
ESP can provide nearly the same security services as AH, and ESP ESP can provide nearly the same security services as AH, and ESP
can also provide data confidentiality service. The main difference can also provide data confidentiality service. The main difference
between authentication services provided by ESP and AH is the between authentication services provided by ESP and AH is the
extent of the coverage; ESP does not protect IP header fields extent of the coverage; ESP does not protect IP header fields
unless they are encapsulated by AH. unless they are encapsulated by AH.
skipping to change at page 25, line 54 skipping to change at page 26, line 20
certification authority or to an attribute authority)." [X509] certification authority or to an attribute authority)." [X509]
(See: authority.) (See: authority.)
Deprecated Term: ISDs SHOULD NOT use this term as defined here; it Deprecated Term: ISDs SHOULD NOT use this term as defined here; it
is ambiguous. Instead, use the full term "certification authority is ambiguous. Instead, use the full term "certification authority
certificate", "attribute authority certificate", "registration certificate", "attribute authority certificate", "registration
authority certificate", etc. at the first instance of usage and authority certificate", etc. at the first instance of usage and
then, if it is necessary to shorten text, use AA, CA, RA, and then, if it is necessary to shorten text, use AA, CA, RA, and
other abbreviations defined in this Glossary. other abbreviations defined in this Glossary.
$ Authority Information Access extension
(I) The private extension defined by PKIX for X.509 certificates
to indicate "how to access CA information and services for the
issuer of the certificate in which the extension appears.
Information and services may include on-line validation services
and CA policy data." [R3280] (See: private extension.)
$ authorization $ authorization
1a. (I) An approval that is granted to a system entity to access a 1a. (I) An approval that is granted to a system entity to access a
system resource. (Compare: permission, privilege.) system resource. (Compare: permission, privilege.)
Usage: Some synonyms are "permission" and "privilege". Specific Usage: Some synonyms are "permission" and "privilege". Specific
terms are preferred in certain contexts: terms are preferred in certain contexts:
- /PKI/ "Authorization" SHOULD be used, to align with - /PKI/ "Authorization" SHOULD be used, to align with
"certification authority" in the standard [X509]. "certification authority" in the standard [X509].
- /role-based access control/ "Permission" SHOULD be used, to - /role-based access control/ "Permission" SHOULD be used, to
align with the standard [ANSI]. align with the standard [ANSI].
- /computer operating systems/ "Privilege" SHOULD be used, to - /computer operating systems/ "Privilege" SHOULD be used, to
align with the literature. align with the literature. (See: privileged process, privileged
user.)
Tutorial: The semantics and granularity of authorizations depend Tutorial: The semantics and granularity of authorizations depend
on the application and implementation (see: (first law under) on the application and implementation (see: "first law" under
Courtney's laws). An authorization may specify a particular access "Courtney's laws"). An authorization may specify a particular
mode -- such as read, write, or execute -- for one or more system access mode -- such as read, write, or execute -- for one or more
resources. system resources.
1b. (I) A process for granting approval to a system entity to 1b. (I) A process for granting approval to a system entity to
access a system resource. access a system resource.
2. (O) /SET/ "The process by which a properly appointed person or 2. (O) /SET/ "The process by which a properly appointed person or
persons grants permission to perform some action on behalf of an persons grants permission to perform some action on behalf of an
organization. This process assesses transaction risk, confirms organization. This process assesses transaction risk, confirms
that a given transaction does not raise the account holder's debt that a given transaction does not raise the account holder's debt
above the account's credit limit, and reserves the specified above the account's credit limit, and reserves the specified
amount of credit. (When a merchant obtains authorization, payment amount of credit. (When a merchant obtains authorization, payment
for the authorized amount is guaranteed -- provided, of course, for the authorized amount is guaranteed -- provided, of course,
that the merchant followed the rules associated with the that the merchant followed the rules associated with the
authorization process.)" [SET2] authorization process.)" [SET2]
$ authorization credential $ authorization credential
(I) See: ("access control" context under) "credential". (I) See: /access control/ under "credential".
$ authorize $ authorize
(I) Grant an authorization to a system entity. (I) Grant an authorization to a system entity.
$ authorized user $ authorized user
(I) /access control/ A system entity that accesses a system (I) /access control/ A system entity that accesses a system
resource for which the entity has received an authorization. resource for which the entity has received an authorization.
(Compare: insider, outsider, unauthorized user.) (Compare: insider, outsider, unauthorized user.)
Usage: The term is used in many ways and could easily be Deprecated Usage: ISDs that use this term SHOULD state a
misunderstood; ISD that use this term SHOULD state a definition definition for it because the term is used in many ways and could
for it. easily be misunderstood.
$ automated information system $ automated information system
See: information system. See: information system.
$ availability $ availability
1. (I) The property of a system or a system resource being 1. (I) The property of a system or a system resource being
accessible, or usable or operational upon demand, by an authorized accessible, or usable or operational upon demand, by an authorized
system entity, according to performance specifications for the system entity, according to performance specifications for the
system; i.e., a system is available if it provides services system; i.e., a system is available if it provides services
according to the system design whenever users request them. (See: according to the system design whenever users request them. (See:
critical, denial of service. Compare: precedence, reliability, critical, denial of service. Compare: precedence, reliability,
survivability.) survivability.)
2. (O) "The property of being accessible and usable upon demand by 2. (O) "The property of being accessible and usable upon demand by
an authorized entity." [I7498 Part 2] an authorized entity." [I7498 Part 2]
Tutorial: This service addresses the security concerns raised by
denial-of-service attacks. It depends on proper management and
control of system resources, and thus depends on access control
service and other security services.
Availability requirements can be specified by quantitative
metrics, but sometimes are stated qualitatively, such as in the
following:
- "Flexible tolerance for delay" may mean that brief system
outages do not endanger mission accomplishment, but extended
outages may endanger the mission.
- "Minimum tolerance for delay" may mean that mission
accomplishment requires the system to provide requested
services in a short time.
$ availability service $ availability service
(I) A security service that protects a system to ensure its (I) A security service that protects a system to ensure its
availability. availability.
Tutorial: This service addresses the security concerns raised by Tutorial: This service addresses the security concerns raised by
denial-of-service attacks. It depends on proper management and denial-of-service attacks. It depends on proper management and
control of system resources, and thus depends on access control control of system resources, and thus depends on access control
service and other security services. service and other security services.
$ B1 computer system, B2 computer system, B3 computer system $ avoidance
(O) See: TCSEC. (I) See: secondary definition under "security".
$ B1, B2, or B3 computer system
(O) /TCSEC/ See: Tutorial under "Trusted Computer System
Evaluation Criteria".
$ back door $ back door
1. (I) /computer security/ A computer system feature -- which may 1. (I) /computer security/ A computer system feature -- which may
be (a) an unintentional flaw, (b) a mechanism deliberately be (a) an unintentional flaw, (b) a mechanism deliberately
installed by the system's creator, or (c) a mechanism installed by the system's creator, or (c) a mechanism
surreptitiously installed by an intruder -- that provides access surreptitiously installed by an intruder -- that provides access
to a system resource by other than the usual procedure and usually to a system resource by other than the usual procedure and usually
is hidden or otherwise not well-known. (Compare: Trojan Horse. is hidden or otherwise not well-known. (See: maintenance hook.
See: maintenance hook.) Compare: Trojan Horse.)
Example: A way to access a computer other than through a normal Example: A way to access a computer other than through a normal
login. Such an access path is not necessarily designed with login. Such an access path is not necessarily designed with
malicious intent; operating systems sometimes are shipped by the malicious intent; operating systems sometimes are shipped by the
manufacturer with hidden accounts intended for use by field manufacturer with hidden accounts intended for use by field
service technicians or the vendor's maintenance programmers. service technicians or the vendor's maintenance programmers.
2. (I) /cryptography/ A feature of a cryptographic system that 2. (I) /cryptography/ A feature of a cryptographic system that
makes it easily possible to break or circumvent the protection makes it easily possible to break or circumvent the protection
that the system is designed to provided. that the system is designed to provided.
Example: A feature that makes it possible to decrypt cipher text Example: A feature that makes it possible to decrypt cipher text
much more quickly than by brute force cryptanalysis, without much more quickly than by brute force cryptanalysis, without
having prior knowledge of the decryption key. having prior knowledge of the decryption key.
$ back up $ back up
(I) /verb/ Create a reserve copy of data (compare: archive) or, (I) /verb/ Create a reserve copy of data or, more generally,
more generally, provide alternate means to perform system provide alternate means to perform system functions despite loss
functions despite loss of system resources. (See: contingency of system resources. (See: contingency plan. Compare: archive.)
plan.)
$ backup $ backup
(I) /noun or adjective/ Refers to alternate means of performing (I) /noun or adjective/ Refers to alternate means of performing
system functions despite loss of system resources. (See: system functions despite loss of system resources. (See:
contingency plan). contingency plan).
Example: A reserve copy of data, preferably one that is stored Example: A reserve copy of data, preferably one that is stored
separately from the original, for use if the original becomes lost separately from the original, for use if the original becomes lost
or damaged. (Compare: archive.) or damaged. (Compare: archive.)
$ baggage $ baggage
(O) /SET/ An "opaque encrypted tuple, which is included in a SET (O) /SET/ An "opaque encrypted tuple, which is included in a SET
message but appended as external data to the PKCS encapsulated message but appended as external data to the PKCS encapsulated
data. This avoids superencryption of the previously encrypted data. This avoids superencryption of the previously encrypted
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Deprecated Usage: ISDs SHOULD NOT use this term to describe a data Deprecated Usage: ISDs SHOULD NOT use this term to describe a data
element, except in the form "SET(trademark) baggage" with the element, except in the form "SET(trademark) baggage" with the
meaning given above. meaning given above.
$ baked-in security $ baked-in security
(I) The inclusion of security mechanisms in an information system (I) The inclusion of security mechanisms in an information system
beginning at an early point in the system's life cycle, i.e., beginning at an early point in the system's life cycle, i.e.,
during the design phase, or at least early in the implementation during the design phase, or at least early in the implementation
phase. (Compare: add-on security.) phase. (Compare: add-on security.)
Deprecated Term: It is likely that other cultures have different Deprecated Term: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ bandwidth $ bandwidth
(I) The total width of the frequency band that is available to or (I) The total width of the frequency band that is available to or
used by a communication channel; usually expressed in Hertz (Hz). used by a communication channel; usually expressed in Hertz (Hz).
[R3753] (Compare: channel capacity.) (RFC 3753) (Compare: channel capacity.)
$ bank identification number (BIN) $ bank identification number (BIN)
1. (O) The digits of a credit card number that identify the 1. (O) The digits of a credit card number that identify the
issuing bank. (See: primary account number.) issuing bank. (See: primary account number.)
2. (O) /SET/ The first six digits of a primary account number. 2. (O) /SET/ The first six digits of a primary account number.
$ Basic Encoding Rules (BER) $ Basic Encoding Rules (BER)
(I) A standard for representing ASN.1 data types as strings of (I) A standard for representing ASN.1 data types as strings of
octets. [X690] (See: Distinguished Encoding Rules.) octets. [X690] (See: Distinguished Encoding Rules.)
Usage: Sometimes incorrectly included under the term ASN.1, which Deprecated Usage: Sometimes incorrectly treated as part of ASN.1.
properly refers only to the syntax description language, and not However, ASN.1 properly refers only to a syntax description
to the encoding rules for the language. language, and not to the encoding rules for the language.
$ Basic Security Option $ Basic Security Option
(I) See: (secondary definition under) IPSO. (I) See: secondary definition under "IPSO".
$ bastion host $ bastion host
(I) A strongly protected computer that is in a network protected (I) A strongly protected computer that is in a network protected
by a firewall (or is part of a firewall) and is the only host (or by a firewall (or is part of a firewall) and is the only host (or
one of only a few) in the network that can be directly accessed one of only a few) in the network that can be directly accessed
from networks on the other side of the firewall. (See: firewall.) from networks on the other side of the firewall. (See: firewall.)
Tutorial: Filtering routers in a firewall typically restrict Tutorial: Filtering routers in a firewall typically restrict
traffic from the outside network to reaching just one host, the traffic from the outside network to reaching just one host, the
bastion host, which usually is part of the firewall. Since only bastion host, which usually is part of the firewall. Since only
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SMTP) have forwarding built in; other services (e.g., TELNET and SMTP) have forwarding built in; other services (e.g., TELNET and
FTP) require a proxy server on the bastion host. FTP) require a proxy server on the bastion host.
$ BBN Technologies $ BBN Technologies
(O) The research-and-development company (originally called Bolt (O) The research-and-development company (originally called Bolt
Baranek and Newman, Inc.) that built the ARPANET. Baranek and Newman, Inc.) that built the ARPANET.
$ BCA $ BCA
(O) See: brand certification authority. (O) See: brand certification authority.
$ BCR (black/crypto/red) $ BCR
(N) An experimental, end-to-end, network packet encryption system (O) See: BLACK/Crypto/RED.
developed in a working prototype form by BBN and the Collins Radio
division of Rockwell Corporation in the 1975-1980 time frame for
the U.S. DoD. BCR was the first network security system to support
TCP/IP traffic, and it incorporated the first DES chips that were
validated by the U.S. National Bureau of Standards (now called
NIST). BCR also was the first to use a KDC and an ACC to manage
connections.
$ BCI $ BCI
(O) See: brand CRL identifier. (O) See: brand CRL identifier.
$ Bell-LaPadula model $ Bell-LaPadula model
(N) A formal, mathematical, state-transition model of (N) A formal, mathematical, state-transition model of
confidentiality policy for multilevel-secure computer systems confidentiality policy for multilevel-secure computer systems
[Bell]. (Compare: Biba model, Brewer-Nash model.) [Bell]. (Compare: Biba model, Brewer-Nash model.)
Tutorial: The model, devised by David Bell and Leonard LaPadula at Tutorial: The model, devised by David Bell and Leonard LaPadula at
The MITRE Corporation in 1973, characterizes computer system The MITRE Corporation in 1973, characterizes computer system
elements as subjects and objects. To determine whether or not a elements as subjects and objects. To determine whether or not a
subject is authorized for a particular access mode on an object, subject is authorized for a particular access mode on an object,
the clearance of the subject is compared to the classification of the clearance of the subject is compared to the classification of
the object. The model defines the notion of a "secure state", in the object. The model defines the notion of a "secure state", in
which the only permitted access modes of subjects to objects are which the only permitted access modes of subjects to objects are
in accordance with a specified security policy. It is proven that in accordance with a specified security policy. It is proven that
each state transition preserves security by moving from secure each state transition preserves security by moving from secure
state to secure state, thereby proving that the system is secure. state to secure state, thereby proving that the system is secure.
In this model, a multilevel-secure system satisfies several rules, In this model, a multilevel-secure system satisfies several rules,
including the "confinement property" (also called "*-property", including the "confinement property" (a.k.a. the "*-property"),
pronounced "star property"), the "simple security property", and the "simple security property", and the "tranquillity property".
the "tranquillity property".
$ benign $ benign
(N) "Condition of cryptographic data [such] that [it] cannot be (N) "Condition of cryptographic data [such] that [it] cannot be
compromised by human access [to the data]." [C4009] compromised by human access [to the data]." [C4009]
$ benign fill $ benign fill
(N) Process by which keying material is generated, distributed, (N) Process by which keying material is generated, distributed,
and placed into an ECU without exposure to any human or other and placed into an ECU without exposure to any human or other
system entity, except the cryptographic module that consumes and system entity, except the cryptographic module that consumes and
uses the material. uses the material.
$ BER $ BER
(I) See: Basic Encoding Rules. (I) See: Basic Encoding Rules.
$ beyond A1 A1
1. (O) /formal/ A level of security assurance that is beyond the 1. (O) /formal/ A level of security assurance that is beyond the
highest level (level A1) of criteria specified by the TCSEC. highest level (level A1) of criteria specified by the TCSEC. (See:
Tutorial under "Trusted Computer System Evaluation Criteria".)
2. (O) /informal/ A level of trust so high that it is beyond 2. (O) /informal/ A level of trust so high that it is beyond
state-of-the-art technology; i.e., it cannot be provided or state-of-the-art technology; i.e., it cannot be provided or
verified by currently available assurance methods, and especially verified by currently available assurance methods, and especially
not by currently available formal methods. not by currently available formal methods.
$ Biba integrity
(N) Synonym for "source integrity".
$ Biba model $ Biba model
(N) A formal, mathematical, state-transition model of integrity (N) A formal, mathematical, state-transition model of integrity
policy for multilevel-secure computer systems [Biba]. (Compare: policy for multilevel-secure computer systems [Biba]. (See: source
Bell-LaPadula model.) integrity. Compare: Bell-LaPadula model.)
Tutorial: This model for integrity control is analogous to the Tutorial: This model for integrity control is analogous to the
Bell-LaPadula model for confidentiality control. Each subject and Bell-LaPadula model for confidentiality control. Each subject and
object is assigned an integrity level and, to determine whether or object is assigned an integrity level and, to determine whether or
not a subject is authorized for a particular access mode on an not a subject is authorized for a particular access mode on an
object, the integrity level of the subject is compared to that of object, the integrity level of the subject is compared to that of
the object. The model prohibits the changing of information in an the object. The model prohibits the changing of information in an
object by a subject with a lesser or incomparable level. The rules object by a subject with a lesser or incomparable level. The rules
of the Biba model are duals of the corresponding rules in the of the Biba model are duals of the corresponding rules in the
Bell-LaPadula model. Bell-LaPadula model.
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System entities are in one-to-one relationships with their System entities are in one-to-one relationships with their
billets, but may be in many-to-one and one-to-many relationships billets, but may be in many-to-one and one-to-many relationships
with their roles. with their roles.
$ BIN $ BIN
(O) See: bank identification number. (O) See: bank identification number.
$ bind $ bind
(I) To inseparably associate by applying some mechanism. (I) To inseparably associate by applying some mechanism.
Example: A CA uses a digital signature to bind together (a) a Example: A CA creates a public-key certificate by using a digital
subject and (b) a public key, and possibly some additional, signature to bind together (a) a subject name, (b) a public key,
secondary data items, to create a public-key certificate. and usually (c) some additional data items (e.g., see "X.509
public-key certificate").
$ biometric authentication $ biometric authentication
(I) A method of generating authentication information for a person (I) A method of generating authentication information for a person
by digitizing measurements of a physical or behavioral by digitizing measurements of a physical or behavioral
characteristic, such as a fingerprint, hand shape, retina pattern, characteristic, such as a fingerprint, hand shape, retina pattern,
voiceprint, handwriting style, or face. voiceprint, handwriting style, or face.
$ birthday attack $ birthday attack
(I) A class of attacks against cryptographic functions, including (I) A class of attacks against cryptographic functions, including
both encryption functions and hash functions. The attacks take both encryption functions and hash functions. The attacks take
advantage of a statistical property: Given a cryptographic advantage of a statistical property: Given a cryptographic
function having an N-bit output, the probability is greater than function having an N-bit output, the probability is greater than
1/2 that for 2**(N/2) randomly chosen inputs, the function will 1/2 that for 2**(N/2) randomly chosen inputs, the function will
produce at least two outputs that are identical. (See: (discussion produce at least two outputs that are identical. (See: Tutorial
under) hash function.) under "hash function".)
Derivation: From the somewhat surprising fact (often called the Derivation: From the somewhat surprising fact (often called the
"birthday paradox") that although there are 365 days in a year, "birthday paradox") that although there are 365 days in a year,
the probability is greater than 1/2 that two of more people share the probability is greater than 1/2 that two of more people share
the same birthday in any randomly chosen group of 23 people. the same birthday in any randomly chosen group of 23 people.
Birthday attacks enable an adversary to find two inputs for which
a cryptographic function produces the same cipher text (or find
two inputs for which a hash functions produces the same hash
result) much faster than a brute force attack can; and a clever
adversary can use such a capability to create considerable
mischief. However, no birthday attack can enable an adversary to
decrypt a given cipher text (or find a hash input that results in
a given hash result) any faster than a brute force attack can.
$ bit $ bit
(I) A contraction of the term "binary digit", the smallest unit of (I) A contraction of the term "binary digit"; the smallest unit of
information storage, which has two possible states or values that information storage, which has two possible states or values. The
are usually represented by the symbols "0" (zero) and "1" (one). values usually are represented by the symbols "0" (zero) and "1"
(See: block, byte, word.) (one). (See: block, byte, word.)
$ bit string $ bit string
(I) A sequence of bits, each of which is either "0" or "1". (I) A sequence of bits, each of which is either "0" or "1".
$ BLACK $ BLACK
1. (I) Designation for data that consists only of cipher text, and 1. (I) Designation for data that consists only of cipher text, and
for information system equipment items or facilities that handle for information system equipment items or facilities that handle
only cipher text. Example: "BLACK key".(Compare: RED. See: color only cipher text. Example: "BLACK key".(See: color change,
change, RED/BLACK separation.) RED/BLACK separation. Compare: RED.)
2. (O) /U.S. Government/ "Designation applied to information 2. (O) /U.S. Government/ "Designation applied to information
systems, and to associated areas, circuits, components, and systems, and to associated areas, circuits, components, and
equipment, in which national security information is encrypted or equipment, in which national security information is encrypted or
is not processed. [C4009] is not processed. [C4009]
$ BLACK/Crypto/RED (BCR)
(N) An experimental, end-to-end, network packet encryption system
developed in a working prototype form by BBN and the Collins Radio
division of Rockwell Corporation in the 1975-1980 time frame for
the U.S. DoD. BCR was the first network security system to support
TCP/IP traffic, and it incorporated the first DES chips that were
validated by the U.S. National Bureau of Standards (now called
NIST). BCR also was the first to use a KDC and an ACC to manage
connections.
$ BLACK key $ BLACK key
(I) A key that is protected with a key-encrypting key and that (I) A key that is protected with a key-encrypting key and that
must be decrypted before use. (Compare: RED key. See: BLACK.) must be decrypted before use. (See: BLACK. Compare: RED key.)
$ BLACKER $ BLACKER
(N) An end-to-end encryption system for computer data networks (O) An end-to-end encryption system for computer data networks
that was developed by the U.S. DoD in the 1980s to provide host- that was developed by the U.S. DoD in the 1980s to provide host-
to-host data confidentiality service for datagrams at OSIRM layer to-host data confidentiality service for datagrams at OSIRM Layer
3. [Weis] (Compare: Caneware, IPsec.) 3. [Weis] (Compare: Caneware, IPsec.)
Tutorial: Each user host connects to its own bump-in-the-wire Tutorial: Each user host connects to its own bump-in-the-wire
encryption device called a BLACKER Front End (BFE, TSEC/KI-111), encryption device called a BLACKER Front End (BFE, TSEC/KI-111),
through which the host connects to the subnetwork. The system also through which the host connects to the subnetwork. The system also
includes two types of centralized devices: one or more KDCs includes two types of centralized devices: one or more KDCs
connect to the subnetwork and communicate with assigned sets of connect to the subnetwork and communicate with assigned sets of
BFEs, and one or more ACCs connect to the subnetwork and BFEs, and one or more ACCs connect to the subnetwork and
communicate with assigned KDCs. BLACKER uses only symmetric communicate with assigned KDCs. BLACKER uses only symmetric
encryption. A KDC distributes session keys to BFE pairs as encryption. A KDC distributes session keys to BFE pairs as
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$ block $ block
(I) A bit string or bit vector of finite length. (See: block (I) A bit string or bit vector of finite length. (See: block
cipher. Compare: byte, word.) cipher. Compare: byte, word.)
Usage: An "N-bit block" contains N bits, which usually are Usage: An "N-bit block" contains N bits, which usually are
numbered from left to right as 1, 2, 3, ..., N. numbered from left to right as 1, 2, 3, ..., N.
$ block cipher $ block cipher
(I) An encryption algorithm that breaks plain text into fixed-size (I) An encryption algorithm that breaks plain text into fixed-size
segments and uses the same key to transform each plaintext segment segments and uses the same key to transform each plaintext segment
into a fixed-size segment of cipher text. Examples: Blowfish, DEA, into a fixed-size segment of cipher text. Examples: AES, Blowfish,
IDEA, RC2, and SKIPJACK. (See: block, mode. Compare: stream DEA, IDEA, RC2, and SKIPJACK. (See: block, mode. Compare: stream
cipher.) cipher.)
Tutorial: A block cipher can be adapted to have a different Tutorial: A block cipher can be adapted to have a different
external interface, such as that of a stream cipher, by using a external interface, such as that of a stream cipher, by using a
mode of operation to "package" the basic algorithm. mode of cryptographic operation to package the basic algorithm.
(See: CBC, CFB, DEA, ECB, OFB.)
$ Blowfish $ Blowfish
(N) A symmetric block cipher with variable-length key (32 to 448 (N) A symmetric block cipher with variable-length key (32 to 448
bits) designed in 1993 by Bruce Schneier as an unpatented, bits) designed in 1993 by Bruce Schneier as an unpatented,
license-free, royalty-free replacement for DES or IDEA. [Schn] license-free, royalty-free replacement for DES or IDEA. [Schn]
(See: Twofish.)
$ brand $ brand
1. (I) A distinctive mark or name that identifies a product or 1. (I) A distinctive mark or name that identifies a product or
business entity. business entity.
2. (O) /SET/ The name of a payment card. 2. (O) /SET/ The name of a payment card. (See: BCA.)
Tutorial: Financial institutions and other companies have founded Tutorial: Financial institutions and other companies have founded
payment card brands, protect and advertise the brands, establish payment card brands, protect and advertise the brands, establish
and enforce rules for use and acceptance of their payment cards, and enforce rules for use and acceptance of their payment cards,
and provide networks to interconnect the financial institutions. and provide networks to interconnect the financial institutions.
These brands combine the roles of issuer and acquirer in These brands combine the roles of issuer and acquirer in
interactions with cardholders and merchants. [SET1] interactions with cardholders and merchants. [SET1]
$ brand certification authority (BCA) $ brand certification authority (BCA)
(O) /SET/ A CA owned by a payment card brand, such as MasterCard, (O) /SET/ A CA owned by a payment card brand, such as MasterCard,
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(I) /cryptography/ To successfully perform cryptanalysis and thus (I) /cryptography/ To successfully perform cryptanalysis and thus
succeed in decrypting data or performing some other cryptographic succeed in decrypting data or performing some other cryptographic
function, without initially having knowledge of the key that the function, without initially having knowledge of the key that the
function requires. (See: penetrate.) function requires. (See: penetrate.)
Usage: This term applies to encrypted data or, more generally, to Usage: This term applies to encrypted data or, more generally, to
a cryptographic algorithm or cryptographic system. a cryptographic algorithm or cryptographic system.
$ Brewer-Nash model $ Brewer-Nash model
(N) A security model [BN89] to enforce the Chinese wall policy. (N) A security model [BN89] to enforce the Chinese wall policy.
(Compare: Bell-LaPadula model, Clark-Wilson model.) (Compare: Bell-LaPadula model, Clark-Wilson model.)
Tutorial: All proprietary information in the set of commercial Tutorial: All proprietary information in the set of commercial
firms F(1), F(2), ..., F(N) is categorized into mutually exclusive firms F(1), F(2), ..., F(N) is categorized into mutually exclusive
conflict-of-interest classes I(1), I(2), ..., I(M) that apply conflict-of-interest classes I(1), I(2), ..., I(M) that apply
across all firms. Each firm belongs to exactly one class. The across all firms. Each firm belongs to exactly one class. The
Brewer-Nash model has the following mandatory rules: Brewer-Nash model has the following mandatory rules:
- Brewer-Nash Read Rule: Subject S can read information object O - Brewer-Nash Read Rule: Subject S can read information object O
from firm F(i) only if either (a) O is from the same firm as from firm F(i) only if either (a) O is from the same firm as
some object previously read by S *or* (b) O belongs to a class some object previously read by S *or* (b) O belongs to a class
I(i) from which S has not previously read any object. (See: I(i) from which S has not previously read any object. (See:
object, subject.) object, subject.)
- Brewer-Nash Write Rule: Subject S can write information object
- Brewer-Nash Write Rule: Subject S can write information object
O to firm F(i) only if (a) S can read O by the Brewer-Nash Read O to firm F(i) only if (a) S can read O by the Brewer-Nash Read
Rule *and* (b) no object can be read by S from a different firm Rule *and* (b) no object can be read by S from a different firm
F(j), no matter whether F(j) belongs to the same class as F(i) F(j), no matter whether F(j) belongs to the same class as F(i)
or to a different class. or to a different class.
$ bridge $ bridge
(I) A gateway for traffic flowing at OSIRM layer 2 between two (I) A gateway for traffic flowing at OSIRM Layer 2 between two
networks (usually two LANs). (Compare: router, bridge CA.) networks (usually two LANs). (Compare: bridge CA, router.)
$ bridge CA $ bridge CA
(I) A PKI consisting of only a CA that cross-certifies with CAs of (I) A PKI consisting of only a CA that cross-certifies with CAs of
some other PKIs. (See: cross-certification. Compare: bridge.) some other PKIs. (See: cross-certification. Compare: bridge.)
Tutorial: A bridge CA functions as a hub that enables a Tutorial: A bridge CA functions as a hub that enables a
certificate user in any of the PKIs that attach to the bridge, to certificate user in any of the PKIs that attach to the bridge, to
validate certficates issued in the other attached PKIs. validate certificates issued in the other attached PKIs.
For example, a bridge CA (BCA) CA1 For example, a bridge CA (BCA) CA1
could cross-certify with four ^ could cross-certify with four ^
PKIs that have the roots CA1, | PKIs that have the roots CA1, |
CA2, CA3, and CA4. The cross- v CA2, CA3, and CA4. The cross- v
certificates that the roots CA2 <-> BCA <-> CA3 certificates that the roots CA2 <-> BCA <-> CA3
exchange with the BCA enable an ^ exchange with the BCA enable an ^
end entity EE1 certified under | end entity EE1 certified under |
under CA1 in PK1 to construct v under CA1 in PK1 to construct v
a certification path needed to CA4 a certification path needed to CA4
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$ bulk encryption $ bulk encryption
(N) "Simultaneous encryption of all channels of a multichannel (N) "Simultaneous encryption of all channels of a multichannel
telecommunications link." [C4009] (Compare: bulk keying material.) telecommunications link." [C4009] (Compare: bulk keying material.)
$ bulk key $ bulk key
(D) In a few published descriptions of hybrid encryption for SSH, (D) In a few published descriptions of hybrid encryption for SSH,
Windows 2000, and other applications, this term refers to a Windows 2000, and other applications, this term refers to a
symmetric key that (a) is used to encrypt a relatively large symmetric key that (a) is used to encrypt a relatively large
amount of data and (b) is itself encrypted with a public key. amount of data and (b) is itself encrypted with a public key.
(Compare: bulk keying material.)
Example: To send a large file to Bob, Alice (a) generates a Example: To send a large file to Bob, Alice (a) generates a
symmetric key and uses it to encrypt the file (i.e., encrypt the symmetric key and uses it to encrypt the file (i.e., encrypt the
bulk of the information that is to be sent) and then (b) encrypts bulk of the information that is to be sent) and then (b) encrypts
that symmetric key (the "bulk key") with Bob's public key. that symmetric key (the "bulk key") with Bob's public key.
Deprecated Term: ISDs SHOULD NOT use this term or definition; they Deprecated Term: ISDs SHOULD NOT use this term or definition; they
are not well-established and could be confused with the are not well-established and could be confused with the
established term "bulk keying material". Instead, use "symmetric established term "bulk keying material". Instead, use "symmetric
key" and carefully explain how the key is applied. key" and carefully explain how the key is applied.
$ bulk keying material $ bulk keying material
(O) Refers to handling keying material in large quantities, e.g., (N) Refers to handling keying material in large quantities, e.g.,
as a dataset that contains many items of keying material. (See: as a dataset that contains many items of keying material. (See:
type 0. Compare: bulk key, bulk encryption.) type 0. Compare: bulk key, bulk encryption.)
$ bump-in-the-stack $ bump-in-the-stack
(I) An implementation approach that places a network security (I) An implementation approach that places a network security
mechanism inside the system that is to be protected. (Compare: mechanism inside the system that is to be protected. (Compare:
bump-in-the-wire.) bump-in-the-wire.)
Example: IPsec can be implemented inboard, in the protocol stack Example: IPsec can be implemented inboard, in the protocol stack
of an existing system or existing system design, by placing a new of an existing system or existing system design, by placing a new
layer placed between the existing IP layer and the OSIRM layer 3 layer between the existing IP layer and the OSIRM Layer 3 drivers.
drivers. Source code access for the existing stack is not Source code access for the existing stack is not required, but the
required, but the system that contains the stack does need to be system that contains the stack does need to be modified [R2401].
modified [R1401].
$ bump-in-the-wire $ bump-in-the-wire
(I) An implementation approach that places a network security (I) An implementation approach that places a network security
mechanism outside of the system that is to be protected. (Compare: mechanism outside of the system that is to be protected. (Compare:
bump-in-the-stack.) bump-in-the-stack.)
Example: IPsec can be implemented outboard, in a physically Example: IPsec can be implemented outboard, in a physically
separate device, so that the system that receives the IPsec separate device, so that the system that receives the IPsec
protection does not need to be modified at all [R1401]. Military- protection does not need to be modified at all [R2401]. Military-
grade link encryption has mainly been implemented as bump-in-the- grade link encryption has mainly been implemented as bump-in-the-
wire devices. wire devices.
$ business case analysis
(N) An extended form of cost-benefit analysis that considers
factors beyond financial metrics, including security factors such
as the requirement for security services, their technical and
programmatic feasibility, their qualitative benefits, and
associated risks. (See: risk analysis.)
$ byte $ byte
(I) A fundamental unit of computer storage; the smallest (I) A fundamental unit of computer storage; the smallest
addressable unit in a computer's architecture. Usually holds one addressable unit in a computer's architecture. Usually holds one
character of information and, today, usually means eight bits. character of information and, today, usually means eight bits.
(Compare: octet.) (Compare: octet.)
Usage: Understood to be larger than a "bit", but smaller than a Usage: Understood to be larger than a "bit", but smaller than a
"word". Although "byte" almost always means "octet" today, some "word". Although "byte" almost always means "octet" today, some
computer architectures have had bytes in other sizes (e.g., six computer architectures have had bytes in other sizes (e.g., six
bits, nine bits). Therefore, an STD SHOULD state the number of bits, nine bits). Therefore, an STD SHOULD state the number of
bits in a byte where the term is first used in the STD. bits in a byte where the term is first used in the STD.
$ C field $ C field
(D) See: Compartments field. (D) See: Compartments field.
$ C1 computer system, C2 computer system $ C1 or C2 computer system
(O) See: TCSEC. (O) /TCSEC/ See: Tutorial under "Trusted Computer System
Evaluation Criteria".
$ CA $ CA
(I) See: certification authority. (I) See: certification authority.
$ CA certificate $ CA certificate
(D) "A [digital] certificate for one CA issued by another CA." (D) "A [digital] certificate for one CA issued by another CA."
[X509] [X509]
Deprecated Definition: An ISD that uses the term SHOULD state Deprecated Definition: ISDs SHOULD NOT use the term with this
precisely how the certificate is constructed and how it is definition; the definition is ambiguous with regard to how the
intended to be used; the X.509 definition is ambiguous with regard certificate is constructed and how it is intended to be used. ISDs
to those details. (See: certificate profile.) that use this term SHOULD provide a technical definition for it.
(See: certificate profile.)
- Constraints: A v3 X.509 public-key certificate may have a Tutorial: There is no single, obvious choice for a technical
"basicConstraints" extension containing a "cA" value of "TRUE" definition of this term. Different PKIs can use different
that specifically indicates that "the certified public key may certificate profiles, and X.509 provides several choices of how to
be used to verify certificate signatures." issue certificates to CAs. For example, one possible definition is
- Key Usage: A v3 X.509 public-key certificate also may have a the following: A v3 X.509 public-key certificate that has a
"key Usage" extension which indicates the purposes for which "basicConstraints" extension containing a "cA" value of "TRUE".
the public key may be used. One purpose is "keyCertSign", for That would specifically indicate that "the certified public key
verifying a CA's signature on certificates; and if this value may be used to verify certificate signatures", i.e., that the
is present, than "cA" is also set to "TRUE" if the certificate private key may be used by a CA.
also has a "basicConstraints" extension.
However, a CA could be issued a certificate in which "keyCertSign" However, there also are other ways to indicate such usage. The
is asserted without "basicConstraints" being present; and an certificate may have a "key Usage" extension that indicates the
entity that acts as a CA could be issued a certificate with purposes for which the public key may be used, and one of the
"keyUsage" set to other values, either with or without values that X.509 defines for that extension is "keyCertSign", to
"keyCertSign". indicate that the certificate may be used for verifying a CA's
signature on certificates. If "keyCertSign" is present in a
certificate that also has a "basicConstraints" extension, than
"cA" is set to "TRUE" in that extension. Alternatively, a CA could
be issued a certificate in which "keyCertSign" is asserted without
"basicConstraints" being present; and an entity that acts as a CA
could be issued a certificate with "keyUsage" set to other values,
either with or without "keyCertSign".
$ Caesar cipher $ Caesar cipher
(I) A cipher that, given an alphabet of N characters, A(1), A(2), (I) A cipher that, given an alphabet of N characters, A(1), A(2),
character A(i) by A(i+K, mod N) for some 0<K<N+1. [Schn] character A(i) by A(i+K, mod N) for some 0<K<N+1. [Schn]
Examples: (a) During the Gallic wars, Julius Caesar used a cipher
Examples: During the Gallic wars, Julius Caesar used a cipher with with K=3. In a Caesar cipher with K=3 for the English alphabet, A
K=3. In a Caesar cipher with K=3 for the English alphabet, A is is replaced by D, B by E, C by F, ..., W by Z, X by A, Y by B, Z
replaced by D, B by E, C by F, ..., W by Z, X by A, Y by B, Z by by C. (b) UNIX systems sometimes include "ROT13" software that
C. implements a Caesar cipher with K=13 (i.e., ROTate by 13).
UNIX systems sometimes include ROT13 software that implements a
Caesar cipher with K=13 (i.e., ROTate by 13).
$ call back $ call back
(I) An authentication technique for terminals that remotely access (I) An authentication technique for terminals that remotely access
a computer via telephone lines; the host system disconnects the a computer via telephone lines; the host system disconnects the
caller and then reconnects on a telephone number that was caller and then reconnects on a telephone number that was
previously authorized for that terminal. previously authorized for that terminal.
$ CAM $ CAM
(O) See: Certificate Arbitrator Module. (O) See: Certificate Arbitrator Module.
$ CANEWARE $ CANEWARE
(N) A end-to-end encryption system for computer data networks that (O) A end-to-end encryption system for computer data networks that
was developed by the U.S. DoD in the 1980s to provide host-to-host was developed by the U.S. DoD in the 1980s to provide host-to-host
data confidentiality service for datagrams in OSIRM layer 3. data confidentiality service for datagrams in OSIRM Layer 3.
[Roge] (Compare: BLACKER, IPsec.) [Roge] (Compare: BLACKER, IPsec.)
Tutorial: Each user host connects to its own bump-in-the-wire Tutorial: Each user host connects to its own bump-in-the-wire
encryption device called a CANEWARE Front End (CFE), through which encryption device called a CANEWARE Front End (CFE), through which
the host connects to the subnetwork. CANEWARE uses symmetric the host connects to the subnetwork. CANEWARE uses symmetric
encryption for CFE-to-CFE traffic, but also uses FIREFLY to encryption for CFE-to-CFE traffic, but also uses FIREFLY to
establish those session keys. The public-key certificates issued establish those session keys. The public-key certificates issued
by the FIREFLY system include credentials for mandatory access by the FIREFLY system include credentials for mandatory access
control. For discretionary access control, the system also control. For discretionary access control, the system also
includes one or more centralized CANEWARE Control Processors includes one or more centralized CANEWARE Control Processors
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subnetwork, so that the subnetwork can operate at a different subnetwork, so that the subnetwork can operate at a different
security level than the hosts. (b) Like BLACKER, the CANEWARE security level than the hosts. (b) Like BLACKER, the CANEWARE
components are trusted to separate datagrams of different security components are trusted to separate datagrams of different security
levels, so that each datagram of a given security level can be levels, so that each datagram of a given security level can be
received only by a host that is authorized for that security received only by a host that is authorized for that security
level; and thus CANEWARE can separate host communities that level; and thus CANEWARE can separate host communities that
operate at different security levels. (c) Unlike a BFE, the host operate at different security levels. (c) Unlike a BFE, the host
side of a CFE is not MLS, and treats all packets received from a side of a CFE is not MLS, and treats all packets received from a
user host as being at the same mandatory security level. user host as being at the same mandatory security level.
$ capability $ capability list
(I) /information system/ A mechanism that implements access
control for a system entity by enumerating the system resources
that the entity is permitted to access and, either implicitly or
explicitly, the access modes granted for each resource. (Compare:
access control list, access control matrix, access profile,
capability token.)
$ capability token
(I) A token, usually an unforgeable data object, that gives the (I) A token, usually an unforgeable data object, that gives the
bearer or holder the right to access a system resource. Possession bearer or holder the right to access a system resource. Possession
of the token is accepted by a system as proof that the holder has of the token is accepted by a system as proof that the holder has
been authorized to access the resource indicated by the token. been authorized to access the resource indicated by the token.
(Compare: access control list. See: attribute certificate, (See: attribute certificate, capability list, credential, digital
credential, digital certificate, ticket.) certificate, ticket, token.)
$ Capability Maturity Model (CMM) $ Capability Maturity Model (CMM)
(N) Method for judging the maturity of software processes in an (N) Method for judging the maturity of software processes in an
organization and for identifying crucial practices needed to organization and for identifying crucial practices needed to
increase process maturity. [Chris] (Compare: Common Criteria.) increase process maturity. [Chris] (Compare: Common Criteria.)
Tutorial: The CMM does not specify security evaluation criteria Tutorial: The CMM does not specify security evaluation criteria
(see: assurance level), but its use may improve security (see: assurance level), but its use may improve security
assurance. The CMM describes principles and practices that can assurance. The CMM describes principles and practices that can
improve software processes in terms of evolving from ad hoc improve software processes in terms of evolving from ad hoc
processes to disciplined processes. The CMM has five levels: processes to disciplined processes. The CMM has five levels:
- Initial: Software processes are ad hoc or chaotic, and few are - Initial: Software processes are ad hoc or chaotic, and few are
well-defined. Success depends on individual effort and heroics. well-defined. Success depends on individual effort and heroics.
- Repeatable: Basic project management processes are established - Repeatable: Basic project management processes are established
to track cost, schedule, and functionality. Necessary process to track cost, schedule, and functionality. Necessary process
discipline is in place to repeat earlier successes on projects discipline is in place to repeat earlier successes on projects
with similar applications. with similar applications.
- Defined: Software process for both management and engineering - Defined: Software process for both management and engineering
activities is documented, standardized, and integrated into a activities is documented, standardized, and integrated into a
standard software process for the organization. All projects standard software process for the organization. Each project
use approved, tailored version of organization's standard uses an approved, tailored version of the organization's
software process for developing and maintaining software. standard process for developing and maintaining software.
- Managed: Detailed measures of software process and product - Managed: Detailed measures of software process and product
quality are collected. Both software process and products are quality are collected. Both software process and products are
quantitatively understood and controlled. quantitatively understood and controlled.
- Optimizing: Continuous process improvement is enabled by - Optimizing: Continuous process improvement is enabled by
quantitative feedback from the process and from piloting quantitative feedback from the process and from piloting
innovative ideas and technologies. innovative ideas and technologies.
$ CAPI $ CAPI
(I) See: cryptographic application programming interface. (I) See: cryptographic application programming interface.
$ CAPSTONE $ CAPSTONE
(N) An integrated microcircuit (in MYK-8x series manufactured by (N) An integrated microcircuit (in MYK-8x series manufactured by
Mykotronx, Inc.) that implements SKIPJACK, KEA, DSA, SHA, and Mykotronx, Inc.) that implements SKIPJACK, KEA, DSA, SHA, and
basic mathematical functions needed to support asymmetric basic mathematical functions needed to support asymmetric
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and payment gateway CAs. [SET2] and payment gateway CAs. [SET2]
$ CAST $ CAST
(N) A design procedure for symmetric encryption algorithms, and a (N) A design procedure for symmetric encryption algorithms, and a
resulting family of algorithms, invented by Carlisle Adams (C.A.) resulting family of algorithms, invented by Carlisle Adams (C.A.)
and Stafford Tavares (S.T.). [R2144, R2612] and Stafford Tavares (S.T.). [R2144, R2612]
$ category $ category
(I) A grouping of sensitive information items to which a non- (I) A grouping of sensitive information items to which a non-
hierarchical restrictive security label is applied to increase hierarchical restrictive security label is applied to increase
protection of the data. (See: compartment. Compare: protection of the data. (See: formal access approval. Compare:
classification.) category, classification.)
$ CAW $ CAW
(O) See: certification authority workstation. (N) See: certification authority workstation.
$ CBC $ CBC
(N) See: cipher block chaining. (N) See: cipher block chaining.
$ CCA $ CCA
(O) See: cardholder certification authority. (O) See: cardholder certification authority.
$ CCEP $ CCEP
(O) See: Commercial COMSEC Endorsement Program. (O) See: Commercial COMSEC Endorsement Program.
$ CCI $ CCI
(O) See: Controlled Cryptographic Item. (O) See: Controlled Cryptographic Item.
$ CCITT $ CCITT
(N) Acronym for French translation of International Telephone and (N) Acronym for French translation of International Telephone and
Telegraph Consultative Committee. Now renamed ITU-T. Telegraph Consultative Committee. Now renamed ITU-T.
$ CERIAS $ CERIAS
(O) Purdue University's Center for Education and Research in (O) Purdue University's Center for Education and Research in
Information Assurance and Security, which includes faculty from Information Assurance and Security, which includes faculty from
multiple schools and departments and takes multidisciplinary multiple schools and departments and takes a multidisciplinary
approach to security problems ranging from technical to ethical, approach to security problems ranging from technical to ethical,
legal, educational, communicational, linguistic, and economic. legal, educational, communicational, linguistic, and economic.
$ CERT $ CERT
(I) See: computer emergency response team. (I) See: computer emergency response team.
$ certificate $ certificate
1. (I) /general English/ A document that attests to the truth of 1. (I) /general English/ A document that attests to the truth of
something or the ownership of something. something or the ownership of something.
2. (I) /general security/ See: capability, digital certificate. 2. (I) /general security/ See: capability token, digital
certificate.
3. (I) /PKI/ See: attribute certificate, public-key certificate. 3. (I) /PKI/ See: attribute certificate, public-key certificate.
$ Certificate Arbitrator Module (CAM) $ Certificate Arbitrator Module (CAM)
(O) An open-source software module that is designed to be (O) An open-source software module that is designed to be
integrated with an application for the purpose of routing, integrated with an application for the purpose of routing,
replying to, and otherwise managing and meditating certificate replying to, and otherwise managing and meditating certificate
validation requests between that application and the CAs in the validation requests between that application and the CAs in the
ACES PKI. ACES PKI.
$ certificate authority $ certificate authority
(D) Synonym for "certification authority". (D) Synonym for "certification authority".
Deprecated Term: ISDs SHOULD NOT use this term; it looks like Deprecated Term: ISDs SHOULD NOT use this term; it suggests
sloppy use of "certification authority", which is the term careless use of the term "certification authority", which is
standardized by X.509. A person who uses this term probably has standardized by X.509. A person who uses this term probably has
not read the PKI standards [X509, R2459]. never read the basic technical standards for PKI [X509, R3280].
$ certificate chain $ certificate chain
(D) Synonym for "certification path". (See: trust chain.) (D) Synonym for "certification path". (See: trust chain.)
Deprecated Term: ISDs SHOULD NOT use this term; it duplicates the Deprecated Term: ISDs SHOULD NOT use this term; it duplicates the
meaning of a standardized term. Instead, use "certification path". meaning of a standardized term. Instead, use "certification path".
$ certificate chain validation $ certificate chain validation
(D) Synonym for "certificate validation" or "path validation". (D) Synonym for "certificate validation" or "path validation".
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Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
the subject of a digital certificate; the term is potentially the subject of a digital certificate; the term is potentially
ambiguous. For example, the term could refer to a system entity or ambiguous. For example, the term could refer to a system entity or
component, such as a repository, that simply has possession of a component, such as a repository, that simply has possession of a
copy of the certificate. copy of the certificate.
$ certificate management $ certificate management
(I) The functions that a CA may perform during the life cycle of a (I) The functions that a CA may perform during the life cycle of a
digital certificate, including the following: digital certificate, including the following:
- Acquire and verify data items to bind into the certificate. - Acquire and verify data items to bind into the certificate.
- Encode and sign the certificate. - Encode and sign the certificate.
- Store the certificate in a directory or repository. - Store the certificate in a directory or repository.
- Renew, rekey, and update the certificate. - Renew, rekey, and update the certificate.
- Revoke the certificate and issue a CRL. - Revoke the certificate and issue a CRL.
(See: archive management, certificate management, key management, (See: archive management, certificate management, key management,
security architecture, token management.) security architecture, token management.)
$ certificate management authority (CMA) $ certificate management authority (CMA)
(D) /U.S. DoD/ Used to mean either a CA or an RA. [DoD3, SP32] (D) /U.S. DoD/ Used to mean either a CA or an RA. [DoD3, SP32]
Deprecated Term: ISDs SHOULD NOT use this term because it is Deprecated Term: ISDs SHOULD NOT use this term because it is
potentially ambiguous, such as in a context involve ICRLs. potentially ambiguous, such as in a context involve ICRLs.
Instead, use CA, RA, or both, depending on what is meant. Instead, use CA, RA, or both, depending on what is meant.
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Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
the subject of a digital certificate; the term is potentially the subject of a digital certificate; the term is potentially
ambiguous. For example, the term could refer to a system entity, ambiguous. For example, the term could refer to a system entity,
such as a corporation, that has acquired a certificate to operate such as a corporation, that has acquired a certificate to operate
equipment, such as a Web server. equipment, such as a Web server.
$ certificate path $ certificate path
(D) Synonym for "certification path". (D) Synonym for "certification path".
Deprecated Term: ISDs SHOULD NOT use this term; it looks like Deprecated Term: ISDs SHOULD NOT use this term; it suggests
sloppy use of "certification path", which is the term standardized careless use of "certification path", which is a term standardized
by X.509. A person who uses this term probably has not read the by X.509. A person who uses this term probably has never read the
PKI standards [X509, R2459]. basic technical standards for PKI [X509, R3280].
$ certificate policy $ certificate policy
(I) "A named set of rules that indicates the applicability of a (I) "A named set of rules that indicates the applicability of a
certificate to a particular community and/or class of application certificate to a particular community and/or class of application
with common security requirements." [X509] (Compare: CPS.) with common security requirements." [X509] (Compare: CPS.)
Example: The U.S. DoD's certificate policy [DoD3] defines four Example: The U.S. DoD's certificate policy [DoD3] defines four
classes (i.e., assurance levels) for X.509 public-key certificates classes (i.e., assurance levels) for X.509 public-key certificates
and defines the applicability of those classes. (See: class 2.) and defines the applicability of those classes. (See: class 2.)
Tutorial: A certificate policy can help a certificate user to Tutorial: A certificate policy can help a certificate user to
decide whether a certificate should be trusted in a particular decide whether a certificate should be trusted in a particular
application. "For example, a particular certificate policy might application. "For example, a particular certificate policy might
indicate applicability of a type of certificate for the indicate applicability of a type of certificate for the
authentication of electronic data interchange transactions for the authentication of electronic data interchange transactions for the
trading of goods within a given price range." [R2527] trading of goods within a given price range." [R3647]
A v3 X.509 public-key certificate may have a "certificatePolicies" A v3 X.509 public-key certificate may have a "certificatePolicies"
extension that lists certificate policies, recognized by the extension that lists certificate policies, recognized by the
issuing CA, that apply to the certificate and govern its use. Each issuing CA, that apply to the certificate and govern its use. Each
policy is denoted by an object identifier and may optionally have policy is denoted by an object identifier and may optionally have
certificate policy qualifiers. (See: certificate profile.) certificate policy qualifiers. (See: certificate profile.)
Each SET certificate specifies at least one certificate policy, Each SET certificate specifies at least one certificate policy,
that of the SET root CA. SET uses certificate policy qualifiers to that of the SET root CA. SET uses certificate policy qualifiers to
point to the actual policy statement and to add qualifying point to the actual policy statement and to add qualifying
policies to the root policy. (See: SET qualifier.) policies to the root policy. (See: SET qualifier.)
$ certificate policy qualifier $ certificate policy qualifier
(I) Information that pertains to a certificate policy and is (I) Information that pertains to a certificate policy and is
included in a "certificatePolicies" extension in a v3 X.509 included in a "certificatePolicies" extension in a v3 X.509
public-key certificate. public-key certificate.
$ certificate profile $ certificate profile
(I) A specification (e.g., [DoD3, R2459]) of the format and (I) A specification (e.g., [DoD3, R3280]) of the format and
semantics of public-key certificates or attribute certificates, semantics of public-key certificates or attribute certificates,
constructed for use in a specific application context by selecting constructed for use in a specific application context by selecting
from among options offered by a broader standard. from among options offered by a broader standard.
$ certificate reactivation $ certificate reactivation
(I) The act or process by which a digital certificate, which a CA (I) The act or process by which a digital certificate, which a CA
has designated for revocation but not yet listed on a CRL, is has designated for revocation but not yet listed on a CRL, is
returned to the valid state. returned to the valid state.
$ certificate rekey $ certificate rekey
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number is assigned) but the binding of the public key to the number is assigned) but the binding of the public key to the
subject and to other data items stays the same. The other data subject and to other data items stays the same. The other data
items are changed, and the old certificate is revoked, only as items are changed, and the old certificate is revoked, only as
required by the PKI and CPS to support the renewal. If changes go required by the PKI and CPS to support the renewal. If changes go
beyond that, the process is a "certificate rekey" or "certificate beyond that, the process is a "certificate rekey" or "certificate
update". update".
$ certificate request $ certificate request
(D) Synonym for "certification request". (D) Synonym for "certification request".
Deprecated Term: ISDs SHOULD NOT use this term; it looks like Deprecated Term: ISDs SHOULD NOT use this term; it suggests
imprecise use of a term standardized by PKCS #10 and used in PKIX. careless use of the term "certification request", which is
Instead, use "certification request". standardized by PKCS #10 and used in PKIX. Instead, use
"certification request".
$ certificate revocation $ certificate revocation
(I) The event that occurs when a CA declares that a previously (I) The event that occurs when a CA declares that a previously
valid digital certificate issued by that CA has become invalid; valid digital certificate issued by that CA has become invalid;
usually stated with a effective date. usually stated with a effective date.
Tutorial: In X.509, a revocation is announced to potential Tutorial: In X.509, a revocation is announced to potential
certificate users by issuing a CRL that mentions the certificate. certificate users by issuing a CRL that mentions the certificate.
Revocation and listing on a CRL is only necessary prior to the Revocation and listing on a CRL is only necessary prior to the
certificate's scheduled expiration. certificate's scheduled expiration.
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have been invalidated by their issuer prior to when they were have been invalidated by their issuer prior to when they were
scheduled to expire. (See: certificate expiration, delta CRL, scheduled to expire. (See: certificate expiration, delta CRL,
X.509 certificate revocation list.) X.509 certificate revocation list.)
2. (O) "A signed list indicating a set of certificates that are no 2. (O) "A signed list indicating a set of certificates that are no
longer considered valid by the certificate issuer. In addition to longer considered valid by the certificate issuer. In addition to
the generic term CRL, some specific CRL types are defined for CRLs the generic term CRL, some specific CRL types are defined for CRLs
that cover particular scopes." [X509] that cover particular scopes." [X509]
$ certificate revocation tree $ certificate revocation tree
(I) A mechanism for distributing notice of certificate (N) A mechanism for distributing notice of certificate
revocations; uses a tree of hash results that is signed by the revocations; uses a tree of hash results that is signed by the
tree's issuer. Offers an alternative to issuing a CRL, but is not tree's issuer. Offers an alternative to issuing a CRL, but is not
supported in X.509. (See: certificate status responder.) supported in X.509. (See: certificate status responder.)
$ certificate serial number $ certificate serial number
1. (I) An integer value that (a) is associated with, and may be 1. (I) An integer value that (a) is associated with, and may be
carried in, a digital certificate; (b) is assigned to the carried in, a digital certificate; (b) is assigned to the
certificate by the certificate's issuer; and (c) is unique among certificate by the certificate's issuer; and (c) is unique among
all the certificates produced by that issuer. all the certificates produced by that issuer.
2. (O) "An integer value, unique within the issuing CA, which is 2. (O) "An integer value, unique within the issuing CA, which is
unambiguously associated with a certificate issued by that CA." unambiguously associated with a certificate issued by that CA."
[X509] [X509]
$ certificate status authority $ certificate status authority
(D) /U.S. DoD/ "A trusted entity that provides on-line (D) /U.S. DoD/ "A trusted entity that provides on-line
verification to a Relying Party of a subject certificate's verification to a Relying Party of a subject certificate's
trustworthiness [should say 'validity'], and may also provide trustworthiness [should instead say 'validity'], and may also
additional attribute information for the subject certificate." provide additional attribute information for the subject
[DoD3] certificate." [DoD3]
Deprecated Term: ISDs SHOULD NOT use this term because it is not Deprecated Term: ISDs SHOULD NOT use this term because it is not
widely accepted; instead, use "certificate status responder" or widely accepted; instead, use "certificate status responder" or
"OCSP server", or otherwise explain what is meant. "OCSP server", or otherwise explain what is meant.
$ certificate status responder $ certificate status responder
(N) /FPKI/ A trusted on-line server that acts for a CA to provide (N) /FPKI/ A trusted on-line server that acts for a CA to provide
authenticated certificate status information to certificate users authenticated certificate status information to certificate users
[FPKI]. Offers an alternative to issuing a CRL, but is not [FPKI]. Offers an alternative to issuing a CRL, but is not
supported in X.509. (See: certificate revocation tree, OCSP.) supported in X.509. (See: certificate revocation tree, OCSP.)
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2. (O) "The process of ensuring that a certificate was valid at a 2. (O) "The process of ensuring that a certificate was valid at a
given time, including possibly the construction and processing of given time, including possibly the construction and processing of
a certification path, and ensuring that all certificates in that a certification path, and ensuring that all certificates in that
path were valid (i.e. were not expired or revoked) at that given path were valid (i.e. were not expired or revoked) at that given
time." [X509] time." [X509]
Tutorial: To validate a certificate, a certificate user checks Tutorial: To validate a certificate, a certificate user checks
that the certificate is properly formed and signed and is that the certificate is properly formed and signed and is
currently in force: currently in force:
- Checks the syntax and semantics: Parses the certificate's
- Checks the syntax and semantics: Parses the certificate's
syntax and interprets its semantics, applying rules specified syntax and interprets its semantics, applying rules specified
for and by its data fields, such as for critical extensions in for and by its data fields, such as for critical extensions in
an X.509 certificate. an X.509 certificate.
- Checks the signature: Uses the issuer's public key to verify - Checks the signature: Uses the issuer's public key to verify
the digital signature of the CA who issued the certificate in the digital signature of the CA who issued the certificate in
question. If the verifier obtains the issuer's public key from question. If the verifier obtains the issuer's public key from
the issuer's own public-key certificate, that certificate the issuer's own public-key certificate, that certificate
should be validated, too. That validation may lead to yet should be validated, too. That validation may lead to yet
another certificate to be validated, and so on. Thus, in another certificate to be validated, and so on. Thus, in
general, certificate validation involves discovering and general, certificate validation involves discovering and
validating a certification path. validating a certification path.
- Checks currency and revocation: Verifies that the certificate - Checks currency and revocation: Verifies that the certificate
is currently in force by checking that the current date and is currently in force by checking that the current date and
time are within the validity period (if that is specified in time are within the validity period (if that is specified in
the certificate) and that the certificate is not listed on a the certificate) and that the certificate is not listed on a
CRL or otherwise announced as invalid. (CRLs themselves require CRL or otherwise announced as invalid. (The CRLs also must be
a similar validation process.) checked by a similar validation process.)
$ certification $ certification
1. (I) /information system/ Comprehensive evaluation (usually made 1. (I) /information system/ Comprehensive evaluation (usually made
in support of an accreditation action) of an information system's in support of an accreditation action) of an information system's
technical security features and other safeguards to establish the technical security features and other safeguards to establish the
extent to which the system's design and implementation meet a set extent to which the system's design and implementation meet a set
of specified security requirements. [C4009, FP102, SP37] (See: of specified security requirements. [C4009, FP102, SP37] (See:
accreditation. Compare: evaluation.) accreditation. Compare: evaluation.)
2. (I) /digital certificate/ The act or process of vouching for 2. (I) /digital certificate/ The act or process of vouching for
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provided by a certificate. Thus, a CA should be someone that provided by a certificate. Thus, a CA should be someone that
certificate users trust, and usually holds an official position certificate users trust, and usually holds an official position
created and granted power by a government, a corporation, or some created and granted power by a government, a corporation, or some
other organization. A CA is responsible for managing the life other organization. A CA is responsible for managing the life
cycle of certificates (see: certificate management) and, depending cycle of certificates (see: certificate management) and, depending
on the type of certificate and the CPS that applies, may be on the type of certificate and the CPS that applies, may be
responsible for the life cycle of key pairs associated with the responsible for the life cycle of key pairs associated with the
certificates (see: key management). certificates (see: key management).
$ certification authority workstation (CAW) $ certification authority workstation (CAW)
(O) A computer system that enables a CA to issue digital (N) A computer system that enables a CA to issue digital
certificates and supports other certificate management functions certificates and supports other certificate management functions
as required. as required.
$ certification hierarchy $ certification hierarchy
1. (I) A tree-structured (loop-free) topology of relationships 1. (I) A tree-structured (loop-free) topology of relationships
among CAs and the entities to whom the CAs issue public-key among CAs and the entities to whom the CAs issue public-key
certificates. (See: hierarchical PKI, hierarchy management.) certificates. (See: hierarchical PKI, hierarchy management.)
Tutorial: In this structure, one CA is the top CA, the highest Tutorial: In this structure, one CA is the top CA, the highest
level of the hierarchy. (See: root, top CA.) The top CA may issue level of the hierarchy. (See: root, top CA.) The top CA may issue
public-key certificates to one or more additional CAs that form public-key certificates to one or more additional CAs that form
the second-highest level. Each of these CAs may issue certificates the second-highest level. Each of these CAs may issue certificates
to more CAs at the third highest level, and so on. The CAs at the to more CAs at the third highest level, and so on. The CAs at the
second-lowest level issue certificates only to non-CA entities second-lowest level issue certificates only to non-CA entities
that form the lowest level (see: end entity). Thus, all that form the lowest level (see: end entity). Thus, all
certification paths begin at the top CA and descend through zero certification paths begin at the top CA and descend through zero
or more levels of other CAs. All certificate users base path or more levels of other CAs. All certificate users base path
validations on the top CA's public key. validations on the top CA's public key.
2. (O) /MISSI/ A certification hierarchy for MISSI has three or 2. (I) /PEM/ A certification hierarchy for PEM has three levels of
CAs [R1422]:
- The highest level is the "Internet Policy Registration
Authority".
- A CA at the second-highest level is a "policy certification
authority".
- A CA at the third-highest level is a "certification authority".
3. (O) /MISSI/ A certification hierarchy for MISSI has three or
four levels of CAs: four levels of CAs:
- A CA at the highest level, the top CA, is a "policy approving - A CA at the highest level, the top CA, is a "policy approving
authority". authority".
- A CA at the second-highest level is a "policy creation - A CA at the second-highest level is a "policy creation
authority". authority".
- A CA at the third-highest level is a local authority called a - A CA at the third-highest level is a local authority called a
"certification authority". "certification authority".
- A CA at the fourth-highest (optional) level is a "subordinate - A CA at the fourth-highest (optional) level is a "subordinate
certification authority". certification authority".
3. (O) /PEM/ A certification hierarchy for PEM has three levels of
CAs [R1422]:
- The highest level is the "Internet Policy Registration
Authority".
- A CA at the second-highest level is a "policy certification
authority".
- A CA at the third-highest level is a "certification authority".
4. (O) /SET/ A certification hierarchy for SET has three or four 4. (O) /SET/ A certification hierarchy for SET has three or four
levels of CAs: levels of CAs:
- The highest level is a "SET root CA". - The highest level is a "SET root CA".
- A CA at the second-highest level is a "brand certification - A CA at the second-highest level is a "brand certification
authority". authority".
- A CA at the third-highest (optional) level is a "geopolitical - A CA at the third-highest (optional) level is a "geopolitical
certification authority". certification authority".
- A CA at the fourth-highest level is a "cardholder CA", a - A CA at the fourth-highest level is a "cardholder CA", a
"merchant CA", or a "payment gateway CA". "merchant CA", or a "payment gateway CA".
$ certification path $ certification path
1. (I) An ordered sequence of public-key certificates (or a 1. (I) A linked sequence of one or more public-key certificates,
sequence of public-key certificates followed by one attribute or one or more public-key certificates and one attribute
certificate) that enables a certificate user to verify the certificate, that enables a certificate user to verify the
signature on the last certificate in the path, and thus enables signature on the last certificate in the path, and thus enables
the user to obtain a certified public key (or certified the user to obtain (from that last certificate) a certified public
attributes) of the entity that is the subject of that last key, or certified attributes, of the system entity that is the
certificate. (See: certificate validation, valid certificate.) subject of that last certificate. (See: trust anchor, certificate
validation, valid certificate.)
2. (O) "An ordered sequence of certificates of objects in the 2. (O) "An ordered sequence of certificates of objects in the
[X.500 Directory Information Tree] which, together with the public [X.500 Directory Information Tree] which, together with the public
key of the initial object in the path, can be processed to obtain key of the initial object in the path, can be processed to obtain
that of the final object in the path." [R2527, X509] that of the final object in the path." [R3647, X509]
Tutorial: The path is the "list of certificates needed to allow a Tutorial: The list is "linked" in the sense that the digital
particular user to obtain the public key of another." [X509] The signature of each certificate (except possibly the first) is
list is "linked" in the sense that the digital signature of each verified by the public key contained in the preceding certificate;
certificate (except the first) is verified by the public key i.e., the private key used to sign a certificate and the public
contained in the preceding certificate; i.e., the private key used key contained in the preceding certificate form a key pair that
to sign a certificate and the public key contained in the has previously been bound to the authority that signed.
preceding certificate form a key pair owned by the entity that
signed.
In the X.509 quotation in the previous paragraph, the word The path is the "list of certificates needed to [enable] a
"particular" points out that a certification path that can be particular user to obtain the public key [or attributes] of
validated by one certificate user might not be able to be another [user]." [X509] Here, the word "particular" points out
validated by another. That is because either the first certificate that a certification path that can be validated by one certificate
should be a trusted certificate (it might be a root certificate) user might not be able to be validated by another. That is because
or the signature on the first certificate should be verified by a either the first certificate needs to be a trusted certificate or
trusted key (it might be a root key), but such trust is defined the signature on the first certificate needs to be verifiable by a
relative to each user, not absolutely for all users. trusted key (e.g., a root key), but such trust is established only
relative to a "particular" (i.e., specific) user, not absolutely
for all users.
$ certification policy $ certification policy
(D) Synonym for either "certificate policy" or "certification (D) Synonym for either "certificate policy" or "certification
practice statement". practice statement".
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
either of the terms given here. Instead, use either "certificate either of those terms; that would be duplicative and would mix
policy" or "certification practice statement", depending on what concepts in a potentially misleading way. Instead, use either
is meant. "certificate policy" or "certification practice statement",
depending on what is meant.
$ certification practice statement (CPS) $ certification practice statement (CPS)
(I) "A statement of the practices which a certification authority (I) "A statement of the practices which a certification authority
employs in issuing certificates." [ABA96, R2527] (See: certificate employs in issuing certificates." [ABA96, R3647] (See: certificate
policy.) policy.)
Tutorial: A CPS is a published security policy that can help a Tutorial: A CPS is a published security policy that can help a
certificate user to decide whether a certificate issued by a certificate user to decide whether a certificate issued by a
particular CA can be trusted enough to use in a particular particular CA can be trusted enough to use in a particular
application. A CPS may be (a) a declaration by a CA of the details application. A CPS may be (a) a declaration by a CA of the details
of the system and practices it uses in its certificate management of the system and practices it uses in its certificate management
operations, (b) part of a contract between the CA and an entity to operations, (b) part of a contract between the CA and an entity to
whom a certificate is issued, (c) a statute or regulation whom a certificate is issued, (c) a statute or regulation
applicable to the CA, or (d) a combination of these types applicable to the CA, or (d) a combination of these types
involving multiple documents. [ABA] involving multiple documents. [ABA]
A CPS is usually more detailed and procedurally oriented than a A CPS is usually more detailed and procedurally oriented than a
certificate policy. A CPS applies to a particular CA or CA certificate policy. A CPS applies to a particular CA or CA
community, while a certificate policy applies across CAs or community, while a certificate policy applies across CAs or
communities. A CA with its single CPS may support multiple communities. A CA with its single CPS may support multiple
certificate policies, which may be used for different application certificate policies, which may be used for different application
purposes or by different user communities. On the other hand, purposes or by different user communities. On the other hand,
multiple CAs, each with a different CPS, may support the same multiple CAs, each with a different CPS, may support the same
certificate policy. [R2527] certificate policy. [R3647]
$ certification request $ certification request
(I) A algorithm-independent transaction format, defined by PCKS (I) A algorithm-independent transaction format, defined by PKCS
#10 and used in PKIX, that contains a DN, a public key, and #10 and used in PKIX, that contains a DN, a public key, and
optionally a set of attributes, collectively signed by the entity optionally a set of attributes, collectively signed by the entity
requesting certification, and sent to a CA, which transforms the requesting certification, and sent to a CA, which transforms the
request to an X.509 public-key certificate or another type of request to an X.509 public-key certificate or another type of
certificate. certificate.
$ certify $ certify
1. (I) Issue a digital certificate and thus vouch for the truth, 1. (I) Issue a digital certificate and thus vouch for the truth,
accuracy, and binding between data items in the certificate (e.g., accuracy, and binding between data items in the certificate (e.g.,
see: X.509 public-key certificate), such as the identity of the see: X.509 public-key certificate), such as the identity of the
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optionally a set of attributes, collectively signed by the entity optionally a set of attributes, collectively signed by the entity
requesting certification, and sent to a CA, which transforms the requesting certification, and sent to a CA, which transforms the
request to an X.509 public-key certificate or another type of request to an X.509 public-key certificate or another type of
certificate. certificate.
$ certify $ certify
1. (I) Issue a digital certificate and thus vouch for the truth, 1. (I) Issue a digital certificate and thus vouch for the truth,
accuracy, and binding between data items in the certificate (e.g., accuracy, and binding between data items in the certificate (e.g.,
see: X.509 public-key certificate), such as the identity of the see: X.509 public-key certificate), such as the identity of the
certificate's subject and the ownership of a public key. (See: certificate's subject and the ownership of a public key. (See:
certification.) certification.)
Usage: To "certify a public key" means to issue a public-key Usage: To "certify a public key" means to issue a public-key
certificate that vouches for the binding between the certificate's certificate that vouches for the binding between the certificate's
subject and the key. subject and the key.
2. (I) The act by which a CA uses measures to verify the truth, 2. (I) The act by which a CA uses measures to verify the truth,
accuracy, and binding between data items in a digital certificate. accuracy, and binding between data items in a digital certificate.
Tutorial: A description of the measures used for verification Tutorial: A description of the measures used for verification
should be included in the CA's CPS. should be included in the CA's CPS.
$ CFB $ CFB
(N) See: cipher feedback. (N) See: cipher feedback.
$ chain $ chain
(D) See: trust chain. (D) See: trust chain.
$ Challenge Handshake Authentication Protocol (CHAP) $ Challenge Handshake Authentication Protocol (CHAP)
(I) A peer entity authentication method for PPP, using a randomly- (I) A peer entity authentication method for PPP, using a randomly
generated challenge and requiring a matching response that depends generated challenge and requiring a matching response that depends
on a cryptographic hash of some combination of the challenge and a on a cryptographic hash of some combination of the challenge and a
secret key. [R1994] (See: challenge-response, PAP.) secret key. [R1994] (See: challenge-response, PAP.)
$ challenge-response $ challenge-response
(I) An authentication process that verifies an identity by (I) An authentication process that verifies an identity by
requiring correct authentication information to be provided in requiring correct authentication information to be provided in
response to a challenge. In a computer system, the authentication response to a challenge. In a computer system, the authentication
information is usually a value that is required to be computed in information is usually a value that is required to be computed in
response to an unpredictable challenge value, but it might be just response to an unpredictable challenge value, but it might be just
password. password.
$ Challenge-Response Authentication Mechanism (CRAM) $ Challenge-Response Authentication Mechanism (CRAM)
(I) IMAP4 usage: A mechanism [R2195], intended for use with IMAP4 (I) /IMAP4/ A mechanism [R2195], intended for use with IMAP4
AUTHENTICATE, by which an IMAP4 client uses a keyed hash [R2104] AUTHENTICATE, by which an IMAP4 client uses a keyed hash [R2104]
to authenticate itself to an IMAP4 server. (See: POP3 APOP.) to authenticate itself to an IMAP4 server. (See: POP3 APOP.)
Tutorial: The server includes a unique timestamp in its ready Tutorial: The server includes a unique timestamp in its ready
response to the client. The client replies with the client's name response to the client. The client replies with the client's name
and the hash result of applying MD5 to a string formed from and the hash result of applying MD5 to a string formed from
concatenating the timestamp with a shared secret that is known concatenating the timestamp with a shared secret that is known
only to the client and the server. only to the client and the server.
$ channel $ channel
1. (I) An information transfer path within a system. (See: covert 1. (I) An information transfer path within a system. (See: covert
channel.) channel.)
2. (I) A subdivision of a physical medium allowing possibly shared 2. (O) "A subdivision of the physical medium allowing possibly
independent uses of the medium. [R3753] shared independent uses of the medium." (RFC 3753)
$ channel capacity $ channel capacity
(I) The total capacity of a link to carry information; usually (I) The total capacity of a link to carry information; usually
expressed in bits per second. [R3753](Compare: bandwidth.) expressed in bits per second. (RFC 3753) (Compare: bandwidth.)
Tutorial: Within a given bandwidth, the theoretical maximum Tutorial: Within a given bandwidth, the theoretical maximum
channel capacity is given by Shannon~Os Law. The actual channel channel capacity is given by Shannon's Law. The actual channel
capacity is determined by the bandwidth, the coding system used, capacity is determined by the bandwidth, the coding system used,
and the signal-to-noise ratio. and the signal-to-noise ratio.
$ CHAP $ CHAP
(I) See: Challenge Handshake Authentication Protocol. (I) See: Challenge Handshake Authentication Protocol.
$ checksum $ checksum
(I) A value that (a) is computed by a function that is dependent (I) A value that (a) is computed by a function that is dependent
on the contents of a data object and (b) is stored or transmitted on the contents of a data object and (b) is stored or transmitted
together with the object, for the purpose of detecting changes in together with the object, for the purpose of detecting changes in
the data. (See: cyclic redundancy check, data integrity service, the data. (See: cyclic redundancy check, data integrity service,
error detection code, hash, keyed hash, protected checksum.) error detection code, hash, keyed hash, parity bit, protected
checksum.)
Tutorial: To gain confidence that a data object has not been Tutorial: To gain confidence that a data object has not been
changed, an entity that later uses the data can compute a checksum changed, an entity that later uses the data can independently
value and compare it with the value that was stored or transmitted recompute the checksum value and compare the result with the value
with the object. that was stored or transmitted with the object.
Computer systems and networks use checksums (and other mechanisms) Computer systems and networks use checksums (and other mechanisms)
to detect accidental changes in data. However, active wiretapping to detect accidental changes in data. However, active wiretapping
that changes data could also change an accompanying checksum to that changes data could also change an accompanying checksum to
match the changed data. Thus, some checksum functions by match the changed data. Thus, some checksum functions by
themselves are not good countermeasures for active attacks. To themselves are not good countermeasures for active attacks. To
protect against active attacks, the checksum function needs to be protect against active attacks, the checksum function needs to be
well-chosen (see: cryptographic hash), and the checksum result well-chosen (see: cryptographic hash), and the checksum result
needs to be cryptographically protected (see: digital signature, needs to be cryptographically protected (see: digital signature,
keyed hash). keyed hash).
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1. (I) /noun/ Data that has been transformed by encryption so that 1. (I) /noun/ Data that has been transformed by encryption so that
its semantic information content (i.e., its meaning) is no longer its semantic information content (i.e., its meaning) is no longer
intelligible or directly available. (See: ciphertext. Compare: intelligible or directly available. (See: ciphertext. Compare:
clear text, plain text.) clear text, plain text.)
2. (O) "Data produced through the use of encipherment. The 2. (O) "Data produced through the use of encipherment. The
semantic content of the resulting data is not available." [I7498 semantic content of the resulting data is not available." [I7498
Part 2] Part 2]
$ ciphertext $ ciphertext
1a. (I) /adjective/ Referring to cipher text. (See: cipher text.) 1. (I) /adjective/ Referring to cipher text. (See: cipher text,
1b. (D) /noun/ A synonym for cipher text. (See: cleartext, Compare: cleartext, plaintext.)
plaintext.)
Deprecated Usage: To avoid ambiguity, ISDs SHOULD differentiate 2. (D) /noun/ A synonym for cipher text.
between the noun phrase "cipher text" and the adjective
"ciphertext". Deprecated Usage: ISDs should not use this term as a synonym for
cipher text. ISDs SHOULD distinguish between the adjective
"ciphertext" and the noun phrase "cipher text".
$ ciphertext auto-key (CTAK) $ ciphertext auto-key (CTAK)
(D) "Cryptographic logic that uses previous cipher text to (D) "Cryptographic logic that uses previous cipher text to
generate a key stream." [C4009, A1523] (See: KAK.) generate a key stream." [C4009, A1523] (See: KAK.)
Deprecated Term: IDS should not use this term; it is neither well- Deprecated Term: IDS SHOULD NOT use this term; it is neither well-
known nor precisely defined. Instead, use terms associated with known nor precisely defined. Instead, use terms associated with
modes that are defined in standards, such as CBC, CFB, and OFB. modes that are defined in standards, such as CBC, CFB, and OFB.
$ ciphertext-only attack $ ciphertext-only attack
(I) A cryptanalysis technique in which the analyst tries to (I) A cryptanalysis technique in which the analyst tries to
determine the key solely from knowledge of intercepted cipher text determine the key solely from knowledge of intercepted cipher text
(although the analyst may also know other clues, such as the (although the analyst may also know other clues, such as the
cryptographic algorithm, the language in which the plain text was cryptographic algorithm, the language in which the plain text was
written, the subject matter of the plain text, and some probable written, the subject matter of the plain text, and some probable
plaintext words.) plaintext words.)
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$ CKL $ CKL
(I) See: compromised key list. (I) See: compromised key list.
$ Clark-Wilson model $ Clark-Wilson model
(N) A security model [Clark] to maintain data integrity in the (N) A security model [Clark] to maintain data integrity in the
commercial world. (Compare: Bell-LaPadula model.) commercial world. (Compare: Bell-LaPadula model.)
$ class 2, 3, 4, 5 $ class 2, 3, 4, 5
(O) /U.S. DoD/ Assurance levels for PKIs, and for X.509 public-key (O) /U.S. DoD/ Assurance levels for PKIs, and for X.509 public-key
certificates issued by a PKI. [DoD3] (See: (first law under) certificates issued by a PKI. [DoD3] (See: "first law" under
Courtney's laws.) "Courtney's laws".)
- "Class 2": Intended for applications handling unclassified, - "Class 2": Intended for applications handling unclassified,
low-value data in minimally or moderately protected low-value data in minimally or moderately protected
environments. environments.
- "Class 3": Intended for applications handling unclassified, - "Class 3": Intended for applications handling unclassified,
medium-value data in moderately protected environments, or medium-value data in moderately protected environments, or
handling unclassified or high-value data in highly protected handling unclassified or high-value data in highly protected
environments, and for discretionary access control of environments, and for discretionary access control of
classified data in highly protected environments. classified data in highly protected environments.
- "Class 4": Intended for applications handling unclassified, - "Class 4": Intended for applications handling unclassified,
high-value data in minimally protected environments. high-value data in minimally protected environments.
- "Class 5": Intended for applications handling classified data - "Class 5": Intended for applications handling classified data
in minimally protected environments, and for authentication of in minimally protected environments, and for authentication of
material that would affect the security of classified systems. material that would affect the security of classified systems.
The environments are defined as follows: The environments are defined as follows:
- "Highly protected environment": Networks that are protected - "Highly protected environment": Networks that are protected
either with encryption devices approved by NSA for protection either with encryption devices approved by NSA for protection
of classified data or via physical isolation, and that are of classified data or via physical isolation, and that are
certified for processing system-high classified data, where certified for processing system-high classified data, where
exposure of unencrypted data is limited to U.S. citizens exposure of unencrypted data is limited to U.S. citizens
holding appropriate security clearances. holding appropriate security clearances.
- "Moderately protected environment": - "Moderately protected environment":
-- Physically isolated unclassified, unencrypted networks in -- Physically isolated unclassified, unencrypted networks in
which access is restricted based on legitimate need. which access is restricted based on legitimate need.
-- Networks protected by NSA-approved, type 1 encryption, -- Networks protected by NSA-approved, type 1 encryption,
accessible by U.S.-authorized foreign nationals. accessible by U.S.-authorized foreign nationals.
- "Minimally protected environments": Unencrypted networks - "Minimally protected environments": Unencrypted networks
connected to either the Internet or NIPRNET, either directly or connected to either the Internet or NIPRNET, either directly or
via a firewall. via a firewall.
$ Class D computer system $ Class A1, B3, B2, B1, C2, or C1 computer system
(O) See: TCSEC. (O) /TCSEC/ See: Tutorial under "Trusted Computer System
Evaluation Criteria".
$ classification $ classification
(I) A grouping of classified information to which a hierarchical, 1. (I) A grouping of classified information to which a
restrictive security label is applied to increase protection of hierarchical, restrictive security label is applied to increase
the data from unauthorized disclosure. (See: classified, data protection of the data from unauthorized disclosure. (See:
confidentiality service. Compare: compartment.) aggregation, classified, data confidentiality service. Compare:
compartment.)
2. (I) An authorized process by which information is determined to
be classified and assigned to a security level. (See:
declassification.)
Usage: Usually understood to involve data confidentiality, but Usage: Usually understood to involve data confidentiality, but
ISDs SHOULD make this clear when data also is sensitive in other ISDs SHOULD make this clear when data also is sensitive in other
ways and SHOULD use other terms for those other sensitivity ways and SHOULD use other terms for those other sensitivity
concepts. (See: sensitive information, data integrity.) concepts. (See: sensitive information, data integrity.)
$ classification label $ classification label
(I) A security label that tells the degree of harm that will (I) A security label that tells the degree of harm that will
result from unauthorized disclosure of the labeled data, and may result from unauthorized disclosure of the labeled data, and may
also tell what countermeasures are required to be applied to also tell what countermeasures are required to be applied to
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Usage: Usually understood to involve data confidentiality, but Usage: Usually understood to involve data confidentiality, but
ISDs SHOULD make this clear when data also is sensitive in other ISDs SHOULD make this clear when data also is sensitive in other
ways and SHOULD use other terms for those other sensitivity ways and SHOULD use other terms for those other sensitivity
concepts. (See: sensitive information, data integrity.) concepts. (See: sensitive information, data integrity.)
$ classified $ classified
1. (I) Refers to information (stored or conveyed, in any form) 1. (I) Refers to information (stored or conveyed, in any form)
that is formally required by a security policy to receive data that is formally required by a security policy to receive data
confidentiality service and to be marked with a security label confidentiality service and to be marked with a security label
(which in some cases might be implicit) to indicate its protected (which in some cases might be implicit) to indicate its protected
status. (See: classification, classification level. Compare: status. (See: classify, security level. Compare: unclassified.)
unclassified.)
Usage: Usually understood to involve data confidentiality, but Usage: Usually understood to involve data confidentiality, but
ISDs SHOULD make this clear when data also is sensitive in other ISDs SHOULD make this clear when data also is sensitive in other
ways and SHOULD use other terms for those other sensitivity ways and SHOULD use other terms for those other sensitivity
concepts. (See: sensitive information, data integrity.) concepts. (See: sensitive information, data integrity.)
Tutorial: The term is mainly used in government, especially in the Tutorial: The term is mainly used in government, especially in the
military, but the underlying concept also applies outside military, but the underlying concept also applies outside
government. government.
2. (O) /U.S. DoD/ Information that has been determined pursuant to 2. (O) /U.S. DoD/ Information that has been determined pursuant to
Executive Order 12958 ("Classified National Security Information", Executive Order 12958 ("Classified National Security Information",
20 April 1995) or any predecessor order to require protection 20 April 1995) or any predecessor order to require protection
against unauthorized disclosure and is marked to indicate its against unauthorized disclosure and is marked to indicate its
classified status when in documentary form. classified status when in documentary form.
$ classify
(I) To officially designate an information item or type of
information as being classified and assigned to a specific
security level. (See: classified, declassify, security level.)
$ clean system $ clean system
(I) A computer system in which the operating system and (I) A computer system in which the operating system and
application system software and files have been freshly installed application system software and files have been freshly installed
from trusted software distribution media. (Compare: secure state.) from trusted software distribution media. (Compare: secure state.)
$ clear $ clear
(D) /verb/ Synonym for "erase". [C4009] (D) /verb/ Synonym for "erase". [C4009]
Deprecated Definition: ISDs SHOULD NOT use the term with this Deprecated Definition: ISDs SHOULD NOT use the term with this
definition; it could be confused with "clear text" in which definition; it could be confused with "clear text" in which
information is directly recoverable. information is directly recoverable.
$ clear text $ clear text
1. (I) /noun/ Data in which the semantic information content 1. (I) /noun/ Data in which the semantic information content
(i.e., the meaning) is intelligible or is directly available, (i.e., the meaning) is intelligible or is directly available,
i.e., not encrypted. (Compare: cipher text, plain text. See: i.e., not encrypted. (See: cleartext, in the clear. Compare:
cleartext, in the clear.) cipher text, plain text.)
2. (O) "Intelligible data, the semantic content of which is 2. (O) "Intelligible data, the semantic content of which is
available." [I7498 Part 2] available." [I7498 Part 2]
3. (D) Synonym for "plain text". 3. (D) Synonym for "plain text".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "plain text", because the plain text that is input to an for "plain text", because the plain text that is input to an
encryption process may itself be cipher text that was output from encryption process may itself be cipher text that was output from
an encryption. (See: superencryption.) an encryption. (See: superencryption.)
$ clearance $ clearance
See: security clearance. See: security clearance.
$ clearance level $ clearance level
(I) The security level of information to which a security (I) The security level of information to which a security
clearance authorizes a person to have access. clearance authorizes a person to have access.
$ cleartext $ cleartext
1a. (I) /adjective/ Referring to clear text. (Compare: ciphertext, 1. (I) /adjective/ Referring to clear text. (See: clear text.
plaintext. See: clear text.) Compare: ciphertext, plaintext.)
Usage: To avoid ambiguity, ISDs SHOULD distinguish between the 2. (D) /noun/ A synonym for clear text.
adjective "cleartext" and the noun phrase "clear text".
Deprecated Usage: ISDs should not use this term as a synonym for
clear text. ISDs SHOULD distinguish between the adjective
"cleartext" and the noun phrase "clear text".
$ CLEF $ CLEF
(N) See: commercially licensed evaluation facility. (N) See: commercially licensed evaluation facility.
$ client $ client
(I) A system entity that requests and uses a service provided by (I) A system entity that requests and uses a service provided by
another system entity, called a "server". (See: server.) another system entity, called a "server". (See: server.)
Tutorial: Usually, the requesting entity is a computer process, Tutorial: Usually, it is understood that the client and server are
and it makes the request on behalf of a human user. In some cases, automated components of the system, and the client makes the
the server may itself be a client of some other server. request on behalf of a human user. In some cases, the server may
itself be a client of some other server.
$ client-server system $ client-server system
(I) A distributed system in which one or more entities, called (I) A distributed system in which one or more entities, called
clients, request a specific service from one or more other clients, request a specific service from one or more other
entities, called servers, that provide the service to the clients. entities, called servers, that provide the service to the clients.
Example: The Word Wide Web, in which servers provided information Example: The Word Wide Web, in which component servers provide
that is requested by clients called browsers. information that is requested by component clients called
"browsers".
$ CLIPPER $ CLIPPER
(N) An integrated microcircuit (in MYK-7x series manufactured by (N) An integrated microcircuit (in MYK-7x series manufactured by
Mykotronx, Inc.) that implements SKIPJACK, has non-deterministic Mykotronx, Inc.) that implements SKIPJACK, has non-deterministic
random number generator, and supports key escrow. (See: Escrowed random number generator, and supports key escrow. (See: Escrowed
Encryption Standard. Compare: CLIPPER.) Encryption Standard. Compare: CLIPPER.)
Tutorial: The chip was mainly intended for protecting Tutorial: The chip was mainly intended for protecting
telecommunications over the public switched network. The key telecommunications over the public switched network. The key
escrow scheme for the chip involves a SKIPJACK key that is common escrow scheme for the chip involves a SKIPJACK key that is common
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Department. Department.
$ closed security environment $ closed security environment
(O) /U.S. DoD/ A system environment that meets both of the (O) /U.S. DoD/ A system environment that meets both of the
following conditions: (a) Application developers (including following conditions: (a) Application developers (including
maintainers) have sufficient clearances and authorizations to maintainers) have sufficient clearances and authorizations to
provide an acceptable presumption that they have not introduced provide an acceptable presumption that they have not introduced
malicious logic. (b) Configuration control provides sufficient malicious logic. (b) Configuration control provides sufficient
assurance that system applications and the equipment they run on assurance that system applications and the equipment they run on
are protected against the introduction of malicious logic prior to are protected against the introduction of malicious logic prior to
and during the operation of applications. [NCS04] (See: (first law and during the operation of applications. [NCS04] (See: "first
under) Courtney's laws. Compare: open security environment.) law" under "Courtney's laws". Compare: open security environment.)
$ CMA $ CMA
(D) See: certificate management authority. (D) See: certificate management authority.
$ CMCS $ CMCS
(O) See: COMSEC Material Control System. (O) See: COMSEC Material Control System.
$ CMM $ CMM
(N) See: Capability Maturity Model. (N) See: Capability Maturity Model.
$ CMS $ CMS
(I) See: Cryptographic Message Syntax. (I) See: Cryptographic Message Syntax.
$ code $ code
1. (I) A system of symbols used to represent information, which 1. (I) A system of symbols used to represent information, which
might originally have some other representation. Examples: ASCII, might originally have some other representation. Examples: ASCII,
BER, country code, Morse code. (See: encode, object code, source BER, country code, Morse code. (See: encode, object code, source
code.) code.)
Deprecated usage: To avoid confusion with definition 1, ISDs Deprecated Abbreviation: To avoid confusion with definition 1,
SHOULD NOT use "code" as an abbreviation for "country code", ISDs SHOULD NOT use "code" as an abbreviation of "country code",
"cyclic redundancy code", "Data Authentication Code", "error "cyclic redundancy code", "Data Authentication Code", "error
detection code", or "Message Authentication Code". To avoid detection code", or "Message Authentication Code". To avoid
misunderstanding, use the fully qualified term in these other misunderstanding, use the fully qualified term in these other
cases, at least at the point of first usage. cases, at least at the point of first usage.
2. (I) /cryptography / An encryption algorithm based on 2. (I) /cryptography/ An encryption algorithm based on
substitution; i.e., a system for providing data confidentiality by substitution; i.e., a system for providing data confidentiality by
using arbitrary groups (called "code groups") of letters, numbers, using arbitrary groups (called "code groups") of letters, numbers,
or symbols to represent units of plain text of varying length. or symbols to represent units of plain text of varying length.
(See: codebook, cryptography.) (See: codebook, cryptography.)
Deprecated Usage: To avoid confusion with definition 1, ISDs Deprecated Usage: To avoid confusion with definition 1, ISDs
SHOULD NOT use "code" as synonym for (a) "cipher", "hash", or SHOULD NOT use "code" as synonym for any of the following terms:
other words that mean "a cryptographic algorithm"; (b) "cipher (a) "cipher", "hash", or other words that mean "a cryptographic
text"; or (c) "encrypt", "hash", or other words that refer to algorithm"; (b) "cipher text"; or (c) "encrypt", "hash", or other
applying a cryptographic algorithm. words that refer to applying a cryptographic algorithm.
3. (I) An algorithm based on substitution, but used to shorten 3. (I) An algorithm based on substitution, but used to shorten
messages rather than to conceal their content. messages rather than to conceal their content.
4. (I) /computer programming/ To write computer software. (See: 4. (I) /computer programming/ To write computer software. (See:
object code, source code.) object code, source code.)
Deprecated Usage: To avoid confusion with definition 1, ISDs
SHOULD NOT use "code" as an abbreviation for "object code" or Deprecated Abbreviation: To avoid confusion with definition 1,
ISDs SHOULD NOT use "code" as an abbreviation of "object code" or
"source code". To avoid misunderstanding, use the fully qualified "source code". To avoid misunderstanding, use the fully qualified
term in these other cases, at least at the point of first usage. term in these other cases, at least at the point of first usage.
$ code book $ code book
1. (I) Document containing a systematically arranged list of 1. (I) Document containing a systematically arranged list of
plaintext units and their ciphertext equivalents. [C4009] plaintext units and their ciphertext equivalents. [C4009]
2. (I) An encryption algorithm that uses a word substitution 2. (I) An encryption algorithm that uses a word substitution
technique. [C4009] (See: code, ECB.) technique. [C4009] (See: code, ECB.)
$ code signing $ code signing
(I) A security mechanism that uses a digital signature to provide (I) A security mechanism that uses a digital signature to provide
data origin authentication for software that is being distributed data origin authentication for software that is being distributed
for use. (See: mobile code, trusted distribution.) for use. (See: mobile code, trusted distribution.)
$ COI $ COI
(I) See: community of interest. (I) See: community of interest.
$ cold start $ cold start
(N) /cryptographic module/ A procedure for initially keying (N) /cryptographic module/ A procedure for initially keying
cryptographic equipment. [C4009] cryptographic equipment. [C4009]
$ color change $ color change
(I) In a system being operated in periods processing mode, the act (I) In a system being operated in periods processing mode, the act
of purging all information from one processing period and then of purging all information from one processing period and then
changing over to the next processing period. (See: BLACK, RED.) changing over to the next processing period. (See: BLACK, RED.)
$ Commercial COMSEC Endorsement Program (CCEP) $ Commercial COMSEC Endorsement Program (CCEP)
(N) "Relationship between NSA and industry in which NSA provides (O) "Relationship between NSA and industry in which NSA provides
the COMSEC expertise (i.e., standards, algorithms, evaluations, the COMSEC expertise (i.e., standards, algorithms, evaluations,
and guidance) and industry provides design, development, and and guidance) and industry provides design, development, and
production capabilities to produce a type 1 or type 2 product." production capabilities to produce a type 1 or type 2 product."
[C4009] [C4009]
$ commercially licensed evaluation facility (CLEF) $ commercially licensed evaluation facility (CLEF)
(N) An organization that has official approval to evaluate the (N) An organization that has official approval to evaluate the
security of products and systems in accordance with the Common security of products and systems in accordance with the Common
Criteria, ITSEC, or some other standard. Criteria, ITSEC, or some other standard.
$ Committee on National Security Systems (CNSS)
(O) A U.S. Government, interagency, standing committee of the
President's Critical Infrastructure Protection Board. The CNSS is
chaired by the Secretary of Defense and provides a forum for the
discussion of policy issues, sets national policy, and promulgates
direction, operational procedures, and guidance for the security
of national security systems. The Secretary of Defense and the
Director of Central Intelligence are responsible for developing
and overseeing the implementation of Government-wide policies,
principles, standards, and guidelines for the security of systems
that handle national security information.
$ Common Criteria for Information Technology Security $ Common Criteria for Information Technology Security
(N) A standard for evaluating information technology (IT) products (N) A standard for evaluating information technology (IT) products
and systems. It states requirements for security functions and for and systems. It states requirements for security functions and for
assurance measures. [CCIB] (See: CLEF, EAL, packages, protection assurance measures. [CCIB] (See: CLEF, EAL, packages, protection
profile, security target, TOE. Compare: CMM.) profile, security target, TOE. Compare: CMM.)
Tutorial: Canada, France, Germany, the Netherlands, the United Tutorial: Canada, France, Germany, the Netherlands, the United
Kingdom, and the United States (NIST and NSA) began developing Kingdom, and the United States (NIST and NSA) began developing
this standard in 1993, based on the European ITSEC, the Canadian this standard in 1993, based on the European ITSEC, the Canadian
Trusted Computer Product Evaluation Criteria (CTCPEC), and the Trusted Computer Product Evaluation Criteria (CTCPEC), and the
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cryptographic algorithms. cryptographic algorithms.
Part 1, Introduction and General Model, defines general concepts Part 1, Introduction and General Model, defines general concepts
and principles of IT security evaluation; presents a general model and principles of IT security evaluation; presents a general model
of evaluation; and defines constructs for expressing IT security of evaluation; and defines constructs for expressing IT security
objectives, for selecting and defining IT security requirements, objectives, for selecting and defining IT security requirements,
and for writing high-level specifications for products and and for writing high-level specifications for products and
systems. systems.
Part 2, Security Functional Requirements, contains a catalog of Part 2, Security Functional Requirements, contains a catalog of
well-defined and understood security functional requirements that well-defined and well-understood functional requirement statements
are intended to be used as a standard way of expressing the that are intended to be used as a standard way of expressing the
security requirements for IT products and systems. security requirements for IT products and systems.
Part 3, Security Assurance Requirements, contains a catalog of Part 3, Security Assurance Requirements, contains a catalog of
assurance components for use as a standard way of expressing the assurance components for use as a standard way of expressing the
such requirements for IT products and systems, and defines such requirements for IT products and systems, and defines
evaluation criteria for protection profiles and security targets. evaluation criteria for protection profiles and security targets.
$ Common IP Security Option (CIPSO) $ Common IP Security Option (CIPSO)
(I) See: (secondary definition under) IPSO. (I) See: secondary definition under "IPSO".
$ common name $ common name
(N) A character string that (a) may be a part of the X.500 DN of a (N) A character string that (a) may be a part of the X.500 DN of a
Directory object ("commonName" attribute), (b) is a (possibly Directory object ("commonName" attribute), (b) is a (possibly
ambiguous) name by which the object is commonly known in some ambiguous) name by which the object is commonly known in some
limited scope (such as an organization), and (c) conforms to the limited scope (such as an organization), and (c) conforms to the
naming conventions of the country or culture with which it is naming conventions of the country or culture with which it is
associated. [X520] (See: ("subject" and "issuer" under) X.509 associated. [X520] (See: "subject" and "issuer" under "X.509
public-key certificate.) public-key certificate".)
Examples: "Dr. Albert Einstein", "The United Nations", and "12-th Examples: "Dr. Albert Einstein", "The United Nations", and "12-th
Floor Laser Printer". Floor Laser Printer".
$ communications cover $ communications cover
(N) "Concealing or altering of characteristic communications (N) "Concealing or altering of characteristic communications
patterns to hide information that could be of value to an patterns to hide information that could be of value to an
adversary." [C4009] (See: operations security, traffic-flow adversary." [C4009] (See: operations security, traffic-flow
confidentiality, TRANSEC.) confidentiality, TRANSEC.)
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$ community of interest (COI) $ community of interest (COI)
1. (I) A set of entities that operate under a common security 1. (I) A set of entities that operate under a common security
policy. (Compare: domain.) policy. (Compare: domain.)
2. (O) /U.S. DoD/ "A collaborative group of users who exchange 2. (O) /U.S. DoD/ "A collaborative group of users who exchange
information in support of shared missions, business processes, and information in support of shared missions, business processes, and
objectives." objectives."
$ community risk $ community risk
(O) Probability that a particular vulnerability will be exploited (N) Probability that a particular vulnerability will be exploited
within an interacting population and adversely affect some members within an interacting population and adversely affect some members
of that population. [C4009] of that population. [C4009] (See: Morris worm.)
$ community string $ community string
(I) A community name in the form of an octet string that serves as (I) A community name in the form of an octet string that serves as
a cleartext password in SNMP version 1. [R1157] a cleartext password in SNMP version 1. (RFC 1157)
$ compartment $ compartment
(I) A grouping of sensitive information items that require special 1. (I) A grouping of sensitive information items that require
access controls beyond those normally provided for the basic special access controls beyond those normally provided for the
classification level of the information. (See: category.) basic classification level of the information. (See: compartmented
security mode. Compare: category, classification.)
Usage: The term is usually understood to include the special Usage: The term is usually understood to include the special
handling procedures to be used for the information. handling procedures to be used for the information.
2. (I) Synonym for "category".
Deprecated Usage: This Glossary defines "category" with a slightly
narrower meaning than "compartment". That is, a security label is
assigned to a category because the data owner needs to handle the
data as compartment. However, a compartment could receive special
protection in a system without being assigned a category label.
$ compartmented security mode
(N) A mode of system operation wherein all users having access to
the system have the necessary security clearance for the single,
hierarchical classification level of all data handled by the
system, but some users do not have the clearance for a non-
hierarchical category of some data handled by the system. (See:
category, /system operation/ under "mode", protection level,
security clearance.)
Usage: Usually abbreviated as "compartmented mode". This term was
defined in U.S. Government policy on system accreditation. In this
mode a system may hand (a) a single hierarchical classification
level and (b) multiple non-hierarchical categories within that
level.
$ Compartments field $ Compartments field
(I) A 16-bit field (the "C field") that specifies compartment (I) A 16-bit field (the "C field") that specifies compartment
values in the security option (option type 130) of version 4 IP's values in the security option (option type 130) of version 4 IP's
datagram header format. The valid field values are assigned by the datagram header format. The valid field values are assigned by the
U.S. Government, as specified in RFC 791. U.S. Government, as specified in RFC 791.
Deprecated Definition: ISDs SHOULD NOT use the abbreviation "C Deprecated Abbreviation: ISDs SHOULD NOT use the abbreviation "C
field"; the abbreviation is potentially ambiguous. Instead, use field"; the abbreviation is potentially ambiguous. Instead, use
"Compartments field". "Compartments field".
$ component $ component
See: system component. See: system component.
$ compression $ compression
(I) A process that encodes information in a way that minimizes the (I) A process that encodes information in a way that minimizes the
number of resulting code symbols and thus reduces storage space or number of resulting code symbols and thus reduces storage space or
transmission time. transmission time.
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before the encryption operation. before the encryption operation.
$ compromise $ compromise
See: data compromise, security compromise. See: data compromise, security compromise.
$ compromise recovery $ compromise recovery
(I) The process of regaining a secure state for a system after (I) The process of regaining a secure state for a system after
detecting that the system has experienced a security compromise. detecting that the system has experienced a security compromise.
$ compromised key list (CKL) $ compromised key list (CKL)
(O) /MISSI/ A list that identifies keys for which unauthorized (N) /MISSI/ A list that identifies keys for which unauthorized
disclosure or alteration may have occurred. (See: compromise.) disclosure or alteration may have occurred. (See: compromise.)
Tutorial: A CKL is issued by an CA, like a CRL is issued. But a Tutorial: A CKL is issued by an CA, like a CRL is issued. But a
CKL lists only KMIDs, not subjects that hold the keys, and not CKL lists only KMIDs, not subjects that hold the keys, and not
certificates in which the keys are bound. certificates in which the keys are bound.
$ COMPUSEC $ COMPUSEC
(I) See: computer security. (I) See: computer security.
$ computer system
(I) A synonym for "information system", or a component thereof.
(Compare: computer platform.)
$ computer emergency response team (CERT) $ computer emergency response team (CERT)
(I) An organization that studies computer and network INFOSEC in (I) An organization that studies computer and network INFOSEC in
order to provide incident response services to victims of attacks, order to provide incident response services to victims of attacks,
publish alerts concerning vulnerabilities and threats, and offer publish alerts concerning vulnerabilities and threats, and offer
other information to help improve computer and network security. other information to help improve computer and network security.
(See: CSIRT, security incident.) (See: CSIRT, security incident.)
Examples: CERT Coordination Center at Carnegie-Mellon University Examples: CERT Coordination Center at Carnegie-Mellon University
(sometimes called "the" CERT); CIAC. (sometimes called "the" CERT); CIAC.
$ Computer Incident Advisory Capability (CIAC) $ Computer Incident Advisory Capability (CIAC)
(O) The centralized CSIRT of the U.S Department of Energy; a (O) The centralized CSIRT of the U.S Department of Energy; a
member of FIRST. member of FIRST.
$ computer network $ computer network
(I) A collection of host computers together with the subnetwork or (I) A collection of host computers together with the subnetwork or
internetwork through which they can exchange data. internetwork through which they can exchange data.
Usage: This definition is intended to cover systems of all sizes Usage: This definition is intended to cover systems of all sizes
and types, ranging from the complex Internet to a simple system and types, ranging from the complex Internet to a simple system
composed of a personal computer dialing in as a remote terminal of composed of a personal computer dialing in as a remote terminal of
another computer. another computer.
$ computer platform $ computer platform
(I) A combination of computer hardware and an operating system (I) A combination of computer hardware and an operating system
(which may consist of software, firmware, or both) for that (which may consist of software, firmware, or both) for that
hardware. hardware. (Compare: computer system.)
$ computer security (COMPUSEC) $ computer security (COMPUSEC)
(I) Measures to implement and assure security services in a (I) Measures to implement and assure security services in a
computer system, particularly those that assure access control computer system, particularly those that assure access control
service. service.
Usage: Usually refers to internal controls (functions, features, Usage: Usually refers to internal controls (functions, features,
and technical characteristics) that are implemented in software and technical characteristics) that are implemented in software
(especially in operating systems); sometimes refers to internal (especially in operating systems); sometimes refers to internal
controls implemented in hardware; rarely used to refer to external controls implemented in hardware; rarely used to refer to external
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Security Foundation chartered by the U.S. Government) have not Security Foundation chartered by the U.S. Government) have not
been implemented at all, and others (e.g., codifying Generally been implemented at all, and others (e.g., codifying Generally
Accepted System Security Principles similar to accounting Accepted System Security Principles similar to accounting
principles) have been implemented but not widely adopted [SP14, principles) have been implemented but not widely adopted [SP14,
SP27]. SP27].
$ COMSEC $ COMSEC
(I) See: communication security. (I) See: communication security.
$ COMSEC account $ COMSEC account
(N) /U.S. Government/ "Administrative entity, identified by an (O) /U.S. Government/ "Administrative entity, identified by an
account number, used to maintain accountability, custody, and account number, used to maintain accountability, custody, and
control of COMSEC material." [C4009] (See: COMSEC custodian.) control of COMSEC material." [C4009] (See: COMSEC custodian.)
$ COMSEC accounting $ COMSEC accounting
(I) /U.S. Government/ The process of creating, collecting, and (I) /U.S. Government/ The process of creating, collecting, and
maintaining data records that describe the status and custody of maintaining data records that describe the status and custody of
designated items of COMSEC material. (See: accounting legend designated items of COMSEC material. (See: accounting legend
code.) code.)
Tutorial: Almost any secure information system needs to record a Tutorial: Almost any secure information system needs to record a
security audit trail, but a system that manages COMSEC material security audit trail, but a system that manages COMSEC material
needs to record additional data about the status and custody of needs to record additional data about the status and custody of
COMSEC items. COMSEC items.
- COMSEC tracking: The process of automatically collecting, - COMSEC tracking: The process of automatically collecting,
recording, and managing information that describes the status recording, and managing information that describes the status
of designated items of COMSEC material at all times during each of designated items of COMSEC material at all times during each
product~Os lifecycle. product's lifecycle.
- COMSEC controlling: The process of supplementing tracking data - COMSEC controlling: The process of supplementing tracking data
with custody data, which consists of explicit acknowledgements with custody data, which consists of explicit acknowledgements
of system entities that they (a) have received specific COMSEC of system entities that they (a) have received specific COMSEC
items and (b) are responsible for preventing exposure of those items and (b) are responsible for preventing exposure of those
items. items.
For example, a key management system that serves a large customer For example, a key management system that serves a large customer
base needs to record tracking data for the same reasons that a base needs to record tracking data for the same reasons that a
national parcel delivery system does, i.e., to answer the question national parcel delivery system does, i.e., to answer the question
"Where is that thing now?". If keys are encrypted immediately upon "Where is that thing now?". If keys are encrypted immediately upon
generation and handled only in BLACK form between the point of generation and handled only in BLACK form between the point of
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controlling is retained indefinitely to ensure accountability and controlling is retained indefinitely to ensure accountability and
support compromise recovery. support compromise recovery.
$ COMSEC boundary $ COMSEC boundary
(N) "Definable perimeter encompassing all hardware, firmware, and (N) "Definable perimeter encompassing all hardware, firmware, and
software components performing critical COMSEC functions, such as software components performing critical COMSEC functions, such as
key generation and key handling and storage." [C4009] [Compare: key generation and key handling and storage." [C4009] [Compare:
cryptographic boundary.] cryptographic boundary.]
$ COMSEC custodian $ COMSEC custodian
(N) /U.S. Government/ "Individual designated by proper authority (O) /U.S. Government/ "Individual designated by proper authority
to be responsible for the receipt, transfer, accounting, to be responsible for the receipt, transfer, accounting,
safeguarding, and destruction of COMSEC material assigned to a safeguarding, and destruction of COMSEC material assigned to a
COMSEC account." [C4009] COMSEC account." [C4009]
$ COMSEC material $ COMSEC material
(N) /U.S. Government/ "Item designed to secure or authenticate (N) /U.S. Government/ "Item designed to secure or authenticate
communications. [It] includes but is not limited to key, communications. [It] includes but is not limited to key,
equipment, devices, documents, firmware, or software that embodies equipment, devices, documents, firmware, or software that embodies
or describes cryptographic logic and other items that perform or describes cryptographic logic and other items that perform
COMSEC functions." [C4009] (Compare: keying material.) COMSEC functions." [C4009] (Compare: keying material.)
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which COMSEC material marked 'CRYPTO' is distributed, controlled, which COMSEC material marked 'CRYPTO' is distributed, controlled,
and safeguarded." [C4009] (See: COMSEC account, COMSEC custodian.) and safeguarded." [C4009] (See: COMSEC account, COMSEC custodian.)
$ confidentiality $ confidentiality
See: data confidentiality. See: data confidentiality.
$ configuration control $ configuration control
(I) The process of regulating changes to hardware, firmware, (I) The process of regulating changes to hardware, firmware,
software, and documentation throughout the development and software, and documentation throughout the development and
operational life of a system. (See: administrative security, operational life of a system. (See: administrative security,
trusted distribution.) harden, trusted distribution.)
Tutorial: Configuration control helps protect against unauthorized Tutorial: Configuration control helps protect against unauthorized
or malicious alteration of a system and thus provides assurance of or malicious alteration of a system and thus provides assurance of
system integrity. (See: malicious logic.) system integrity. (See: malicious logic.)
$ confinement property $ confinement property
(N) /formal model/ Property of a system whereby a subject has (N) /formal model/ Property of a system whereby a subject has
write access to an object only if the classification of the object write access to an object only if the classification of the object
dominates the clearance of the subject. (See: *-property, Bell- dominates the clearance of the subject. (See: *-property, Bell-
LaPadula model.) LaPadula model.)
$ connectionless data integrity service $ connectionless integrity service
(I) A security service that provides data integrity service for an (I) Synonym for "datagram integrity service".
individual IP datagram, by detecting modification of the datagram,
without regard to the ordering of the datagram in a stream of
datagrams.
Tutorial: In contrast, a connection-oriented data integrity
service usually would be able to detect lost or reordered
datagrams within a stream of datagrams.
$ constraint $ constraint
(I) /access control/ A limitation on the function of an identity, (I) /access control/ A limitation on the function of an identity,
role, or privilege. (See: rule-based access control.) role, or privilege. (See: rule-based access control.)
Tutorial: In effect, a constraint is a form of security policy and Tutorial: In effect, a constraint is a form of security policy and
may be either static or dynamic: may be either static or dynamic:
- "Static constraint": A constraint that must be satisfied at the - "Static constraint": A constraint that must be satisfied at the
time the policy is defined, and then continues to be satisfied time the policy is defined, and then continues to be satisfied
until the constraint is removed. until the constraint is removed.
- "Dynamic constraint": A constraint that may be defined to apply - "Dynamic constraint": A constraint that may be defined to apply
at various times that the identity, role, or other object of at various times that the identity, role, or other object of
the constraint is active in the system. the constraint is active in the system.
$ content filter $ content filter
(I) /World Wide Web/ Application software used to prevent access (I) /World Wide Web/ Application software used to prevent access
to certain Web servers, such as by parents who do not want their to certain Web servers, such as by parents who do not want their
children to access pornography. (See: filter, guard.) children to access pornography. (See: filter, guard.)
Tutorial: The filter is usually browser-based, but could be part Tutorial: The filter is usually browser-based, but could be part
of an intermediate cache server. The two basic content filtering of an intermediate cache server. The two basic content filtering
techniques are (a) to block a specified list of URLs and (b) to techniques are (a) to block a specified list of URLs and (b) to
block material that contains specified words and phrases. block material that contains specified words and phrases.
$ contingency plan $ contingency plan
(I) A plan for emergency response, backup operations, and post- (I) A plan for emergency response, backup operations, and post-
disaster recovery in a system as part of a security program to disaster recovery in a system as part of a security program to
ensure availability of critical system resources and facilitate ensure availability of critical system resources and facilitate
continuity of operations in a crisis. [NCS04] (See: availability.) continuity of operations in a crisis. [NCS04] (See: availability.)
$ controlled access protection $ controlled access protection
(N) The C2 level of criteria described in the TCSEC. (O) /TCSEC/ The level of evaluation criteria for a C2 computer
system.
Tutorial: The major features of the C2 level are individual Tutorial: The major features of the C2 level are individual
accountability, audit, access control, and object reuse. accountability, audit, access control, and object reuse.
$ controlled cryptographic item (CCI) $ controlled cryptographic item (CCI)
(O) /U.S. Government/ "Secure telecommunications or information (O) /U.S. Government/ "Secure telecommunications or information
handling equipment, or associated cryptographic component, that is handling equipment, or associated cryptographic component, that is
unclassified but governed by a special set of control unclassified but governed by a special set of control
requirements." [C4009] (Compare: EUCI.) requirements." [C4009] (Compare: EUCI.)
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CCI equipment uses a classified cryptographic logic, but the CCI equipment uses a classified cryptographic logic, but the
hardware or firmware embodiment of that logic is unclassified. hardware or firmware embodiment of that logic is unclassified.
Drawings, software implementations, and other descriptions of that Drawings, software implementations, and other descriptions of that
logic remain classified. [N4001] logic remain classified. [N4001]
$ controlled interface $ controlled interface
(I) A mechanism that facilitates the adjudication of the different (I) A mechanism that facilitates the adjudication of the different
security policies of interconnected systems. (See: domain, guard.) security policies of interconnected systems. (See: domain, guard.)
$ controlled security mode $ controlled security mode
(D) /U.S. DoD/ A mode of operation of an information system, (D) A mode of system operation wherein (a) two or more security
wherein at least some users with access to the system have neither levels of information are allowed to be handled concurrently
a security clearance nor need to know for all classified material within the same system when some users having access to the system
contained in the system. However, separation and control of users have neither a security clearance nor need-to-know for some of the
and classified material on the basis, respectively, of clearance data handled by the system, but (b) separation of the users and
and classification level are not essentially under operating the classified material on the basis, respectively, of clearance
system control like they are in multilevel security mode. [DoD2] and classification level are not dependent only on operating
system control (like they are in multilevel security mode). (See:
/system operation/ under "mode", protection level.)
Deprecated Term: ISDs SHOULD NOT use this term. It was defined in Deprecated Term: ISDs SHOULD NOT use this term. It was defined in
a version of U.S. DoD policy on system accreditation but was a Government policy regarding system accreditation but was
subsumed by "partitioned security mode" in a later version. subsumed by "partitioned security mode" in a later policy.
Tutorial: Controlled mode was intended to encourage ingenuity in Tutorial: Controlled mode was intended to encourage ingenuity in
meeting the security requirements of Defense policy in ways less meeting data confidentiality requirements in ways less restrictive
restrictive than "dedicated security mode" and "system high than "dedicated security mode" and "system-high security mode",
security mode", but at a level of risk lower than that generally but at a level of risk lower than that generally associated with
associated with the true "multilevel security mode". This was to the true "multilevel security mode". This was intended to be
be accomplished by implementation of explicit augmenting measures accomplished by implementation of explicit augmenting measures to
to reduce or remove a substantial measure of system software reduce or remove a substantial measure of system software
vulnerability together with specific limitation of the security vulnerability together with specific limitation of the security
clearance levels of users permitted concurrent access to the clearance levels of users having concurrent access to the system.
system.
$ controlling authority $ controlling authority
(O) /U.S. Government/ "Official responsible for directing the (O) /U.S. Government/ "Official responsible for directing the
operation of a cryptonet and for managing the operational use and operation of a cryptonet and for managing the operational use and
control of keying material assigned to the cryptonet." [C4009, control of keying material assigned to the cryptonet." [C4009,
N4006] N4006]
$ cookie $ cookie
1. (I) /HTTP/ Data exchanged between an HTTP server and a browser 1. (I) /HTTP/ Data exchanged between an HTTP server and a browser
(a client of the server) to store state information on the client (a client of the server) to store state information on the client
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may include a description of the range of URLs for which the state may include a description of the range of URLs for which the state
is valid. Future requests made by the client in that range will is valid. Future requests made by the client in that range will
also send the current value of the cookie to the server. Cookies also send the current value of the cookie to the server. Cookies
can be used to generate profiles of web usage habits, and thus may can be used to generate profiles of web usage habits, and thus may
infringe on personal privacy. infringe on personal privacy.
2. (I) /IPsec/ Data objects exchanged by ISAKMP to prevent certain 2. (I) /IPsec/ Data objects exchanged by ISAKMP to prevent certain
denial-of-service attacks during the establishment of a security denial-of-service attacks during the establishment of a security
association. association.
3. (D) /access control/ Synonym for "capability" or "ticket. 3. (D) /access control/ Synonym for "capability token" or "ticket.
Deprecated Definition: ISDs SHOULD NOT use this term with this Deprecated Definition: ISDs SHOULD NOT use this term with this
definition; that would duplicate the meaning of better-established definition; that would duplicate the meaning of better-established
terms and mix concepts in a potentially misleading way. terms and mix concepts in a potentially misleading way.
$ Coordinated Universal Time (UTC) $ Coordinated Universal Time (UTC)
(N) UTC is derived from International Atomic Time (TAI) by adding (N) UTC is derived from International Atomic Time (TAI) by adding
a number of leap seconds. The International Bureau of Weights and a number of leap seconds. The International Bureau of Weights and
Measures computes TAI once each month by averaging data from many Measures computes TAI once each month by averaging data from many
laboratories. (See: GeneralizedTime, UTCTime.) laboratories. (See: GeneralizedTime, UTCTime.)
$ copy $ copy
See: card copy. See: card copy.
$ correction
(I) See: secondary definition under "security".
$ correctness $ correctness
(I) "The property of a system that is guaranteed as the result of (I) "The property of a system that is guaranteed as the result of
formal verification activities." [Huff] (See: correctness proof, formal verification activities." [Huff] (See: correctness proof,
verification.) verification.)
$ correctness integrity $ correctness integrity
(I) Accuracy and consistency of the information that data values (I) The property that the information represented by data is
represent, rather than of the data itself. Closely related to accurate and consistent. (Compare: data integrity, source
issues of accountability and error handling. (See: data integrity, integrity.)
source integrity.) Tutorial: IDS SHOULD NOT use this term without providing a
definition; the term is neither well-known nor precisely defined.
Data integrity refers to the constancy of data values, and source
integrity refers to confidence in data values. However,
correctness integrity refers to confidence in the underlying
information that data values represent, and this property is
closely related to issues of accountability and error handling.
$ correctness proof $ correctness proof
(I) A mathematical proof of consistency between a specification (I) A mathematical proof of consistency between a specification
for system security and the implementation of that specification. for system security and the implementation of that specification.
(See: correctness, formal specification.) (See: correctness, formal specification.)
$ corruption $ corruption
A type of threat action that undesirably alters system operation (I) A type of threat action that undesirably alters system
by adversely modifying system functions or data. (See: operation by adversely modifying system functions or data. (See:
disruption.) disruption.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Tampering": In context of corruption, deliberately altering a - "Tampering": In context of corruption, deliberately altering a
system's logic, data, or control information to interrupt or system's logic, data, or control information to interrupt or
prevent correct operation of system functions. (See: (main prevent correct operation of system functions. (See: misuse,
entry for) tampering.) main entry for "tampering".)
- "Malicious logic": In context of corruption, any hardware, - "Malicious logic": In context of corruption, any hardware,
firmware, or software (e.g., a computer virus) intentionally firmware, or software (e.g., a computer virus) intentionally
introduced into a system to modify system functions or data. introduced into a system to modify system functions or data.
(See: (main entry for) malicious logic.) (See: incapacitation, main entry for "malicious logic",
- "Human error": In context of corruption, human action or masquerade, misuse.)
- "Human error": In context of corruption, human action or
inaction that unintentionally results in the alteration of inaction that unintentionally results in the alteration of
system functions or data. system functions or data.
- "Hardware or software error": In context of corruption, error - "Hardware or software error": In context of corruption, error
that results in the alteration of system functions or data. that results in the alteration of system functions or data.
- "Natural disaster": In context of corruption, any "act of God" - "Natural disaster": In context of corruption, any "act of God"
(e.g., power surge caused by lightning) that alters system (e.g., power surge caused by lightning) that alters system
functions or data. [FP031 section 2] functions or data. [FP031 section 2]
$ counter-countermeasure $ counter-countermeasure
(I) An action, device, procedure, or technique used by an attacker (I) An action, device, procedure, or technique used by an attacker
to offset a defensive countermeasure. to offset a defensive countermeasure.
Tutorial: For every countermeasure devised to protect computers Tutorial: For every countermeasure devised to protect computers
and networks, some cracker probably will be able to devise a and networks, some cracker probably will be able to devise a
counter-countermeasure. Thus, systems must use "defense in depth". counter-countermeasure. Thus, systems must use "defense in depth".
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$ country code $ country code
(I) An identifier that is defined for a nation by ISO. [I3166] (I) An identifier that is defined for a nation by ISO. [I3166]
Tutorial: For each nation, ISO Standard 3166 defines a unique two- Tutorial: For each nation, ISO Standard 3166 defines a unique two-
character alphabetic code, a unique three-character alphabetic character alphabetic code, a unique three-character alphabetic
code, and a three-digit code. Among many uses of these codes, the code, and a three-digit code. Among many uses of these codes, the
two-character codes are used as top-level domain names. two-character codes are used as top-level domain names.
$ Courtney's laws $ Courtney's laws
Tutorial: The following principles for managing system security (N) Principles for managing system security that were stated by
were stated by Robert H. Courtney, Jr.: [Murr] Robert H. Courtney, Jr.
- Courtney's first law: You cannot say anything interesting about
the security of a system except in the context of a particular Tutorial: Bill Murray codified Courtney's laws as follows: [Murr]
application and environment. - Courtney's first law: You cannot say anything interesting
- Courtney's second law: Never spend more money eliminating a (i.e., significant) about the security of a system except in
the context of a particular application and environment.
- Courtney's second law: Never spend more money eliminating a
security exposure than tolerating it will cost you. (See: security exposure than tolerating it will cost you. (See:
acceptable risk, risk analysis.) acceptable risk, risk analysis.)
-- First corollary: Perfect security has infinite cost. -- First corollary: Perfect security has infinite cost.
-- Second corollary: There is no such thing as zero risk. -- Second corollary: There is no such thing as zero risk.
- Courtney's third law: There are no technical solutions to - Courtney's third law: There are no technical solutions to
management problems, but there are management solutions to management problems, but there are management solutions to
technical problems. technical problems.
$ covert action $ covert action
(I) An operation that is planned and executed in a way that (I) An operation that is planned and executed in a way that
conceals the identity of the operator. conceals the identity of the operator.
$ covert channel $ covert channel
1. (I) An unintended or unauthorized intra-system channel that 1. (I) An unintended or unauthorized intra-system channel that
enables two cooperating entities to transfer information in a way enables two cooperating entities to transfer information in a way
that violates the system's security policy but does not exceed the that violates the system's security policy but does not exceed the
entities' access authorizations. (See: covert storage channel, entities' access authorizations. (See: covert storage channel,
covert timing channel, out of band.) covert timing channel, out-of-band, tunnel.)
2. (O) "A communications channel that allows two cooperating 2. (O) "A communications channel that allows two cooperating
processes to transfer information in a manner that violates the processes to transfer information in a manner that violates the
system's security policy." [NCS04] system's security policy." [NCS04]
Tutorial: The cooperating entities can be either two insiders or Tutorial: The cooperating entities can be either two insiders or
an insider and an outsider. Of course, an outsider has no access an insider and an outsider. Of course, an outsider has no access
authorization at all. A covert channel is a system feature that authorization at all. A covert channel is a system feature that
the system architects neither designed nor intended for the system architects neither designed nor intended for
information transfer. information transfer.
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$ covert timing channel $ covert timing channel
(I) A system feature that enable one system entity to signal (I) A system feature that enable one system entity to signal
information to another by modulating its own use of a system information to another by modulating its own use of a system
resource in such a way as to affect system response time observed resource in such a way as to affect system response time observed
by the second entity. (See: covert channel.) by the second entity. (See: covert channel.)
$ CPS $ CPS
(I) See: certification practice statement. (I) See: certification practice statement.
$ cracker $ cracker
(I) Someone who tries to break the security of, and gain access (I) Someone who tries to break the security of, and gain
to, someone else's system without being invited. (Compare: hacker. unauthorized access to, someone else's system, often with
See: adversary, intruder, packet monkey, script kiddy.) malicious intent. (See: adversary, intruder, packet monkey, script
kiddy. Compare: hacker.)
$ CRAM $ CRAM
(I) See: Challenge-Response Authentication Mechanism. (I) See: Challenge-Response Authentication Mechanism.
$ CRC $ CRC
(I) See: cyclic redundancy check. (I) See: cyclic redundancy check.
$ credential $ credential
1. (I) /authentication/ "Identity credential": A data object that 1. (I) /authentication/ "identifier credential": A data object
is a portable representation of the association between an that is a portable representation of the association between a
identifier and a unit of authentication information, and that can identifier and a unit of authentication information, and that can
be transferred or presented for use in proving a claim of that be presented for use in verifying an identity claimed by an entity
identity. Example: X.509 public-key certificate. (See: anonymous that attempts to access a system. Example: X.509 public-key
credential.) certificate. (See: anonymous credential.)
2. (I) /access control/ "Authorization credential": A data object 2. (I) /access control/ "authorization credential": A data object
that is a portable representation of the association between an that is a portable representation of the association between an
identifier and one or more access, and that can be transferred or identifier and one or more access authorizations, and that can be
presented for use when attempting to exercise such access. presented for use in verifying those authorizations for an entity
Example: X.509 attribute certificate. (See: capability, ticket.) that attempts such access. Example: X.509 attribute certificate.
(See: capability token, ticket.)
3. (D) /OSIRM/ "Data that is transferred to establish the claimed 3. (D) /OSIRM/ "Data that is transferred to establish the claimed
identity of an entity." [I7498 Part 2] identity of an entity." [I7498 Part 2]
Deprecated Definition: ISDs should not use the term with this Deprecated Definition: ISDs SHOULD NOT use the term with this
definition. As explained in the tutorial below, an authentication definition. As explained in the tutorial below, an authentication
process can involve the transfer of multiple data objects, and not process can involve the transfer of multiple data objects, and not
all of those are credentials. all of those are credentials.
4. (D) /U.S. Government/ "An object that is verified when 4. (D) /U.S. Government/ "An object that is verified when
presented to the verifier in an authentication transaction." presented to the verifier in an authentication transaction."
[M0404] [M0404]
Deprecated Definition: ISDs should not use the term with this Deprecated Definition: ISDs SHOULD NOT use the term with this
definition; it mixes concepts in a potentially misleading way. For definition; it mixes concepts in a potentially misleading way. For
example, in an authentication process, it is the identity that is example, in an authentication process, it is the identity that is
"verified", not the credential; the credential is "validated". "verified", not the credential; the credential is "validated".
(See: validate vs. verify.) (See: validate vs. verify.)
Tutorial: In general English, "credentials" are evidence or Tutorial: In general English, "credentials" are evidence or
testimonials that (a) support a claim of identity or authorization testimonials that (a) support a claim of identity or authorization
and (b) usually are intended to be used more than once (i.e., a and (b) usually are intended to be used more than once (i.e., a
credential's life is long compared to the time needed for one credential's life is long compared to the time needed for one
use). Some examples are a policeman's badge, an automobile use). Some examples are a policeman's badge, an automobile
driver's license, and a national passport. An authentication or driver's license, and a national passport. An authentication or
access control process that uses a badge, license, or passport is access control process that uses a badge, license, or passport is
outwardly simple: the holder just shows the thing. outwardly simple: the holder just shows the thing.
The problem with adopting this term in Internet security is that The problem with adopting this term in Internet security is that
an automation authentication or access control process requires an automated process for authentication or access control usually
multiple steps using multiple data objects, and it might not be requires multiple steps using multiple data objects, and it might
immediately obvious which of those objects should get the name not be immediately obvious which of those objects should get the
"credential". name "credential".
For example, if the verification step in a user authentication For example, if the verification step in a user authentication
process employs public-key technology, then the process involves process employs public-key technology, then the process involves
at least three data items: (a) the user's private key, (b) a at least three data items: (a) the user's private key, (b) a
signed value -- signed with that private key and passed to the signed value -- signed with that private key and passed to the
system, perhaps in response to a challenge from the system -- and system, perhaps in response to a challenge from the system -- and
(c) the user's public-key certificate, which is validated by the (c) the user's public-key certificate, which is validated by the
system and provides the public key needed to verify the signature. system and provides the public key needed to verify the signature.
- Private key: The private key is *not* a credential, because it - Private key: The private key is *not* a credential, because it
is never transferred or presented. Instead, the private key is is never transferred or presented. Instead, the private key is
"authentication information", which is associated with the "authentication information", which is associated with the
user's identifier for a specified period of time and can be user's identifier for a specified period of time and can be
used in multiple authentications during that time. used in multiple authentications during that time.
- Signed value: The signed value is *not* a credential; the - Signed value: The signed value is *not* a credential; the
signed value is only ephemeral, not long lasting. The OSIRM signed value is only ephemeral, not long lasting. The OSIRM
definition could be interpreted to call the signed value a definition could be interpreted to call the signed value a
credential, but that would conflict with general English. credential, but that would conflict with general English.
- Certificate. The user's certificate *is* a credential. It can - Certificate: The user's certificate *is* a credential. It can
be "transferred" or "presented" to any person or process that be "transferred" or "presented" to any person or process that
needs it at any time. A public-key certificate may be used as needs it at any time. A public-key certificate may be used as
an "identity credential", and an attribute certificate may be an "identity credential", and an attribute certificate may be
used as an "authorization credential". used as an "authorization credential".
$ critical $ critical
1. (I) /system resource/ A condition of a system resource such 1. (I) /system resource/ A condition of a system resource such
that denial of access to, or lack of availability of, that that denial of access to, or lack of availability of, that
resource would jeopardize a system user's ability to perform a resource would jeopardize a system user's ability to perform a
primary function or would result in other serious consequences, primary function or would result in other serious consequences,
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ciphertext; and these generalize to the other kinds of ciphertext; and these generalize to the other kinds of
cryptography. cryptography.
$ crypto, CRYPTO $ crypto, CRYPTO
1. (N) A prefix ("crypto-") that means "cryptographic". 1. (N) A prefix ("crypto-") that means "cryptographic".
Usage: ISDs MAY use this prefix when it part of a term listed in Usage: ISDs MAY use this prefix when it part of a term listed in
this Glossary. Otherwise, ISDs SHOULD avoid this prefix; instead, this Glossary. Otherwise, ISDs SHOULD avoid this prefix; instead,
use the adjective "cryptographic". use the adjective "cryptographic".
2. (D) /slang/ In lower case, "crypto" is a synonym for the 2. (D) In lower case, "crypto" is an abbreviation for the
adjective "cryptographic", or for the nouns "cryptography" or adjective "cryptographic", or for the nouns "cryptography" or
"cryptographic component". "cryptographic component".
Deprecated Term: ISDs SHOULD NOT use this slang term; it could be Deprecated Abbreviation: ISDs SHOULD NOT use this term because it
misunderstood. could easily be misunderstood.
3. (O) /U.S. Government/ In upper case, "CRYPTO" is a marking or 3. (O) /U.S. Government/ In upper case, "CRYPTO" is a marking or
designator that identifies "COMSEC keying material used to secure designator that identifies "COMSEC keying material used to secure
or authenticate telecommunications carrying classified or or authenticate telecommunications carrying classified or
sensitive U.S. Government or U.S. Government-derived information." sensitive U.S. Government or U.S. Government-derived information."
[C4009] [C4009]
$ cryptographic $ cryptographic
(I) An adjective that refers to cryptography. (I) An adjective that refers to cryptography.
$ cryptographic algorithm $ cryptographic algorithm
(I) An algorithm that uses the science of cryptography, including (I) An algorithm that uses the science of cryptography, including
(a) encryption algorithms, (b) cryptographic hash algorithms, (c) (a) encryption algorithms, (b) cryptographic hash algorithms, (c)
digital signature algorithms, and (d) key agreement algorithms. digital signature algorithms, and (d) key-agreement algorithms.
$ cryptographic application programming interface (CAPI) $ cryptographic application programming interface (CAPI)
(I) The source code formats and procedures through which an (I) The source code formats and procedures through which an
application program accesses cryptographic services, which are application program accesses cryptographic services, which are
defined abstractly compared to their actual implementation. defined abstractly compared to their actual implementation.
Example, see: PKCS #11, [R2628]. Example, see: PKCS #11, [R2628].
$ cryptographic association $ cryptographic association
(I) A security association that involves the use of cryptography (I) A security association that involves the use of cryptography
to provide security services for data exchanged by the associated to provide security services for data exchanged by the associated
entities. (See: ISAKMP.) entities. (See: ISAKMP.)
$ cryptographic boundary $ cryptographic boundary
(I) See: (secondary definition under) cryptographic module. (I) See: secondary definition under "cryptographic module".
$ cryptographic card $ cryptographic card
(I) A cryptographic token in the form of a smart card or a PC (I) A cryptographic token in the form of a smart card or a PC
card. card.
$ cryptographic component $ cryptographic component
(I) A generic term for any system component that involves (I) A generic term for any system component that involves
cryptography. (See: cryptographic module.) cryptography. (See: cryptographic module.)
$ cryptographic hash $ cryptographic hash
(I) See: (secondary definition under) hash function. (I) See: secondary definition under "hash function".
$ cryptographic ignition key (CIK) $ cryptographic ignition key (CIK)
1. (I) A physical (usually electronic) token used to store, 1. (I) A physical (usually electronic) token used to store,
transport, and protect cryptographic keys. Usage: Sometimes transport, and protect cryptographic keys. Usage: Sometimes
abbreviated as "crypto-ignition key". (Compare: fill device.) abbreviated as "crypto-ignition key". (Compare: fill device.)
Tutorial: A typical use is to divide a split key between a CIK and Tutorial: A typical use is to divide a split key between a CIK and
a cryptographic module, so that it is necessary to combine the two a cryptographic module, so that it is necessary to combine the two
to regenerate a key-encrypting key and thus activate the module to regenerate a key-encrypting key and thus activate the module
and other keys it contains. and other keys it contains.
2. (O) "Device or electronic key used to unlock the secure mode of 2. (O) "Device or electronic key used to unlock the secure mode of
cryptographic equipment." [C4009] cryptographic equipment." [C4009]
$ cryptographic key $ cryptographic key
(I) See: key. Usage: Usually shortened to just "key". (I) See: key. Usage: Usually shortened to just "key".
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$ cryptographic system $ cryptographic system
1. (I) A set of cryptographic algorithms together with the key 1. (I) A set of cryptographic algorithms together with the key
management processes that support use of the algorithms in some management processes that support use of the algorithms in some
application context. application context.
Usage: ISDs SHOULD use definition 1 because it covers a wider Usage: ISDs SHOULD use definition 1 because it covers a wider
range of algorithms than definition 2. range of algorithms than definition 2.
2. (O) "A collection of transformations from plain text into 2. (O) "A collection of transformations from plain text into
cipher text and vice versa [which would exclude digital signature, cipher text and vice versa [which would exclude digital signature,
cryptographic hash, and key agreement algorithms], the particular cryptographic hash, and key-agreement algorithms], the particular
transformation(s) to be used being selected by keys. The transformation(s) to be used being selected by keys. The
transformations are normally defined by a mathematical algorithm." transformations are normally defined by a mathematical algorithm."
[X509] [X509]
$ cryptographic token $ cryptographic token
1. (I) A portable, user-controlled, physical device (e.g., smart 1. (I) A portable, user-controlled, physical device (e.g., smart
card or PCMCIA card) used to store cryptographic information and card or PCMCIA card) used to store cryptographic information and
possibly also perform cryptographic functions. (See: cryptographic possibly also perform cryptographic functions. (See: cryptographic
card, token.) card, token.)
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methods used in encipherment and decipherment." [I7498 Part 2] methods used in encipherment and decipherment." [I7498 Part 2]
Tutorial: Comprehensive coverage of applied cryptographic Tutorial: Comprehensive coverage of applied cryptographic
protocols and algorithms is provided by Schneier [Schn]. protocols and algorithms is provided by Schneier [Schn].
Businesses and governments use cryptography to make data Businesses and governments use cryptography to make data
incomprehensible to outsiders; to make data incomprehensible to incomprehensible to outsiders; to make data incomprehensible to
both outsiders and insiders, the data is sent to lawyers for a both outsiders and insiders, the data is sent to lawyers for a
rewrite. rewrite.
$ Cryptoki $ Cryptoki
(N) See: (secondary definition under) PKCS #11. (N) A CAPI defined in PKCS #11. Pronunciation: "CRYPTO-key".
Derivation: Abbreviation of "cryptographic token interface".
$ cryptology $ cryptology
(I) The science of secret communication, that includes both (I) The science of secret communication, that includes both
cryptography and cryptanalysis. cryptography and cryptanalysis.
Tutorial: Sometimes the term is used more broadly to denote Tutorial: Sometimes the term is used more broadly to denote
activity that includes both rendering signals secure (see: signal activity that includes both rendering signals secure (see: signal
security) and extracting information from signals (see: signal security) and extracting information from signals (see: signal
intelligence) [Kahn]. intelligence) [Kahn].
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$ cyclic redundancy check (CRC) $ cyclic redundancy check (CRC)
(I) A type of checksum algorithm that is not a cryptographic hash (I) A type of checksum algorithm that is not a cryptographic hash
but is used to implement data integrity service where accidental but is used to implement data integrity service where accidental
changes to data are expected. Sometimes called "cyclic redundancy changes to data are expected. Sometimes called "cyclic redundancy
code". code".
$ DAC $ DAC
(N) See: Data Authentication Code, discretionary access control. (N) See: Data Authentication Code, discretionary access control.
Deprecated Usage: This abbreviation is ambiguous; therefore, ISDs Deprecated Usage: ISDs that use this term SHOULD state a
that use it SHOULD state a definition for it. definition for it because this abbreviation is ambiguous.
$ daemon $ daemon
(I) A computer program that is not invoked explicitly but waits (I) A computer program that is not invoked explicitly but waits
until a specified condition occurs, and then runs with no until a specified condition occurs, and then runs with no
associated user (principal), usually for an administrative associated user (principal), usually for an administrative
purpose. (See: zombie.) purpose. (See: zombie.)
$ dangling threat $ dangling threat
(N) A threat to a system for which there is no corresponding (O) A threat to a system for which there is no corresponding
vulnerability and, therefore, no implied risk. [C4009] vulnerability and, therefore, no implied risk. [C4009]
$ dangling vulnerability $ dangling vulnerability
(N) A vulnerability of a system for which there is no (O) A vulnerability of a system for which there is no
corresponding threat and, therefore, no implied risk. [C4009] corresponding threat and, therefore, no implied risk. [C4009]
$ DASS $ DASS
(I) See: Distributed Authentication Security Service. (I) See: Distributed Authentication Security Service.
$ data $ data
(I) Information in a specific representation, usually as a (I) Information in a specific representation, usually as a
sequence of symbols that have meaning and especially a sequence of symbols that have meaning.
representation that can be processed or produced by a computer.
Usage: Refers to both (a) representations that can be recognized,
processed, or produced by a computer or other type of machine, and
(b) representations that can be handled by a human.
$ Data Authentication Algorithm, data authentication algorithm $ Data Authentication Algorithm, data authentication algorithm
(N) /capitalized/ The ANSI standard for a keyed hash function that (N) /capitalized/ The ANSI standard for a keyed hash function that
is equivalent to DES cipher block chaining with IV = 0. [A9009] is equivalent to DES cipher block chaining with IV = 0. [A9009]
(D) /not capitalized/ Synonym for "checksum". (D) /not capitalized/ Synonym for "checksum".
Deprecated Term: ISDs SHOULD NOT use the uncapitalized form, "data Deprecated Term: ISDs SHOULD NOT use the uncapitalized form, "data
authentication algorithm", as a synonym for other kinds of authentication algorithm", as a synonym for other kinds of
checksums. checksums.
$ Data Authentication Code, data authentication code $ Data Authentication Code, data authentication code
1. (N) /capitalized/ A specific U.S. Government standard [FP113] 1. (N) /capitalized/ A specific U.S. Government standard [FP113]
for a checksum that is computed by the Data Authentication for a checksum that is computed by the Data Authentication
Algorithm. (Also known as the ANSI standard Message Authentication Algorithm. Usage: a.k.a. Message Authentication Code [A9009].)
Code [A9009].) (See: DAC.) (See: DAC.)
2. (D) /not capitalized/ Synonym for checksum. 2. (D) /not capitalized/ Synonym for checksum.
Deprecated Term: ISDs SHOULD NOT use "data authentication code" as Deprecated Term: ISDs SHOULD NOT use "data authentication code" as
a synonym for other kinds of checksums; that usage would mix a synonym for other kinds of checksums; that usage would mix
concepts in a potentially misleading way (see: authentication concepts in a potentially misleading way (see: authentication
code). Instead, use "checksum", "error detection code", "hash", code). Instead, use "checksum", "error detection code", "hash",
"keyed hash", "Message Authentication Code", or "protected "keyed hash", "Message Authentication Code", or "protected
checksum", depending on what is meant. checksum", depending on what is meant.
$ data compromise $ data compromise
(I) A security incident in which information is exposed to (I) A security incident in which information is exposed to
potential unauthorized access, such that unauthorized disclosure, potential unauthorized access, such that unauthorized disclosure,
alteration, or use of the information may have occurred. (Compare: alteration, or use of the information may have occurred. (Compare:
security compromise.) security compromise.)
(O) A "compromise" is "A communication or physical transfer of (O) A "compromise" is a "communication or physical transfer of
information to an unauthorized recipient." [DoD5] information to an unauthorized recipient." [DoD5]
$ data confidentiality $ data confidentiality
(I) The property that data is not disclosed to system entities (I) The property that data is not disclosed to system entities
unless they have been authorized to know the data. (See: Bell- unless they have been authorized to know the data. (See: Bell-
LaPadula model, classification, data confidentiality service. LaPadula model, classification, data confidentiality service.
Compare: privacy.) Compare: privacy.)
(D) "The property that information is not made available or (D) "The property that information is not made available or
disclosed to unauthorized individuals, entities, or processes disclosed to unauthorized individuals, entities, or processes
[i.e., to any unauthorized system entity]." [I7498 Part 2]. [i.e., to any unauthorized system entity]." [I7498 Part 2].
Deprecated Definition: The phrase "made available" might be Deprecated Definition: The phrase "made available" might be
interpreted to mean that the data could be altered, and that would interpreted to mean that the data could be altered, and that would
confuse this term with the concept of "data integrity". confuse this term with the concept of "data integrity".
$ data confidentiality service $ data confidentiality service
(I) A security service that protects data against unauthorized (I) A security service that protects data against unauthorized
disclosure. (See: access control, data confidentiality, flow disclosure. (See: access control, data confidentiality, datagram
control, inference control.) confidentiality service, flow control, inference control.)
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "privacy", which is a different concept. for "privacy", which is a different concept.
$ Data Encryption Algorithm (DEA) $ Data Encryption Algorithm (DEA)
(N) A symmetric block cipher, defined in the U.S. Government's (N) A symmetric block cipher, defined in the U.S. Government's
DES. DEA uses a 64-bit key, of which 56 bits are independently DES. DEA uses a 64-bit key, of which 56 bits are independently
chosen and 8 are parity bits, and maps a 64-bit block into another chosen and 8 are parity bits, and maps a 64-bit block into another
64-bit block. [FP046] (See: AES, symmetric cryptography.) 64-bit block. [FP046] (See: AES, symmetric cryptography.)
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(I) A cryptographic key that is used to encipher application data. (I) A cryptographic key that is used to encipher application data.
(Compare: key-encrypting key.) (Compare: key-encrypting key.)
$ Data Encryption Standard (DES) $ Data Encryption Standard (DES)
(N) A U.S. Government standard [FP046] that specifies the DEA and (N) A U.S. Government standard [FP046] that specifies the DEA and
states policy for using the algorithm to protect unclassified, states policy for using the algorithm to protect unclassified,
sensitive data. (See: AES.) sensitive data. (See: AES.)
$ data integrity $ data integrity
1. (I) The property that data has not been changed, destroyed, or 1. (I) The property that data has not been changed, destroyed, or
lost in an unauthorized or accidental manner. (See: Biba model, lost in an unauthorized or accidental manner. (See: data integrity
data integrity service.) service. Compare: correctness integrity, source integrity.)
2. (O) "The property that information has not been modified or 2. (O) "The property that information has not been modified or
destroyed in an unauthorized manner." [I7498 Part 2] destroyed in an unauthorized manner." [I7498 Part 2]
Usage: Deals with (a) constancy of and confidence in data values, Usage: Deals with (a) constancy of and confidence in data values,
and not with either (b) information that the values represent and not with either (b) information that the values represent
(see: correctness integrity) or (c) the trustworthiness of the (see: correctness integrity) or (c) the trustworthiness of the
source of the values (see: source integrity). source of the values (see: source integrity).
$ data integrity service $ data integrity service
(I) A security service that protects against unauthorized changes (I) A security service that protects against unauthorized changes
to data, including both intentional change or destruction and to data, including both intentional change or destruction and
accidental change or loss, by ensuring that changes to data are accidental change or loss, by ensuring that changes to data are
detectable. (See: data integrity.) detectable. (See: data integrity, checksum, datagram integrity
service.)
Tutorial: A data integrity service can only detect a change and Tutorial: A data integrity service can only detect a change and
report it to an appropriate system entity; changes cannot be report it to an appropriate system entity; changes cannot be
prevented unless the system is perfect (error-free) and no prevented unless the system is perfect (error-free) and no
malicious user has access. However, a system that offers data malicious user has access. However, a system that offers data
integrity service might also attempt to correct and recover from integrity service might also attempt to correct and recover from
changes. changes.
The ability of this service to detect changes is limited by the
technology of the mechanisms used to implement the service. For
example, if the mechanism were a one-bit parity check across each
entire SDU, then changes to an odd number of bits in an SDU would
be detected, but changes to an even number of bits would not.
Relationship between data integrity service and authentication Relationship between data integrity service and authentication
services: Although data integrity service is defined separately services: Although data integrity service is defined separately
from data origin authentication service and peer entity from data origin authentication service and peer entity
authentication service, it is closely related to them. authentication service, it is closely related to them.
Authentication services depend, by definition, on companion data Authentication services depend, by definition, on companion data
integrity services. Data origin authentication service provides integrity services. Data origin authentication service provides
verification that the identity of the original source of a verification that the identity of the original source of a
received data unit is as claimed; there can be no such received data unit is as claimed; there can be no such
verification if the data unit has been altered. Peer entity verification if the data unit has been altered. Peer entity
authentication service provides verification that the identity of authentication service provides verification that the identity of
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service, this service is independent of any association between service, this service is independent of any association between
the originator and the recipient, and the data in question may the originator and the recipient, and the data in question may
have originated at any time in the past. have originated at any time in the past.
A digital signature mechanism can be used to provide this service, A digital signature mechanism can be used to provide this service,
because someone who does not know the private key cannot forge the because someone who does not know the private key cannot forge the
correct signature. However, by using the signer's public key, correct signature. However, by using the signer's public key,
anyone can verify the origin of correctly signed data. anyone can verify the origin of correctly signed data.
This service is usually bundled with connectionless data integrity This service is usually bundled with connectionless data integrity
service. (See: ("relationship between data integrity service and service. (See: "relationship between data integrity service and
authentication services" under) data integrity service. authentication services" under "data integrity service".
$ data owner $ data owner
(O) /U.S. Government/ The organization that has the final (N) The organization that has the final statutory and operational
statutory and operational authority for specified information. authority for specified information.
$ data privacy $ data privacy
(D) Synonym for "data confidentiality". (D) Synonym for "data confidentiality".
Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts
in a potentially misleading way. Instead, use either "data in a potentially misleading way. Instead, use either "data
confidentiality" or "privacy" or both, depending on what is meant. confidentiality" or "privacy" or both, depending on what is meant.
$ data recovery $ data recovery
1. (I) /cryptanalysis/ A process for learning, from some cipher 1. (I) /cryptanalysis/ A process for learning, from some cipher
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$ data security $ data security
(I) The protection of data from disclosure, alteration, (I) The protection of data from disclosure, alteration,
destruction, or loss that either is accidental or is intentional destruction, or loss that either is accidental or is intentional
but unauthorized. but unauthorized.
Tutorial: Both data confidentiality service and data integrity Tutorial: Both data confidentiality service and data integrity
service are needed to achieve data security. service are needed to achieve data security.
$ datagram $ datagram
(I) "A self-contained, independent entity of data [i.e., a data (I) "A self-contained, independent entity of data [i.e., a packet]
object, a discrete set of bits] carrying sufficient information to carrying sufficient information to be routed from the source
be routed from the source to the destination." [R1983] [computer] to the destination computer without reliance on earlier
exchanges between this source and destination computer and the
transporting network." Example: A PDU of IP. [R1983]
$ datagram confidentiality service
(I) A data confidentiality service that preserves the
confidentiality of data in a single, independent, packet; i.e.,
the service applies to datagrams one-at-a-time. Example: ESP.
(See: data confidentiality.)
Usage: When a protocol is said to provide data confidentiality
service, this is usually understood to mean that only the SDU is
protected in each packet. ISDs that use the term to mean that the
entire PDU is protected should include a highlighted definition.
Tutorial: This basic form of network confidentiality service
suffices for protecting the data in a stream of packets in both
connectionless and connection-oriented protocols. Except perhaps
for traffic flow confidentiality, nothing further is needed to
protect the confidentiality of data carried by a packet stream.
The OSIRM distinguishes between connection confidentiality and
connectionless confidentiality. The IPS need not make that
distinction, because those services are just instances of the same
service (i.e., datagram confidentiality) being offered in two
different protocol contexts. (For data integrity service, however,
additional effort is needed to protect a stream, and the IPS does
need to distinguish between "datagram integrity service" and
"stream integrity service".)
$ datagram integrity service
(I) A data integrity service that preserves the integrity of data
in a single, independent, data packet (i.e., the service applies
to datagrams one-at-a-time). (See: data integrity. Compare: stream
integrity service.)
Tutorial: The ability to provide appropriate data integrity is
important in many Internet security situations, and so there are
different kinds of data integrity services suited to different
applications. This service is the simplest kind; it is suitable
for connectionless data transfers.
Datagram integrity service usually is designed only to attempt to
detect changes to the SDU in each packet, but it might also
attempt to detect changes to some or all of the PCI in each packet
(see: selective field integrity). In contrast to this simple, one-
at-a-time service, some security situations demand a more complex
service that also attempts to detect deleted, inserted, or
reordered datagrams within a stream of datagrams (see: stream
integrity service).
$ DEA $ DEA
(N) See: Data Encryption Algorithm. (N) See: Data Encryption Algorithm.
$ deception $ deception
(I) A circumstance or event that may result in an authorized (I) A circumstance or event that may result in an authorized
entity receiving false data and believing it to be true. (See: entity receiving false data and believing it to be true. (See:
authentication.) authentication.)
Tutorial: This is a type of threat consequence, and it can be Tutorial: This is a type of threat consequence, and it can be
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$ decipher $ decipher
(D) Synonym for "decrypt". (D) Synonym for "decrypt".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "decrypt". However, see usage note under "encryption". for "decrypt". However, see usage note under "encryption".
$ decipherment $ decipherment
(D) Synonym for "decryption". (D) Synonym for "decryption".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "decryption". However, see the usage note under "encryption". for "decryption". However, see the Usage note under "encryption".
$ declassification
(I) An authorized process by which information is declassified.
(See: classification.)
$ declassify
(I) To officially remove the security level designation of a
classified information item or information type, such that the
information is no longer classified (i.e., becomes unclassified).
(See: classified, classify, security level. Compare: downgrade.)
$ decode $ decode
1. (I) Convert encoded data back to its original form of 1. (I) Convert encoded data back to its original form of
representation. (Compare: decrypt.) representation. (Compare: decrypt.)
2. (D) Synonym for "decrypt". 2. (D) Synonym for "decrypt".
Deprecated Definition: Encoding is not usually meant to conceal Deprecated Definition: Encoding is not usually meant to conceal
meaning. Therefore, ISDs SHOULD NOT use this term as a synonym for meaning. Therefore, ISDs SHOULD NOT use this term as a synonym for
"decrypt", because that would mix concepts in a potentially "decrypt", because that would mix concepts in a potentially
misleading way. misleading way.
$ decrypt $ decrypt
(I) Cryptographically restore cipher text to the plaintext form it (I) Cryptographically restore cipher text to the plaintext form it
had before encryption. had before encryption.
$ decryption $ decryption
(I) See: (secondary definition under) encryption. (I) See: secondary definition under "encryption".
$ dedicated security mode $ dedicated security mode
(I) A mode of operation of an information system, wherein all (I) A mode of system operation wherein all users having access to
users have the clearance or authorization, and the need-to-know, the system possess, for all data handled by the system, both (a)
for all data handled by the system. In this mode, the system may all necessary authorizations (i.e., security clearance and formal
handle either (a) a single classification level or category of access approval) and (b) a need-to-know. (See: /system operation/
information or (b) a range of levels and categories. [DoD2] under "mode", formal access approval, need to know, protection
level, security clearance.)
Usage: This mode was defined in U.S. DoD policy on system Usage: Usually abbreviated as "dedicated mode". This mode was
accreditation, but the term is also used outside the Government. defined in U.S. Government policy on system accreditation, but the
term is also used outside the Government. In this mode, the system
may handle either (a) a single classification level or category of
information or (b) a range of levels and categories.
$ default account $ default account
(I) A system login account (usually accessed with a user (I) A system login account (usually accessed with a user
identifier and password) that has been predefined in a identifier and password) that has been predefined in a
manufactured system to permit initial access when the system is manufactured system to permit initial access when the system is
first put into service. first put into service. (See: harden.]
Tutorial: Sometimes, the default user name and password are the Tutorial: A default account becomes a serious vulnerability if not
same in each copy of the system. In any case, when the system is properly administered. Sometimes, the default identifier and
put into service, the default password should immediately be password are well-known because they are the same in each copy of
changed or the default account should be disabled. the system. In any case, when a system is put into service, any
default password should immediately be changed or the default
account should be disabled.
$ defense in depth $ defense in depth
(I) An approach to constructing security architectures that uses (I) An approach to constructing security architectures that uses
layered and complementary security mechanisms and countermeasures, layered and complementary security mechanisms and countermeasures,
so that if one security mechanism is defeated, one or more other so that if one security mechanism is defeated, one or more other
mechanisms (which are "behind" or "beneath" the first mechanism) mechanisms (which are "behind" or "beneath" the first mechanism)
still provide protection. still provide protection.
Tutorial: This concept is appealing because it aligns with Tutorial: This concept is appealing because it aligns with
traditional warfare doctrine, which applies defense in depth to traditional warfare doctrine, which applies defense in depth to
physical, geospatial structures. It is more difficult to apply the physical, geospatial structures. It is more difficult to apply the
concept to logical, cyberspace structures of computer networks. concept to logical, cyberspace structures of computer networks.
The concept assumes that networks have a spatial or topological The concept assumes that networks have a spatial or topological
representation. It also assumes that there can be implemented -- representation. It also assumes that there can be implemented --
from the "outer perimeter" of a network, through its various from the "outer perimeter" of a network, through its various
"layers" of components, to its "center" (i.e., to the subscriber "layers" of components, to its "center" (i.e., to the subscriber
application systems supported by the network) -- a varied series application systems supported by the network) -- a varied series
of countermeasures that together provide adequate protection. of countermeasures that together provide adequate protection.
However, it is more difficult to map the topology of networks and However, it is more difficult to map the topology of networks and
make certain that no paths exist by which an attacker could bypass make certain that no path exists by which an attacker could bypass
defensive layers. all defensive layers.
$ Defense Information Infrastructure (DII) $ Defense Information Infrastructure (DII)
(O) /U.S. DoD/ The U.S. DoD's shared or interconnected system of (O) /U.S. DoD/ The U.S. DoD's shared, interconnected system of
computers, communications, data, applications, security, people, computers, communications, data, applications, security, people,
training, and other support structure, serving local and worldwide training, and support structures, serving information needs
information needs. (See: DISN.) worldwide. (See: DISN.) Usage: Has evolved to be called the GIG.
Tutorial: The DII connects U.S. DoD mission support, command and Tutorial: The DII connects mission support, command and control,
control, and intelligence computers and users through voice, data, and intelligence computers and users through voice, data, imagery,
imagery, video, and multimedia services, and provides information video, and multimedia services, and provides information
processing and value-added services to subscribers over the DISN. processing and value-added services to subscribers over the DISN.
Users' own data and application software are not considered part Users' own data and application software are not considered part
of the DII. of the DII.
$ Defense Information Systems Network (DISN) $ Defense Information Systems Network (DISN)
(O) /U.S. DoD/ The U.S. DoD's consolidated, worldwide, enterprise (O) /U.S. DoD/ The U.S. DoD's consolidated, worldwide, enterprise
level telecommunications infrastructure that provides end-to-end level telecommunications infrastructure that provides end-to-end
information transfer for supporting military operations; a part of information transfer for supporting military operations; a part of
the DII. the DII. (Compare: GIG.)
$ degauss $ degauss
1a. (N) Apply a magnetic field to permanently remove, erase, or 1a. (N) Apply a magnetic field to permanently remove, erase, or
clear data from a magnetic storage medium, such as a tape or disk clear data from a magnetic storage medium, such as a tape or disk
[NCS25]. [NCS25].
1b. (N) Reduce magnetic flux density to zero by applying a 1b. (N) Reduce magnetic flux density to zero by applying a
reversing magnetic field. (See: magnetic remanence.) reversing magnetic field. (See: magnetic remanence.)
$ degausser $ degausser
(N) An electrical device that can degauss magnetic storage media. (N) An electrical device that can degauss magnetic storage media.
$ DEK $ DEK
(I) See: data encryption key. (I) See: data encryption key.
$ delay
(I) /packet/ See: secondary definition under "stream integrity
service".
$ deletion
(I) /packet/ See: secondary definition under "stream integrity
service".
$ delta CRL $ delta CRL
(I) A partial CRL that only contains entries for X.509 (I) A partial CRL that only contains entries for X.509
certificates that have been revoked since the issuance of a prior, certificates that have been revoked since the issuance of a prior,
base CRL. This method can be used to partition CRLs that become base CRL. This method can be used to partition CRLs that become
too large and unwieldy. (Compare: CRL distribution point.) too large and unwieldy. (Compare: CRL distribution point.)
$ demilitarized zone (DMZ) $ demilitarized zone (DMZ)
(D) Synonym for "buffer zone". (D) Synonym for "buffer zone".
Deprecated Term: ISDs SHOULD NOT use this term with this Deprecated Usage: ISDs SHOULD NOT use this definition because such
definition; that would mix concepts in a potentially misleading usage would mix concepts in a potentially misleading way. (See:
way. (See: (Deprecated Usage under) Green Book.) Deprecated Usage under "Green Book".)
$ denial of service $ denial of service
(I) The prevention of authorized access to a system resource or (I) The prevention of authorized access to a system resource or
the delaying of system operations and functions. (See: the delaying of system operations and functions. (See:
availability, critical, flooding.) availability, critical, flooding.)
Tutorial: A denial-of-service attack can prevent the normal Tutorial: A denial-of-service attack can prevent the normal
conduct of business on the Internet. There are four types of conduct of business on the Internet. There are four types of
solutions to this security problem: solutions to this security problem:
- Awareness: Maintaining cognizance of security threats and - Awareness: Maintaining cognizance of security threats and
vulnerabilities. (See: CERT.) vulnerabilities. (See: CERT.)
- Detection: Finding attacks on end systems and subnetworks. - Detection: Finding attacks on end systems and subnetworks.
(See: intrusion detection.) (See: intrusion detection.)
- Prevention: Following defensive practices on network-connected - Prevention: Following defensive practices on network-connected
systems. (See: [RFC 2167].) systems. (See: [R2827].)
- Response: Reacting effectively when attacks occur. (See: CSIRT, - Response: Reacting effectively when attacks occur. (See: CSIRT,
contingency plan.) contingency plan.)
$ DES $ DES
(N) See: Data Encryption Standard. (N) See: Data Encryption Standard.
$ designated approving authority (DAA) $ designated approving authority (DAA)
(O) /U.S. Government/ Synonym for "accreditor". (O) /U.S. Government/ Synonym for "accreditor".
$ detection
(I) See: secondary definition under "security".
$ deterrence
(I) See: secondary definition under "security".
$ dictionary attack $ dictionary attack
(I) An attack that uses a brute-force technique of successively (I) An attack that uses a brute-force technique of successively
trying all the words in some large, exhaustive list. trying all the words in some large, exhaustive list.
Examples: An attack on an authentication service by trying all Examples: Attack an authentication service by trying all possible
possible passwords. An attack on encryption by encrypting some passwords. Attack an encryption service by encrypting some known
known plaintext phrase with all possible keys so that the key for plaintext phrase with all possible keys so that the key for any
any given encrypted message containing that phrase may be obtained given encrypted message containing that phrase may be obtained by
by lookup. lookup.
$ Diffie-Hellman $ Diffie-Hellman
(N) A key-agreement algorithm published in 1976 by Whitfield (N) A key-agreement algorithm published in 1976 by Whitfield
Diffie and Martin Hellman [DH76, R2631]. Diffie and Martin Hellman [DH76, R2631].
Tutorial: Diffie-Hellman does key establishment, not encryption. Tutorial: Diffie-Hellman does key establishment, not encryption.
However, the key that it produces may be used for encryption, for However, the key that it produces may be used for encryption, for
further key management operations, or for any other cryptography. further key management operations, or for any other cryptography.
The algorithm is described in [R2631] and [Schn]. In brief, Alice The algorithm is described in [R2631] and [Schn]. In brief, Alice
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authenticate each party to the other, a protocol based on the authenticate each party to the other, a protocol based on the
algorithm may be vulnerable to a man-in-the-middle attack. algorithm may be vulnerable to a man-in-the-middle attack.
$ digest $ digest
See: message digest. See: message digest.
$ digital certificate $ digital certificate
(I) A certificate document in the form of a digital data object (a (I) A certificate document in the form of a digital data object (a
data object used by a computer) to which is appended a computed data object used by a computer) to which is appended a computed
digital signature value that depends on the data object. (See: digital signature value that depends on the data object. (See:
attribute certificate, capability, public-key certificate.) attribute certificate, public-key certificate.)
Deprecated Usage: ISDs SHOULD NOT use this term to refer to a Deprecated Usage: ISDs SHOULD NOT use this term to refer to a
signed CRL or CKL. Although the recommended definition can be signed CRL or CKL. Although the recommended definition can be
interpreted to include other signed items, the security community interpreted to include other signed items, the security community
does not use the term with those meanings. does not use the term with those meanings.
$ digital certification $ digital certification
(D) Synonym for "certification". (D) Synonym for "certification".
Deprecated Definition: ISDs SHOULD NOT use this definition unless Deprecated Definition: ISDs SHOULD NOT use this definition unless
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originally written in a non-electronic, non-magnetic medium originally written in a non-electronic, non-magnetic medium
(usually ink on paper) or is an analogue of a document of that (usually ink on paper) or is an analogue of a document of that
type. type.
$ digital envelope $ digital envelope
(I) A combination of (a) encrypted content data (of any kind) (I) A combination of (a) encrypted content data (of any kind)
intended for a recipient and (b) the content encryption key in an intended for a recipient and (b) the content encryption key in an
encrypted form that has been prepared for the use of the encrypted form that has been prepared for the use of the
recipient. recipient.
Usage: In ISDs, the term should be defined at the point of first Usage: In ISDs, the term SHOULD be defined at the point of first
use because, although the term is defined in PKCS #7 and used in use because, although the term is defined in PKCS #7 and used in
S/MIME, it is not widely known. S/MIME, it is not widely known.
Tutorial: Digital enveloping is not simply a synonym for Tutorial: Digital enveloping is not simply a synonym for
implementing data confidentiality with encryption; digital implementing data confidentiality with encryption; digital
enveloping is a hybrid encryption scheme to "seal" a message or enveloping is a hybrid encryption scheme to "seal" a message or
other data, by encrypting the data and sending both it and a other data, by encrypting the data and sending both it and a
protected form of the key to the intended recipient, so that no protected form of the key to the intended recipient, so that no
one other than the intended recipient can "open" the message. In one other than the intended recipient can "open" the message. In
PCKS #7, it means first encrypting the data using a symmetric PKCS #7, it means first encrypting the data using a symmetric
encryption algorithm and a secret key, and then encrypting the encryption algorithm and a secret key, and then encrypting the
secret key using an asymmetric encryption algorithm and the public secret key using an asymmetric encryption algorithm and the public
key of the intended recipient. In S/MIME, additional methods are key of the intended recipient. In S/MIME, additional methods are
defined for encrypting the content encryption key. defined for encrypting the content encryption key.
$ Digital ID(service mark) $ Digital ID(service mark)
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for (D) Synonym for "digital certificate".
"digital certificate". The term (a) is the service mark of a
commercial firm and (b) unnecessarily duplicates the meaning of Deprecated Term: ISDs SHOULD NOT use this term. It is a service
other, well-established terms. (See: credential.) mark of a commercial firm, and it unnecessarily duplicates the
meaning of a better-established term. (See: credential.)
$ digital key $ digital key
Usage: The adjective "digital" need not be used with "key" or (D) A synonym for an input parameter of a cryptographic algorithm
"cryptographic key", unless the context is insufficient to or other process.
distinguish the digital key from another kind of key, such as a
Deprecated Usage: The adjective "digital" need not be used with
"key" or "cryptographic key", unless the context is insufficient
to distinguish the digital key from another kind of key, such as a
metal key for a door lock. metal key for a door lock.
$ digital notary $ digital notary
(I) An electronic functionary analogous to a notary public. (I) An electronic functionary analogous to a notary public.
Provides a trusted time stamp for a digital document, so that Provides a trusted time stamp for a digital document, so that
someone can later prove that the document existed at that point in someone can later prove that the document existed at that point in
time; verifies the signature(s) on a signed document before time; verifies the signature(s) on a signed document before
applying the stamp. (See: notarization.) applying the stamp. (See: notarization.)
$ digital signature $ digital signature
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integrity. (See: data origin authentication service, data integrity. (See: data origin authentication service, data
integrity service, signer. Compare: digitized signature, integrity service, signer. Compare: digitized signature,
electronic signature.) electronic signature.)
2. (I) "Data appended to, or a cryptographic transformation of, a 2. (I) "Data appended to, or a cryptographic transformation of, a
data unit that allows a recipient of the data unit to prove the data unit that allows a recipient of the data unit to prove the
source and integrity of the data unit and protect against forgery, source and integrity of the data unit and protect against forgery,
e.g. by the recipient." [I7498 Part 2] e.g. by the recipient." [I7498 Part 2]
Tutorial: A digital signature should have these properties: Tutorial: A digital signature should have these properties:
- Uniquely identify a system entity as being the signer. - Uniquely identify a system entity as being the signer.
- Be under the signer's sole control, so that it cannot be - Be under the signer's sole control, so that it cannot be
created by any other entity. created by any other entity.
- Be capable of being verified. (See: validate vs. verify.) - Be capable of being verified. (See: validate vs. verify.)
- Be bound to the signed data object in such a way that if the - Be bound to the signed data object in such a way that if the
data is changed, then when an attempt is made to verify the data is changed, then when an attempt is made to verify the
signature, it will be seen as not authentic. signature, it will be seen as not authentic.
To achieve these properties, the data object is first input to a To achieve these properties, the data object is first input to a
hash function, and then the hash result is cryptographically hash function, and then the hash result is cryptographically
transformed using a private key of the signer. The final resulting transformed using a private key of the signer. The final resulting
value is called the digital signature of the data object. The value is called the digital signature of the data object. The
signature value is a protected checksum, because the properties of signature value is a protected checksum, because the properties of
a cryptographic hash ensure that if the data object is changed, a cryptographic hash ensure that if the data object is changed,
the digital signature will no longer match it. The digital the digital signature will no longer match it. The digital
signature is unforgeable because one cannot be certain of signature is unforgeable because one cannot be certain of
correctly creating or changing the signature without knowing the correctly creating or changing the signature without knowing the
private key of the supposed signer. private key of the supposed signer.
Some digital signature schemes use a asymmetric encryption Some digital signature schemes use an asymmetric encryption
algorithm (e.g., see: RSA) to transform the hash result. Thus, algorithm (e.g., see: RSA) to transform the hash result. Thus,
when Alice needs to sign a message to send to Bob, she can use her when Alice needs to sign a message to send to Bob, she can use her
private key to encrypt the hash result. Bob receives both the private key to encrypt the hash result. Bob receives both the
message and the digital signature. Bob can use Alice's public key message and the digital signature. Bob can use Alice's public key
to decrypt the signature, and then compare the plaintext result to to decrypt the signature, and then compare the plaintext result to
the hash result that he computes by hashing the message himself. the hash result that he computes by hashing the message himself.
If the values are equal, Bob accepts the message because he is If the values are equal, Bob accepts the message because he is
certain that it is from Alice and has arrived unchanged. If the certain that it is from Alice and has arrived unchanged. If the
values are not equal, Bob rejects the message because either the values are not equal, Bob rejects the message because either the
message or the signature was altered in transit. message or the signature was altered in transit.
skipping to change at page 88, line 11 skipping to change at page 92, line 54
unobtrusive. Depending on the particular technique that is used, unobtrusive. Depending on the particular technique that is used,
digital watermarking can assist in proving ownership, controlling digital watermarking can assist in proving ownership, controlling
duplication, tracing distribution, ensuring data integrity, and duplication, tracing distribution, ensuring data integrity, and
performing other functions to protect intellectual property performing other functions to protect intellectual property
rights. [ACM] rights. [ACM]
$ digitized signature $ digitized signature
(D) Denotes various forms of digitized images of handwritten (D) Denotes various forms of digitized images of handwritten
signatures. (Compare: digital signature). signatures. (Compare: digital signature).
Deprecated Term: ISDs SHOULD NOT use this term; it looks like Deprecated Term: ISDs SHOULD NOT use this term without including
sloppy use of "digital signature", which is the term standardized this definition. This term suggests careless use of "digital
by [I7498 Part 2]. (See: electronic signature.) signature", which is the term standardized by [I7498 Part 2].
(See: electronic signature.)
$ DII $ DII
(O) See: Defense Information Infrastructure. (O) See: Defense Information Infrastructure.
$ directory, Directory $ directory, Directory
1. (I) /not capitalized/ Refers generically to a database server 1. (I) /not capitalized/ Refers generically to a database server
or other system that provides information -- such as a digital or other system that stores and provides access to values of
certificate or CRL -- about an entity whose name is known. descriptive or operational data items that are associated with the
(Compare: repository.) components of a system. (Compare: repository.)
2. (N) /capitalized/ Refers specifically to the X.500 Directory. 2. (N) /capitalized/ Refers specifically to the X.500 Directory.
(See: DN, X.500.) (See: DN, X.500.)
$ Directory Access Protocol (DAP) $ Directory Access Protocol (DAP)
(N) An OSI protocol [X519] for communication between a Directory (N) An OSI protocol [X519] for communication between a Directory
User Agent (a type of X.500 client) and a Directory System Agent User Agent (a type of X.500 client) and a Directory System Agent
(a type of X.500 server). (See: LDAP.) (a type of X.500 server). (See: LDAP.)
$ disaster plan $ disaster plan
(O) Synonym for "contingency plan". (O) Synonym for "contingency plan".
Deprecated Term: ISDs SHOULD NOT use this term; instead, for Deprecated Term: ISDs SHOULD NOT use this term; instead, for
consistency and neutrality of language, ISDs SHOULD use consistency and neutrality of language, ISDs SHOULD use
"contingency plan". "contingency plan".
$ disclosure $ disclosure
See: unauthorized disclosure. Compare: exposure. See: unauthorized disclosure. Compare: exposure.
$ discretionary access control $ discretionary access control
1a. (I) An access control service that enforces a security policy 1a. (I) An access control service that (a) enforces a security
based on the identity of system entities and the authorizations policy based on the identity of system entities and the
associated with those identities. (See: access control list, DAC, authorizations associated with the identities and (b) incorporates
identity-based security policy, mandatory access control.) a concept of ownership in which access rights for a system
resource may be granted and revoked by the entity that owns the
resource. (See: access control list, DAC, identity-based security
policy, mandatory access control.)
Derivation: This service is termed "discretionary" because an Derivation: This service is termed "discretionary" because an
entity can be granted access rights to a resource such that the entity can be granted access rights to a resource such that the
entity can by its own volition enable other entities to access the entity can by its own volition enable other entities to access the
resource. That is, the service can incorporate a concept of resource.
ownership in which access rights can be granted and revoked by the
user that owns the resource.
1b. (O) /formal model/ "A means of restricting access to objects 1b. (O) /formal model/ "A means of restricting access to objects
based on the identity of subjects and/or groups to which they based on the identity of subjects and/or groups to which they
belong. The controls are discretionary in the sense that a subject belong. The controls are discretionary in the sense that a subject
with a certain access permission is capable of passing that with a certain access permission is capable of passing that
permission (perhaps indirectly) on to any other subject." [DoD1] permission (perhaps indirectly) on to any other subject." [DoD1]
$ DISN $ DISN
(O) See: Defense Information Systems Network (DISN). (O) See: Defense Information Systems Network (DISN).
$ disruption $ disruption
(I) A circumstance or event that interrupts or prevents the (I) A circumstance or event that interrupts or prevents the
correct operation of system services and functions. (See: correct operation of system services and functions. (See:
availability, critical, system integrity.) availability, critical, system integrity, threat consequence.)
Tutorial: Disruption is a type of threat consequence; it can be Tutorial: Disruption is a type of threat consequence; it can be
caused by the following types of threat actions: incapacitation, caused by the following types of threat actions: incapacitation,
corruption, and obstruction. corruption, and obstruction.
$ Distinguished Encoding Rules (DER) $ Distinguished Encoding Rules (DER)
(N) A subset of the Basic Encoding Rules, which gives exactly one (N) A subset of the Basic Encoding Rules that always provides only
way to represent any ASN.1 value as an octet string [X690]. one way to encode any data structure defined by ASN.1. [X690].
Tutorial: There usually is more than one way to encode ASN.1 in Tutorial: For a data structure defined abstractly in ASN.1, BER
BER. Therefore, DER is used in applications in which a unique often provides for encoding the structure into an octet string in
more than one way, so that two separate BER implementations can
legitimately produce different octet strings for the same ASN.1
definition. However, some applications require all encodings of a
structure to be the same, so that encodings can be compared for
equality. Therefore, DER is used in applications in which unique
encoding is needed, such as when a digital signature is computed encoding is needed, such as when a digital signature is computed
on an ASN.1 value. on a structure defined by ASN.1.
$ distinguished name (DN) $ distinguished name (DN)
(N) An identifier that uniquely represents an object in the X.500 (N) An identifier that uniquely represents an object in the X.500
Directory Information Tree (DIT) [X501]. (Compare: domain name, Directory Information Tree (DIT) [X501]. (Compare: domain name,
identity.) identity.)
Tutorial: A DN is a set of attribute values that identify the path Tutorial: A DN is a set of attribute values that identify the path
leading from the base of the DIT to the object that is named. An leading from the base of the DIT to the object that is named. An
X.509 public-key certificate or CRL contains a DN that identifies X.509 public-key certificate or CRL contains a DN that identifies
its issuer, and an X.509 attribute certificate contains a DN or its issuer, and an X.509 attribute certificate contains a DN or
skipping to change at page 90, line 35 skipping to change at page 95, line 35
$ DNS $ DNS
(I) See: Domain Name System. (I) See: Domain Name System.
$ doctrine $ doctrine
See: security doctrine. See: security doctrine.
$ DoD $ DoD
(N) Department of Defense. (N) Department of Defense.
Usage: To ensure international understanding, ISDs should use this Usage: To avoid international misunderstanding, ISDs SHOULD use
abbreviation only with a national qualifier (e.g., U.S. DoD). this abbreviation only with a national qualifier (e.g., U.S. DoD).
$ DOI $ DOI
(I) See: Domain of Interpretation. (I) See: Domain of Interpretation.
$ domain $ domain
1a. (I) /general security/ An environment or context that is 1a. (I) /general security/ An environment or context that (a)
includes a set of system resources and a set of system entities
that have the right to access the resources and (b) usually is
defined by a security policy, security model, or security defined by a security policy, security model, or security
architecture to include a set of system resources and a set of architecture. (See: domain of interpretation, security perimeter.
system entities that have the right to access the resources. (See: Compare: COI, enclave.)
domain of interpretation, security perimeter. Compare: COI,
enclave.)
Tutorial: A "controlled interface" or "guard" is required to Tutorial: A "controlled interface" or "guard" is required to
transfer information between network domains that operate under transfer information between network domains that operate under
different security policies. different security policies.
1b. (O) /security policy/ A set of users, their information 1b. (O) /security policy/ A set of users, their information
objects, and a common security policy. [DGSA, SP33] objects, and a common security policy. [DGSA, SP33]
2. (N) /computer security/ A operating state or mode of a set of
1c. (O) /security policy/ A system or collection of systems that
(a) belongs to a community of interest that implements a
consistent security policy and (b) is administered by a single
authority.
2. (O) /computer security/ A operating state or mode of a set of
computer hardware. computer hardware.
Tutorial: Most computers have at least two hardware operating Tutorial: Most computers have at least two hardware operating
modes [Gass]: modes [Gass]:
- "Privileged" mode: Also called "executive", "master", "system", - "Privileged" mode: Also called "executive", "master", "system",
kernel", or "supervisor" mode. In this mode, software can kernel", or "supervisor" mode. In this mode, software can
execute any machine instruction and access any machine storage. execute all machine instructions and access all storage
- "Unprivileged" mode: Also called "user", "application", or locations.
- "Unprivileged" mode: Also called "user", "application", or
"problem" mode. In this mode, software is restricted to a "problem" mode. In this mode, software is restricted to a
subset of the instructions and a subset of the storage. subset of the instructions and a subset of the storage
locations.
3. (I) /Internet/ That part of the Internet domain name space tree 3. (O) "A distinct scope within which certain common
(RFC 1034) that is at or below the name that specifies the domain. characteristics are exhibited and common rules are observed."
A domain is a subdomain of another domain if it is contained [CORBA]
within that domain. For example, D.C.B.A is a subdomain of C.B.A.
(See: Domain Name System.)
4. (O) /MISSI/ The domain of a MISSI CA is the set of MISSI users 4. (O) /MISSI/ The domain of a MISSI CA is the set of MISSI users
whose certificates are signed by the CA. whose certificates are signed by the CA.
5. (O) /OSI/ An administrative partition of a complex distributed 5. (I) /Internet/ That part of the tree-structured name space of
OSI system. the DNS that is at or below the name that specifies the domain. A
domain is a subdomain of another domain if it is contained within
that domain. For example, D.C.B.A is a subdomain of C.B.A
6. (O) "A distinct scope within which certain common 6. (O) /OSI/ An administrative partition of a complex distributed
characteristics are exhibited and common rules are observed." OSI system.
[CORBA]
$ domain name $ domain name
(I) The style of identifier -- a sequence of case-insensitive (I) The style of identifier that is defined for subtrees in the
ASCII labels separated by dots (e.g., "bbn.com") -- defined for Internet DNS -- i.e., a sequence of case-insensitive ASCII labels
subtrees in the Internet DNS and used in other Internet separated by dots (e.g., "bbn.com") -- and also is used in other
identifiers, like host names (e.g., "rosslyn.bbn.com"), mailbox types of Internet identifiers, such as host names (e.g.,
names (e.g., "rshirey@bbn.com."), and URLs (e.g., "rosslyn.bbn.com"), mailbox names (e.g., "rshirey@bbn.com.") and
"http://www.rosslyn.bbn.com./foo"). (See: DN, domain.) URLs (e.g., "http://www.rosslyn.bbn.com./foo"). (See: DN, domain.)
Tutorial: The name space of the DNS (RFC 1591) is a tree structure Tutorial: The name space of the DNS is a tree structure in which
in which each node and leaf holds records describing a resource. each node and leaf holds records describing a resource. Each node
Each node has a label. The domain name of a node is the list of has a label. The domain name of a node is the list of labels on
labels on the path from the node to the root of the tree. The the path from the node to the root of the tree. The labels in a
labels in a domain name are printed or read left to right, from domain name are printed or read left to right, from the most
the most specific (lowest, farthest from the root) to the least specific (lowest, farthest from the root) to the least specific
specific (highest, closest to the root), but the root's label is (highest, closest to the root), but the root's label is the null
the null string. (See: country code.) string. (See: country code.)
$ Domain Name System (DNS) $ Domain Name System (DNS)
(I) The main Internet operations database, which is distributed (I) The main Internet operations database, which is distributed
over a collection of servers and used by client software for over a collection of servers and used by client software for
purposes such as translating a domain name-style host name into an purposes such as (a) translating a domain name-style host name
IP address (e.g., "rosslyn.bbn.com" is "192.1.7.10") and locating into an IP address (e.g., "rosslyn.bbn.com" translates to
a host that accepts mail for some mailbox address. [R1034] "192.1.7.10") and (b) locating a host that accepts mail for a
Tutorial: The DNS has three major components: (a) Domain name given mailbox address. (RFC 1034)
space and resource records: Specifications for the tree-structured
domain name space, and data associated with the names. (b) Name
servers: Programs that hold information about a subset of the
tree's structure and data holdings, and also hold pointers to
other name servers that can provide information from any part of
the tree. (c) Resolvers: Programs that extract information from
name servers in response to client requests; typically, system
routines directly accessible to user programs.
Extensions to the DNS [R2065, R2137, R2536] support (a) key Tutorial: The DNS has three major components:
- Domain name space and resource records: Specifications for the
tree-structured domain name space, and data associated with the
names.
- Name servers: Programs that hold information about a subset of
the tree's structure and data holdings, and also hold pointers
to other name servers that can provide information from any
part of the tree.
- Resolvers: Programs that extract information from name servers
in response to client requests; typically, system routines
directly accessible to user programs.
Extensions to the DNS [R2535, R2536, R3007] support (a) key
distribution for public keys needed for the DNS and for other distribution for public keys needed for the DNS and for other
protocols, (b) data origin authentication service and data protocols, (b) data origin authentication service and data
integrity service for resource records, (c) data origin integrity service for resource records, (c) data origin
authentication service for transactions between resolvers and authentication service for transactions between resolvers and
servers, and (d) access control of records. servers, and (d) access control of records.
$ domain of interpretation (DOI) $ domain of interpretation (DOI)
(I) /IPsec/ An ISAKMP/IKE DOI defines payload formats, exchange (I) /IPsec/ An DOI for ISAKMP or IKE defines payload formats,
types, and conventions for naming security-relevant information exchange types, and conventions for naming security-relevant
such as security policies or cryptographic algorithms and modes. information such as security policies or cryptographic algorithms
Example: See [R2407]. and modes. Example: See [R2407].
Derivation: The DOI concept is based on work by the TSIG's CIPSO Derivation: The DOI concept is based on work by the TSIG's CIPSO
Working Group. Working Group.
$ dominate $ dominate
(I) Security level A is said to "dominate" security level B if the (I) Security level A is said to "dominate" security level B if the
hierarchical classification level of A is greater (higher) than or (hierarchical) classification level of A is greater (higher) than
equal to that of B and the nonhierarchical categories of A include or equal to that of B, and A's (nonhierarchical) categories
all of those of B. (See: lattice, lattice model.) include all of B's categories. (See: lattice, lattice model.)
$ dongle $ dongle
(I) A portable, physical, usually electronic device that is (I) A portable, physical, usually electronic device that is
required to be attached to a computer to enable a particular required to be attached to a computer to enable a particular
software program to run. (See: token.) software program to run. (See: token.)
Tutorial: A dongle is essentially a physical key used for copy Tutorial: A dongle is essentially a physical key used for copy
protection of software, because the program will not run unless protection of software; that is, the program will not run unless
the matching dongle is attached. When the software runs, it the matching dongle is attached. When the software runs, it
periodically queries the dongle and quits if the dongle does not periodically queries the dongle and quits if the dongle does not
reply with the proper authentication information. Dongles were reply with the proper authentication information. Dongles were
originally constructed as an EPROM (erasable programmable read- originally constructed as an EPROM (erasable programmable read-
only memory) to be connected to a serial input-output port of a only memory) to be connected to a serial input-output port of a
personal computer. personal computer.
$ downgrade $ downgrade
(I) /data security/ Reduce the classification level of data (I) /data security/ Reduce the security level of data (especially
without changing the information content of the data. (Compare: the classification level) without changing the information content
upgrade. See: regrade.) of the data. (See: regrade, upgrade. Compare: declassify.)
$ draft RFC $ draft RFC
Deprecated Term: ISDs SHOULD NOT use this term; the Request for (D) A preliminary, temporary version of a document that is
Comment series is archival in nature and does not have a "draft" intended to become an RFC.
category. (See: Internet Draft, (Draft Standard under) Internet
Standard).) Deprecated Term: ISDs SHOULD NOT use this term. The RFC series is
archival in nature and consists only of documents in permanent
form. A document that is intended to become an RFC usually needs
to be published first as an "Internet-Draft" (RFC 2026). (See:
"Draft Standard" under "Internet Standard".)
$ Draft Standard $ Draft Standard
(I) See: (secondary definition under) Internet Standard. (I) See: secondary definition under "Internet Standard".
$ DSA $ DSA
(N) See: Digital Signature Algorithm. (N) See: Digital Signature Algorithm.
$ DSS $ DSS
(N) See: Digital Signature Standard. (N) See: Digital Signature Standard.
$ dual control $ dual control
(I) A procedure that uses two or more entities (usually persons) (I) A procedure that uses two or more entities (usually persons)
operating in concert to protect a system resource, such that no operating in concert to protect a system resource, such that no
single entity acting alone can access that resource. (See: no-lone single entity acting alone can access that resource. (See: no-lone
zone, separation of duties, split knowledge.) zone, separation of duties, split knowledge.)
$ dual signature $ dual signature
(O) /SET/ A single digital signature that protects two separate (O) /SET/ A single digital signature that protects two separate
messages by including the hash results for both sets in a single messages by including the hash results for both sets in a single
encrypted value. [SET2] encrypted value. [SET2]
Deprecated Term: ISDs SHOULD NOT use this term except when Deprecated Usage: ISDs SHOULD NOT use this term except when
qualified as "SET(trademark) dual signature" with this definition. qualified as "SET(trademark) dual signature" with this definition.
Tutorial: Generated by hashing each message separately, Tutorial: Generated by hashing each message separately,
concatenating the two hash results, and then hashing that value concatenating the two hash results, and then hashing that value
and encrypting the result with the signer's private key. Done to and encrypting the result with the signer's private key. Done to
reduce the number of encryption operations and to enable reduce the number of encryption operations and to enable
verification of data integrity without complete disclosure of the verification of data integrity without complete disclosure of the
data. data.
$ dual-use certificate $ dual-use certificate
(I) A certificate that is intended for use with both digital (O) A certificate that is intended for use with both digital
signature and data encryption services. [SP32] signature and data encryption services. [SP32]
Usage: An ISD that uses the term SHOULD state a definition by Usage: ISDs that use this term SHOULD state a definition for it by
identifying the intended uses of the certificate, because there identifying the intended uses of the certificate, because there
are more than just these two. A v3 X.509 public-key certificate are more than just these two uses mentioned in the NIST
may have a "key Usage" extension, which indicates the purposes for publication. A v3 X.509 public-key certificate may have a "key
which the public key may be used. (See: certificate profile.) Usage" extension, which indicates the purposes for which the
public key may be used. (See: certificate profile.)
$ duty $ duty
(I) An attribute of a role that obligates an entity playing the (I) An attribute of a role that obligates an entity playing the
role to perform one or more tasks, which usually are essential for role to perform one or more tasks, which usually are essential for
the functioning of the system. [Sand] (Compare authorization, the functioning of the system. [Sand] (Compare authorization,
privilege. See: role, billet.) privilege. See: role, billet.)
$ e-cash $ e-cash
(D) Electronic cash; money that is in the form of data and can be (O) Electronic cash; money that is in the form of data and can be
used as a payment mechanism on the Internet. used as a payment mechanism on the Internet.
Deprecated Usage: Many different types of electronic cash have Deprecated Usage: ISDs that use this term SHOULD state a
been devised, using a variety of security mechanisms; therefore, definition for it because many different types of electronic cash
ISDs that use the term SHOULD state a definition for it. have been devised with a variety of security mechanisms.
$ EAP $ EAP
(I) See: Extensible Authentication Protocol. (I) See: Extensible Authentication Protocol.
$ EAL $ EAL
(O) See: evaluation assurance level. (O) See: evaluation assurance level.
$ Easter egg $ Easter egg
(D) "Hidden functionality within an application program, which (D) "Hidden functionality within an application program, which
becomes activated when an undocumented, and often convoluted, set becomes activated when an undocumented, and often convoluted, set
of commands and keystrokes is entered. Easter eggs are typically of commands and keystrokes is entered. Easter eggs are typically
used to display the credits for the development team and [are] used to display the credits for the development team and [are]
intended to be non-threatening" [SP28], but Easter eggs have the intended to be non-threatening" [SP28], but Easter eggs have the
potential to contain malicious code. potential to contain malicious code.
Deprecated Usage: It is likely that other cultures have different Deprecated Usage: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ eavesdropping $ eavesdropping
(I) Passive wiretapping done secretly, i.e., without the knowledge (I) Passive wiretapping done secretly, i.e., without the knowledge
of the originator or the intended recipients of the communication. of the originator or the intended recipients of the communication.
$ ECB $ ECB
(N) See: electronic codebook. (N) See: electronic codebook.
$ ECDSA $ ECDSA
(N) See: Elliptic Curve Digital Signature Algorithm. (N) See: Elliptic Curve Digital Signature Algorithm.
skipping to change at page 94, line 45 skipping to change at page 100, line 4
$ ECB $ ECB
(N) See: electronic codebook. (N) See: electronic codebook.
$ ECDSA $ ECDSA
(N) See: Elliptic Curve Digital Signature Algorithm. (N) See: Elliptic Curve Digital Signature Algorithm.
$ economy of alternatives $ economy of alternatives
(I) The principle that a security mechanism should be designed to (I) The principle that a security mechanism should be designed to
minimize the number of alternative ways of achieving a service. minimize the number of alternative ways of achieving a service.
(Compare: economy of mechanism.) (Compare: economy of mechanism.)
$ economy of mechanism $ economy of mechanism
(I) The principle that a security mechanism should be designed to (I) The principle that a security mechanism should be designed to
be as simple as possible, so that (a) the mechanism can be be as simple as possible, so that (a) the mechanism can be
correctly implemented and (b) it can be verified that the correctly implemented and (b) it can be verified that the
operation of the mechanism enforces the system's security policy. operation of the mechanism enforces the system's security policy.
(Compare: economy of alternatives, least privilege.) (Compare: economy of alternatives, least privilege.)
$ ECU $ ECU
(N) See: end cryptographic unit. (N) See: end cryptographic unit.
$ EDI $ EDI
(I) See: electronic data interchange. (I) See: electronic data interchange.
$ EDIFACT $ EDIFACT
(N) See: (secondary definition under) electronic data interchange. (N) See: secondary definition under "electronic data interchange".
$ EE $ EE
Deprecated Term: ISDs SHOULD NOT use this abbreviation; there (D) Abbreviation of "end entity" and other terms.
could be confusion among "end entity", "end-to-end encryption",
"escrowed encryption standard", and other terms. Deprecated Abbreviation: ISDs SHOULD NOT use this abbreviation;
there could be confusion among "end entity", "end-to-end
encryption", "escrowed encryption standard", and other terms.
$ EES $ EES
(O) See: Escrowed Encryption Standard. (O) See: Escrowed Encryption Standard.
$ effective key length $ effective key length
(O) "A measure of strength of a cryptographic algorithm, (O) "A measure of strength of a cryptographic algorithm,
regardless of actual key length." [IATF] regardless of actual key length." [IATF]
$ effectiveness $ effectiveness
(O) /ITSEC/ A property of a TOE representing how well it provides (O) /ITSEC/ A property of a TOE representing how well it provides
skipping to change at page 95, line 36 skipping to change at page 100, line 50
$ El Gamal algorithm $ El Gamal algorithm
(N) An algorithm for asymmetric cryptography, invented in 1985 by (N) An algorithm for asymmetric cryptography, invented in 1985 by
Taher El Gamal, that is based on the difficulty of calculating Taher El Gamal, that is based on the difficulty of calculating
discrete logarithms and can be used for both encryption and discrete logarithms and can be used for both encryption and
digital signatures. digital signatures.
$ electronic codebook (ECB) $ electronic codebook (ECB)
(N) An block cipher mode in which a plaintext block is used (N) An block cipher mode in which a plaintext block is used
directly as input to the encryption algorithm and the resultant directly as input to the encryption algorithm and the resultant
output block is used directly as cipher text [FP081]. output block is used directly as cipher text [FP081]. (See: block
cipher.)
$ electronic commerce $ electronic commerce
1. (I) Business conducted through paperless exchanges of 1. (I) Business conducted through paperless exchanges of
information, using electronic data interchange, electronic funds information, using electronic data interchange, electronic funds
transfer (EFT), electronic mail, computer bulletin boards, transfer (EFT), electronic mail, computer bulletin boards,
facsimile, and other paperless technologies. facsimile, and other paperless technologies.
2. (O) /SET/ "The exchange of goods and services for payment 2. (O) /SET/ "The exchange of goods and services for payment
between the cardholder and merchant when some or all of the between the cardholder and merchant when some or all of the
transaction is performed via electronic communication." [SET2] transaction is performed via electronic communication." [SET2]
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create a single, global EDI standard. create a single, global EDI standard.
$ Electronic Key Management System (EKMS) $ Electronic Key Management System (EKMS)
(O) "Interoperable collection of systems developed by ... the U.S. (O) "Interoperable collection of systems developed by ... the U.S.
Government to automate the planning, ordering, generating, Government to automate the planning, ordering, generating,
distributing, storing, filling, using, and destroying of distributing, storing, filling, using, and destroying of
electronic keying material and the management of other types of electronic keying material and the management of other types of
COMSEC material." [C4009] COMSEC material." [C4009]
$ electronic signature $ electronic signature
(D) Synonym for "digital signature" or "digitized signature".
Deprecated Term: ISDs SHOULD NOT use this term; there is no Deprecated Term: ISDs SHOULD NOT use this term; there is no
current consensus on its definition. Instead, use "digital current consensus on its definition. Instead, use "digital
signature", if that is what was intended. (See: digitized signature", if that is what was intended
signature.)
$ electronic wallet $ electronic wallet
Deprecated Term: ISDs SHOULD NOT use this term; there is no (D) A secure container to hold, in digitized form, some sensitive
current consensus on its definition. Meanings range from "digital data objects that belong to the owner, such as electronic money,
certificate" to "smartcard", and some uses and definitions may be authentication material, and various types of personal
proprietary. (See: (Deprecated Usage under) Green Book.) information.
Deprecated Term: ISDs SHOULD NOT use this term. There is no
current consensus on its definition; and some uses and definitions
may be proprietary. Meanings range from virtual wallets
implemented by data structures to physical wallets implemented by
cryptographic tokens. (See: Deprecated Usage under "Green Book".)
$ elliptic curve cryptography (ECC) $ elliptic curve cryptography (ECC)
(I) A type of asymmetric cryptography based on mathematics of (I) A type of asymmetric cryptography based on mathematics of
groups that are defined by the points on a curve, where the curve groups that are defined by the points on a curve, where the curve
is defined by a quadratic equation in a finite field. [Schn] is defined by a quadratic equation in a finite field. [Schn]
Tutorial: The most efficient implementation of ECC is claimed to Tutorial: The most efficient implementation of ECC is claimed to
be stronger per bit of key (against cryptanalysis that uses a be stronger per bit of key (against cryptanalysis that uses a
brute force attack) than any other known form of asymmetric brute force attack) than any other known form of asymmetric
cryptography. ECC is based on mathematics different than the kinds cryptography. ECC is based on mathematics different than the kinds
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$ emanation $ emanation
(I) An signal (e.g., electromagnetic or acoustic) that is emitted (I) An signal (e.g., electromagnetic or acoustic) that is emitted
by a system (e.g., through radiation or conductance) as a by a system (e.g., through radiation or conductance) as a
consequence (i.e., byproduct) of the system's operation, and that consequence (i.e., byproduct) of the system's operation, and that
may contain information. (See: emanations security.) may contain information. (See: emanations security.)
$ emanations security (EMSEC) $ emanations security (EMSEC)
(I) Physical security measures to protect against data compromise (I) Physical security measures to protect against data compromise
that could occur because of emanations that might be received and that could occur because of emanations that might be received and
read by an unauthorized party. (See: TEMPEST.) read by an unauthorized party. (See: emanation, TEMPEST.)
Usage: Refers both to preventing or limiting emanations from a Usage: Refers both to preventing or limiting emanations from a
system and to preventing or limiting the ability of unauthorized system and to preventing or limiting the ability of unauthorized
parties to receive the emissions. parties to receive the emissions.
$ embedded cryptography $ embedded cryptography
(N) "Cryptography engineered into an equipment or system whose (N) "Cryptography engineered into an equipment or system whose
basic function is not cryptographic." [C4009] basic function is not cryptographic." [C4009]
$ emergency plan $ emergency plan
(D) Synonym for "contingency plan". (D) Synonym for "contingency plan".
Deprecated Term: ISDs SHOULD NOT use this term. Instead, for Deprecated Term: ISDs SHOULD NOT use this term. Instead, for
neutrality and consistency of language, use "contingency plan". neutrality and consistency of language, use "contingency plan".
$ emergency response $ emergency response
(O) An urgent response to a fire, flood, civil commotion, natural (O) An urgent response to a fire, flood, civil commotion, natural
disaster, bomb threat, or other serious situation, with the intent disaster, bomb threat, or other serious situation, with the intent
of protecting lives, limiting damage to property, and minimizing of protecting lives, limiting damage to property, and minimizing
disruption of system operations. [FP087] (See: availability, disruption of system operations. [FP087] (See: availability, CERT,
CERT.) emergency plan.)
$ EMSEC $ EMSEC
(I) See: emanations security. (I) See: emanations security.
$ EMV $ EMV
(N) An abbreviation of "Europay, MasterCard, Visa". Refers to a (N) Abbreviation of "Europay, MasterCard, Visa". Refers to a
specification for smart cards that are used as payment cards, and specification for smart cards that are used as payment cards, and
for related terminals and applications. [EMV1, EMV2, EMV3] for related terminals and applications. [EMV1, EMV2, EMV3]
$ Encapsulating Security Payload (ESP) $ Encapsulating Security Payload (ESP)
(I) An Internet protocol [R2406] designed to provide data (I) An Internet protocol [R2406] designed to provide data
confidentiality service and other security services for IP confidentiality service and other security services for IP
datagrams. (See: IPsec. Compare: AH.) datagrams. (See: IPsec. Compare: AH.)
Tutorial: ESP may be used alone, or in combination with AH, or in Tutorial: ESP may be used alone, or in combination with AH, or in
a nested fashion with tunneling. Security services can be provided a nested fashion with tunneling. Security services can be provided
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data confidentiality service, data origin authentication service, data confidentiality service, data origin authentication service,
connectionless data integrity service, an anti-replay service, and connectionless data integrity service, an anti-replay service, and
limited traffic-flow confidentiality. The set of services depends limited traffic-flow confidentiality. The set of services depends
on the placement of the implementation and on options selected on the placement of the implementation and on options selected
when the security association is established. when the security association is established.
$ encipher $ encipher
(D) Synonym for "encrypt". (D) Synonym for "encrypt".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "encrypt". However, see usage note under "encryption". for "encrypt". However, see Usage note under "encryption".
$ encipherment $ encipherment
(D) Synonym for "encryption". (D) Synonym for "encryption".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "encryption". However, see usage note under "encryption". for "encryption". However, see Usage note under "encryption".
$ enclave $ enclave
1. (I) A set of system resources that operate in the same security 1. (I) A set of system resources that operate in the same security
domain and that share the protection of a common, continuous domain and that share the protection of a common, continuous
security perimeter. (Compare: domain.) security perimeter. (Compare: domain.)
2. (O) /U.S. Government/ "Collection of computing environments 2. (O) /U.S. Government/ "Collection of computing environments
connected by one or more internal networks under the control of a connected by one or more internal networks under the control of a
single authority and security policy, including personnel and single authority and security policy, including personnel and
physical security." [C4009] physical security." [C4009]
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Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "encrypt"; encoding is not always meant to conceal meaning. for "encrypt"; encoding is not always meant to conceal meaning.
$ encrypt $ encrypt
(I) Cryptographically transform data to produce cipher text. (See: (I) Cryptographically transform data to produce cipher text. (See:
encryption. Compare: seal.) encryption. Compare: seal.)
$ encryption $ encryption
1. (I) Cryptographic transformation of data (called "plain text") 1. (I) Cryptographic transformation of data (called "plain text")
into a form (called "cipher text") that conceals the data's into a different form (called "cipher text") that conceals the
original meaning to prevent it from being known or used. If the data's original meaning and prevents the original form from being
transformation is reversible, the corresponding reversal process used. If the transformation is reversible, the corresponding
is called "decryption", which is a transformation that restores reversal process is called "decryption", which is a transformation
encrypted data to its original state. (See: cryptography.) that restores encrypted data to its original state. (See:
cryptography.)
2. (O) "The cryptographic transformation of data to produce 2. (O) "The cryptographic transformation of data to produce
ciphertext." [I7498 Part 2] ciphertext." [I7498 Part 2]
Usage: For this concept, ISDs SHOULD use the verb "to encrypt" Usage: For this concept, ISDs SHOULD use the verb "to encrypt"
(and related variations: encryption, decrypt, and decryption). (and related variations: encryption, decrypt, and decryption).
However, because of cultural biases involving human burial, some However, because of cultural biases involving human burial, some
international documents (particularly ISO and CCITT standards) international documents (particularly ISO and CCITT standards)
avoid "to encrypt" and instead use the verb "to encipher" (and avoid "to encrypt" and instead use the verb "to encipher" (and
related variations: encipherment, decipher, decipherment). related variations: encipherment, decipher, decipherment).
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Tutorial: Whether a subject can play both CA and non-CA roles, Tutorial: Whether a subject can play both CA and non-CA roles,
with either the same or different certificates, is a matter of with either the same or different certificates, is a matter of
policy. (See: CPS.) A v3 X.509 public-key certificate may have a policy. (See: CPS.) A v3 X.509 public-key certificate may have a
"basicConstraints" extension containing a "cA" value that "basicConstraints" extension containing a "cA" value that
specifically "indicates whether or not the public key may be used specifically "indicates whether or not the public key may be used
to verify certificate signatures". (See: certificate profile.) to verify certificate signatures". (See: certificate profile.)
$ end system $ end system
(N) /OSIRM/ A computer that implements all seven layers of the (N) /OSIRM/ A computer that implements all seven layers of the
OSIRM and may attach to a subnetwork. Usage: In the IPS context, a OSIRM and may attach to a subnetwork. Usage: In the IPS context,
end system is called a "host". an end system is called a "host".
$ end-to-end encryption $ end-to-end encryption
(I) Continuous protection of data that flows between two points in (I) Continuous protection of data that flows between two points in
a network, effected by encrypting data when it leaves its source, a network, effected by encrypting data when it leaves its source,
leaving it encrypted while it passes through any intermediate keeping it encrypted while it passes through any intermediate
computers (such as routers), and decrypting only when the data computers (such as routers), and decrypting it only when it
arrives at the intended final destination. (See: wiretapping. arrives at the intended final destination. (See: wiretapping.
Compare: link encryption.) Compare: link encryption.)
Examples: BLACKER, CANEWARE, IPLI, IPsec, PLI, SDNS, SILS. Examples: BLACKER, CANEWARE, IPLI, IPsec, PLI, SDNS, SILS.
Tutorial: When two points are separated by multiple communication Tutorial: When two points are separated by multiple communication
links that are connected by one or more intermediate relays, end- links that are connected by one or more intermediate relays, end-
to-end encryption enables the source and destination systems to to-end encryption enables the source and destination systems to
protect their communications without depending on the intermediate protect their communications without depending on the intermediate
systems to provide the protection. systems to provide the protection.
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purpose of detecting attempted penetrations or confusing an purpose of detecting attempted penetrations or confusing an
intruder about which flaws to exploit." [FP039] (See: honey pot.) intruder about which flaws to exploit." [FP039] (See: honey pot.)
$ entropy $ entropy
1. (I) An information-theoretic measure (usually stated as a 1. (I) An information-theoretic measure (usually stated as a
number of bits) of the amount of uncertainty that an attacker number of bits) of the amount of uncertainty that an attacker
faces to determine the value of a secret. [SP63] (See: strength.) faces to determine the value of a secret. [SP63] (See: strength.)
Example: If a password is said to contain at least 20 bits of Example: If a password is said to contain at least 20 bits of
entropy, that means that it must be as hard to find the password entropy, that means that it must be as hard to find the password
as to guess an 20-bit random number. as to guess a 20-bit random number.
2. (I) An information-theoretic measure (usually stated as a 2. (I) An information-theoretic measure (usually stated as a
number of bits) of the amount of information in a message; i.e., number of bits) of the amount of information in a message; i.e.,
the minimum number of bits needed to encode all possible meanings the minimum number of bits needed to encode all possible meanings
of that message. [Schn] (See: uncertainty.) of that message. [Schn] (See: uncertainty.)
$ ephemeral $ ephemeral
(I) /adjective/ Refers to a cryptographic key or other parameter (I) /adjective/ Refers to a cryptographic key or other
that is short-lived, temporary, or used one time. (See: session cryptographic parameter or data object that is short-lived,
key. Compare: static.) temporary, or used one time. (See: session key. Compare: static.)
$ erase $ erase
(I) Delete magnetically stored data in such a way that the data is (I) Delete magnetically stored data in such a way that the data is
irretrievable by ordinary means, but might be recovered using irretrievable by ordinary means, but might be recovered using
laboratory methods. [C4009] (Compare: purge.) laboratory methods. [C4009] (Compare: purge.)
$ error detection code $ error detection code
(I) A checksum designed to detect, but not correct, accidental (I) A checksum designed to detect, but not correct, accidental
(i.e., unintentional) changes in data. (i.e., unintentional) changes in data.
$ Escrowed Encryption Standard (EES) $ Escrowed Encryption Standard (EES)
(N) A U.S. Government standard [FP185] that specifies use of a (N) A U.S. Government standard [FP185] that specifies how to use a
symmetric encryption algorithm (SKIPJACK) and a Law Enforcement symmetric encryption algorithm (SKIPJACK) and create a Law
Access Field (LEAF) creation method to implement part of a key Enforcement Access Field (LEAF) for implementing part of a key
escrow system that provides for decryption of telecommunications escrow system that enables decryption of telecommunications when
when interception is lawfully authorized. interception is lawfully authorized.
Tutorial: Both SKIPJACK and the LEAF are intended for use in Tutorial: Both SKIPJACK and the LEAF are intended for use in
equipment used to encrypt and decrypt unclassified, sensitive equipment used to encrypt and decrypt sensitive, unclassified,
telecommunications data. telecommunications data.
$ ESP $ ESP
(I) See: Encapsulating Security Payload. (I) See: Encapsulating Security Payload.
$ Estelle $ Estelle
(N) A language (ISO 9074-1989) for formal specification of (N) A language (ISO 9074-1989) for formal specification of
computer network protocols. computer network protocols.
$ ETSI $ ETSI
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$ EUCI $ EUCI
(O) See: endorsed-for-unclassified cryptographic item. (O) See: endorsed-for-unclassified cryptographic item.
$ European Telecommunication Standards Institute (ETSI) $ European Telecommunication Standards Institute (ETSI)
(N) An independent, non-profit organization, based in France, that (N) An independent, non-profit organization, based in France, that
is officially recognized by the European Commission and is officially recognized by the European Commission and
responsible for standardization of information and communication responsible for standardization of information and communication
technologies within Europe. technologies within Europe.
Tutorial: ETSI is the custodian of a number of security Tutorial: ETSI maintains the standards for a number of security
algorithms, including encryption algorithms for mobile telephone algorithms, including encryption algorithms for mobile telephone
systems in Europe. systems in Europe.
$ evaluated products list, Evaluated Products List $ evaluated products list, Evaluated Products List
1. (I) /not capitalized/ A list of information system equipment 1. (I) /not capitalized/ A list of information system equipment
items that have been evaluated against, and found to be compliant items that have been evaluated against, and found to be compliant
with, a particular set of criteria. with, a particular set of criteria.
2. (N) /capitalized, U.S. Government/ The Evaluated Products List 2. (N) /capitalized, U.S. Government/ The Evaluated Products List
(http://www.radium.ncsc.mil/tpep/epl/) contains items that have (http://www.radium.ncsc.mil/tpep/epl/) contains items that have
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certification.) certification.)
$ evaluation assurance level (EAL) $ evaluation assurance level (EAL)
(N) A predefined package of assurance components that represents a (N) A predefined package of assurance components that represents a
point on the Common Criteria's scale for rating confidence in the point on the Common Criteria's scale for rating confidence in the
security of information technology products and systems. security of information technology products and systems.
Tutorial: The Common Criteria defines a scale of seven, Tutorial: The Common Criteria defines a scale of seven,
hierarchically ordered EALs for rating a TOE. From highest to hierarchically ordered EALs for rating a TOE. From highest to
lowest, they are as follows: lowest, they are as follows:
- EAL7. Formally verified design and tested. - EAL7. Formally verified design and tested.
- EAL6. Semiformally verified design and tested. - EAL6. Semiformally verified design and tested.
- EAL5. Semiformally designed and tested. - EAL5. Semiformally designed and tested.
- EAL4. Methodically designed, tested, and reviewed. - EAL4. Methodically designed, tested, and reviewed.
- EAL3. Methodically tested and checked. - EAL3. Methodically tested and checked.
- EAL2. Structurally tested. - EAL2. Structurally tested.
- EAL1. Functionally tested. - EAL1. Functionally tested.
An EAL is a consistent, baseline set of requirements. The increase An EAL is a consistent, baseline set of requirements. The increase
in assurance from EAL to EAL is accomplished by substituting in assurance from EAL to EAL is accomplished by substituting
higher assurance components (i.e. criteria of increasing rigor, higher assurance components (i.e. criteria of increasing rigor,
scope, or depth) from seven assurance classes: (a) configuration scope, or depth) from seven assurance classes: (a) configuration
management, (b) delivery and operation, (c) development, (d) management, (b) delivery and operation, (c) development, (d)
guidance documents, (e) life cycle support, (f) tests, and (g) guidance documents, (e) life cycle support, (f) tests, and (g)
vulnerability assessment. vulnerability assessment.
The EALs were developed with the goal of preserving concepts of The EALs were developed with the goal of preserving concepts of
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$ expire $ expire
(I) See: certificate expiration. (I) See: certificate expiration.
$ exposure $ exposure
(I) A type of threat action whereby sensitive data is directly (I) A type of threat action whereby sensitive data is directly
released to an unauthorized entity. (See: unauthorized released to an unauthorized entity. (See: unauthorized
disclosure.) disclosure.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Deliberate Exposure": Intentional release of sensitive data to - "Deliberate Exposure": Intentional release of sensitive data to
an unauthorized entity. an unauthorized entity.
- "Scavenging": Searching through data residue in a system to - "Scavenging": Searching through data residue in a system to
gain unauthorized knowledge of sensitive data. gain unauthorized knowledge of sensitive data.
- "Human error": In context of exposure, human action or inaction
- "Human error": In context of exposure, human action or inaction
that unintentionally results in an entity gaining unauthorized that unintentionally results in an entity gaining unauthorized
knowledge of sensitive data. knowledge of sensitive data. (Compare: corruption,
- "Hardware or software error": In context of exposure, system incapacitation.)
- "Hardware or software error": In context of exposure, system
failure that unintentionally results in an entity gaining failure that unintentionally results in an entity gaining
unauthorized knowledge of sensitive data. unauthorized knowledge of sensitive data. (Compare: corruption,
incapacitation.)
$ Extended Security Option $ Extended Security Option
(I) See: (secondary definition under) IPSO. (I) See: secondary definition under "IPSO".
$ Extensible Authentication Protocol (EAP) $ Extensible Authentication Protocol (EAP)
(I) A extension framework for PPP that supports multiple, optional (I) A extension framework for PPP that supports multiple, optional
authentication mechanisms, including cleartext passwords, authentication mechanisms, including cleartext passwords,
challenge-response, and arbitrary dialog sequences. [R3748] challenge-response, and arbitrary dialog sequences. [R3748]
Tutorial: This protocol is intended for use primarily by a host or Tutorial: This protocol is intended for use primarily by a host or
router that connects to a network server via switched circuits or router that connects to a network server via switched circuits or
dial-up lines. EAP typically runs directly over IPS data link dial-up lines. EAP typically runs directly over IPS data link
protocols or OSIRM layer 2 protocols, such as PPP or IEEE 802, protocols or OSIRM Layer 2 protocols, such as PPP or IEEE 802,
without requiring IP. without requiring IP.
$ Extensible Markup Language (XML) $ Extensible Markup Language (XML)
(N) A version of Standard Generalized Markup Language (ISO 8879), (N) A version of Standard Generalized Markup Language (ISO 8879),
which separately represents both a document's content and its which separately represents both a document's content and its
structure. XML was designed by W3C for use on the World Wide Web. structure. XML was designed by W3C for use on the World Wide Web.
$ extension $ extension
(I) A data item defined for optional inclusion in a v3 X.509 (I) A data item defined for optional inclusion in a v3 X.509
public-key certificate or a v2 X.509 CRL. public-key certificate or a v2 X.509 CRL.
Tutorial: The formats defined in X.509 can be extended to provide Tutorial: The formats defined in X.509 can be extended to provide
methods for associating additional attributes with subjects and methods for associating additional attributes with subjects and
public keys and for managing a certification hierarchy: public keys and for managing a certification hierarchy:
- "Certificate extension": X.509 defines standard extensions that - A "certificate extension": X.509 defines standard extensions
may be included in v3 certificates to provide additional key that may be included in v3 certificates to provide additional
and security policy information, subject and issuer attributes, key and security policy information, subject and issuer
and certification path constraints. attributes, and certification path constraints.
- "CRL extension": X.509 defines extensions that may be included - A "CRL extension": X.509 defines extensions that may be
in v2 CRLs to provide additional issuer key and name included in v2 CRLs to provide additional issuer key and name
information, revocation reasons and constraints, and information, revocation reasons and constraints, and
information about distribution points and delta CRLs. information about distribution points and delta CRLs.
- "Private extension": Additional extensions, each named by an - A "private extension": Additional extensions, each named by an
OID, can be locally defined as needed by applications or OID, can be locally defined as needed by applications or
communities. (See: PKIX private extension, SET private communities. (See: Authority Information Access extension, SET
extensions.) private extensions.)
$ external controls $ external controls
(I) /computer security/ Refers to administrative security, (I) /computer security/ Refers to administrative security,
personnel security, and physical security. (Compare: internal personnel security, and physical security. (Compare: internal
controls.) controls.)
$ extranet $ extranet
(I) A computer network that an organization uses for application (I) A computer network that an organization uses for application
data traffic between the organization and its business partners. data traffic between the organization and its business partners.
(Compare: intranet.) (Compare: intranet.)
Tutorial: An extranet can be implemented securely, either on the Tutorial: An extranet can be implemented securely, either on the
Internet or using Internet technology, by constructing the Internet or using Internet technology, by constructing the
extranet as a VPN. extranet as a VPN.
$ extraction resistance $ extraction resistance
(O) Capability of cryptographic equipment to resist efforts to (O) Ability of cryptographic equipment to resist efforts to
extract keying material directly from the equipment (as opposed to extract keying material directly from the equipment (as opposed to
gaining knowledge of keying material by cryptanalysis). [C4009] gaining knowledge of keying material by cryptanalysis). [C4009]
$ fail safe $ fail safe
(I) A mode of system termination that automatically leaves system (I) A mode of termination of system functions (when a failure
processes and components in a secure state when a failure occurs occurs or is detected in the system) that automatically leaves
or is detected in the system. system processes and components in a secure state.
$ fail soft $ fail soft
(I) Selective termination of affected non-essential system (I) Selective termination of affected, non-essential system
functions and processes when a failure occurs or is detected in functions when a failure occurs or is detected in the system.
the system.
$ failure control $ failure control
(I) A methodology used to provide fail-safe or fail-soft (I) A methodology used to provide fail-safe or fail-soft
termination and recovery of functions and processes when failures termination and recovery of system functions. [FP039]
occur or are detected in a system. [FP039]
$ fairness $ fairness
(I) A property of an access protocol for a system resource whereby (I) A property of an access protocol for a system resource whereby
the resource is made equitably or impartially available to all the resource is made equitably or impartially available to all
eligible users. [R3753] eligible users. (RFC 3753)
Tutorial: Fairness can prevent flooding, but not jamming. Tutorial: Fairness can be used to defend against some types of
denial-of-service attacks on a system connected to a network.
However, this technique assumes that the system can properly
receive and process inputs from the network. Therefore, the
technique can mitigate flooding but is ineffective against
jamming.
$ falsification $ falsification
(I) A type of threat action whereby false data deceives an (I) A type of threat action whereby false data deceives an
authorized entity. (See: active wiretapping, deception.) authorized entity. (See: active wiretapping, deception.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Substitution": Altering or replacing valid data with false - "Substitution": Altering or replacing valid data with false
data that serves to deceive an authorized entity. data that serves to deceive an authorized entity.
- "Insertion": Introducing false data that serves to deceive an - "Insertion": Introducing false data that serves to deceive an
authorized entity. authorized entity.
$ fault tree $ fault tree
(I) A branching, hierarchical data structure that is used to (I) A branching, hierarchical data structure that is used to
represent events and to determine the various combinations of represent events and to determine the various combinations of
component failures and human acts that could result in a specified component failures and human acts that could result in a specified
undesirable system event. (See: attack tree, flaw hypothesis undesirable system event. (See: attack tree, flaw hypothesis
methodology.) methodology.)
Tutorial: "Fault-tree analysis" is a technique in which an Tutorial: "Fault-tree analysis" is a technique in which an
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(O) A PKI being planned to establish facilities, specifications, (O) A PKI being planned to establish facilities, specifications,
and policies needed by the U.S. Government to use public-key and policies needed by the U.S. Government to use public-key
certificates in systems involving unclassified but sensitive certificates in systems involving unclassified but sensitive
applications and interactions between Federal agencies as well as applications and interactions between Federal agencies as well as
with entities of other branches of the Federal Government, state, with entities of other branches of the Federal Government, state,
and local governments, business, and the public. [FPKI] and local governments, business, and the public. [FPKI]
$ Federal Standard 1027 $ Federal Standard 1027
(N) An U.S. Government document defining emanation, anti-tamper, (N) An U.S. Government document defining emanation, anti-tamper,
security fault analysis, and manual key management criteria for security fault analysis, and manual key management criteria for
DES encryption devices, primary for OSIRM layer 2. Was renamed DES encryption devices, primary for OSIRM Layer 2. Was renamed
"FIPS PUB 140" when responsibility for protecting unclassified, "FIPS PUB 140" when responsibility for protecting unclassified,
sensitive information was transferred from NSA to NIST, and has sensitive information was transferred from NSA to NIST, and has
since been superseded by newer versions of that standard [FP140]. since been superseded by newer versions of that standard [FP140].
$ File Transfer Protocol (FTP) $ File Transfer Protocol (FTP)
(I) A TCP-based, application-level, Internet Standard protocol (I) A TCP-based, Application-Layer, Internet Standard protocol
(RFC 959) for moving data files from one computer to another. (RFC 959) for moving data files from one computer to another.
$ fill device $ fill device
(N) /COMSEC/ A device used to transfer or store keying material in (N) /COMSEC/ A device used to transfer or store keying material in
electronic form or to insert keying material into cryptographic electronic form or to insert keying material into cryptographic
equipment. equipment.
$ filter $ filter
(I) Synonym for "guard". (Compare: content filter, filtering 1. (I) /noun/ Synonym for "guard". (Compare: content filter,
router.) filtering router.)
2. (I) /verb/ To process a flow of data and selectively block
passage or permit passage of individual data items in accordance
with a security policy.
$ filtering router $ filtering router
(I) An internetwork router that selectively prevents the passage (I) An internetwork router that selectively prevents the passage
of data packets according to a security policy. (See: guard.) of data packets according to a security policy. (See: guard.)
Tutorial: A router usually receives a packet from a network and Tutorial: A router usually has two or more physical connections to
decides where to forward it on a second network. A filtering networks or other systems; and when the router receives a packet
router does the same, but first decides whether the packet should on one of those connections, it forwards the packet on a second
be forwarded at all, according to some security policy. The policy connection. A filtering router does the same; but it first
is implemented by rules (packet filters) loaded into the router. decides, according to some security policy, whether the packet
The rules mostly involve values of data packet control fields should be forwarded at all. The policy is implemented by rules
(especially IP source and destination addresses and TCP port (packet filters) loaded into the router. The rules mostly involve
numbers) [R2179]. A filtering router may be used as a firewall or values of data packet control fields (especially IP source and
part of a firewall. destination addresses and TCP port numbers) [R2179]. A filtering
router may be used alone as a simple firewall or be used as a
component of a more complex firewall.
$ financial institution $ financial institution
(N) "An establishment responsible for facilitating customer- (N) "An establishment responsible for facilitating customer-
initiated transactions or transmission of funds for the extension initiated transactions or transmission of funds for the extension
of credit or the custody, loan, exchange, or issuance of money." of credit or the custody, loan, exchange, or issuance of money."
[SET2] [SET2]
$ fingerprint $ fingerprint
1. (I) A pattern of curves formed by the ridges on a fingertip. 1. (I) A pattern of curves formed by the ridges on a fingertip.
(See: biometric authentication, thumbprint.) (See: biometric authentication. Compare: thumbprint.)
2. (O) PGP usage: A hash result used to authenticate a public key 2. (D) /PGP/ A hash result ("key fingerprint") used to
(key fingerprint) or other data. [PGP] authenticate a public key or other data. [PGP]
Deprecated Definition: ISDs SHOULD NOT use this term with the Deprecated Definition: ISDs SHOULD NOT use this term with the
specific PGP definition, and SHOULD NOT use this term as a synonym specific PGP definition, and SHOULD NOT use this term as a synonym
for "hash result" of *any* kind, because either use would mix for "hash result" of *any* kind. Either use would mix concepts in
concepts in a potentially misleading way. a potentially misleading way.
$ FIPS $ FIPS
(N) See: Federal Information Processing Standards. (N) See: Federal Information Processing Standards.
$ FIPS PUB 140-1 $ FIPS PUB 140-1
(N) The U.S. Government standard [FP140] for security requirements (N) The U.S. Government standard [FP140] for security requirements
to be met by a cryptographic module used to protect unclassified to be met by a cryptographic module when the module is used to
information in computer and communication systems. (See: Common protect unclassified information in computer and communication
Criteria, FIPS, Federal Standard 1027.) systems. (See: Common Criteria, FIPS, Federal Standard 1027.)
Tutorial: The standard specifies four increasing levels (from Tutorial: The standard specifies four increasing levels (from
"Level 1" to "Level 4") of requirements to cover a wide range of "Level 1" to "Level 4") of requirements to cover a wide range of
potential applications and environments. The requirements address potential applications and environments. The requirements address
basic design and documentation, module interfaces, authorized basic design and documentation, module interfaces, authorized
roles and services, physical security, software security, roles and services, physical security, software security,
operating system security, key management, cryptographic operating system security, key management, cryptographic
algorithms, electromagnetic interference and electromagnetic algorithms, electromagnetic interference and electromagnetic
compatibility (EMI/EMC), and self-testing. NIST and the Canadian compatibility (EMI/EMC), and self-testing. NIST and the Canadian
Communication Security Establishment jointly certify modules. Communication Security Establishment jointly certify modules.
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(O) /U.S. Government/ "Key management protocol based on public-key (O) /U.S. Government/ "Key management protocol based on public-key
cryptography." [C4009] cryptography." [C4009]
$ firewall $ firewall
1. (I) An internetwork gateway that restricts data communication 1. (I) An internetwork gateway that restricts data communication
traffic to and from one of the connected networks (the one said to traffic to and from one of the connected networks (the one said to
be "inside" the firewall) and thus protects that network's system be "inside" the firewall) and thus protects that network's system
resources against threats from the other network (the one that is resources against threats from the other network (the one that is
said to be "outside" the firewall). (See: guard, security said to be "outside" the firewall). (See: guard, security
gateway.) gateway.)
2. (O) A device or system that controls the flow of traffic 2. (O) A device or system that controls the flow of traffic
between networks using differing security postures. [SP41] between networks using differing security postures. [SP41]
Tutorial: A firewall typically protects a smaller, secure network Tutorial: A firewall typically protects a smaller, secure network
(such as a corporate LAN, or even just one host) from a larger (such as a corporate LAN, or even just one host) from a larger
network (such as the Internet). The firewall is installed at the network (such as the Internet). The firewall is installed at the
point where the networks connect, and the firewall applies point where the networks connect, and the firewall applies policy
security policy rules to control traffic that flows in and out of rules to control traffic that flows in and out of the protected
the protected network. network.
A firewall is not always a single computer. For example, a A firewall is not always a single computer. For example, a
firewall may consist of a pair of filtering routers and one or firewall may consist of a pair of filtering routers and one or
more proxy servers running on one or more bastion hosts, all more proxy servers running on one or more bastion hosts, all
connected to a small, dedicated LAN (see: DMZ) between the two connected to a small, dedicated LAN (see: buffer zone) between the
routers. The external router blocks attacks that use IP to break two routers. The external router blocks attacks that use IP to
security (IP address spoofing, source routing, packet fragments), break security (IP address spoofing, source routing, packet
while proxy servers block attacks that would exploit a fragments), while proxy servers block attacks that would exploit a
vulnerability in a higher layer protocol or service. The internal vulnerability in a higher layer protocol or service. The internal
router blocks traffic from leaving the protected network except router blocks traffic from leaving the protected network except
through the proxy servers. The difficult part is defining criteria through the proxy servers. The difficult part is defining criteria
by which packets are denied passage through the firewall, because by which packets are denied passage through the firewall, because
a firewall not only needs to keep intruders out, but usually also a firewall not only needs to keep unauthorized traffic (i.e.,
needs to let authorized users in and out. intruders) out, but usually also needs to let authorized traffic
pass both in and out.
$ firmware $ firmware
(I) Computer programs and data stored in hardware -- typically in (I) Computer programs and data stored in hardware -- typically in
read-only memory (ROM) or programmable read-only memory (PROM) -- read-only memory (ROM) or programmable read-only memory (PROM) --
such that the programs and data cannot be dynamically written or such that the programs and data cannot be dynamically written or
modified during execution of the programs. (See: hardware, modified during execution of the programs. (See: hardware,
software.) software.)
$ FIRST $ FIRST
(N) See: Forum of Incident Response and Security Teams. (N) See: Forum of Incident Response and Security Teams.
skipping to change at page 108, line 51 skipping to change at page 114, line 32
result in a vulnerability. (Compare: vulnerability.) result in a vulnerability. (Compare: vulnerability.)
$ flaw hypothesis methodology $ flaw hypothesis methodology
(I) An evaluation or attack technique in which specifications and (I) An evaluation or attack technique in which specifications and
documentation for a system are analyzed to hypothesize flaws in documentation for a system are analyzed to hypothesize flaws in
the system. The list of hypothetical flaws is prioritized on the the system. The list of hypothetical flaws is prioritized on the
basis of the estimated probability that a flaw exists and, basis of the estimated probability that a flaw exists and,
assuming it does, on the ease of exploiting it and the extent of assuming it does, on the ease of exploiting it and the extent of
control or compromise it would provide. The prioritized list is control or compromise it would provide. The prioritized list is
used to direct a penetration test or attack against the system. used to direct a penetration test or attack against the system.
[NCS04] (See: fault tree.) [NCS04] (See: fault tree, flaw.)
$ flooding $ flooding
1. (I) An attack that attempts to cause a failure in a system by 1. (I) An attack that attempts to cause a failure in a system by
providing more input than the system can process properly. (See: providing more input than the system can process properly. (See:
denial of service, fairness. Compare: jamming.) denial of service, fairness. Compare: jamming.)
Tutorial: Flooding uses "overload" as a type of "obstruction" Tutorial: Flooding uses "overload" as a type of "obstruction"
intended to cause "disruption". intended to cause "disruption".
2. (I) The process of delivering data or control messages to every 2. (I) The process of delivering data or control messages to every
node of a network. [R3753] node of a network. (RFC 3753)
$ flow analysis $ flow analysis
(I) An analysis performed on a nonprocedural formal system (I) An analysis performed on a nonprocedural, formal, system
specification that locates potential flows of information between specification that locates potential flows of information between
system variables. By assigning security levels to the variables, system variables. By assigning security levels to the variables,
the analysis can find some types of covert channels. [Huff] the analysis can find some types of covert channels. [Huff]
$ flow control $ flow control
(I) A procedure or technique to ensure that information transfers (I) A procedure or technique to ensure that information transfers
within a system are not made from one security level to another within a system are not made from one security level to another
security level, and especially not from a higher level to a lower security level, and especially not from a higher level to a lower
level. [Denns] (See: covert channel, confinement property, level. [Denns] (See: covert channel, confinement property,
information flow policy, simple security property.) information flow policy, simple security property.)
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cause a foreseeable harm to an interest protected by one of the cause a foreseeable harm to an interest protected by one of the
exemptions stated in the Freedom of Information Act (Section 552 exemptions stated in the Freedom of Information Act (Section 552
of title 5, United States Code). (See: security label, security of title 5, United States Code). (See: security label, security
marking. Compare: classified.) marking. Compare: classified.)
$ formal $ formal
(I) Expressed in a restricted syntax language with defined (I) Expressed in a restricted syntax language with defined
semantics based on well-established mathematical concepts. [CCIB] semantics based on well-established mathematical concepts. [CCIB]
(Compare: informal, semiformal.) (Compare: informal, semiformal.)
$ formal access approval
(O) /U.S. Government/ Documented approval by a data owner to allow
access to a particular category of information in a system. (See:
category.)
$ Formal Development Methodology $ Formal Development Methodology
See: Ina Jo. (O) See: Ina Jo.
$ formal model $ formal model
(I) A security model that is formal. Example: Bell-LaPadula model. (I) A security model that is formal. Example: Bell-LaPadula model.
(See: formal, security model.) [Land] [Land] (See: formal, security model.)
$ formal proof $ formal proof
(I) A complete and convincing mathematical argument presenting the (I) A complete and convincing mathematical argument presenting the
full logical justification for each step in the proof of the truth full logical justification for each step in the proof of the truth
of a theorem or set of theorems. of a theorem or set of theorems.
$ formal specification $ formal specification
(I) A specification of hardware or software functionality in a (I) A specification of hardware or software functionality in a
computer-readable language; usually a precise mathematical computer-readable language; usually a precise mathematical
description of the behavior of the system with the aim of description of the behavior of the system with the aim of
providing a correctness proof. [Huff] (See: Affirm, Gypsy, HDM, providing a correctness proof. [Huff] (See: Affirm, Gypsy, HDM,
Ina Jo.) Ina Jo.)
$ formulary $ formulary
(I) A technique for enabling a decision to grant or deny access to (I) A technique for enabling a decision to grant or deny access to
be made dynamically at the time the access is attempted, rather be made dynamically at the time the access is attempted, rather
than earlier when an access control list or ticket is created. than earlier when an access control list or ticket is created.
$ FORTEZZA(trademark) $ FORTEZZA(trademark)
(N) A registered trademark of NSA, used for a family of (O) A registered trademark of NSA, used for a family of
interoperable security products that implement a NIST/NSA-approved interoperable security products that implement a NIST/NSA-approved
suite of cryptographic algorithms for digital signature, hash, suite of cryptographic algorithms for digital signature, hash,
encryption, and key exchange. The products include a PC card (that encryption, and key exchange. The products include a PC card (that
contains a CAPSTONE chip), and compatible serial port modems, contains a CAPSTONE chip), and compatible serial port modems,
server boards, and software implementations. server boards, and software implementations.
$ Forum of Incident Response and Security Teams (FIRST) $ Forum of Incident Response and Security Teams (FIRST)
(N) An international consortium of CSIRTs (e.g., CIAC) that work (N) An international consortium of CSIRTs (e.g., CIAC) that work
together to handle computer security incidents and promote together to handle computer security incidents and promote
preventive activities. (See: CSIRT, security incident.) preventive activities. (See: CSIRT, security incident.)
Tutorial: FIRST was founded in 1990 and, as of July 2004, had more Tutorial: FIRST was founded in 1990 and, as of July 2004, had more
than 100 members spanning the globe. Its mission includes: than 100 members spanning the globe. Its mission includes:
- Provide members with technical information, tools, methods, - Provide members with technical information, tools, methods,
assistance, and guidance. assistance, and guidance.
- Coordinate proactive liaison activities and analytical support. - Coordinate proactive liaison activities and analytical support.
- Encourage development of quality products and services. - Encourage development of quality products and services.
- Improve national and international information security for - Improve national and international information security for
government, private industry, academia, and the individual. government, private industry, academia, and the individual.
- Enhance the image and status of the CSIRT community. - Enhance the image and status of the CSIRT community.
$ forward secrecy $ forward secrecy
See: public-key forward secrecy. See: public-key forward secrecy.
$ FOUO $ FOUO
(O) See: For Official Use Only. (O) See: For Official Use Only.
$ FPKI $ FPKI
(O) See: Federal Public-Key Infrastructure. (O) See: Federal Public-Key Infrastructure.
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Tutorial: Frequency hopping is a TRANSEC technique to minimize the Tutorial: Frequency hopping is a TRANSEC technique to minimize the
potential for unauthorized interception or jamming. potential for unauthorized interception or jamming.
$ FTP $ FTP
(I) See: File Transfer Protocol. (I) See: File Transfer Protocol.
$ gateway $ gateway
(I) An intermediate system (interface, relay) that attaches to two (I) An intermediate system (interface, relay) that attaches to two
(or more) computer networks that have similar functions but (or more) computer networks that have similar functions but
dissimilar implementations and that enables inter-network dissimilar implementations and that enables either one-way or two-
communication. (See: bridge, firewall, guard, internetwork, proxy way communication between the networks. (See: bridge, firewall,
server, router, and subnetwork.) guard, internetwork, proxy server, router, and subnetwork.)
Tutorial: The networks may differ in any of several aspects, Tutorial: The networks may differ in any of several aspects,
including protocols and security mechanisms. When two computer including protocols and security mechanisms. When two computer
networks differ in the protocol by which they offer service to networks differ in the protocol by which they offer service to
hosts, a gateway may translate one protocol into the other or hosts, a gateway may translate one protocol into the other or
otherwise facilitate interoperation of hosts (see: Internet otherwise facilitate interoperation of hosts (see: Internet
Protocol). In theory, gateways between computer networks are Protocol). In theory, gateways between computer networks are
conceivable at any OSIRM layer. In practice, they usually operate conceivable at any OSIRM layer. In practice, they usually operate
at OSIRM layer 2 (see: bridge), 3 (see: router), or 7 (see: proxy at OSIRM Layer 2 (see: bridge), 3 (see: router), or 7 (see: proxy
server). server).
$ GCA $ GCA
(O) See: geopolitical certificate authority. (O) See: geopolitical certificate authority.
$ GDOI $ GDOI
(O) See: Group Domain of Interpretation. (O) See: Group Domain of Interpretation.
$ GeldKarte $ GeldKarte
(O) A smartcard-based electronic money system that is maintained (O) A smartcard-based, electronic money system that is maintained
by the German banking industry, incorporates cryptography, and can by the German banking industry, incorporates cryptography, and can
be used to make payments via the Internet. (See: IOTP.) be used to make payments via the Internet. (See: IOTP.)
$ GeneralizedTime $ GeneralizedTime
(N) The ASN.1 data type "GeneralizedTime" (ISO 8601) contains a (N) The ASN.1 data type "GeneralizedTime" (ISO 8601) contains a
calendar date (YYYYMMDD) and a time of day, which is either (a) calendar date (YYYYMMDD) and a time of day, which is either (a)
the local time, (b) the Coordinated Universal Time, or (c) both the local time, (b) the Coordinated Universal Time, or (c) both
the local time and an offset allowing Coordinated Universal Time the local time and an offset that enables Coordinated Universal
to be calculated. (See: Coordinated Universal Time, UTCTime.) Time to be calculated. (See: Coordinated Universal Time, UTCTime.)
$ Generic Security Service Application Program Interface (GSS-API) $ Generic Security Service Application Program Interface (GSS-API)
(I) An Internet Standard protocol [R2078] that specifies calling (I) An Internet Standard protocol [R2078] that specifies calling
conventions by which an application (typically another conventions by which an application (typically another
communication protocol) can obtain authentication, integrity, and communication protocol) can obtain authentication, integrity, and
confidentiality security services independently of the underlying confidentiality security services independently of the underlying
security mechanisms and technologies, thus allowing the security mechanisms and technologies, thus enabling the
application source code to be ported to different environments. application source code to be ported to different environments.
Tutorial: "A GSS-API caller accepts tokens provided to it by its Tutorial: "A GSS-API caller accepts tokens provided to it by its
local GSS-API implementation and transfers the tokens to a peer on local GSS-API implementation and transfers the tokens to a peer on
a remote system; that peer passes the received tokens to its local a remote system; that peer passes the received tokens to its local
GSS-API implementation for processing. The security services GSS-API implementation for processing. The security services
available through GSS-API in this fashion are implementable (and available through GSS-API in this fashion are implementable (and
have been implemented) over a range of underlying mechanisms based have been implemented) over a range of underlying mechanisms based
on [symmetric] and [asymmetric cryptography]." [R2078] on [symmetric] and [asymmetric cryptography]." [R2078]
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between regions as needed. between regions as needed.
$ GIG $ GIG
(O) See: Global Information Grid. (O) See: Global Information Grid.
$ Global Information Grid. $ Global Information Grid.
(O) /U.S. DoD/ "A globally interconnected, end-to-end set of (O) /U.S. DoD/ "A globally interconnected, end-to-end set of
information capabilities, associated processes and personnel for information capabilities, associated processes and personnel for
collecting, processing, storing, disseminating, and managing collecting, processing, storing, disseminating, and managing
information on demand to warfighters, policy makers, and support information on demand to warfighters, policy makers, and support
personnel." [IATF] personnel." [IATF] Usage: Formerly called the DII.
$ good engineering practice(s)
(N) A term used to specify or characterize design, implementation,
installation, or operating practices for an information system,
when a more explicit specification is not possible. Generally
understood to refer to the state of the engineering art for
commercial systems that have problems and solutions equivalent to
the system in question.
$ granularity $ granularity
1. (N) "Relative fineness to which an access control mechanism can 1. (N) "Relative fineness to which an access control mechanism can
be adjusted." [C4009] be adjusted." [C4009]
2. (O) "The size of the smallest protectable unit of information" 2. (O) "The size of the smallest protectable unit of information"
in a trusted computer system. [Huff] in a trusted computer system. [Huff]
$ Green Book $ Green Book
(D) Synonym for "Defense Password Management Guideline" [CSC2]. (D) /slang/ Synonym for "Defense Password Management Guideline"
[CSC2].
Deprecated Term: Except as an explanatory appositive, ISDs SHOULD Deprecated Term: Except as an explanatory appositive, ISDs SHOULD
NOT use this term, regardless of the associated definition. NOT use this term, regardless of the associated definition.
Instead, use the full proper name of the document or, in Instead, use the full proper name of the document or, in
subsequent references, a conventional abbreviation. (See: Rainbow subsequent references, a conventional abbreviation. (See: Rainbow
Series.) Series.)
Deprecated Usage: To improve international comprehensibility of Deprecated Usage: To improve international comprehensibility of
Internet Standards and the Internet Standards Process, ISDs SHOULD Internet Standards and the Internet Standards Process, ISDs SHOULD
NOT use "cute" synonyms. No matter how clearly understood or NOT use "cute" synonyms. No matter how clearly understood or
popular a nickname may be in one community, it is likely to cause popular a nickname may be in one community, it is likely to cause
confusion or offense in others. For example, several other confusion or offense in others. For example, several other
information system standards also are called "the Green Book". The information system standards also are called "the Green Book"; the
following are examples: following are some examples:
- Each volume of 1992 ITU-T (known at that time as CCITT) - Each volume of 1992 ITU-T (known at that time as CCITT)
standards. standards.
- "PostScript Language Program Design", Adobe Systems, Addison- - "PostScript Language Program Design", Adobe Systems, Addison-
Wesley, 1988. Wesley, 1988.
- IEEE 1003.1 POSIX Operating Systems Interface. - IEEE 1003.1 POSIX Operating Systems Interface.
- "Smalltalk-80: Bits of History, Words of Advice", Glenn - "Smalltalk-80: Bits of History, Words of Advice", Glenn
Krasner, Addison-Wesley, 1983. Krasner, Addison-Wesley, 1983.
- "X/Open Compatibility Guide". - "X/Open Compatibility Guide".
- A particular CD-ROM format developed by Phillips. - A particular CD-ROM format developed by Phillips.
$ GRIP $ GRIP
(I) A contraction of "Guidelines and Recommendations for Security (I) A contraction of "Guidelines and Recommendations for Security
Incident Processing", the name of the IETF working group that Incident Processing", the name of the IETF working group that
seeks to facilitate consistent handling of security incidents in seeks to facilitate consistent handling of security incidents in
the Internet community. (See: security incident.) the Internet community. (See: security incident.)
Tutorial: Guidelines to be produced by the WG will address Tutorial: Guidelines to be produced by the WG will address
technology vendors, network service providers, and response teams technology vendors, network service providers, and response teams
in their roles assisting organizations in resolving security in their roles assisting organizations in resolving security
skipping to change at page 113, line 34 skipping to change at page 119, line 25
"group controller/key server", which establishes security "group controller/key server", which establishes security
associations [R2401] among authorized group members. The GDOI associations [R2401] among authorized group members. The GDOI
protocol is itself protected by an ISAKMP phase 1 association. protocol is itself protected by an ISAKMP phase 1 association.
For example, multicast applications may use ESP to protect their For example, multicast applications may use ESP to protect their
data traffic. GDOI carries the needed security association data traffic. GDOI carries the needed security association
parameters for ESP. In this way, GDOI supports multicast ESP with parameters for ESP. In this way, GDOI supports multicast ESP with
group authentication of ESP packets using a shared, group key. group authentication of ESP packets using a shared, group key.
$ group identity $ group identity
(I) See: (secondary definition under) identity. (I) See: secondary definition under "identity".
$ group security association $ group security association
(I) "A bundling of [security associations] (SAs) that together (I) "A bundling of [security associations] (SAs) that together
define how a group communicates securely. The [group SA] may define how a group communicates securely. The [group SA] may
include a registration protocol SA, a rekey protocol SA, and one include a registration protocol SA, a rekey protocol SA, and one
or more data security protocol SAs." [R3740] or more data security protocol SAs." [R3740]
$ GSS-API $ GSS-API
(I) See: Generic Security Service Application Program Interface. (I) See: Generic Security Service Application Program Interface.
$ guard $ guard
(I) A computer system that acts as gateway between two information (I) A computer system that (a) acts as gateway between two
systems operating under different security policies and is trusted information systems operating under different security policies
to mediate information data transfers between the two systems. and (b) is trusted to mediate information data transfers between
(See: controlled interface, domain.) the two. (See: controlled interface, domain, filter. Compare:
firewall.)
Usage: Frequently understood to mean that one system is operating Usage: Frequently understood to mean that one system is operating
at a higher security level than the other, and that the gateway's at a higher security level than the other, and that the gateway's
purpose is to prevent unauthorized disclosure of data from the purpose is to prevent unauthorized disclosure of data from the
higher system to the lower. However, the purpose might also be to higher system to the lower. However, the purpose might also be to
protect the data integrity, availability, or general system protect the data integrity, availability, or general system
integrity of one system from threats posed by connecting to the integrity of one system from threats posed by connecting to the
other system. The mediation may be entirely automated or may other system. The mediation may be entirely automated or may
involve reliable human review. (See: filter, firewall.) involve reliable human review.
$ guest login $ guest login
(I) See: anonymous login. (I) See: anonymous login.
$ GULS $ GULS
(I) Generic Upper Layer Security service element (ISO 11586), a (I) Generic Upper Layer Security service element (ISO 11586), a
five-part standard for the exchange of security information and five-part standard for the exchange of security information and
security-transformation functions that protect confidentiality and security-transformation functions that protect confidentiality and
integrity of application data. integrity of application data.
$ Gypsy verification environment $ Gypsy verification environment
(O) A methodology, language, and integrated set of software tools (O) A methodology, language, and integrated set of software tools
developed at the University of Texas for specifying, coding, and developed at the University of Texas for specifying, coding, and
verifying software to produce correct and reliable programs. verifying software to produce correct and reliable programs.
[Cheh] [Cheh]
$ H field $ H field
(D) See: Handling Restrictions field. (D) See: "Deprecated Usage" under "Handling Restrictions field".
$ hack
1a. (I) /verb/ To work on something, especially to program a
computer. (See: hacker.)
1b. (I) /verb/ To do some kind of mischief, especially to play a
prank on, or penetrate, a system. (See: hacker, cracker.)
2. (I) /noun/ An item of completed work or an instance of dealing
with a problem, especially when that involves computer programming
or other use of a computer.
$ hacker $ hacker
(I) Someone with a strong interest in computers, who enjoys 1. (I) Someone with a strong interest in computers, who enjoys
learning about them and experimenting with them. (See: cracker.) learning about them, programming them, and experimenting and
otherwise working with them. (See: hack. Compare: cracker.)
Usage: The recommended definition is the original meaning of the Usage: This first definition is the original meaning of the term
term (circa 1960), which then had a neutral or positive (circa 1960); it then had a neutral or positive connotation of
connotation of "someone who figures things out and makes something "someone who figures things out and makes something cool happen".
cool happen". Today, the term is frequently misused, especially by
journalists, to have the pejorative meaning of "cracker". 2. (D) Synonym for "cracker".
Deprecated Usage: Today, the term is frequently misused
(especially by journalists) with this second meaning.
$ handle $ handle
1. (I) /verb/ Perform processing operations on data, such as 1. (I) /verb/ Perform processing operations on data, such as
receive and transmit, collect and disseminate, create and delete, receive and transmit, collect and disseminate, create and delete,
store and retrieve, read and write, and compare. (See: access.) store and retrieve, read and write, and compare. (See: access.)
2. (I) /noun/ An on-line pseudonym, particularly one used by a 2. (I) /noun/ An on-line pseudonym, particularly one used by a
cracker; derived from citizens band radio culture. cracker; derived from citizens band radio culture.
$ handling restriction $ handling restriction
(I) A type of access control other than (a) the rule-based (I) A type of access control other than (a) the rule-based
protections of mandatory access control and (b) the identity-based protections of mandatory access control and (b) the identity-based
protections of discretionary access control; usually procedural in protections of discretionary access control; usually involves
nature. administrative security.
$ Handling Restrictions field $ Handling Restrictions field
(I) A 16-bit field (the "H field") that specifies a control and (I) A 16-bit field that specifies a control and release marking in
release marking in the security option (option type 130) of IP's the security option (option type 130) of IP's datagram header
datagram header format. The valid field values are alphanumeric format. The valid field values are alphanumeric digraphs assigned
digraphs assigned by the U.S. Government, as specified in RFC 791. by the U.S. Government, as specified in RFC 791.
Deprecated Abbreviation: ISDs SHOULD NOT use the abbreviation "H Deprecated Abbreviation: ISDs SHOULD NOT use the abbreviation "H
field" because it is potentially ambiguous. Instead, use "Handling field" because it is potentially ambiguous. Instead, use "Handling
Restrictions field". Restrictions field".
$ handshake $ handshake
(I) Protocol dialogue between two systems for identifying and (I) Protocol dialogue between two systems for identifying and
authenticating themselves to each other, or for synchronizing authenticating themselves to each other, or for synchronizing
their operations with each other. their operations with each other.
$ Handshake Protocol $ Handshake Protocol
(I) /TLS/ The TLS Handshake Protocol consists of three sub- (I) /TLS/ The TLS Handshake Protocol consists of three parts
protocols that enable peer entities to agree upon security (i.e., subprotocols) that enable peer entities to agree upon
parameters for the record layer, authenticate themselves to each security parameters for the record layer, authenticate themselves
other, instantiate negotiated security parameters, and report to each other, instantiate negotiated security parameters, and
error conditions to each other. [R2246] report error conditions to each other. [R2246]
$ harden $ harden
(I) To protect a system by configuring it to operate in a way that (I) To protect a system by configuring it to operate in a way that
eliminates or mitigates known vulnerabilities. eliminates or mitigates known vulnerabilities. Example: [RSCG].
(See: default account.)
$ hardware $ hardware
(I) The material physical components of an information system. (I) The material physical components of an information system.
(See: firmware, software.) (See: firmware, software.)
$ hardware token $ hardware token
See: token. See: token.
$ hash code $ hash code
Deprecated Term: ISDs SHOULD NOT use this term (especially not as (D) Synonym for "hash result" or "hash function".
a synonym for "hash result" or "hash function"); the term mixes
concepts in a potentially misleading way. A hash result is not a Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts
"code", and a hash function does not "encode" in any sense defined in a potentially misleading way. A hash result is not a "code",
by this glossary. (See: hash value, message digest.) and a hash function does not "encode" in any sense defined by this
glossary. (See: hash value, message digest.)
$ hash function $ hash function
1. (I) A function H that maps an arbitrary, variable-length bit 1. (I) A function H that maps an arbitrary, variable-length bit
string, s, into a fixed-length string, h = H(s) (called the "hash string, s, into a fixed-length string, h = H(s) (called the "hash
result"). For most computing applications, it is desirable that result"). For most computing applications, it is desirable that
given a string s with H(s) = h, any change to s that creates a given a string s with H(s) = h, any change to s that creates a
different string s' will result in an unpredictable hash result different string s' will result in an unpredictable hash result
H(s') that is, with high probability, not equal to H(s). H(s') that is, with high probability, not equal to H(s).
2. (O) "A (mathematical) function which maps values from a large 2. (O) "A (mathematical) function which maps values from a large
(possibly very large) domain into a smaller range. A 'good' hash (possibly very large) domain into a smaller range. A 'good' hash
function is such that the results of applying the function to a function is such that the results of applying the function to a
(large) set of values in the domain will be evenly distributed (large) set of values in the domain will be evenly distributed
(and apparently at random) over the range." [X509] (and apparently at random) over the range." [X509]
Tutorial: A hash function operates on variable-length input (e.g., Tutorial: A hash function operates on variable-length input (e.g.,
a message or a file) and outputs a fixed-length output, which a message or a file) and outputs a fixed-length output, which
typically is shorter than most input values. If the algorithm is typically is much shorter than most input values. If the algorithm
"good" as described in the "O" definition, then the hash function is "good" as described in the "O" definition, then the hash
may be a candidate for use in a security mechanism to detect function may be a candidate for use in a security mechanism to
accidental changes in data, but not necessarily for a mechanism to detect accidental changes in data, but not necessarily for a
detect changes made by active wiretapping (See: (discussion under) mechanism to detect changes made by active wiretapping (See:
checksum). Tutorial under "checksum".)
Security mechanisms require a "cryptographic hash function" (e.g., Security mechanisms require a "cryptographic hash function" (e.g.,
MD2, MD4, MD5, SHA-1, Snefru), i.e., a good hash function that MD2, MD4, MD5, SHA-1, Snefru), i.e., a good hash function that
also has the one-way property and one of the two collision-free also has the one-way property and one of the two collision-free
properties: properties:
- "One-way property": Given H and a hash result h = H(s), it is - "One-way property": Given H and a hash result h = H(s), it is
hard (i.e., computationally infeasible) to find s. (Of course, hard (i.e., computationally infeasible) to find s. (Of course,
given H and an input s, it must be relatively easy to compute given H and an input s, it must be relatively easy to compute
the hash result H(s).) the hash result H(s).)
- "Weakly collision-free property": Given H and an input s, it is - "Weakly collision-free property": Given H and an input s, it is
hard to find a different input, s', such that H(s) = H(s'). hard to find a different input, s', such that H(s) = H(s').
- "Strongly collision-free property": Given H, it is hard to find - "Strongly collision-free property": Given H, it is hard to find
any pair of inputs s and s' such that H(s) = H(s'). any pair of inputs s and s' such that H(s) = H(s').
If H produces a hash result N bits long, then to find an s' where If H produces a hash result N bits long, then to find an s' where
H(s') = H(s) for a specific given s, the amount of computation H(s') = H(s) for a specific given s, the amount of computation
required is O(2**n); i.e., it is necessary to try on the order of required is O(2**n); i.e., it is necessary to try on the order of
2 to the power n values of s' before finding a collision. However, 2 to the power n values of s' before finding a collision. However,
to simply find any pair of values s and s' that collide, the to simply find any pair of values s and s' that collide, the
amount of computation required is only O(2**(n/2)); i.e., after amount of computation required is only O(2**(n/2)); i.e., after
computing H(s) for 2 to the power n/2 randomly chosen values of s, computing H(s) for 2 to the power n/2 randomly chosen values of s,
the probability is greater than 1/2 that two of those values have the probability is greater than 1/2 that two of those values have
the same hash result. (See: birthday attack.) the same hash result. (See: birthday attack.)
$ hash result $ hash result
1. (I) The output of a hash function. (See: hash code, hash 1. (I) The output of a hash function. (See: hash code, hash value.
value.) Compare: hash value.)
Usage: The "I" definition is recommended to avoid the unusual
usage of "message" that is seen in the following "O" definition.
2. (O) "The output produced by a hash function upon processing a 2. (O) "The output produced by a hash function upon processing a
message" (where "message" is broadly defined as "a digital message" (where "message" is broadly defined as "a digital
representation of data"). [ABA] representation of data"). [ABA]
Usage: ISDs SHOULD avoid the unusual usage of "message" that is
seen in the "O" definition.
$ hash value $ hash value
(D) Synonym for "hash result". (D) Synonym for "hash result".
Deprecated Term: ISDs SHOULD NOT use this term; it could be Deprecated Term: ISDs SHOULD NOT use this term for the output of a
confused with "hashed value", which is the input to a hash hash function; the term could easily be confused with "hashed
function. (See: hash code, hash result, message digest.) value", which means the input to a hash function. (See: hash code,
hash result, message digest.)
$ HDM $ HDM
(O) See: Hierarchical Development Methodology. (O) See: Hierarchical Development Methodology.
$ Hierarchical Development Methodology (HDM) $ Hierarchical Development Methodology (HDM)
(O) A methodology, language, and integrated set of software tools (O) A methodology, language, and integrated set of software tools
developed at SRI International for specifying, coding, and developed at SRI International for specifying, coding, and
verifying software to produce correct and reliable programs. verifying software to produce correct and reliable programs.
[Cheh] [Cheh]
$ hierarchical PKI $ hierarchical PKI
(I) A PKI architecture based on a certification hierarchy. (I) A PKI architecture based on a certification hierarchy.
(Compare: mesh PKI, trust-file PKI.) (Compare: mesh PKI, trust-file PKI.)
$ hierarchy management $ hierarchy management
(I) The process of generating configuration data and issuing (I) The process of generating configuration data and issuing
public-key certificates to build and operate a certification public-key certificates to build and operate a certification
hierarchy. (See: certificate management.) hierarchy. (See: certificate management.)
$ hierarchy of trust $ hierarchy of trust
(D) Synonym for "certification hierarchy". (D) Synonym for "certification hierarchy".
Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts
in a potentially misleading way. (See: certification hierarchy, in a potentially misleading way. (See: certification hierarchy,
trust, web of trust.) trust, web of trust.)
$ high-assurance guard $ high-assurance guard
(N) "An oxymoron," said Lt. Gen. William H. Campbell, former U.S. (O) "An oxymoron," said Lt. Gen. William H. Campbell, former U.S.
Army chief information officer, speaking at an Armed Forces Army chief information officer, speaking at an Armed Forces
Communications and Electronics Association conference. Communications and Electronics Association conference.
Deprecated Usage: This term mixes concepts and could easily be Usage: ISDs that use this term SHOULD state a definition for it
misunderstood; therefore, ISDs that use this term SHOULD state a because the term mixes concepts and could easily be misunderstood.
definition for it.
$ hijack attack $ hijack attack
(I) A form of active wiretapping in which the attacker seizes (I) A form of active wiretapping in which the attacker seizes
control of a previously established communication association. control of a previously established communication association.
(See: man-in-the-middle attack, pagejacking, piggyback attack.) (See: man-in-the-middle attack, pagejacking, piggyback attack.)
$ HIPAA $ HIPAA
(N) Health Information Portability and Accountability Act of 1996, (N) Health Information Portability and Accountability Act of 1996,
a U.S. law (Public Law 104-191) that protects the privacy of a U.S. law (Public Law 104-191) that protects the privacy of
patients' medical records and other health information in all patients' medical records and other health information in all
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(I) A keyed hash [R2104] that can be based on any iterated (I) A keyed hash [R2104] that can be based on any iterated
cryptographic hash (e.g., MD5 or SHA-1), so that the cryptographic cryptographic hash (e.g., MD5 or SHA-1), so that the cryptographic
strength of HMAC depends on the properties of the selected strength of HMAC depends on the properties of the selected
cryptographic hash. (See: [R2202, R2403, R2404].) cryptographic hash. (See: [R2202, R2403, R2404].)
Tutorial: Assume that H is a generic cryptographic hash in which a Tutorial: Assume that H is a generic cryptographic hash in which a
function is iterated on data blocks of length B bytes. L is the function is iterated on data blocks of length B bytes. L is the
length of the of hash result of H. K is a secret key of length L length of the of hash result of H. K is a secret key of length L
<= K <= B. The values IPAD and OPAD are fixed strings used as <= K <= B. The values IPAD and OPAD are fixed strings used as
inner and outer padding and defined as follows: IPAD = the byte inner and outer padding and defined as follows: IPAD = the byte
0x36 repeated B times, OPAD = the byte 0x5C repeated B times. HMAC 0x36 repeated B times, and OPAD = the byte 0x5C repeated B times.
is computed by H(K XOR OPAD, H(K XOR IPAD, inputdata)). HMAC is computed by H(K XOR OPAD, H(K XOR IPAD, inputdata)).
HMAC has the following goals: HMAC has the following goals:
- To use available cryptographic hash functions without - To use available cryptographic hash functions without
modification, particularly functions that perform well in modification, particularly functions that perform well in
software and for which software is freely and widely available. software and for which software is freely and widely available.
- To preserve the original performance of the selected hash - To preserve the original performance of the selected hash
without significant degradation. without significant degradation.
- To use and handle keys in a simple way. - To use and handle keys in a simple way.
- To have a well-understood cryptographic analysis of the - To have a well-understood cryptographic analysis of the
strength of the mechanism based on reasonable assumptions about strength of the mechanism based on reasonable assumptions about
the underlying hash function. the underlying hash function.
- To enable easy replacement of the hash function in case a - To enable easy replacement of the hash function in case a
faster or stronger hash is found or required. faster or stronger hash is found or required.
$ honey pot $ honey pot
(D) A system (e.g., a web server) or a system resource (e.g., a (D) A system (e.g., a web server) or system resource (e.g., a file
file on a server), that is designed to be attractive to potential on a server) that is designed to be attractive to potential
crackers and intruders, like honey is attractive to bears. (See: crackers and intruders, like honey is attractive to bears. (See:
entrapment.) entrapment.)
Deprecated Term: It is likely that other cultures have different Deprecated Term: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book.")
$ host $ host
1. (I) /general/ A computer that is attached to a communication 1. (I) /general/ A computer that is attached to a communication
subnetwork or internetwork and can use services provided by the subnetwork or internetwork and can use services provided by the
network to exchange data with other attached systems. (See: end network to exchange data with other attached systems. (See: end
system. Compare: server.) system. Compare: server.)
2. (I) /IPS/ A networked computer that does not forward IP packets 2. (I) /IPS/ A networked computer that does not forward IP packets
that are not addressed to the computer itself. (Compare: router.) that are not addressed to the computer itself. (Compare: router.)
Derivation: As viewed by its users, a host "entertains" them, Derivation: As viewed by its users, a host "entertains" them,
providing application layer services or access to other computers providing Application-Layer services or access to other computers
attached to the network. However, even though some traditional attached to the network. However, even though some traditional
peripheral service devices, such as printers, can now be peripheral service devices, such as printers, can now be
independently connected to networks, they are not usually called independently connected to networks, they are not usually called
hosts. hosts.
$ HTML $ HTML
(I) See: Hypertext Markup Language. (I) See: Hypertext Markup Language.
$ HTTP $ HTTP
(I) See: Hypertext Transfer Protocol. (I) See: Hypertext Transfer Protocol.
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$ hybrid encryption $ hybrid encryption
(I) An application of cryptography that combines two or more (I) An application of cryptography that combines two or more
encryption algorithms, particularly a combination of symmetric and encryption algorithms, particularly a combination of symmetric and
asymmetric encryption. Examples: digital envelope, MSP, PEM, PGP. asymmetric encryption. Examples: digital envelope, MSP, PEM, PGP.
(Compare: superencryption.) (Compare: superencryption.)
Tutorial: Asymmetric algorithms require more computation than Tutorial: Asymmetric algorithms require more computation than
equivalently strong symmetric ones. Thus, asymmetric encryption is equivalently strong symmetric ones. Thus, asymmetric encryption is
not normally used for data confidentiality except to distribute a not normally used for data confidentiality except to distribute a
symmetric keys in a hybrid encryption scheme, where the symmetric symmetric key in a hybrid encryption scheme, where the symmetric
key is usually very short (in terms of bits) compared to the data key is usually very short (in terms of bits) compared to the data
file it protects. (See: bulk key.) file it protects. (See: bulk key.)
$ hyperlink $ hyperlink
(I) In hypertext or hypermedia, an information object (such as a (I) In hypertext or hypermedia, an information object (such as a
word, a phrase, or an image; usually highlighted by color or word, a phrase, or an image, which usually is highlighted by color
underscoring) that points (indicates how to connect) to related or underscoring) that points (i.e., indicates how to connect) to
information that is located elsewhere and can be retrieved by related information that is located elsewhere and can be retrieved
activating the link (e.g., by selecting the object with a mouse by activating the link (e.g., by selecting the object with a mouse
pointer and then clicking). pointer and then clicking).
$ hypermedia $ hypermedia
(I) A generalization of hypertext; any media that contain (I) A generalization of hypertext; any media that contain
hyperlinks that point to material in the same or another data hyperlinks that point to material in the same or another data
object. object.
$ hypertext $ hypertext
(I) A computer document, or part of a document, that contains (I) A computer document, or part of a document, that contains
hyperlinks to other documents; i.e., text that contains active hyperlinks to other documents; i.e., text that contains active
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a web browser. (See: hypermedia.) a web browser. (See: hypermedia.)
$ Hypertext Markup Language (HTML) $ Hypertext Markup Language (HTML)
(I) A platform-independent system of syntax and semantics (RFC (I) A platform-independent system of syntax and semantics (RFC
1866) for adding characters to data files (particularly text 1866) for adding characters to data files (particularly text
files) to represent the data's structure and to point to related files) to represent the data's structure and to point to related
data, thus creating hypertext for use in the World Wide Web and data, thus creating hypertext for use in the World Wide Web and
other applications. (Compare: XML.) other applications. (Compare: XML.)
$ Hypertext Transfer Protocol (HTTP) $ Hypertext Transfer Protocol (HTTP)
(I) An TCP-based, application-level, client-server, Internet (I) An TCP-based, Application-Layer, client-server, Internet
protocol (RFC 2616) that is used to carry data requests and protocol (RFC 2616) that is used to carry data requests and
responses in the World Wide Web. (See: hypertext.) responses in the World Wide Web. (See: hypertext.)
$ IAB $ IAB
(I) See: Internet Architecture Board. (I) See: Internet Architecture Board.
$ IANA $ IANA
(I) See: Internet Assigned Numbers Authority. (I) See: Internet Assigned Numbers Authority.
$ IATF $ IATF
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$ IDEA $ IDEA
(N) See: International Data Encryption Algorithm. (N) See: International Data Encryption Algorithm.
$ identification $ identification
(I) An act or process that presents an identifier to a system so (I) An act or process that presents an identifier to a system so
that the system can recognize a system entity and distinguish it that the system can recognize a system entity and distinguish it
from other entities. (See: authentication.) from other entities. (See: authentication.)
$ identification information $ identification information
(D) Synonym for "identifier" or "authentication information". (D) Synonym for either "identifier" or "authentication
(See: authentication.) information". (See: authentication.)
Deprecated Term: ISDs SHOULD NOT use this term; it duplicates the Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
meaning of standardized terms and mixes concepts in a potentially for either of those terms; that would be duplicative and would mix
misleading way. Instead, use "identifier" or "authentication concepts in a potentially misleading way. Instead, use
information ", depending on what is meant. "identifier" or "authentication information ", depending on what
is meant.
$ Identification Protocol $ Identification Protocol
(I) An client-server Internet protocol [R1413] for learning the (I) An client-server Internet protocol [R1413] for learning the
identity of a user of a particular TCP connection. identity of a user of a particular TCP connection.
Tutorial: Given a TCP port number pair, the server returns a Tutorial: Given a TCP port number pair, the server returns a
character string that identifies the owner of that connection on character string that identifies the owner of that connection on
the server's system. The protocol is not intended for the server's system. The protocol does not provide an
authorization or access control; at best, it provides additional authentication service and is not intended for authorization or
auditing information with respect to TCP. access control. At best, it provides additional auditing
information with respect to TCP.
$ identifier $ identifier
(I) A data object -- often, a printable, non-blank character (I) A data object -- often, a printable, non-blank character
string -- that definitively represents a specific identity of a string -- that definitively represents a specific identity of a
system entity, distinguishing that identity from all others. system entity, distinguishing that identity from all others.
(Compare: identity.) (Compare: identity.)
$ identifier credential
1. (I) See: /authentication/ under "credential".
2. (D) Synonym for "signature certificate".
Usage: ISDs that use this term SHOULD state a definition for it
because the term is used in many ways and could easily be
misunderstood.
$ identity $ identity
(I) The collective aspect of a set of attribute values (i.e., (I) The collective aspect of a set of attribute values (i.e.,
characteristics) by which a system entity is recognizable or characteristics) by which a system entity is recognizable or
known, and which is sufficient to distinguish the entity from all known, and which is sufficient to (1) distinguish the entity from
other entities in the system, and also sufficient to distinguish all other entities in the system and (2) distinguish the identity
the identity from any other identities of the same entity. (See: from any other identities of the same entity. (See: authenticate,
authenticate. Compare: identifier.) registration. Compare: identifier.)
Tutorial: When a user's identity is registered in a system, the
system may require presentation of evidence that proves both the
user's eligibility to register and the identity's authenticity
(i.e., that the user has the right to claim the identity).
The set of attributes used for identities must, of course, be
sufficient to uniquely represent each entity, i.e., to distinguish
each entity from all others in the system. However, a PKI or other
system may permit a subscriber to have two or more concurrent
identities. (This is different from concurrently associating two
different identifiers with the same identity, and also different
from a single identity concurrently accessing the system in two
different roles. (See: role-based access control.)) Having two or
more identities registered in a system for the same entity implies
that the entity has two separate justifications for registration
eligibility. In that case, the set of attributes used for
identities must be able to uniquely represent multiple identities
for a single entity.
Tutorial: This term relates to some other basic security terms as Tutorial: At the time when a user's identity is being registered
shown in the following diagram: in a system, the system may require presentation of evidence that
proves both the user's eligibility to register and the identity's
authenticity (i.e., that the user has the right to claim the
identity).
Relationships: === One-To-One, ==> One-To-Many, <=> Many-to-Many. The set of attributes used to recognize identities must, of
+- - - - - - - - - - - - - - - - - - - - - - - - - - + course, be sufficient to uniquely represent each entity, i.e., to
| PKI System | distinguish each entity from all others in the system. However, a
+ - - - - + | +------------------+ +-------------------------+ | PKI or other system may permit a subscriber to have two or more
| User | | | Subscriber, i.e. | | Subscriber Identity | | concurrent identities. (This is different from concurrently
| +-----+ | | | Registered User | | | | associating two different identifiers with the same identity, and
| |Human| | | |(Is System-Unique)| | (Is System-Unique) | | also different from a single identity concurrently accessing the
| |Being| | | | +--------------+ | | +---------------------+ | | system in two different roles. (See: principal, role-based access
| +-----+ | | | | User's Core | | | | Subscriber | | | control.)) Having two or more identities registered in a system
| ^ |===| | Registration | |==>| | Identity's | | | for the same entity implies that the entity has two separate
| | | | | | Data, i.e., | | | | Registration Data | | | justifications for registration eligibility. In that case, the set
| | | | | | An Entity's | | | |+-------------------+| | | of attributes used for identities must be able to uniquely
| v | | | |Distinguishing|========| Same Core Data || | | represent multiple identities for a single entity.
| +-----+ | | | | Attribute | | | ||For All Identities || | |
| | Set | | | | | Values | | +===|| Of The Same User || | |
| +-----+ | | | +--------------+ | | | |+-------------------+| | |
| ^ | | +------------------+ | | +---------------------+ | |
| | | | | +=======+ +------------|------------+ |
| | | | +-------v----|----------------------|------------+ |
| v | | | +----------v-----+ +------------v----------+ | |
| +-----+ | | | | Authentication |<=>| Subscriber Identifier | | |
| |Auto-| | | | | Information | | (Is System Unique) | | |
| |mated| | | | +----------------+ +-----------------------+ | |
| |Pro- | | | | Identity Credential | |
| |cess | | | |(Associates Authentication Info. and Identifier)| |
| +-----+ | | +------------------------------------------------+ |
+ - - - - + + - - - - - - - - - - - - - - - - - - - - - - - - - -+
An ISD may apply this term to a user that is an individual entity An ISD may apply this term to a user that is an individual entity
or one that is a set. If an ISD involves both meanings, the ISD or one that is a set. If an ISD involves both meanings, the ISD
SHOULD use the following definitions to avoid ambiguity: SHOULD use the following definitions to avoid ambiguity:
- "Singular identity": An identity that is registered for a user - "Singular identity": An identity that is registered for a user
that is exactly one person or one process. that is exactly one person or one process.
- "Shared identity": An identity that is registered for a user - "Shared identity": An identity that is registered for a user
that is a set of entities of which each member is authorized to that is a set of entities of which each member is authorized to
assume the identity individually and for which the registering assume the identity individually and for which the registering
system maintains a record of the singular entities that system maintains a record of the singular entities that
comprise the set. In this case, we would expect each member comprise the set. In this case, we would expect each member
entity to be registered with a singular identity. entity to be registered with a singular identity.
- "Group identity": An identity that is registered for a user - "Group identity": An identity that is registered for a user
that is a set of entities for which the registering system does that is a set of entities for which the registering system does
not maintain a record of the singular entities that comprise not maintain a record of the singular entities that comprise
the set. the set.
The following diagram illustrates how this term relates to some
other terms in a PKI system: authentication information,
identifier, identifier credential, registration, registered user,
subscriber, and user.
Relationships: === one-to-one, ==> one-to-many, <=> many-to-many.
+- - - - - - - - - - - - - - - - - - - - - - - - - - +
| PKI System |
+ - - - - + | +------------------+ +-------------------------+ |
| User, | | |Subscriber, i.e., | | Identity of Subscriber | |
|i.e., one| | | Registered User, | | is system-unique | |
| of the | | | is system-unique | | +---------------------+ | |
|following| | | +--------------+ | | | Subscriber | | |
| | | | | User's core | | | | Identity's | | |
| +-----+ |===| | Registration | |==>| | Registration data | | |
| |human| | | | | data, i.e., | | | |+-------------------+| | |
| |being| | | | | an entity's | | | || same core data || | |
| +-----+ | | | |distinguishing|========|for all Identities || | |
| or | | | | attribute | | | || of the same User || | |
| +-----+ | | | | values | | +===|+-------------------+| | |
| |auto-| | | | +--------------+ | | | +---------------------+ | |
| |mated| | | +------------------+ | +------------|------------+ |
| |pro- | | | | +=======+ | |
| |cess | | | +-------v----|----------------------|------------+ |
| +-----+ | | | +----------v---+ +------------v----------+ | |
| or | | | |Authentication|<===>|Identifier of Identity | | |
|+-------+| | | | Information | | is system-unique | | |
|| a set || | | +--------------+ +-----------------------+ | |
|| of || | | Identifier Credential that associates unit of | |
|| either|| | | Authentication Information with the Identifier | |
|+-------+| | +------------------------------------------------+ |
+ - - - - + + - - - - - - - - - - - - - - - - - - - - - - - - - -+
$ identity-based security policy $ identity-based security policy
(I) "A security policy based on the identities and/or attributes (I) "A security policy based on the identities and/or attributes
of users, a group of users, or entities acting on behalf of the of users, a group of users, or entities acting on behalf of the
users and the resources/objects being accessed." [I7498 Part 2] users and the resources/objects being accessed." [I7498 Part 2]
(See: rule-based security policy.) (See: rule-based security policy.)
$ identity credential
1. (I) See: ("authentication" context under) "credential".
2. (I) Synonym for "signature certificate.
Usage: The term is used in many ways and could easily be
misunderstood; therefore, ISDs that use this term SHOULD state a
definition for it.
$ identity proofing $ identity proofing
(I) A process that vets and verifies the information that is used (I) A process that vets and verifies the information that is used
to establish the identity of a system entity. to establish the identity of a system entity. (See: registration.)
$ IDS $ IDS
(I) See: intrusion detection system. (I) See: intrusion detection system.
$ IEEE $ IEEE
(N) See: Institute of Electrical and Electronics Engineers, Inc. (N) See: Institute of Electrical and Electronics Engineers, Inc.
$ IEEE 802.10 $ IEEE 802.10
(N) An IEEE committee developing security standards for local area (N) An IEEE committee developing security standards for local area
networks. (See: SILS.) networks. (See: SILS.)
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$ IETF $ IETF
(I) See: Internet Engineering Task Force. (I) See: Internet Engineering Task Force.
$ IKE $ IKE
(I) See: IPsec Key Exchange. (I) See: IPsec Key Exchange.
$ IMAP4 $ IMAP4
(I) See: Internet Message Access Protocol, version 4. (I) See: Internet Message Access Protocol, version 4.
$ IMAP4 AUTHENTICATE $ IMAP4 AUTHENTICATE
(I) A IMAP4 "command" (better described as a transaction type, or (I) A IMAP4 command (better described as a transaction type, or
a protocol-within-a-protocol) by which an IMAP4 client optionally subprotocol) by which an IMAP4 client optionally proposes a
proposes a mechanism to an IMAP4 server to authenticate the client mechanism to an IMAP4 server to authenticate the client to the
to the server and provide other security services. (See: POP3.) server and provide other security services. (See: POP3.)
Tutorial: If the server accepts the proposal, the command is Tutorial: If the server accepts the proposal, the command is
followed by performing a challenge-response authentication followed by performing a challenge-response authentication
protocol and, optionally, negotiating a protection mechanism for protocol and, optionally, negotiating a protection mechanism for
subsequent POP3 interactions. The security mechanisms that are subsequent POP3 interactions. The security mechanisms that are
used by IMAP4 AUTHENTICATE -- including Kerberos, GSSAPI, and used by IMAP4 AUTHENTICATE -- including Kerberos, GSSAPI, and
S/Key -- are described in [R1731]. S/Key -- are described in [R1731].
$ in the clear $ in the clear
(I) Not encrypted. (See: clear text.) (I) Not encrypted. (See: clear text.)
$ Ina Jo $ Ina Jo
(O) A methodology, language, and integrated set of software tools (O) A methodology, language, and integrated set of software tools
developed at the System Development Corporation for specifying, developed at the System Development Corporation for specifying,
coding, and verifying software to produce correct and reliable coding, and verifying software to produce correct and reliable
programs. Also known as the Formal Development Methodology. [Cheh] programs. Usage: a.k.a. the Formal Development Methodology. [Cheh]
$ incapacitation $ incapacitation
(I) A type of threat action that prevents or interrupts system (I) A type of threat action that prevents or interrupts system
operation by disabling a system component. (See: disruption.) operation by disabling a system component. (See: disruption.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Malicious logic": In context of incapacitation, any hardware, - "Malicious logic": In context of incapacitation, any hardware,
firmware, or software (e.g., logic bomb) intentionally firmware, or software (e.g., logic bomb) intentionally
introduced into a system to destroy system functions or introduced into a system to destroy system functions or
resources. (See: (main entry for) malicious logic.) resources. (See: corruption, main entry for "malicious logic",
- "Physical destruction": Deliberate destruction of a system masquerade, misuse.)
- "Physical destruction": Deliberate destruction of a system
component to interrupt or prevent system operation. component to interrupt or prevent system operation.
- "Human error": In context of incapacitation, action or inaction - "Human error": In context of incapacitation, action or inaction
that unintentionally disables a system component. that unintentionally disables a system component. (See:
- "Hardware or software error": In context of incapacitation, corruption, exposure.)
- "Hardware or software error": In context of incapacitation,
error that unintentionally causes failure of a system component error that unintentionally causes failure of a system component
and leads to disruption of system operation. and leads to disruption of system operation. (See: corruption,
- "Natural disaster": In context of incapacitation, any "act of exposure.)
- "Natural disaster": In context of incapacitation, any "act of
God" (e.g., fire, flood, earthquake, lightning, or wind) that God" (e.g., fire, flood, earthquake, lightning, or wind) that
disables a system component. [FP031 section 2] disables a system component. [FP031 section 2]
$ incident $ incident
See: security incident. See: security incident.
$ INCITS $ INCITS
See: (International Committee for Information Technology (N) See: "International Committee for Information Technology
Standardization under) ANSI. Standardization" under "ANSI".
$ indicator $ indicator
(N) An action -- either specific, generalized, or theoretical -- (N) An action -- either specific, generalized, or theoretical --
that an adversary might be expected to take in preparation for an that an adversary might be expected to take in preparation for an
attack. [C4009] (See: attack sensing, warning, and response.) attack. [C4009] (See: attack sensing, warning, and response.)
$ indirect certificate revocation list (ICRL) $ indirect certificate revocation list (ICRL)
(N) In X.509, a CRL that may contain certificate revocation (N) In X.509, a CRL that may contain certificate revocation
notifications for certificates issued by CAs other than the issuer notifications for certificates issued by CAs other than the issuer
(i.e., signer) of the ICRL. (i.e., signer) of the ICRL.
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(O) A publicly available document [IATF], developed through a (O) A publicly available document [IATF], developed through a
collaborative effort by organizations in the U.S. Government and collaborative effort by organizations in the U.S. Government and
industry, and issued by NSA. Intended for security managers and industry, and issued by NSA. Intended for security managers and
system security engineers as a tutorial and reference document system security engineers as a tutorial and reference document
about security problems in information systems and networks, to about security problems in information systems and networks, to
improve awareness of tradeoffs among available technology improve awareness of tradeoffs among available technology
solutions and of desired characteristics of security approaches solutions and of desired characteristics of security approaches
for particular problems. (See: ISO 17799, [SP14].) for particular problems. (See: ISO 17799, [SP14].)
$ information domain $ information domain
(O) See: (secondary definition under) domain. (O) See: secondary definition under "domain".
$ information domain security policy $ information domain security policy
(O) See: (secondary definition under) domain. (O) See: secondary definition under "domain".
$ information flow policy $ information flow policy
(N) /formal model/ A triple consisting of a set of security (N) /formal model/ A triple consisting of a set of security
levels (or their equivalent security labels), a binary operator levels (or their equivalent security labels), a binary operator
that maps each pair of security levels into a security level, and that maps each pair of security levels into a security level, and
a binary relation on the set that selects a set of pairs of levels a binary relation on the set that selects a set of pairs of levels
such that information is permitted to flow from an object of the such that information is permitted to flow from an object of the
first level to an object of the second level. (See: flow control, first level to an object of the second level. (See: flow control,
lattice model.) lattice model.)
$ information operations condition (INFOCON) $ information operations condition (INFOCON)
(O) /U.S. DoD/ A comprehensive defense posture and response based (O) /U.S. DoD/ A comprehensive defense posture and response based
on the status of information systems, military operations, and on the status of information systems, military operations, and
intelligence assessments of adversary capabilities and intent. intelligence assessments of adversary capabilities and intent.
(See: threat) (See: threat)
Derivation: From DEFCON, i.e., defense condition. Derivation: From DEFCON, i.e., defense condition.
Tutorial: The U.S. DoD INFOCON levels are: NORMAL (normal Tutorial: The U.S. DoD defines five INFOCON levels: NORMAL (normal
activity), ALPHA (increased risk of attack), BRAVO (specific risk activity), ALPHA (increased risk of attack), BRAVO (specific risk
of attack), CHARLIE (limited attack), and DELTA (general attack). of attack), CHARLIE (limited attack), and DELTA (general attack).
$ information security (INFOSEC) $ information security (INFOSEC)
(N) Measures that implement and assure security services in (N) Measures that implement and assure security services in
information systems, including in computer systems (see: COMPUSEC) information systems, including in computer systems (see: COMPUSEC)
and in communication systems (see: COMSEC). and in communication systems (see: COMSEC).
$ information system $ information system
(I) An organized assembly of computing and communication resources (I) An organized assembly of computing and communication resources
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$ Information Technology Security Evaluation Criteria (ITSEC) $ Information Technology Security Evaluation Criteria (ITSEC)
(N) A Standard [ITSEC] jointly developed by France, Germany, the (N) A Standard [ITSEC] jointly developed by France, Germany, the
Netherlands, and the United Kingdom for use in the European Union; Netherlands, and the United Kingdom for use in the European Union;
accommodates a wider range of security assurance and functionality accommodates a wider range of security assurance and functionality
combinations than the TCSEC. Superseded by the Common Criteria. combinations than the TCSEC. Superseded by the Common Criteria.
$ INFOSEC $ INFOSEC
(I) See: information security. (I) See: information security.
$ ingress filtering $ ingress filtering
(I) A method [R2267] for countering attacks that use packets with (I) A method [R2827] for countering attacks that use packets with
false IP source addresses, by blocking such packets at the false IP source addresses, by blocking such packets at the
boundary between connected networks. boundary between connected networks.
Tutorial: Suppose network A of an internet service provider (ISP) Tutorial: Suppose network A of an internet service provider (ISP)
includes a filtering router that is connected to customer network includes a filtering router that is connected to customer network
B, and an attacker in B at IP source address "foo" attempts to B, and an attacker in B at IP source address "foo" attempts to
send packets with false source address "bar" into A. The false send packets with false source address "bar" into A. The false
address may be either fixed or randomly changing, and it may address may be either fixed or randomly changing, and it may
either be unreachable or be a forged address that legitimately either be unreachable or be a forged address that legitimately
exists within either B or some other network C. In ingress exists within either B or some other network C. In ingress
filtering, the ISP's router blocks all inbound packet that arrive filtering, the ISP's router blocks all inbound packet that arrive
from B with a source address that is not within the range of from B with a source address that is not within the range of
legitimately advertised addresses for B. This method does not legitimately advertised addresses for B. This method does not
prevent all attacks that can originate from B, but the actual prevent all attacks that can originate from B, but the actual
source of such attacks can be more easily traced because the source of such attacks can be more easily traced because the
originating network is known. originating network is known.
$ initialization value (IV) $ initialization value (IV)
(I) An input parameter that sets the starting state of a (I) /cryptography/ An input parameter that sets the starting state
cryptographic algorithm or mode. of a cryptographic algorithm or mode.
Usage: Sometimes called "initialization vector" or "message Usage: Sometimes called "initialization vector" or "message
indicator", but ISDs SHOULD NOT use these synonyms because they indicator", but ISDs SHOULD NOT use these synonyms because they
mix concepts in potentially confusing ways. mix concepts in potentially confusing ways.
Tutorial: An IV can be used to synchronize one cryptographic Tutorial: An IV can be used to synchronize one cryptographic
process with another; e.g., CBC, CFB, and OFB use IVs. An IV also process with another; e.g., CBC, CFB, and OFB use IVs. An IV also
can be used to introduce cryptographic variance (see: salt) in can be used to introduce cryptographic variance (see: salt) in
addition to that provided by a key. addition to that provided by a key.
$ initialization vector $ initialization vector
(D) /cryptographic function/ Synonym for "initialization value". (D) /cryptographic function/ Synonym for "initialization value".
Deprecated Term: For consistency, ISDs SHOULD NOT use this term in Deprecated Term: For consistency, ISDs SHOULD NOT use this term in
the context of cryptographic functions. the context of cryptographic functions.
$ insertion
(I) /packet/ See: secondary definition under "stream integrity
service".
$ inside attack $ inside attack
(I) See: (secondary definition under) attack. Compare: insider.) (I) See: secondary definition under "attack". Compare: insider.
$ insider $ insider
1. (I) A user (usually a person) that accesses a system from a 1. (I) A user (usually a person) that accesses a system from a
position that is inside the system's security perimeter. (Compare: position that is inside the system's security perimeter. (Compare:
authorized user, outsider, unauthorized user.) authorized user, outsider, unauthorized user.)
Tutorial: An insider has been assigned a role that has more Tutorial: An insider has been assigned a role that has more
privileges to access system resources than do some other types of privileges to access system resources than do some other types of
users, or can access those resources without being constrained by users, or can access those resources without being constrained by
some access controls that are applied to outside users. For some access controls that are applied to outside users. For
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$ Institute of Electrical and Electronics Engineers, Inc. (IEEE) $ Institute of Electrical and Electronics Engineers, Inc. (IEEE)
(N) The IEEE is a not-for-profit association of approximately (N) The IEEE is a not-for-profit association of approximately
300,000 individual members in 150 countries. The IEEE produces 300,000 individual members in 150 countries. The IEEE produces
nearly one third of the world's published literature in electrical nearly one third of the world's published literature in electrical
engineering, computers, and control technology; holds hundreds of engineering, computers, and control technology; holds hundreds of
major, annual conferences; and maintains more than 800 active major, annual conferences; and maintains more than 800 active
standards, with many more under development. (See: SILS.) standards, with many more under development. (See: SILS.)
$ integrity $ integrity
See: data integrity, correctness integrity, source integrity, See: data integrity, datagram integrity service, correctness
system integrity. integrity, source integrity, stream integrity service, system
integrity.
$ integrity check $ integrity check
(D) A computation that is part of a mechanism to provide data (D) A computation that is part of a mechanism to provide data
integrity service or data origin authentication service. (Compare: integrity service or data origin authentication service. (Compare:
checksum.) checksum.)
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
"cryptographic hash" or "protected checksum. This term "cryptographic hash" or "protected checksum. This term
unnecessarily duplicates the meaning of other, well-established unnecessarily duplicates the meaning of other, well-established
terms; this term only mentions integrity, even though the intended terms; this term only mentions integrity, even though the intended
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is cryptographically protected. is cryptographically protected.
$ integrity label $ integrity label
(I) A security label that tells the degree of confidence that may (I) A security label that tells the degree of confidence that may
be placed in the data, and may also tell what countermeasures are be placed in the data, and may also tell what countermeasures are
required to be applied to protect the data against from alteration required to be applied to protect the data against from alteration
and destruction. (See: integrity. Compare: classification label.) and destruction. (See: integrity. Compare: classification label.)
$ intelligent threat $ intelligent threat
(I) A circumstance in which an adversary has the technical and (I) A circumstance in which an adversary has the technical and
operational capability to detect and exploit a vulnerability and operational ability to detect and exploit a vulnerability and also
also has the demonstrated, presumed, or inferred intent to do so. has the demonstrated, presumed, or inferred intent to do so. (See:
(See: threat.) threat.)
$ interception $ interception
(I) A type of threat action whereby an unauthorized entity (I) A type of threat action whereby an unauthorized entity
directly accesses sensitive data while the data is traveling directly accesses sensitive data while the data is traveling
between authorized sources and destinations. (See: unauthorized between authorized sources and destinations. (See: unauthorized
disclosure.) disclosure.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Theft": Gaining access to sensitive data by stealing a - "Theft": Gaining access to sensitive data by stealing a
shipment of a physical medium, such as a magnetic tape or disk, shipment of a physical medium, such as a magnetic tape or disk,
that holds the data. that holds the data.
- "Wiretapping (passive)": Monitoring and recording data that is - "Wiretapping (passive)": Monitoring and recording data that is
flowing between two points in a communication system. (See: flowing between two points in a communication system. (See:
wiretapping.) wiretapping.)
- "Emanations analysis": Gaining direct knowledge of communicated - "Emanations analysis": Gaining direct knowledge of communicated
data by monitoring and resolving a signal that is emitted by a data by monitoring and resolving a signal that is emitted by a
system and that contains the data but is not intended to system and that contains the data but was not intended to
communicate the data. (See: emanation.) communicate the data. (See: emanation.)
$ interference $ interference
See: (secondary definition under) obstruction. (I) /threat action/ See: secondary definition under "obstruction".
$ intermediate CA $ intermediate CA
(D) The CA that issues a cross-certificate to another CA. [X509] (D) The CA that issues a cross-certificate to another CA. [X509]
(See: cross-certification.) (See: cross-certification.)
Deprecated Term: ISDs SHOULD NOT use this term because it is not Deprecated Term: ISDs SHOULD NOT use this term because it is not
widely known and mixes concepts in a potentially misleading way. widely known and mixes concepts in a potentially misleading way.
For example, suppose that end entity 1 ("EE1) is in one PKI For example, suppose that end entity 1 ("EE1) is in one PKI
("PKI1"), end entity 2 ("EE2) is in another PKI ("PKI2"), and the ("PKI1"), end entity 2 ("EE2) is in another PKI ("PKI2"), and the
root in PKI1 ("CA1") cross-certifies the root CA in PKI2 ("CA2"). root in PKI1 ("CA1") cross-certifies the root CA in PKI2 ("CA2").
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characteristics of computer hardware and software, especially of characteristics of computer hardware and software, especially of
operating systems. Includes mechanisms to regulate the operation operating systems. Includes mechanisms to regulate the operation
of a computer system with regard to access control, flow control, of a computer system with regard to access control, flow control,
and inference control. (Compare: external controls.) and inference control. (Compare: external controls.)
$ International Data Encryption Algorithm (IDEA) $ International Data Encryption Algorithm (IDEA)
(N) A patented, symmetric block cipher that uses a 128-bit key and (N) A patented, symmetric block cipher that uses a 128-bit key and
operates on 64-bit blocks. [Schn] (See: symmetric cryptography.) operates on 64-bit blocks. [Schn] (See: symmetric cryptography.)
$ International Standard $ International Standard
(N) See: (secondary definition under) ISO. (N) See: secondary definition under "ISO".
$ International Traffic in Arms Regulations (ITAR) $ International Traffic in Arms Regulations (ITAR)
(O) Rules issued by the U.S. State Department, by authority of the (O) Rules issued by the U.S. State Department, by authority of the
Arms Export Control Act (22 U.S.C. 2778), to control export and Arms Export Control Act (22 U.S.C. 2778), to control export and
import of defense articles and defense services, including import of defense articles and defense services, including
information security systems, such as cryptographic systems, and information security systems, such as cryptographic systems, and
TEMPEST suppression technology. (See: type 1 product, Wassenaar TEMPEST suppression technology. (See: type 1 product, Wassenaar
Arrangement.) Arrangement.)
$ internet, Internet $ internet, Internet
1. (I) /not capitalized/ The term "internet" is a popular short 1. (I) /not capitalized/ Abbreviation of "internetwork".
synonym for "internetwork".
2. (I) /capitalized/ "The Internet" is the single, interconnected, 2. (I) /capitalized/ The Internet is the single, interconnected,
worldwide system of commercial, government, educational, and other worldwide system of commercial, government, educational, and other
computer networks that share the protocol suite specified by the computer networks that share (a) the protocol suite specified by
IAB [R2026] and the name and address spaces managed by the ICANN. the IAB (RFC 2026) and (b) the name and address spaces managed by
the ICANN. (See: Internet Layer, Internet Protocol Suite.)
Tutorial: The set of protocols is called the "Internet Protocol
Suite" (IPS). It also is popularly known as "TCP/IP", because TCP
and IP are two of its most important protocols. The IPS makes it
possible for users of any one of the networks in the Internet to
communicate with, or use services located on, any of the other
networks.
Although the Internet does have architectural principles
(described in RFC 1958), no Internet Standard defines a layered
reference model for the IPS that is similar to the OSIRM. However,
Internet community documents do refer (inconsistently) to layers:
application, socket, transport, internetwork, network, data link,
and physical.
Usage: In this Glossary, Internet protocol layers are referred to Usage: Use with definite article "the" when using as a noun. E.g.,
by name to avoid confusing them with OSIRM layers, which are say "My LAN is small, but the Internet is large." Don't say "My
referred to by number. (See: OSI.) LAN is small, but Internet is large."
$ Internet Architecture Board (IAB) $ Internet Architecture Board (IAB)
(I) A technical advisory group of the ISOC, chartered by the ISOC (I) A technical advisory group of the ISOC, chartered by the ISOC
Trustees to provide oversight of Internet architecture and Trustees to provide oversight of Internet architecture and
protocols and, in the context of Internet Standards, a body to protocols and, in the context of Internet Standards, a body to
which decisions of the IESG may be appealed. Responsible for which decisions of the IESG may be appealed. Responsible for
approving appointments to the IESG from among nominees submitted approving appointments to the IESG from among nominees submitted
by the IETF nominating committee. [R2026] by the IETF nominating committee. (RFC 2026)
$ Internet Assigned Numbers Authority (IANA) $ Internet Assigned Numbers Authority (IANA)
(I) From the early days of the Internet, the IANA was chartered by (I) From the early days of the Internet, the IANA was chartered by
the ISOC and the U.S. Government's Federal Network Council to be the ISOC and the U.S. Government's Federal Network Council to be
the central coordination, allocation, and registration body for the central coordination, allocation, and registration body for
parameters for Internet protocols. Superseded by ICANN. parameters for Internet protocols. Superseded by ICANN.
$ Internet Control Message Protocol (ICMP) $ Internet Control Message Protocol (ICMP)
(I) An Internet Standard protocol (RFC 792) that is used to report (I) An Internet Standard protocol (RFC 792) that is used to report
error conditions during IP datagram processing and to exchange error conditions during IP datagram processing and to exchange
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management information base OIDs, including private enterprise management information base OIDs, including private enterprise
numbers, and many others. The Internet community requires that the numbers, and many others. The Internet community requires that the
values used in these parameter fields be assigned uniquely. ICANN values used in these parameter fields be assigned uniquely. ICANN
makes those assignments as requested and maintains a registry of makes those assignments as requested and maintains a registry of
the current values. the current values.
ICANN was formed in October 1998, by a coalition of the Internet's ICANN was formed in October 1998, by a coalition of the Internet's
business, technical, and academic communities. The U.S. Government business, technical, and academic communities. The U.S. Government
designated ICANN to serve as the global consensus entity with designated ICANN to serve as the global consensus entity with
responsibility for coordinating four key functions for the responsibility for coordinating four key functions for the
Internet: the allocation of IP address space, the assignment of Internet: allocation of IP address space, assignment of protocol
protocol parameters, and the management of the DNS and the DNS parameters, management of the DNS, and management of the DNS root
root server system. server system.
$ Internet Draft $ Internet-Draft
(I) A working document of the IETF, its areas, and its working (I) A working document of the IETF, its areas, and its working
groups. (Other groups may also distribute working documents as groups. (RFC 2026)
Internet Drafts.) An Internet Draft is not an archival document
like an RFC is. Instead, an Internet Draft is a preliminary or Usage: The term is customarily hyphenated when used either as a
working document that is valid for a maximum of six months and may adjective or a noun, even though the latter is not standard
be updated, replaced, or made obsolete by other documents at any English punctuation.
Tutorial: An Internet-Draft is not an archival document like an
RFC is. Instead, an Internet-Draft is a preliminary or working
document that is valid for a maximum of six months and may be
updated, replaced, or made obsolete by other documents at any
time. It is inappropriate to use an Internet Draft as reference time. It is inappropriate to use an Internet Draft as reference
material or to cite it other than as "work in progress". material or to cite it other than as "work in progress". Although
most of the Internet-Drafts are produced by the IETF, any
interested organization may request to have its working documents
published as Internet-Drafts.
$ Internet Engineering Steering Group (IESG) $ Internet Engineering Steering Group (IESG)
(I) The part of the ISOC responsible for technical management of (I) The part of the ISOC responsible for technical management of
IETF activities and administration of the Internet Standards IETF activities and administration of the Internet Standards
Process according to procedures approved by the ISOC Trustees. Process according to procedures approved by the ISOC Trustees.
Directly responsible for actions along the "standards track", Directly responsible for actions along the "standards track",
including final approval of specifications as Internet Standards. including final approval of specifications as Internet Standards.
Composed of IETF Area Directors and the IETF chairperson, who also Composed of IETF Area Directors and the IETF chairperson, who also
chairs the IESG. [R2026] chairs the IESG. (RFC 2026)
$ Internet Engineering Task Force (IETF) $ Internet Engineering Task Force (IETF)
(I) A self-organized group of people who make contributions to the (I) A self-organized group of people who make contributions to the
development of Internet technology. The principal body engaged in development of Internet technology. The principal body engaged in
developing Internet Standards, although not itself a part of the developing Internet Standards, although not itself a part of the
ISOC. Composed of Working Groups, which are arranged into Areas ISOC. Composed of Working Groups, which are arranged into Areas
(such as the Security Area), each coordinated by one or more Area (such as the Security Area), each coordinated by one or more Area
Directors. Nominations to the IAB and the IESG are made by a Directors. Nominations to the IAB and the IESG are made by a
committee selected at random from regular IETF meeting attendees committee selected at random from regular IETF meeting attendees
who have volunteered. [R2026, R2323] who have volunteered. (RFC 2026) [RFC 2323]
$ Internet Layer
(I) See: Internet Protocol Suite.
$ Internet Message Access Protocol, version 4 (IMAP4) $ Internet Message Access Protocol, version 4 (IMAP4)
(I) An Internet protocol (RFC 2060) by which a client workstation (I) An Internet protocol (RFC 2060) by which a client workstation
can dynamically access a mailbox on a server host to manipulate can dynamically access a mailbox on a server host to manipulate
and retrieve mail messages that the server has received and is and retrieve mail messages that the server has received and is
holding for the client. (See: POP3.) holding for the client. (See: POP3.)
Tutorial: IMAP4 has mechanisms for optionally authenticating a Tutorial: IMAP4 has mechanisms for optionally authenticating a
client to a server and providing other security services. (See: client to a server and providing other security services. (See:
IMAP4 AUTHENTICATE.) IMAP4 AUTHENTICATE.)
skipping to change at page 132, line 39 skipping to change at page 138, line 39
(I) An Internet protocol (RFC 2801) proposed as a general (I) An Internet protocol (RFC 2801) proposed as a general
framework for Internet commerce, able to encapsulate transactions framework for Internet commerce, able to encapsulate transactions
of various proprietary payment systems (e.g., GeldKarte, Mondex, of various proprietary payment systems (e.g., GeldKarte, Mondex,
SET, VisaCash). Provides optional security services by SET, VisaCash). Provides optional security services by
incorporating various Internet security mechanisms (e.g., MD5) and incorporating various Internet security mechanisms (e.g., MD5) and
protocols (e.g., TLS). protocols (e.g., TLS).
$ Internet Policy Registration Authority (IPRA) $ Internet Policy Registration Authority (IPRA)
(I) An X.509-compliant CA that is the top CA of the Internet (I) An X.509-compliant CA that is the top CA of the Internet
certification hierarchy operated under the auspices of the ISOC certification hierarchy operated under the auspices of the ISOC
[R1422]. (See: (PEM usage under) certification hierarchy.) [R1422]. (See: /PEM/ under "certification hierarchy".)
$ Internet Private Line Interface (IPLI) $ Internet Private Line Interface (IPLI)
(I) A successor to the PLI, updated to use TCP/IP and newer (O) A successor to the PLI, updated to use TCP/IP and newer
military-grade COMSEC equipment (TSEC/KG-84). The IPLI was a military-grade COMSEC equipment (TSEC/KG-84). The IPLI was a
portable, modular system that was developed for use in tactical, portable, modular system that was developed for use in tactical,
packet-radio networks. packet-radio networks.
$ Internet Protocol (IP) $ Internet Protocol (IP)
(I) A Internet Standard protocol (version 4 is specified in RFC (I) A Internet Standard, Internet-Layer protocol that moves
791, and version 6 in RFC 2460) that moves datagrams (discrete datagrams (discrete sets of bits) from one computer to another
sets of bits) from one computer to another across an internetwork across an internetwork but does not provide reliable delivery,
but does not provide reliable delivery, flow control, sequencing, flow control, sequencing, or other end-to-end services that TCP
or other end-to-end services that TCP provides. (See: IP address, provides. IP version 4 (IPv4) is specified in RFC 791, and IP
version 6 (IPv6) is specified in RFC 2460. (See: IP address,
TCP/IP.) TCP/IP.)
Tutorial: In the OSIRM, IP would be located at the top of layer 3. Tutorial: If IP were used in an OSIRM stack, IP would be placed at
the top of Layer 3, above other Layer 3 protocols in the stack.
In any IPS stack, IP is always present in the Internet Layer and
is always placed at the top of that layer, on top of any other
protocols that are used in that layer. In some sense, IP is the
only protocol specified for the IPS Internet Layer; other
protocols used there, such as AH and ESP, are just IP variations.
$ Internet Protocol security $ Internet Protocol security
See: IPsec. See: IPsec.
$ Internet Protocol Security Option (IPSO) $ Internet Protocol Security Option (IPSO)
(I) Refers to one of three types of IP security options, which are (I) Refers to one of three types of IP security options, which are
fields that may be added to an IP datagram for the purpose of fields that may be added to an IP datagram for the purpose of
carrying security information about the datagram. (Compare: carrying security information about the datagram. (Compare:
IPsec.) IPsec.)
Deprecated Usage: ISDs SHOULD NOT use this term without a modifier Deprecated Usage: ISDs SHOULD NOT use this term without a modifier
to indicate which of the following three types is meant. to indicate which of the following three types is meant.
- "DoD Basic Security Option" (IP option type 130): Defined for - "DoD Basic Security Option" (IP option type 130): Defined for
use on U.S. DoD common-use data networks. Identifies the DoD use on U.S. DoD common-use data networks. Identifies the DoD
classification level at which the datagram is to be protected classification level at which the datagram is to be protected
and the protection authorities whose rules apply to the and the protection authorities whose rules apply to the
datagram. (A "protection authority" is a National Access datagram. (A "protection authority" is a National Access
Program (e.g., GENSER, SIOP-ESI, SCI, NSA, Department of Program (e.g., GENSER, SIOP-ESI, SCI, NSA, Department of
Energy) or Special Access Program that specifies protection Energy) or Special Access Program that specifies protection
rules for transmission and processing of the information rules for transmission and processing of the information
contained in the datagram.) [R1108] contained in the datagram.) [R1108]
- "DoD Extended Security Option" (IP option type 133): Permits - "DoD Extended Security Option" (IP option type 133): Permits
additional security labeling information, beyond that present additional security labeling information, beyond that present
in the Basic Security Option, to be supplied in the datagram to in the Basic Security Option, to be supplied in the datagram to
meet the needs of registered authorities. [R1108] meet the needs of registered authorities. [R1108]
- "Common IP Security Option" (CIPSO) (IP option type 134): - "Common IP Security Option" (CIPSO) (IP option type 134):
Designed by TSIG to carry hierarchic and non-hierarchic Designed by TSIG to carry hierarchic and non-hierarchic
security labels. (Formerly called "Commercial IP Security security labels. (Formerly called "Commercial IP Security
Option"; a version 2.3 draft was published 9 Mar 1993 as an Option"; a version 2.3 draft was published 9 March 1993 as an
Internet-Draft but did not advance to RFC form.) [CIPSO] Internet-Draft but did not advance to RFC form.) [CIPSO]
$ Internet Protocol Suite (IPS) $ Internet Protocol Suite (IPS)
(I) See: (secondary definition under) Internet. (I) The set of network communication protocols that are specified
by the IETF, and approved as Internet Standards by the IESG,
within the oversight of the IAB. (See: OSIRM Security
Architecture. Compare: OSIRM.)
Usage: This set of protocols is popularly known as "TCP/IP"
because TCP and IP are its most basic and important components.
For clarity, this Glossary refers to IPS protocol layers by name
and capitalizes those names, and refers to OSIRM protocol layers
by number.
Tutorial: The IPS does have architectural principles [R1958], but
there is no Internet Standard that defines a layered IPS reference
model like the OSIRM. Still, Internet community literature has
referred (inconsistently) to IPS layers since early in the
Internet's development [Padl].
This Glossary treats the IPS as having five protocol layers --
Application, Transport, Internet, Network Interface, and Network
Hardware (or Network Substrate) -- which are illustrated in the
following diagram:
OSIRM Layers Examples IPS Layers Examples
------------------ --------------- --------------- --------------
Message Format: P2 [X420] Message Format: ARPA (RFC 822)
+----------------+ +-------------+
|7.Application | P1 [X419] | Application | SMTP (RFC 821)
+----------------+ - - - - - - | |
|6.Presentatation| [I8823] | |
+----------------+ - - - - - - | |
|5.Session | [I8327] +-------------+
+----------------+ - - - - - - | Transport | TCP (RFC 793)
|4.Transport | TP4 [I8073] | |
+----------------+ - - - - - - +-------------+
|3.Network | CLNP [I8473] | Internet | IP (RFC 791)
| | +-------------+
| | | Network | IP over IEEE
+----------------+ - - - - - - | Interface | 802 (RFC 1042)
|2.Data Link | +-------------+
| | LLC [I8802-2] - Network - The IPS does
| | MAC [I8802-3] - Hardware - not include
+----------------+ - (or Network - standards for
|1.Physical | Baseband - Substrate) - this layer.
+----------------+ Signaling [Stal] + - - - - - - +
The diagram approximates how the five IPS layers align with the
seven OSIRM layers, and it offers examples of protocol stacks that
provide roughly equivalent electronic mail service over a private
local area network that uses baseband signaling.
- IPS Application Layer: The user runs an application program.
The program selects the data transport service it needs --
either a sequence of data messages or a continuous stream of
data -- and hands application data to the Transport Layer for
delivery.
- IPS Transport Layer: This layer divides application data into
packets, adds a destination address to each, and communicates
them end-to-end -- from one application program to another --
optionally regulating the flow and ensuring reliable (error-
free and sequenced) delivery.
- IPS Internet Layer: This layer carries transport packets in IP
datagrams. It moves each datagram independently, from its
source computer to its addressed destination computer, routing
the datagram through a sequence of networks and relays and
selecting appropriate network interfaces en route.
- IPS Network Interface Layer: This layer accepts datagrams for
transmission over a specific network. This layer specifies
interface conventions for carrying IP over OSIRM Layer 3
protocols and over Media Access Control sublayer protocols of
OSIRM Layer 2. An example is IP over IEEE 802 (RFD 1042).
- IPS Network Hardware Layer: This layer consists of specific,
physical communication media. However, the IPS does not specify
its own peer-to-peer protocols in this layer. Instead, the
layering conventions specified by the Network Interface Layer
use Layer 2 and Layer 3 protocols that are specified by bodies
other than the IETF. That it, the IPS addresses *inter*-network
functions and does not address *intra*-network functions.
The two models are most dissimilar in the upper layers, where the
IPS model does not include Session and Presentation layers.
However, this omission causes fewer functional differences between
the models than might be imagined, and the differences have
relatively few security implications:
- Formal separation of OSIRM Layers 5, 6, and 7 is not needed in
implementations; the functions of these layers sometimes are
mixed in a single software unit, even in protocols in the OSI
suite.
- Some OSIRM Layer 5 services -- for example, connection
termination -- are built into TCP, and the remaining Layer 5
and 6 functions are built into IPS Application-Layer protocols
where needed.
- The OSIRM does not place any security services in Layer 5 (see:
OSIRM Security Architecture).
- The lack of an explicit Presentation Layer in the IPS sometimes
makes it simpler to implement security in IPS applications. For
example, a primary function of Layer 6 is to convert data
between internal and external forms, using a transfer syntax to
unambiguously encode data for transmission. If an OSIRM
application encrypts data to protect against disclosure during
transmission, the transfer encoding must be done before the
encryption. If an application does encryption, as is done in
OSI message handling and directory service protocols, then
Layer 6 functions must be replicated in Layer 7. [X400, X500].
The two models are most alike at the top of OSIRM Layer 3, where
the OSI Connectionless Network Layer Protocol (CLNP) and the IPS
IP are quite similar. Connection-oriented security services
offered in OSIRM Layer 3 are inapplicable in the IPS, because the
IPS Internet Layer lacks the explicit, connection-oriented service
offered in the OSIRM.
$ Internet Security Association and Key Management Protocol (ISAKMP) $ Internet Security Association and Key Management Protocol (ISAKMP)
(I) An Internet IPsec protocol [R2408] to negotiate, establish, (I) An Internet IPsec protocol [R2408] to negotiate, establish,
modify, and delete security associations, and to exchange key modify, and delete security associations, and to exchange key
generation and authentication data, independent of the details of generation and authentication data, independent of the details of
any specific key generation technique, key establishment protocol, any specific key generation technique, key establishment protocol,
encryption algorithm, or authentication mechanism. encryption algorithm, or authentication mechanism.
Tutorial: ISAKMP supports negotiation of security associations for Tutorial: ISAKMP supports negotiation of security associations for
protocols at all TCP/IP layers. By centralizing management of protocols at all IPS layers. By centralizing management of
security associations, ISAKMP reduces duplicated functionality security associations, ISAKMP reduces duplicated functionality
within each protocol. ISAKMP can also reduce connection setup within each protocol. ISAKMP can also reduce connection setup
time, by negotiating a whole stack of services at once. Strong time, by negotiating a whole stack of services at once. Strong
authentication is required on ISAKMP exchanges, and a digital authentication is required on ISAKMP exchanges, and a digital
signature algorithm based on asymmetric cryptography is used signature algorithm based on asymmetric cryptography is used
within ISAKMP's authentication component. within ISAKMP's authentication component.
ISAKMP includes two "phases" of negotiation: the phase 1 ISAKMP negotiations are conducted in two "phases":
negotiation establishes a basic security association to be used - "Phase 1 negotiation". A phase 1 negotiation establishes a
for ISAKMP operations. Then, protected by the phase 1 association, security association to be used by ISAKMP to protect its own
phase 2 negotiations are used to establish security associations protocol operations.
for other protocols, such as ESP. - "Phase 2 negotiation". A phase 2 negotiation (which is
protected by a security association that was established by a
phase 1 negotiation) establishes a security association to be
used to protect the operations of a protocol other than ISAKMP,
such as ESP.
$ Internet Society (ISOC) $ Internet Society (ISOC)
(I) A professional society concerned with Internet development (I) A professional society concerned with Internet development
(including technical Internet Standards); with how the Internet is (including technical Internet Standards); with how the Internet is
and can be used; and with social, political, and technical issues and can be used; and with social, political, and technical issues
that result. The ISOC Board of Trustees approves appointments to that result. The ISOC Board of Trustees approves appointments to
the IAB from among nominees submitted by the IETF nominating the IAB from among nominees submitted by the IETF nominating
committee. [R2026] committee. (RFC 2026)
$ Internet Standard $ Internet Standard
(I) A specification, approved by the IESG and published as an RFC, (I) A specification, approved by the IESG and published as an RFC,
that is stable and well-understood, is technically competent, has that is stable and well-understood, is technically competent, has
multiple, independent, and interoperable implementations with multiple, independent, and interoperable implementations with
substantial operational experience, enjoys significant public substantial operational experience, enjoys significant public
support, and is recognizably useful in some or all parts of the support, and is recognizably useful in some or all parts of the
Internet. [R2026] (See: RFC.) Internet. (RFC 2026) (Compare: RFC.)
Tutorial: The "Internet Standards Process" is an activity of the Tutorial: The "Internet Standards Process" is an activity of the
ISOC and is organized and managed by the IAB and the IESG. The ISOC and is organized and managed by the IAB and the IESG. The
process is concerned with all protocols, procedures, and process is concerned with all protocols, procedures, and
conventions used in or by the Internet, whether or not they are conventions used in or by the Internet, whether or not they are
part of the IPS. The "Internet Standards Track" has three levels part of the IPS. The "Internet Standards Track" has three levels
of increasing maturity: Proposed Standard, Draft Standard, and of increasing maturity: Proposed Standard, Draft Standard, and
Standard. (Compare: ISO, W3C.) Standard. (Compare: ISO, W3C.)
$ Internet Standards document (ISD) $ Internet Standards document (ISD)
(I) An RFC or an Internet-Draft that is produced as part of the (I) An RFC or an Internet-Draft that is produced as part of the
Internet Standards Process [R2026]. (See: Internet Standard.) Internet Standards Process (RFC 2026). (See: Internet Standard.)
Deprecated Usage: Neither the term nor the abbreviation is widely Deprecated Usage: ISDs that use this term SHOULD state a
accepted; therefore, ISDs that use this term SHOULD state a definition for it because neither the term nor the abbreviation is
definition for it. widely accepted.
$ internetwork $ internetwork
(I) A system of interconnected networks; a network of networks. (I) A system of interconnected networks; a network of networks.
Usually shortened to "internet". (See: internet.) Usually shortened to "internet". (See: internet, Internet.)
Tutorial: An internet is usually built using OSIRM layer 3 Tutorial: An internet can be built using OSIRM Layer 3 gateways to
gateways to connect a set of subnetworks. When the subnetworks implement connections between a set of similar subnetworks. With
differ in the layer 3 protocol service they provide, the gateways dissimilar subnetworks, i.e., subnetworks that differ in the Layer
sometimes implement a uniform internetwork protocol (e.g., IP) 3 protocol service they offer, an internet can be built by
that operates at the top of layer 3 and hides the underlying implementing a uniform internetwork protocol (e.g., IP) that
heterogeneity from hosts that use communication services provided operates at the top of Layer 3 and hides the underlying
by the internet. (See: router.) subnetworks' heterogeneity from hosts that use communication
services provided by the internet. (See: router.)
$ intranet $ intranet
(I) A computer network, especially one based on Internet (I) A computer network, especially one based on Internet
technology, that an organization uses for its own internal, and technology, that an organization uses for its own internal (and
usually private, purposes and that is closed to outsiders. (See: usually private) purposes and that is closed to outsiders. (See:
extranet, virtual private network.) extranet, virtual private network.)
$ intruder $ intruder
(I) An entity that gains or attempts to gain access to a system or (I) An entity that gains or attempts to gain access to a system or
system resource without having authorization to do so. (See: system resource without having authorization to do so. (See:
intrusion. Compare: adversary, cracker.) intrusion. Compare: adversary, cracker.)
$ intrusion $ intrusion
1. (I) A security event, or a combination of multiple security 1. (I) A security event, or a combination of multiple security
events, that constitutes a security incident in which an intruder events, that constitutes a security incident in which an intruder
gains, or attempts to gain, access to a system or system resource gains, or attempts to gain, access to a system or system resource
without having authorization to do so. (See: IDS.) without having authorization to do so. (See: IDS.)
2. (I) A type of threat action whereby an unauthorized entity 2. (I) A type of threat action whereby an unauthorized entity
gains access to sensitive data by circumventing a system's gains access to sensitive data by circumventing a system's
security protections. (See: unauthorized disclosure.) security protections. (See: unauthorized disclosure.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Trespass": Gaining physical access to sensitive data by - "Trespass": Gaining physical access to sensitive data by
circumventing a system's protections. circumventing a system's protections.
- "Penetration": Gaining logical access to sensitive data by - "Penetration": Gaining logical access to sensitive data by
circumventing a system's protections. circumventing a system's protections.
- "Reverse engineering": Acquiring sensitive data by - "Reverse engineering": Acquiring sensitive data by
disassembling and analyzing the design of a system component. disassembling and analyzing the design of a system component.
- "Cryptanalysis": Transforming encrypted data into plain text - "Cryptanalysis": Transforming encrypted data into plain text
without having prior knowledge of encryption parameters or without having prior knowledge of encryption parameters or
processes. (See: (main Glossary entry for) cryptanalysis.) processes. (See: main entry for "cryptanalysis".)
$ intrusion detection $ intrusion detection
(I) Sensing and analyzing system events for the purpose of (I) Sensing and analyzing system events for the purpose of
noticing (i.e., becoming aware of) attempts to access system noticing (i.e., becoming aware of) attempts to access system
resources in an unauthorized manner. (See: anomaly detection, IDS, resources in an unauthorized manner. (See: anomaly detection, IDS,
misuse detection.) [IDSAN, IDSSC, IDSSE, IDSSY] misuse detection.) [IDSAN, IDSSC, IDSSE, IDSSY]
Usage: This includes the following subtypes: Usage: This includes the following subtypes:
- "Active detection": Real-time or near-real-time analysis of - "Active detection": Real-time or near-real-time analysis of
system event data to detect current intrusions, which result in system event data to detect current intrusions, which result in
an immediate protective response. an immediate protective response.
- "Passive detection": Off-line analysis of audit data to detect - "Passive detection": Off-line analysis of audit data to detect
past intrusions, which are reported to the system security past intrusions, which are reported to the system security
officer for corrective action. (Compare: security audit.) officer for corrective action. (Compare: security audit.)
$ intrusion detection system (IDS) $ intrusion detection system (IDS)
1. (N) A process or subsystem, implemented in software or 1. (N) A process or subsystem, implemented in software or
hardware, that automates the tasks of (a) monitoring events that hardware, that automates the tasks of (a) monitoring events that
occur in a computer network and (b) analyzing them for signs of occur in a computer network and (b) analyzing them for signs of
security problems. [SP31] (See: intrusion detection.) security problems. [SP31] (See: intrusion detection.)
2. (N) A security alarm system to detect unauthorized entry. 2. (N) A security alarm system to detect unauthorized entry.
[DC6/9]. [DC6/9].
Tutorial: Active intrusion detection processes can be either host- Tutorial: Active intrusion detection processes can be either host-
based or network-based: based or network-based:
- "Host-based": Intrusion detection components -- traffic sensors - "Host-based": Intrusion detection components -- traffic sensors
and analyzers -- run directly on the hosts that they are and analyzers -- run directly on the hosts that they are
intended to protect. intended to protect.
- "Network-based": Sensors are placed on subnetwork components, - "Network-based": Sensors are placed on subnetwork components,
and analysis components run either on subnetwork components or and analysis components run either on subnetwork components or
hosts. hosts.
$ invalidity date $ invalidity date
(N) An X.509 CRL entry extension that "indicates the date at which (N) An X.509 CRL entry extension that "indicates the date at which
it is known or suspected that the [revoked certificate's private it is known or suspected that the [revoked certificate's private
key] was compromised or that the certificate should otherwise be key] was compromised or that the certificate should otherwise be
considered invalid." [X509]. considered invalid." [X509].
Tutorial: This date may be earlier than the revocation date in the Tutorial: This date may be earlier than the revocation date in the
CRL entry, and may even be earlier than the date of issue of CRL entry, and may even be earlier than the date of issue of
earlier CRLs. However, the invalidity date is not, by itself, earlier CRLs. However, the invalidity date is not, by itself,
sufficient for purposes of non-repudiation service. For example, sufficient for purposes of non-repudiation service. For example,
to fraudulently repudiate a validly-generated signature, a private to fraudulently repudiate a validly generated signature, a private
key holder may falsely claim that the key was compromised at some key holder may falsely claim that the key was compromised at some
time in the past. time in the past.
$ IOTP $ IOTP
(I) See: Internet Open Trading Protocol. (I) See: Internet Open Trading Protocol.
$ IP $ IP
(I) See: Internet Protocol. (I) See: Internet Protocol.
$ IP address $ IP address
(I) A computer's internetwork address that is assigned for use by (I) A computer's internetwork address that is assigned for use by
IP and other protocols. IP and other protocols.
Tutorial: An IP version 4 address (RFC 791) is written as a series Tutorial: An IP version 4 address (RFC 791) has four 8-bit parts
of four 8-bit numbers separated by periods. For example, the and is written as a series of four decimal numbers separated by
address of the host named "rosslyn.bbn.com" is 192.1.7.10. periods. Example: The address of the host named "rosslyn.bbn.com"
is 192.1.7.10.
An IP version 6 address (RFC 2373) is written as x:x:x:x:x:x:x:x, An IP version 6 address (RFC 2373) has eight 16-bit parts and is
where each "x" is the hexadecimal value of one of the eight 16-bit written as eight hexadecimal numbers separated by colons.
parts of the address. For example, 1080:0:0:0:8:800:200C:417A and Examples: 1080:0:0:0:8:800:200C:417A and
FEDC:BA98:7654:3210:FEDC:BA98:7654:3210. FEDC:BA98:7654:3210:FEDC:BA98:7654:3210.
$ IP Security Option $ IP Security Option
(I) See: Internet Protocol Security Option. (I) See: Internet Protocol Security Option.
$ IPLI $ IP Security Protocol (IPsec)
(I) See: Internet Private Line Interface. 1a. (I) The name of the IETF working group that is specifying an
architecture [R2401] and set of protocols to provide security
$ IPRA services for IP traffic. (See: AH, ESP, IKE, SAD, SPD. Compare:
(I) See: Internet Policy Registration Authority. IPSO.)
$ IPS
(I) See: Internet Protocol Suite.
$ IPsec
1a. (I) A contraction of "Internet Protocol security", the name of
the IETF working group that is specifying an architecture [R2401]
and set of protocols to provide security services for IP traffic.
(See: AH, ESP, IKE, SAD, SPD. Compare: IPSO.)
1b. (I) A collective name for that IP security architecture and 1b. (I) A collective name for the IP security architecture and
associated set of protocols. associated set of protocols (primarily AH, ESP, and IKE).
Usage: Note that the letters "sec" are in lower case in "IPsec". Usage: Note that the letters "sec" are in lower case in "IPsec".
Tutorial: The security services provided by IPsec include access Tutorial: The security services provided by IPsec include access
control service, connectionless data integrity service, data control service, connectionless data integrity service, data
origin authentication service, protection against replays origin authentication service, protection against replays
(detection of the arrival of duplicate datagrams, within a (detection of the arrival of duplicate datagrams, within a
constrained window), data confidentiality service, and limited constrained window), data confidentiality service, and limited
traffic-flow confidentiality. IPsec specifies (a) security traffic-flow confidentiality. IPsec specifies (a) security
protocols (AH and ESP), (b) security associations (what they are, protocols (AH and ESP), (b) security associations (what they are,
how they work, how they are managed, and associated processing), how they work, how they are managed, and associated processing),
(c) key management (IKE), and (d) algorithms for authentication (c) key management (IKE), and (d) algorithms for authentication
and encryption. Implementation of IPsec is optional for IP version and encryption. Implementation of IPsec is optional for IP version
4, but mandatory for IP version 6. 4, but mandatory for IP version 6.
$ IPLI
(I) See: Internet Private Line Interface.
$ IPRA
(I) See: Internet Policy Registration Authority.
$ IPS
(I) See: Internet Protocol Suite.
$ IPsec
(I) See: IP Security Protocol.
$ IPsec Key Exchange (IKE) $ IPsec Key Exchange (IKE)
(I) An Internet, IPsec, key-establishment protocol [R2409] for (I) An Internet, IPsec, key-establishment protocol [R2409] for
putting in place authenticated keying material (a) for use with putting in place authenticated keying material (a) for use with
ISAKMP and (b) for other security associations, such as in AH and ISAKMP and (b) for other security associations, such as in AH and
ESP. ESP.
Tutorial: IKE is based on three earlier protocol designs: ISAKMP, Tutorial: IKE is based on three earlier protocol designs: ISAKMP,
OAKLEY, and SKEME. OAKLEY, and SKEME.
$ IPSO $ IPSO
skipping to change at page 138, line 16 skipping to change at page 146, line 48
participate in developing international standards through ISO and participate in developing international standards through ISO and
IEC technical committees that deal with particular fields of IEC technical committees that deal with particular fields of
activity. Other international governmental and non-governmental activity. Other international governmental and non-governmental
organizations, in liaison with ISO and IEC, also take part. (ANSI organizations, in liaison with ISO and IEC, also take part. (ANSI
is the U.S. voting member of ISO. ISO is a class D member of is the U.S. voting member of ISO. ISO is a class D member of
ITU-T.) ITU-T.)
The ISO standards development process has four levels of The ISO standards development process has four levels of
increasing maturity: Working Draft (WD), Committee Draft (CD), increasing maturity: Working Draft (WD), Committee Draft (CD),
Draft International Standard (DIS), and International Standard Draft International Standard (DIS), and International Standard
(IS). (Compare: (standards track levels under) Internet Standard.) (IS). (Compare: "Internet Standards Track" under "Internet
In information technology, ISO and IEC have a joint technical Standard".) In information technology, ISO and IEC have a joint
committee, ISO/IEC JTC 1. DISs adopted by JTC 1 are circulated to technical committee, ISO/IEC JTC 1. DISs adopted by JTC 1 are
national bodies for voting, and publication as an IS requires circulated to national bodies for voting, and publication as an IS
approval by at least 75% of the national bodies casting a vote. requires approval by at least 75% of the national bodies casting a
vote.
$ ISO 17799 $ ISO 17799
(N) An International Standard that is a code of practice, derived (N) An International Standard that is a code of practice, derived
from Part 1 of British Standard 7799, for managing the security of from Part 1 of British Standard 7799, for managing the security of
information systems in an organization. This standard does not information systems in an organization. This standard does not
provide definitive or specific material on any security topic. It provide definitive or specific material on any security topic. It
provides general guidance on a wide variety of topics, but provides general guidance on a wide variety of topics, but
typically does not go into depth. (See: IATF, [SP14].) typically does not go into depth. (See: IATF, [SP14].)
$ ISOC $ ISOC
skipping to change at page 140, line 13 skipping to change at page 148, line 44
(I) See: key-encrypting key. (Compare: KAK.) (I) See: key-encrypting key. (Compare: KAK.)
$ Kerberos $ Kerberos
(N) A system developed at the Massachusetts Institute of (N) A system developed at the Massachusetts Institute of
Technology that depends on passwords and symmetric cryptography Technology that depends on passwords and symmetric cryptography
(DES) to implement ticket-based, peer entity authentication (DES) to implement ticket-based, peer entity authentication
service and access control service distributed in a client-server service and access control service distributed in a client-server
network environment. [R1510, Stei] network environment. [R1510, Stei]
Tutorial: Kerberos was developed by Project Athena and is named Tutorial: Kerberos was developed by Project Athena and is named
for the three-headed dog guarding Hades. The system architecture for the mythical three-headed dog that guards Hades. The system
includes servers that function as an ACC and a KDC. architecture includes servers that function as an ACC and a KDC.
$ kernel $ kernel
(I) A small, trusted part of a system that provides services on (I) A small, trusted part of a system that provides services on
which the other parts of the system depend. (See: security which the other parts of the system depend. (See: security
kernel.) kernel.)
$ Kernelized Secure Operating System (KSOS) $ Kernelized Secure Operating System (KSOS)
(O) An MLS computer operating system, designed to be a provably (O) An MLS computer operating system, designed to be a provably
secure replacement for UNIX Version 6, and consisting of a secure replacement for UNIX Version 6, and consisting of a
security kernel, non-kernel security-related utility programs, and security kernel, non-kernel security-related utility programs, and
optional UNIX application development and support environments. optional UNIX application development and support environments.
[Perr] [Perr]
Tutorial: KSOS-6 was the implementation on a SCOMP. KSOS-11 was Tutorial: KSOS-6 was the implementation on a SCOMP. KSOS-11 was
the implementation by Ford Aerospace and Communications the implementation by Ford Aerospace and Communications
Corporation on the DEC PDP-11/45 and PDP-111/70 computers. Corporation on the DEC PDP-11/45 and PDP-111/70 computers.
$ key $ key
1. (I) /cryptography/ An input parameter used to vary a 1. (I) /cryptography/ An input parameter used to vary a
transformation function performed by a cryptographic algorithm. transformation function performed by a cryptographic algorithm.
(Compare: initialization value.) (See: private key, public key, storage key, symmetric key, traffic
key. Compare: initialization value.)
2. (I) /anti-jam/ An input parameter used to vary a process that 2. (I) /anti-jam/ An input parameter used to vary a process that
determines patterns for an anti-jam measure. (See: frequency determines patterns for an anti-jam measure. (See: frequency
hopping, spread spectrum.) hopping, spread spectrum.)
Tutorial: A key is usually specified as a sequence of bits or Tutorial: A key is usually specified as a sequence of bits or
other symbols. If a key value needs to be kept secret, the other symbols. If a key value needs to be kept secret, the
sequence of symbols that comprise it should be random, or at least sequence of symbols that comprise it should be random, or at least
pseudorandom, because that makes the key hard for an adversary to pseudorandom, because that makes the key harder for an adversary
guess. (See: cryptanalysis, brute force attack.) to guess. (See: brute force attack, cryptanalysis, strength.)
$ key agreement (algorithm or protocol) $ key agreement (algorithm or protocol)
1. (I) A key establishment method (especially one involving 1. (I) A key establishment method (especially one involving
asymmetric cryptography) by which two or more entities, without asymmetric cryptography) by which two or more entities, without
prior arrangement except a public exchange of data (such as public prior arrangement except a public exchange of data (such as public
keys), each can generate the same key value. That is, the method keys), each can generate the same key value. That is, the method
does not send a secret from one entity to the other (compare: key does not send a secret from one entity to the other; instead, both
transport); instead, both entities, without prior arrangement entities, without prior arrangement except a public exchange of
except a public exchange of data, can compute the same secret data, can compute the same secret value, but that value cannot be
value, but that value cannot be computed by other, unauthorized computed by other, unauthorized entities. (See: Diffie-Hellman,
entities. (See: Diffie-Hellman, key establishment, KEA, MQV.) key establishment, KEA, MQV. Compare: key transport.)
2. (O) "A method for negotiating a key value on line without 2. (O) "A method for negotiating a key value on line without
transferring the key, even in an encrypted form, e.g., the Diffie- transferring the key, even in an encrypted form, e.g., the Diffie-
Hellman technique." [X509] Hellman technique." [X509]
3. (O) "The procedure whereby two different parties generate 3. (O) "The procedure whereby two different parties generate
shared symmetric keys such that any of the shared symmetric keys shared symmetric keys such that any of the shared symmetric keys
is a function of the information contributed by all legitimate is a function of the information contributed by all legitimate
participants, so that no party [alone] can predetermine the value participants, so that no party [alone] can predetermine the value
of the key." [A9042] of the key." [A9042]
Example: A message originator and the intended recipient can each Example: A message originator and the intended recipient can each
use their own private key and the other's public key with the use their own private key and the other's public key with the
Diffie-Hellman algorithm to first compute a shared secret value Diffie-Hellman algorithm to first compute a shared secret value
and, from that value, derive a session key to encrypt the message. and, from that value, derive a session key to encrypt the message.
$ key authentication $ key authentication
(N) "The assurance of the legitimate participants in a key (N) "The assurance of the legitimate participants in a key
agreement that no non-legitimate party possesses the shared agreement [i.e., in a key-agreement protocol] that no non-
symmetric key." [A9042] legitimate party possesses the shared symmetric key." [A9042]
$ key-auto-key (KAK) $ key-auto-key (KAK)
(D) "Cryptographic logic using previous key to produce key." (D) "Cryptographic logic [i.e., a mode of operation] using
[C4009, A1523] (See: CTAK.) previous key to produce key." [C4009, A1523] (See: CTAK,
/cryptographic operation/ under "mode".)
Deprecated Term: IDS should not use this term; it is neither well- Deprecated Term: IDS SHOULD NOT use this term; it is neither well-
known nor precisely defined. Instead, use terms associated with known nor precisely defined. Instead, use terms associated with
modes that are defined in standards, such as CBC, CFB, and OFB. modes that are defined in standards, such as CBC, CFB, and OFB.
$ key center $ key center
(I) A centralized key distribution process (used in symmetric (I) A centralized, key-distribution process (used in symmetric
cryptography), usually a separate computer system, that uses cryptography), usually a separate computer system, that uses
master keys (i.e., KEKs) to encrypt and distribute session keys master keys (i.e., KEKs) to encrypt and distribute session keys
needed in a community of users. needed by a community of users.
Tutorial: An ANSI standard [A9017] defines two types of key Tutorial: An ANSI standard [A9017] defines two types of key
center: key distribution center and key translation center. center: "key distribution center" and "key translation center".
$ key confirmation $ key confirmation
(N) "The assurance [provided to] the legitimate participants in a (N) "The assurance [provided to] the legitimate participants in a
key establishment protocol that the [parties that are intended to key establishment protocol that the [parties that are intended to
share] the symmetric key actually possess the shared symmetric share] the symmetric key actually possess the shared symmetric
key." [A9042] key." [A9042]
$ key distribution $ key distribution
(I) A process that delivers a cryptographic key from the location (I) A process that delivers a cryptographic key from the location
where it is generated to the locations where it is used in a where it is generated to the locations where it is used in a
cryptographic algorithm. (See: key management.) cryptographic algorithm. (See: key establishment, key management.)
$ key distribution center (KDC) $ key distribution center (KDC)
1. (I) A type of key center (used in symmetric cryptography) that 1. (I) A type of key center (used in symmetric cryptography) that
implements a key distribution protocol to provide keys (usually, implements a key-distribution protocol to provide keys (usually,
session keys) to two (or more) entities that wish to communicate session keys) to two (or more) entities that wish to communicate
securely. (Compare: key translation center.) securely. (Compare: key translation center.)
2. (N) "COMSEC facility generating and distributing key in 2. (N) "COMSEC facility generating and distributing key in
electrical form." [C4009] electrical form." [C4009]
Tutorial: A KDC distributes keys to Alice and Bob, who (a) wish to Tutorial: A KDC distributes keys to Alice and Bob, who (a) wish to
communicate with each other but do not currently share keys, (b) communicate with each other but do not currently share keys, (b)
each share a KEK with the KDC, and (c) may not be able to generate each share a KEK with the KDC, and (c) may not be able to generate
or acquire keys by themselves. Alice requests the keys from the or acquire keys by themselves. Alice requests the keys from the
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techniques. For example, the Escrowed Encryption Standard [FP185] techniques. For example, the Escrowed Encryption Standard [FP185]
entrusts two components of a device-unique split key to separate entrusts two components of a device-unique split key to separate
escrow agents. The agents provide the components only to someone escrow agents. The agents provide the components only to someone
legally authorized to conduct electronic surveillance of legally authorized to conduct electronic surveillance of
telecommunications encrypted by that specific device. The telecommunications encrypted by that specific device. The
components are used to reconstruct the device-unique key, and it components are used to reconstruct the device-unique key, and it
is used to obtain the session key needed to decrypt is used to obtain the session key needed to decrypt
communications. communications.
$ key establishment (algorithm or protocol) $ key establishment (algorithm or protocol)
1. (I) A procedure that combines the key generation and key 1. (I) A procedure that combines the key generation and key-
distribution steps needed to set up or install a secure distribution steps needed to set up or install a secure
communication association. communication association.
2. (I) A procedure that results in keying material being shared 2. (I) A procedure that results in keying material being shared
among two or more system entities. [A9042, SP56] among two or more system entities. [A9042, SP56]
Tutorial: The two basic techniques for key establishment are "key Tutorial: The two basic techniques for key establishment are "key
agreement" and "key transport". agreement" and "key transport".
$ Key Exchange Algorithm (KEA) $ Key Exchange Algorithm (KEA)
(N) A key-agreement method [SKIP, R2773] based on the Diffie- (N) A key-agreement method [SKIP, R2773] that is based on the
Hellman algorithm and uses 1024-bit asymmetric keys. (See: Diffie-Hellman algorithm and uses 1024-bit asymmetric keys. (See:
CAPSTONE, CLIPPER, FORTEZZA, SKIPJACK.) CAPSTONE, CLIPPER, FORTEZZA, SKIPJACK.)
Tutorial: KEA was developed by NSA and formerly classified at the Tutorial: KEA was developed by NSA and formerly classified at the
U.S. DoD "Secret" level. On 23 June 1998, the NSA announced that U.S. DoD "Secret" level. On 23 June 1998, the NSA announced that
KEA had been declassified. KEA had been declassified.
$ key generation $ key generation
(I) A process that creates the sequence of symbols that comprise a (I) A process that creates the sequence of symbols that comprise a
cryptographic key. (See: key management.) cryptographic key. (See: key management.)
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mechanism and applies the key to plain text to produce cipher text mechanism and applies the key to plain text to produce cipher text
(e.g., by exclusive OR-ing (a) a bit string representation of the (e.g., by exclusive OR-ing (a) a bit string representation of the
key with (b) a bit string representation of the plaintext). key with (b) a bit string representation of the plaintext).
$ key length $ key length
(I) The number of symbols (usually stated as a number of bits) (I) The number of symbols (usually stated as a number of bits)
needed to be able to represent any of the possible values of a needed to be able to represent any of the possible values of a
cryptographic key. (See: key space.) cryptographic key. (See: key space.)
$ key lifetime $ key lifetime
(N) /MISSI/ An attribute of a MISSI key pair that specifies a time 1. (D) Synonym for "cryptoperiod".
span that bounds the validity period of any MISSI X.509 public-key
certificate that contains the public component of the pair. (See: Deprecated Definition: ISDs SHOULD NOT use this term with this
cryptoperiod.) definition because a key's cryptoperiod may be only a part of the
key's lifetime. A key could be generated at some time prior to
when its cryptoperiod begins and might not be destroyed (i.e.,
zeroized) until some time after its cryptoperiod ends.
2. (O) /MISSI/ An attribute of a MISSI key pair that specifies a
time span that bounds the validity period of any MISSI X.509
public-key certificate that contains the public component of the
pair. (See: cryptoperiod.)
$ key loader $ key loader
(N) Synonym for "fill device". (N) Synonym for "fill device".
$ key management $ key management
1a. (I) The process of handling keying material during its life 1a. (I) The process of handling keying material during its life
cycle in a cryptographic system; and the supervision and control cycle in a cryptographic system; and the supervision and control
of that process. (See: key distribution, key escrow, keying of that process. (See: key distribution, key escrow, keying
material, public-key infrastructure.) material, public-key infrastructure.)
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$ key pair $ key pair
(I) A set of mathematically related keys -- a public key and a (I) A set of mathematically related keys -- a public key and a
private key -- that are used for asymmetric cryptography and are private key -- that are used for asymmetric cryptography and are
generated in a way that makes it computationally infeasible to generated in a way that makes it computationally infeasible to
derive the private key from knowledge of the public key. (See: derive the private key from knowledge of the public key. (See:
Diffie-Hellman, RSA.) Diffie-Hellman, RSA.)
Tutorial: A key pair's owner discloses the public key to other Tutorial: A key pair's owner discloses the public key to other
system entities so they can use the key to (a) encrypt data, (b) system entities so they can use the key to (a) encrypt data, (b)
verify a digital signature, (c) compute a protected checksum, or verify a digital signature, or (c) generate a key with a key-
(d) generate a key in a key agreement algorithm. The matching agreement algorithm. The matching private key is kept secret by
private key is kept secret by the owner, who uses it to (a') the owner, who uses it to (a') decrypt data, (b') generate a
decrypt data, (b') generate a digital signature, (c') verify a digital signature, or (c') generate a key with a key-agreement
protected checksum, or (d') generate a key in a key agreement
algorithm. algorithm.
$ key recovery $ key recovery
1. (I) /cryptanalysis/ A process for learning the value of a 1. (I) /cryptanalysis/ A process for learning the value of a
cryptographic key that was previously used to perform some cryptographic key that was previously used to perform some
cryptographic operation. (See: cryptanalysis, recovery.) cryptographic operation. (See: cryptanalysis, recovery.)
2. (I) /backup/ Techniques that provide an intentional, alternate, 2. (I) /backup/ Techniques that provide an intentional, alternate,
means to access the key used for data confidentiality service in means to access the key used for data confidentiality service in
an encrypted association. [DoD4] (Compare: recovery.) an encrypted association. [DoD4] (Compare: recovery.)
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algorithm or protocol. For the secondary means, there are two algorithm or protocol. For the secondary means, there are two
classes of key recovery techniques: key encapsulation and key classes of key recovery techniques: key encapsulation and key
escrow. escrow.
$ key space $ key space
(I) The range of possible values of a cryptographic key; or the (I) The range of possible values of a cryptographic key; or the
number of distinct transformations supported by a particular number of distinct transformations supported by a particular
cryptographic algorithm. (See: key length.) cryptographic algorithm. (See: key length.)
$ key translation center $ key translation center
(I) A type of key center that implements a key distribution (I) A type of key center that implements a key-distribution
protocol (based on symmetric cryptography) to convey keys between protocol (based on symmetric cryptography) to convey keys between
two (or more) parties who wish to communicate securely. (Compare: two (or more) parties who wish to communicate securely. (Compare:
key distribution center.) key distribution center.)
Tutorial: A key translation center transfers keys for future Tutorial: A key translation center transfers keys for future
communication between Bob and Alice, who (a) wish to communicate communication between Bob and Alice, who (a) wish to communicate
with each other but do not currently share keys, (b) each share a with each other but do not currently share keys, (b) each share a
KEK with the center, and (c) have the ability to generate or KEK with the center, and (c) have the ability to generate or
acquire keys by themselves. Alice generates or acquires a set of acquire keys by themselves. Alice generates or acquires a set of
keys for communication with Bob. Alice encrypts the set in the KEK keys for communication with Bob. Alice encrypts the set in the KEK
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(I) A cryptographic hash (e.g., [R1828]) in which the mapping to a (I) A cryptographic hash (e.g., [R1828]) in which the mapping to a
hash result is varied by a second input parameter that is a hash result is varied by a second input parameter that is a
cryptographic key. (See: checksum.) cryptographic key. (See: checksum.)
Tutorial: If the input data object is changed, a new, Tutorial: If the input data object is changed, a new,
corresponding hash result cannot be correctly computed without corresponding hash result cannot be correctly computed without
knowledge of the secret key. Thus, the secret key protects the knowledge of the secret key. Thus, the secret key protects the
hash result so it can be used as a checksum even when there is a hash result so it can be used as a checksum even when there is a
threat of an active attack on the data. There are two basic types threat of an active attack on the data. There are two basic types
of keyed hash: of keyed hash:
- A function based on a keyed encryption algorithm. Example: Data - A function based on a keyed encryption algorithm. Example: Data
Authentication Code. Authentication Code.
- A function based on a keyless hash that is enhanced by - A function based on a keyless hash that is enhanced by
combining (e.g., by concatenating) the input data object combining (e.g., by concatenating) the input data object
parameter with a key parameter before mapping to the hash parameter with a key parameter before mapping to the hash
result. Example: HMAC. result. Example: HMAC.
$ keying material $ keying material
(I) Data that is needed to establish and maintain a cryptographic (I) Data that is needed to establish and maintain a cryptographic
security association, such as keys, key pairs, and IVs. security association, such as keys, key pairs, and IVs.
(O) "Key, code, or authentication information in physical or (O) "Key, code, or authentication information in physical or
magnetic form." [C4009] (Compare: COMSEC material.) magnetic form." [C4009] (Compare: COMSEC material.)
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result. Example: HMAC. result. Example: HMAC.
$ keying material $ keying material
(I) Data that is needed to establish and maintain a cryptographic (I) Data that is needed to establish and maintain a cryptographic
security association, such as keys, key pairs, and IVs. security association, such as keys, key pairs, and IVs.
(O) "Key, code, or authentication information in physical or (O) "Key, code, or authentication information in physical or
magnetic form." [C4009] (Compare: COMSEC material.) magnetic form." [C4009] (Compare: COMSEC material.)
$ keying material identifier (KMID) $ keying material identifier (KMID)
1. (I) An identifier assigned to an item of keying material. 1. (I) An identifier assigned to an item of keying material.
2. (O) /MISSI/ A 64-bit identifier that is assigned to a key pair 2. (O) /MISSI/ A 64-bit identifier that is assigned to a key pair
when the public key is bound in a MISSI X.509 public-key when the public key is bound in a MISSI X.509 public-key
certificate. certificate.
$ Khafre $ Khafre
(N) A patented, symmetric block cipher designed by Ralph C. Merkle (N) A patented, symmetric block cipher designed by Ralph C. Merkle
as a plug-in replacement for DES. [Schn] as a plug-in replacement for DES. [Schn]
Tutorial: Khafre was designed for efficient encryption of small Tutorial: Khafre was designed for efficient encryption of small
amounts of data. However, because Khafre does not precompute amounts of data. However, because Khafre does not precompute
tables used for encryption, it is slower than Khufu for large tables used for encryption, it is slower than Khufu for large
amounts of data. amounts of data.
$ Khufu $ Khufu
(N) A patented, symmetric block cipher designed by Ralph C. Merkle (N) A patented, symmetric block cipher designed by Ralph C. Merkle
as a plug-in replacement for DES. [Schn] as a plug-in replacement for DES. [Schn]
Tutorial: Khufu was designed for fast encryption of large amounts Tutorial: Khufu was designed for fast encryption of large amounts
of data. However, because Khufu precomputes tables used in of data. However, because Khufu precomputes tables used in
encryption, it is less efficient that Khafre for small amounts of encryption, it is less efficient that Khafre for small amounts of
data. data.
$ KMID $ KMID
(I) See: keying material identifier. (I) See: keying material identifier.
$ known-plaintext attack $ known-plaintext attack
(I) A cryptanalysis technique in which the analyst tries to (I) A cryptanalysis technique in which the analyst tries to
determine the key from knowledge of some plaintext-ciphertext determine the key from knowledge of some plaintext-ciphertext
pairs (although the analyst may also have other clues, such as the pairs (although the analyst may also have other clues, such as
knowing the cryptographic algorithm). knowing the cryptographic algorithm).
$ KSOS, KSOS-6, KSOS-11 $ KSOS, KSOS-6, KSOS-11
(O) See: Kernelized Secure Operating System. (O) See: Kernelized Secure Operating System.
$ L2F $ L2F
(N) See: Layer 2 Forwarding Protocol. (N) See: Layer 2 Forwarding Protocol.
$ L2TP $ L2TP
(N) See: Layer 2 Tunneling Protocol. (N) See: Layer 2 Tunneling Protocol.
$ label $ label
See: time stamp, security label. See: time stamp, security label.
$ laboratory attack $ laboratory attack
(O) "Use of sophisticated signal recovery equipment in a (O) "Use of sophisticated signal recovery equipment in a
laboratory environment to recover information from data storage laboratory environment to recover information from data storage
media." [C4009] media." [C4009]
$ LAN $ LAN
(I) Local area network. (I) local area network.
$ land attack $ land attack
(I) A denial-of-service attack that sends an IP packet that (a) (I) A denial-of-service attack that sends an IP packet that (a)
has the same address in both the Source Address and Destination has the same address in both the Source Address and Destination
Address fields and (b) contains a TCP SYN packet that has the same Address fields and (b) contains a TCP SYN packet that has the same
port number in both the Source Port and Destination Port fields. port number in both the Source Port and Destination Port fields.
Derivation: This single-packet attack was named for "land", the Derivation: This single-packet attack was named for "land", the
program originally published by the cracker who invented this program originally published by the cracker who invented this
exploit. Perhaps that name was chosen because the inventor thought exploit. Perhaps that name was chosen because the inventor thought
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finite set X of hierarchically ordered classification levels X(1), finite set X of hierarchically ordered classification levels X(1),
non-hierarchical categories C(1), ..., C(M) -- together with the non-hierarchical categories C(1), ..., C(M) -- together with the
"dominate" relation. Security level (x,c) is said to "dominate" "dominate" relation. Security level (x,c) is said to "dominate"
(x',c') if and only if (a) x is greater (higher) than or equal to (x',c') if and only if (a) x is greater (higher) than or equal to
x' and (b) c includes at least all of the elements of c'. (See: x' and (b) c includes at least all of the elements of c'. (See:
dominate, lattice model.) dominate, lattice model.)
$ lattice model $ lattice model
1. (I) A description of the semantic structure formed by a finite 1. (I) A description of the semantic structure formed by a finite
set of security levels, such as those used in military set of security levels, such as those used in military
organizations. (See: dominate, security model.) organizations. (See: dominate, lattice, security model.)
2. (I) /formal model/ A model for flow control in a system, based 2. (I) /formal model/ A model for flow control in a system, based
on the lattice that is formed by the finite security levels in a on the lattice that is formed by the finite security levels in a
system and their partial ordering. [Denn] system and their partial ordering. [Denn]
$ Law Enforcement Access Field (LEAF) $ Law Enforcement Access Field (LEAF)
(N) A data item that is automatically embedded in data encrypted (N) A data item that is automatically embedded in data encrypted
by devices (e.g., CLIPPER chip) that implement the Escrowed by devices (e.g., CLIPPER chip) that implement the Escrowed
Encryption Standard. Encryption Standard.
$ layer 1, 2, 3, 4, 5, 6, 7 $ Layer 1, 2, 3, 4, 5, 6, 7
(N) See: OSIRM. (N) See: OSIRM.
$ Layer 2 Forwarding Protocol (L2F) $ Layer 2 Forwarding Protocol (L2F)
(N) An Internet protocol (originally developed by Cisco (N) An Internet protocol (originally developed by Cisco
Corporation) that uses tunneling of PPP over IP to create a Corporation) that uses tunneling of PPP over IP to create a
virtual extension of a dial-up link across a network, initiated by virtual extension of a dial-up link across a network, initiated by
the dial-up server and transparent to the dial-up user. (See: the dial-up server and transparent to the dial-up user. (See:
L2TP.) L2TP.)
$ Layer 2 Tunneling Protocol (L2TP) $ Layer 2 Tunneling Protocol (L2TP)
(N) An Internet client-server protocol that combines aspects of (N) An Internet client-server protocol that combines aspects of
PPTP and L2F and supports tunneling of PPP over an IP network or PPTP and L2F and supports tunneling of PPP over an IP network or
over frame relay or other switched network. (See: virtual private over frame relay or other switched network. (See: virtual private
network.) network.)
Tutorial: PPP can in turn encapsulate any OSIRM layer 3 protocol.
Tutorial: PPP can in turn encapsulate any OSIRM Layer 3 protocol.
Thus, L2TP does not specify security services; it depends on Thus, L2TP does not specify security services; it depends on
protocols layered above and below it to provide any needed protocols layered above and below it to provide any needed
security. security.
$ LDAP $ LDAP
(I) See: Lightweight Directory Access Protocol. (I) See: Lightweight Directory Access Protocol.
$ least common mechanism $ least common mechanism
(I) The principle that a security architecture should minimize (I) The principle that a security architecture should minimize
reliance on mechanisms that are shared by many users. reliance on mechanisms that are shared by many users.
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(I) The principle that a security architecture should be designed (I) The principle that a security architecture should be designed
in a way that minimizes (a) the number of components that require in a way that minimizes (a) the number of components that require
trust and (b) the extent to which each component is trusted. trust and (b) the extent to which each component is trusted.
(Compare: least privilege, trust level.) (Compare: least privilege, trust level.)
$ legacy system $ legacy system
(I) A system that is in operation but will not be improved or (I) A system that is in operation but will not be improved or
expanded while a new system is being developed to supersede it. expanded while a new system is being developed to supersede it.
$ legal non-repudiation $ legal non-repudiation
(I) See: (secondary definition under) non-repudiation. (I) See: secondary definition under "non-repudiation".
$ level of concern $ level of concern
(N) /U.S. DoD/ A rating assigned to an information system that (N) /U.S. DoD/ A rating assigned to an information system that
indicates the extent to which protective measures, techniques, and indicates the extent to which protective measures, techniques, and
procedures must be applied. (See: level of robustness.) procedures must be applied. (See: critical, sensitive, level of
robustness.)
$ level of robustness $ level of robustness
(N) /U.S. DoD/ A characterization of the strength of a security (N) /U.S. DoD/ A characterization of the strength of a security
function, mechanism, service, or solution, and the assurance (or function, mechanism, service, or solution, and the assurance (or
confidence) that is implemented and functioning correctly to confidence) that is implemented and functioning. [Cons, IATF]
support the level of concern assigned to a particular information (See: level of concern.)
system.
$ Lightweight Directory Access Protocol (LDAP) $ Lightweight Directory Access Protocol (LDAP)
(I) An Internet client-server protocol (RFC 3377) that supports (I) An Internet client-server protocol (RFC 3377) that supports
basic use of the X.500 Directory (or other directory servers) basic use of the X.500 Directory (or other directory servers)
without incurring the resource requirements of the full Directory without incurring the resource requirements of the full Directory
Access Protocol (DAP). Access Protocol (DAP).
Tutorial: Designed for simple management and browser applications Tutorial: Designed for simple management and browser applications
that provide simple read/write interactive directory service. that provide simple read/write interactive directory service.
Supports both simple authentication and strong authentication of Supports both simple authentication and strong authentication of
the client to the directory server. the client to the directory server.
$ link $ link
1a. (I) A communication facility or physical medium that can 1a. (I) A communication facility or physical medium that can
sustain data communications between multiple network nodes, in the sustain data communications between multiple network nodes, in the
protocol layer immediately below IP. [R3573] protocol layer immediately below IP. (RFC 3753)
1b. (I) /subnetwork/ A communication channel connecting subnetwork 1b. (I) /subnetwork/ A communication channel connecting subnetwork
relays (especially one between two packet switches) that is relays (especially one between two packet switches) that is
implemented at OSIRM layer 2. (See: link encryption.) implemented at OSIRM Layer 2. (See: link encryption.)
Tutorial: The relay computers assume that links are logically Tutorial: The relay computers assume that links are logically
passive. If a computer at one end of a link sends a sequence of passive. If a computer at one end of a link sends a sequence of
bits, the sequence simply arrives at the other end after a finite bits, the sequence simply arrives at the other end after a finite
time, although some bits may have been changed either accidentally time, although some bits may have been changed either accidentally
(errors) or by active wiretapping. (errors) or by active wiretapping.
2. (I) /World Wide Web/ See: hyperlink. 2. (I) /World Wide Web/ See: hyperlink.
$ link encryption $ link encryption
(I) Stepwise (link-by-link) protection of data that flows between (I) Stepwise (link-by-link) protection of data that flows between
two points in a network, provided by encrypting data separately on two points in a network, provided by encrypting data separately on
each network link, i.e., by encrypting data when it leaves a host each network link, i.e., by encrypting data when it leaves a host
or subnetwork relay and decrypting when it arrives at the next or subnetwork relay and decrypting when it arrives at the next
host or relay. Each link may use a different key or even a host or relay. Each link may use a different key or even a
different algorithm. [R1455] (Compare: end-to-end encryption.) different algorithm. [R1455] (Compare: end-to-end encryption.)
$ liveness
(I) A property of a communication association or a feature of a
communication protocol that provides assurance to the recipient of
data that the data is being freshly transmitted by its originator,
i.e., that the data is not being replayed, by either the
originator or a third party, from a previous transmission. (See:
nonce, replay attack.)
$ logic bomb $ logic bomb
(I) Malicious logic that activates when specified conditions are (I) Malicious logic that activates when specified conditions are
met. Usually intended to cause denial of service or otherwise met. Usually intended to cause denial of service or otherwise
damage system resources. (See: Trojan horse, virus, worm.) damage system resources. (See: Trojan horse, virus, worm.)
$ login $ login
(I) The act by which a system entity establishes a session in (I) The act by which a system entity establishes a session in
which the entity can use system resources. (See: principal, which the entity can use system resources. (See: principal,
session.) session.)
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$ low probability of intercept $ low probability of intercept
(I) Result of TRANSEC measures used to prevent interception of a (I) Result of TRANSEC measures used to prevent interception of a
communication. communication.
$ LOTOS $ LOTOS
(N) See: Language of Temporal Ordering Specification. (N) See: Language of Temporal Ordering Specification.
$ MAC $ MAC
(N) See: mandatory access control, Message Authentication Code. (N) See: mandatory access control, Message Authentication Code.
Deprecated Usage: This abbreviation is ambiguous; therefore, ISDs Deprecated Usage: ISDs that use this term SHOULD state a
that use it SHOULD state a definition for it. definition for it because this abbreviation is ambiguous.
$ magnetic remanence $ magnetic remanence
(N) Magnetic representation of residual information remaining on a (N) Magnetic representation of residual information remaining on a
magnetic medium after the medium has been cleared. [NCS25] (See: magnetic medium after the medium has been cleared. [NCS25] (See:
clear, degauss, purge.) clear, degauss, purge.)
$ main mode
(I) See: /IKE/ under "mode".
$ maintenance hook $ maintenance hook
(N) "Special instructions (trapdoors) in software allowing easy (N) "Special instructions (trapdoors) in software allowing easy
maintenance and additional feature development. Since maintenance maintenance and additional feature development. Since maintenance
hooks frequently allow entry into the code without the usual hooks frequently allow entry into the code without the usual
checks, they are a serious security risk if they are not removed checks, they are a serious security risk if they are not removed
prior to live implementation." [C4009] (See: back door.) prior to live implementation." [C4009] (See: back door.)
$ malicious logic $ malicious logic
(I) Hardware, software, or firmware that is intentionally included (I) Hardware, firmware, or software that is intentionally included
or inserted in a system for a harmful purpose. (See: logic bomb, or inserted in a system for a harmful purpose. (See: logic bomb,
Trojan horse, spyware, virus, worm. Compare: (secondary Trojan horse, spyware, virus, worm. Compare: secondary definitions
definitions under) corruption, incapacitation, masquerade, and under "corruption", "incapacitation", "masquerade", and "misuse".)
misuse.)
$ malware $ malware
(D) A contraction of "malicious software". (See: malicious logic.) (D) A contraction of "malicious software". (See: malicious logic.)
Deprecated Term: ISDs SHOULD NOT use this term; it is not listed Deprecated Term: ISDs SHOULD NOT use this term; it is not listed
in most dictionaries and could confuse international readers. in most dictionaries and could confuse international readers.
$ MAN $ MAN
(I) metropolitan area network. (I) metropolitan area network.
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"checksum"; the word "manipulation" implies protection against "checksum"; the word "manipulation" implies protection against
active attacks, which an ordinary checksum might not provide. active attacks, which an ordinary checksum might not provide.
Instead, if such protection is intended, use "protected checksum" Instead, if such protection is intended, use "protected checksum"
or some particular type thereof, depending on which is meant. If or some particular type thereof, depending on which is meant. If
such protection is not intended, use "error detection code" or such protection is not intended, use "error detection code" or
some specific type of checksum that is not protected. some specific type of checksum that is not protected.
$ marking $ marking
See: time stamp, security marking. See: time stamp, security marking.
$ MARS
(O) A symmetric, 128-bit block cipher with variable key length
(128 to 448 bits), developed by IBM as a candidate for the AES.
$ Martian $ Martian
(D) A packet that arrives unexpectedly at the wrong address or on (D) /slang/ A packet that arrives unexpectedly at the wrong
the wrong network because of incorrect routing or because it has a address or on the wrong network because of incorrect routing or
non-registered or ill-formed IP address. because it has a non-registered or ill-formed IP address.
Deprecated Term: It is likely that other cultures have different Deprecated Term: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ masquerade $ masquerade
(I) A type of threat action whereby an unauthorized entity gains (I) A type of threat action whereby an unauthorized entity gains
access to a system or performs a malicious act by illegitimately access to a system or performs a malicious act by illegitimately
posing as an authorized entity. (See: deception.) posing as an authorized entity. (See: deception.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Spoof": Attempt by an unauthorized entity to gain access to a - "Spoof": Attempt by an unauthorized entity to gain access to a
system by posing as an authorized user. system by posing as an authorized user.
- "Malicious logic": In context of masquerade, any hardware, - "Malicious logic": In context of masquerade, any hardware,
firmware, or software (e.g., Trojan horse) that appears to firmware, or software (e.g., Trojan horse) that appears to
perform a useful or desirable function, but actually gains perform a useful or desirable function, but actually gains
unauthorized access to system resources or tricks a user into unauthorized access to system resources or tricks a user into
executing other malicious logic. (See: (main entry for) executing other malicious logic. (See: corruption,
malicious logic.) incapacitation, main entry for "malicious logic", misuse.)
$ MCA $ MCA
(O) See: merchant certification authority. (O) See: merchant certification authority.
$ MD2 $ MD2
(N) A cryptographic hash [R1319] that produces a 128-bit hash (N) A cryptographic hash [R1319] that produces a 128-bit hash
result, was designed by Ron Rivest, and is similar to MD4 and MD5 result, was designed by Ron Rivest, and is similar to MD4 and MD5
but slower. but slower.
Derivation: Apparently an abbreviation of "message digest", but Derivation: Apparently an abbreviation of "message digest", but
that term is deprecated by this Glossary. that term is deprecated by this Glossary.
$ MD4 $ MD4
(N) A cryptographic hash [R1320] that produces a 128-bit hash (N) A cryptographic hash [R1320] that produces a 128-bit hash
result and was designed by Ron Rivest. (See: SHA-1, (Derivation result and was designed by Ron Rivest. (See: Derivation under
under) MD2.) "MD2", SHA-1.)
$ MD5 $ MD5
(N) A cryptographic hash [R1321] that produces a 128-bit hash (N) A cryptographic hash [R1321] that produces a 128-bit hash
result and was designed by Ron Rivest to be an improved version of result and was designed by Ron Rivest to be an improved version of
MD4. (See: (Derivation under) MD2.) MD4. (See: Derivation under "MD2".)
$ merchant $ merchant
(O) /SET/ "A seller of goods, services, and/or other information (O) /SET/ "A seller of goods, services, and/or other information
who accepts payment for these items electronically." [SET2] A who accepts payment for these items electronically." [SET2] A
merchant may also provide electronic selling services and/or merchant may also provide electronic selling services and/or
electronic delivery of items for sale. With SET, the merchant can electronic delivery of items for sale. With SET, the merchant can
offer its cardholders secure electronic interactions, but a offer its cardholders secure electronic interactions, but a
merchant that accepts payment cards is required to have a merchant that accepts payment cards is required to have a
relationship with an acquirer. [SET1, SET2] relationship with an acquirer. [SET1, SET2]
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trusted CAs rather than a single root. Each certificate user bases trusted CAs rather than a single root. Each certificate user bases
path validations on the public key of one of the trusted CAs, path validations on the public key of one of the trusted CAs,
usually the one that issued that user's own public-key usually the one that issued that user's own public-key
certificate. Rather than having superior-to-subordinate certificate. Rather than having superior-to-subordinate
relationships between CAs, the relationships are peer-to-peer, and relationships between CAs, the relationships are peer-to-peer, and
CAs issue cross-certificates to each other. (Compare: hierarchical CAs issue cross-certificates to each other. (Compare: hierarchical
PKI, trust-file PKI.) PKI, trust-file PKI.)
$ Message Authentication Code, message authentication code $ Message Authentication Code, message authentication code
(N) /capitalized/ A specific ANSI standard for a checksum that is (N) /capitalized/ A specific ANSI standard for a checksum that is
computed with a keyed hash that is based on DES. [A9009] Also computed with a keyed hash that is based on DES. [A9009] Usage:
known as the U.S. Government standard Data Authentication Code. a.k.a. Data Authentication Code, which is a U.S. Government
[FP113] (See: MAC.) standard. [FP113] (See: MAC.)
(D) /not capitalized/ Synonym for "error detection code". (D) /not capitalized/ Synonym for "error detection code".
Deprecated Term: ISDs SHOULD NOT use the uncapitalized form Deprecated Term: ISDs SHOULD NOT use the uncapitalized form
"message authentication code"; that form mixes concepts in a "message authentication code". Instead, use "checksum", "error
potentially misleading way. Instead, use "checksum", "error
detection code", "hash", "keyed hash", "Message Authentication detection code", "hash", "keyed hash", "Message Authentication
Code", or "protected checksum", depending on what is meant. (See: Code", or "protected checksum", depending on what is meant. (See:
authentication code.) authentication code.)
In the uncapitalized form, the word "message" is misleading The uncapitalized form mixes concepts in a potentially misleading
because it implies that the mechanism is particularly suitable for way. The word "message" is misleading because it implies that the
or limited to electronic mail (see: Message Handling Systems), the mechanism is particularly suitable for or limited to electronic
word "authentication" is misleading because the mechanism mail (see: Message Handling Systems). The word "authentication" is
primarily serves a data integrity function rather than an misleading because the mechanism primarily serves a data integrity
authentication function, and the word "code" is misleading because function rather than an authentication function. The word "code"
it implies that either encoding or encryption is involved or that is misleading because it implies that either encoding or
the term refers to computer software. encryption is involved or that the term refers to computer
software.
$ message digest $ message digest
(D) Synonym for "hash result". (See: cryptographic hash.) (D) Synonym for "hash result". (See: cryptographic hash.)
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
"hash result"; the term unnecessarily duplicates the meaning of "hash result"; the term unnecessarily duplicates the meaning of
the other, more general term and mixes concepts in a potentially the other, more general term and mixes concepts in a potentially
misleading way. The word "message" is misleading because it misleading way. The word "message" is misleading because it
implies that the mechanism is particularly suitable for or limited implies that the mechanism is particularly suitable for or limited
to electronic mail (see: Message Handling Systems). to electronic mail (see: Message Handling Systems).
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$ message integrity check $ message integrity check
$ message integrity code (MIC) $ message integrity code (MIC)
(D) Synonyms for some form of "checksum". (D) Synonyms for some form of "checksum".
Deprecated Term: ISDs SHOULD NOT use these terms for any form of Deprecated Term: ISDs SHOULD NOT use these terms for any form of
checksum. Instead, use "checksum", "error detection code", "hash", checksum. Instead, use "checksum", "error detection code", "hash",
"keyed hash", "Message Authentication Code", or "protected "keyed hash", "Message Authentication Code", or "protected
checksum", depending on what is meant. checksum", depending on what is meant.
The terms mix concepts in potentially misleading ways. The word These two terms mix concepts in potentially misleading ways. The
"message" is misleading because it suggests that the mechanism is word "message" is misleading because it suggests that the
particularly suitable for or limited to electronic mail. The word mechanism is particularly suitable for or limited to electronic
"integrity" is misleading because the checksum may be used to mail. The word "integrity" is misleading because the checksum may
perform a data origin authentication function rather than an be used to perform a data origin authentication function rather
integrity function. The word "code" is misleading because it than an integrity function. The word "code" is misleading because
suggests either that either encoding or encryption is involved or it suggests either that either encoding or encryption is involved
that the term refers to computer software. or that the term refers to computer software.
$ Message Security Protocol (MSP) $ Message Security Protocol (MSP)
(N) A secure message handling protocol [SDNS7] for use with X.400 (N) A secure message handling protocol [SDNS7] for use with X.400
and Internet mail protocols. Developed by NSA's SDNS program and and Internet mail protocols. Developed by NSA's SDNS program and
used in the U.S. DoD's Defense Message System. used in the U.S. DoD's Defense Message System.
$ meta-data $ meta-data
(I) Descriptive information about a data object; i.e., data about (I) Descriptive information about a data object; i.e., data about
data, or data labels that describe other data. (See: security data, or data labels that describe other data. (See: security
label. Compare: metadata) label. Compare: metadata)
Tutorial: Meta-data can serve various management purposes: Tutorial: Meta-data can serve various management purposes:
- System management: File name, type, size, creation date. - System management: File name, type, size, creation date.
- Application management: Document title, version, author. - Application management: Document title, version, author.
- Usage management: Data categories, keywords, classifications. - Usage management: Data categories, keywords, classifications.
Meta-data can be associated with a data object in two basic ways: Meta-data can be associated with a data object in two basic ways:
- Explicitly: Be part of the data object (e.g., a header field of - Explicitly: Be part of the data object (e.g., a header field of
a data file or packet) or be linked to the object. a data file or packet) or be linked to the object.
- Implicitly: Be associated with the data object because of some - Implicitly: Be associated with the data object because of some
other, explicit attribute of the object. other, explicit attribute of the object.
$ metadata, Metadata(trademark), METADATA(trademark) $ metadata, Metadata(trademark), METADATA(trademark)
(O) A proprietary variant of "meta-data". (See: SPAM(trademark).) (D) Proprietary variants of "meta-data". (See: SPAM(trademark).)
Deprecated Usage: The terms "Metadata" and "METADATA" are claimed Deprecated Terms: ISDs SHOULD NOT use these unhypenated forms;
as registered trademarks (numbers 1,409,260 and 2,185,504) owned ISDs SHOULD use only the uncapitalized, hyphenated "meta-data".
by The Metadata Company, originally known as Metadata Information The terms "Metadata" and "METADATA" are claimed as registered
Partners, a company founded by Jack Myers. To avoid litigation, trademarks (numbers 1,409,260 and 2,185,504) owned by The Metadata
this Glossary recommends a hyphenated form, "meta-data". Company, originally known as Metadata Information Partners, a
company founded by Jack Myers. The status of "metadata" is
unclear.
$ MHS $ MHS
(N) See: message handling system. (N) See: message handling system.
$ MIC $ MIC
(D) See: message integrity code. (D) See: message integrity code.
$ MIME $ MIME
(I) See: Multipurpose Internet Mail Extensions. (I) See: Multipurpose Internet Mail Extensions.
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between PKI components from different vendors; consists primarily between PKI components from different vendors; consists primarily
of a profile of certificate and CRL extensions and a set of of a profile of certificate and CRL extensions and a set of
transactions for PKI operation. [SP15] transactions for PKI operation. [SP15]
$ misappropriation $ misappropriation
(I) A type of threat action whereby an entity assumes unauthorized (I) A type of threat action whereby an entity assumes unauthorized
logical or physical control of a system resource. (See: logical or physical control of a system resource. (See:
usurpation.) usurpation.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- Theft of data: Unauthorized acquisition and use of data - Theft of data: Unauthorized acquisition and use of data
contained in a system. contained in a system.
- Theft of service: Unauthorized use of a system service. - Theft of service: Unauthorized use of a system service.
- Theft of functionality: Unauthorized acquisition of actual - Theft of functionality: Unauthorized acquisition of actual
hardware, software, or firmware of a system component. hardware, firmware, or software of a system component.
$ MISPC $ MISPC
(N) See: Minimum Interoperability Specification for PKI (N) See: Minimum Interoperability Specification for PKI
Components. Components.
$ MISSI $ MISSI
(N) Multilevel Information System Security Initiative, an NSA (O) Multilevel Information System Security Initiative, an NSA
program to encourage development of interoperable, modular program to encourage development of interoperable, modular
products for constructing secure network information systems in products for constructing secure network information systems in
support of a wide variety of Government missions. (See: MSP, SP3, support of a wide variety of Government missions. (See: MSP, SP3,
SP4.) SP4.)
$ MISSI user $ MISSI user
(O) /MISSI/ A system entity that is the subject of one or more (O) /MISSI/ A system entity that is the subject of one or more
MISSI X.509 public-key certificates issued under a MISSI MISSI X.509 public-key certificates issued under a MISSI
certification hierarchy. (See: personality.) certification hierarchy. (See: personality.)
Tutorial: MISSI users include both end users and the authorities Tutorial: MISSI users include both end users and the authorities
that issue certificates. A MISSI user is usually a person but may that issue certificates. A MISSI user is usually a person but may
be a machine or other automated process. Some machines are be a machine or other automated process. Machines that are
required to operate non-stop. To avoid downtime needed to exchange required to operate non-stop may be issued their own certificates
the FORTEZZA cards of machine operators at shift changes, the to avoid downtime needed to exchange the FORTEZZA cards of machine
machines may be issued their own cards, as if they were persons. operators at shift changes.
$ mission $ mission
(I) A statement of a (relatively long-term) duty or (relatively (I) A statement of a (relatively long-term) duty or (relatively
short-term) task that is assigned to an organization or system, short-term) task that is assigned to an organization or system,
indicates the purpose and objectives of the duty or task, and may indicates the purpose and objectives of the duty or task, and may
indicate the actions to be taken to achieve it. indicate the actions to be taken to achieve it.
$ mission critical $ mission critical
(I) A condition of a system service or other system resource such (I) A condition of a system service or other system resource such
that denial of access to, or lack of availability of, the resource that denial of access to, or lack of availability of, the resource
would jeopardize a system user~Os ability to perform a primary would jeopardize a system user's ability to perform a primary
mission function or would result in other serious consequences. mission function or would result in other serious consequences.
(Compare: mission essential.) (See: Critical. Compare: mission essential.)
$ mission essential $ mission essential
(O) /DoD/ Refers to materiel that is authorized and available to (O) /DoD/ Refers to materiel that is authorized and available to
combat, combat support, combat service support, and combat combat, combat support, combat service support, and combat
readiness training forces to accomplish their assigned missions. readiness training forces to accomplish their assigned missions.
[JCSP1] (Compare: mission critical.) [JCSP1] (Compare: mission critical.)
$ misuse $ misuse
1. (I) The intentional use (by authorized users) of system 1. (I) The intentional use (by authorized users) of system
resources for other than authorized purposes. Example: An resources for other than authorized purposes. Example: An
authorized system administrator creates an unauthorized account authorized system administrator creates an unauthorized account
for a friend. for a friend.
2. (I) A type of threat action that causes a system component to 2. (I) A type of threat action that causes a system component to
perform a function or service that is detrimental to system perform a function or service that is detrimental to system
security. (See: usurpation.) security. (See: usurpation.)
Usage: This type includes the following subtypes: Usage: This type includes the following subtypes:
- "Tampering": In context of misuse, deliberately altering a - "Tampering": In context of misuse, deliberately altering a
system's logic, data, or control information to cause the system's logic, data, or control information to cause the
system to perform unauthorized functions or services. (See: system to perform unauthorized functions or services. (See:
(main entry for) tampering.) corruption, main entry for "tampering".)
- "Malicious logic": In context of misuse, any hardware, - "Malicious logic": In context of misuse, any hardware,
software, or firmware intentionally introduced into a system to firmware, or software intentionally introduced into a system to
perform or control execution of an unauthorized function or perform or control execution of an unauthorized function or
service. (See: (main entry for) malicious logic.) service. (See: corruption, incapacitation, main entry for
- "Violation of authorizations": Action by an entity that exceeds "malicious logic", masquerade.)
- "Violation of authorizations": Action by an entity that exceeds
the entity's system privileges by executing an unauthorized the entity's system privileges by executing an unauthorized
function. (See: authorization.) function. (See: authorization.)
$ misuse detection $ misuse detection
(I) An intrusion detection method that is based on rules that (I) An intrusion detection method that is based on rules that
specify system events, sequences of events, or observable specify system events, sequences of events, or observable
properties of a system that are believed to be symptomatic of properties of a system that are believed to be symptomatic of
security incidents. (See: IDS. Compare: anomaly detection.) security incidents. (See: IDS. Compare: anomaly detection.)
$ MLS $ MLS
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$ mobile code $ mobile code
1a. (I) Software that originates from a remote server or is 1a. (I) Software that originates from a remote server or is
embedded in a document or other application file, is transmitted embedded in a document or other application file, is transmitted
across a network, and is loaded onto and executed on a local across a network, and is loaded onto and executed on a local
client system. client system.
1b. (O) /U.S. DoD/ "Software obtained from remote systems outside 1b. (O) /U.S. DoD/ "Software obtained from remote systems outside
the enclave boundary, transferred across a network, and then the enclave boundary, transferred across a network, and then
downloaded and executed on a local system without explicit downloaded and executed on a local system without explicit
installation or execution by the recipient." installation or execution by the recipient."
2a. (O) /U.S. DoD/ "Technology that enables the creation of 2a. (O) /U.S. DoD/ "Technology that enables the creation of
executable information that can be delivered to an information executable information that can be delivered to an information
system and directly executed on any hardware/software architecture system and directly executed on any hardware/software architecture
that has an appropriate host execution environment." that has an appropriate host execution environment."
2b. (O) "Programs (e.g., script, macro, or other portable 2b. (O) "Programs (e.g., script, macro, or other portable
instruction) that can be shipped unchanged to a heterogeneous instruction) that can be shipped unchanged to a heterogeneous
collection of platforms and execute with identical semantics" [SP- collection of platforms and executed with identical semantics"
28]. (See: active content.) [SP-28]. (See: active content.)
Tutorial: Mobile code might be malicious. Using techniques such as Tutorial: Mobile code might be malicious. Using techniques such as
"code signing" and a "sandbox" can reduce the risks of receiving "code signing" and a "sandbox" can reduce the risks of receiving
and executing mobile code. and executing mobile code.
$ mode $ mode
$ mode of operation $ mode of operation
1. (I) /encryption/ A technique for enhancing the effect of a 1. (I) /cryptographic operation/ A technique for enhancing the
cryptographic algorithm or adapting the algorithm for an effect of a cryptographic algorithm or adapting the algorithm for
application, such as applying a block cipher to a sequence of data an application, such as applying a block cipher to a sequence of
blocks or a data stream. (See: ECB, CBC, CFB, OFB.) data blocks or a data stream. (See: ECB, CBC, CFB, OFB.)
2. (I) /system operation/ A type of security policy that states 2. (I) /system operation/ A type of security policy that states
the range of classification levels of information that a system is the range of classification levels of information that a system is
permitted to handle and the range of clearances and authorizations permitted to handle and the range of clearances and authorizations
of users who are permitted to access the system. (See: dedicated of users who are permitted to access the system. (See:
compartmented security mode, controlled security mode, dedicated
security mode, multilevel security mode, partitioned security security mode, multilevel security mode, partitioned security
mode, system high security mode.) mode, system-high security mode. Compare: protection level.)
3. (I) /IKE/ IKE refers to its various types of ISAKMP-scripted
exchanges of messages as "modes". Among these are the following:
- "Main mode": One of IKE's two phase 1 modes. (See: ISAKMP.)
- "Quick mode": IKE's only phase 2 mode. (See: ISAKMP.)
$ modulus $ modulus
(I) The defining constant in modular arithmetic, and usually a (I) The defining constant in modular arithmetic, and usually a
part of the public key in asymmetric cryptography that is based on part of the public key in asymmetric cryptography that is based on
modular arithmetic. (See: Diffie-Hellman, RSA.) modular arithmetic. (See: Diffie-Hellman, RSA.)
$ Mondex $ Mondex
(O) A smartcard-based electronic money system that incorporates (O) A smartcard-based electronic money system that incorporates
cryptography and can be used to make payments via the Internet. cryptography and can be used to make payments via the Internet.
(See: IOTP.) (See: IOTP.)
$ Morris Worm $ Morris Worm
(I) A worm program that flooded the ARPANET in November, 1988, (I) A worm program that flooded the ARPANET in November, 1988,
causing problems for thousands of hosts. [R1135] (See: worm.) causing problems for thousands of hosts. [R1135] (See: community
risk, worm)
$ MOSS $ MOSS
(I) See: MIME Object Security Services. (I) See: MIME Object Security Services.
$ MQV $ MQV
(N) A key-agreement protocol [Mene] that was proposed by A.J. (N) A key-agreement protocol [Mene] that was proposed by A.J.
Menezes, M. Qu, and S.A. Vanstone in 1995 and is based on the Menezes, M. Qu, and S.A. Vanstone in 1995 and is based on the
Diffie-Hellman algorithm. Diffie-Hellman algorithm.
$ MSP $ MSP
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and maintain separation between, resources (particularly stored and maintain separation between, resources (particularly stored
data) of different security levels. (Examples: BLACKER, CANEWARE, data) of different security levels. (Examples: BLACKER, CANEWARE,
KSOS, Multics, SCOMP.) KSOS, Multics, SCOMP.)
Usage: Usually understood to mean that the system permits Usage: Usually understood to mean that the system permits
concurrent access by users who differ in their access concurrent access by users who differ in their access
authorizations, while denying users access to resources for which authorizations, while denying users access to resources for which
they lack authorization. they lack authorization.
$ multilevel security mode $ multilevel security mode
1. (N) A mode of system operation that allows two or more security 1. (N) A mode of system operation wherein (a) two or more security
levels of information to be handled concurrently within the same levels of information are allowed to be to be handled concurrently
system when not all users have a clearance or specific access within the same system when some users having access to the system
authorization for all data handled by the system. [DoD2] have neither a security clearance nor need-to-know for some of the
data handled by the system and (b) separation of the users and the
classified material on the basis, respectively, of clearance and
classification level are dependent on operating system control.
(See: /system operation/ under "mode", need to know, protection
level, security clearance. Compare: controlled mode.)
Usage: This term was defined in U.S. DoD policy regarding system Usage: Usually abbreviated as "multilevel mode". This term was
accreditation [DoD2], but the term is also used outside the defined in Government policy regarding system accreditation, but
Defense Department and outside government. This term can be the term is also used outside the Government.
defined more precisely as follows:
2. (N) A mode of system operation in which all three of the 2. (O) A mode of system operation in which all three of the
following statements are true: (a) Some authorized users do not following statements are true: (a) Some authorized users do not
have a security clearance for all the information handled in the have a security clearance for all the information handled in the
system. (b) All authorized users have the proper security system. (b) All authorized users have the proper security
clearance and appropriate specific access approval for the clearance and appropriate specific access approval for the
information to which they have access. (c) All authorized users information to which they have access. (c) All authorized users
have a need-to-know only for information to which they have have a need-to-know only for information to which they have
access. [C4009] access. [C4009] (See: formal access approval, protection level.)
$ Multipurpose Internet Mail Extensions (MIME) $ Multipurpose Internet Mail Extensions (MIME)
(I) An Internet protocol (RFC 2045) that enhances the basic format (I) An Internet protocol (RFC 2045) that enhances the basic format
of Internet electronic mail messages (RFC 822) to be able to use of Internet electronic mail messages (RFC 822) (1) to enable
character sets other than U.S. ASCII for textual headers and text character sets other than U.S. ASCII to be used for textual
content, and to carry non-textual and multi-part content. (See: headers and content and (2) to carry non-textual and multi-part
S/MIME.) content. (See: S/MIME.)
$ mutual suspicion $ mutual suspicion
(I) The state that exists between two interacting system entities (I) The state that exists between two interacting system entities
in which neither entity can trust the other to function correctly in which neither entity can trust the other to function correctly
with regard to some security requirement. with regard to some security requirement.
$ name $ name
(I) Synonym for "identifier". (I) Synonym for "identifier".
$ National Computer Security Center (NCSC) $ National Computer Security Center (NCSC)
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$ National Information Assurance Partnership (NIAP) $ National Information Assurance Partnership (NIAP)
(N) An joint initiative of NIST and NSA to enhance the quality of (N) An joint initiative of NIST and NSA to enhance the quality of
commercial products for information security and increase consumer commercial products for information security and increase consumer
confidence in those products through objective evaluation and confidence in those products through objective evaluation and
testing methods. testing methods.
Tutorial: NIAP is registered, through the U.S. DoD, as a National Tutorial: NIAP is registered, through the U.S. DoD, as a National
Performance Review Reinvention Laboratory. NIAP functions include Performance Review Reinvention Laboratory. NIAP functions include
the following: the following:
- Developing tests, test methods, and other tools that developers - Developing tests, test methods, and other tools that developers
and testing laboratories may use to improve and evaluate and testing laboratories may use to improve and evaluate
security products. security products.
- Collaborating with industry and others on research and testing - Collaborating with industry and others on research and testing
programs. programs.
- Using the Common Criteria to develop protection profiles and
- Using the Common Criteria to develop protection profiles and
associated test sets for security products and systems. associated test sets for security products and systems.
- Cooperating with the NIST National Voluntary Laboratory - Cooperating with the NIST National Voluntary Laboratory
Accreditation Program to develop a program to accredit private- Accreditation Program to develop a program to accredit private-
sector laboratories for the testing of information security sector laboratories for the testing of information security
products using the Common Criteria. products using the Common Criteria.
- Working to establish a formal, international mutual recognition - Working to establish a formal, international mutual recognition
scheme for a Common Criteria-based evaluation. scheme for a Common Criteria-based evaluation.
$ National Institute of Standards and Technology (NIST) $ National Institute of Standards and Technology (NIST)
(N) A U.S. Department of Commerce organization that promotes U.S. (N) A U.S. Department of Commerce organization that promotes U.S.
economic growth by working with industry to develop and apply economic growth by working with industry to develop and apply
technology, measurements, and standards. Has primary Government technology, measurements, and standards. Has primary Government
responsibility for INFOSEC standards for unclassified but responsibility for INFOSEC standards for sensitive unclassified
sensitive information. (See: ANSI, DES, DSA, DSS, FIPS, NIAP, information. (See: ANSI, DES, DSA, DSS, FIPS, NIAP, NSA.)
NSA.)
$ National Security Agency (NSA) $ National Security Agency (NSA)
(N) A U.S. DoD organization that has primary Government (N) A U.S. DoD organization that has primary Government
responsibility for INFOSEC standards for classified information responsibility for INFOSEC standards for classified information
and for unclassified but sensitive information handled by national and for sensitive unclassified information handled by national
security systems. (See: FORTEZZA, KEA, MISSI, NIAP, NIST, security systems. (See: FORTEZZA, KEA, MISSI, national security
SKIPJACK.) system, NIAP, NIST, SKIPJACK.)
$ national security information $ national security information
(N) /U.S. Government/ Information that has been determined, (N) /U.S. Government/ Information that has been determined,
pursuant to Executive Order 12958 or any predecessor order, to pursuant to Executive Order 12958 or any predecessor order, to
require protection against unauthorized disclosure. [C4009] require protection against unauthorized disclosure. [C4009]
$ national security system $ national security system
(O) /U.S. Government/ Any Government-operated information system (O) /U.S. Government/ Any Government-operated information system
for which the function, operation, or use (a) involves for which the function, operation, or use (a) involves
intelligence activities; (b) involves cryptologic activities intelligence activities; (b) involves cryptologic activities
related to national security; (c) involves command and control of related to national security; (c) involves command and control of
military forces; (d) involves equipment that is an integral part military forces; (d) involves equipment that is an integral part
of a weapon or weapon system; or (c) is critical to the direct of a weapon or weapon system; or (e) is critical to the direct
fulfillment of military or intelligence missions and does not fulfillment of military or intelligence missions and does not
include a system that is to be used for routine administrative and include a system that is to be used for routine administrative and
business applications (including payroll, finance, logistics, and business applications (including payroll, finance, logistics, and
personnel management applications). [Title 40 U.S.C. Section 1552, personnel management applications). [Title 40 U.S.C. Section 1552,
Information Technology Management Reform Act of 1996.] (See: type Information Technology Management Reform Act of 1996.] (See: type
2 product.) 2 product.)
$ NCSC $ NCSC
(O) See: National Computer Security Center. (O) See: National Computer Security Center.
$ need to know $ need to know, need-to-know
(I) The necessity for access to, knowledge of, or possession of (I) The necessity for access to, knowledge of, or possession of
specific information required to carry out official duties. specific information required to carry out official duties.
Usage: The compound "need-to-know" is used as both an adjective
and a noun.
Tutorial: The need-to-know criterion is used in security Tutorial: The need-to-know criterion is used in security
procedures that require a custodian of sensitive information, procedures that require a custodian of sensitive information,
prior to disclosing the information to someone else, to establish prior to disclosing the information to someone else, to establish
that the intended recipient has proper authorization to access the that the intended recipient has proper authorization to access the
information. information.
$ network $ network
(I) An information system comprised of a collection of (I) An information system comprised of a collection of
interconnected modes. (See: computer network.) interconnected nodes. (See: computer network.)
$ Network Hardware Layer
(I) See: Internet Protocol Suite.
$ Network Interface Layer
(I) See: Internet Protocol Suite.
$ Network Layer Security Protocol (NLSP). $ Network Layer Security Protocol (NLSP).
(N) An OSI protocol (IS0 11577) for end-to-end encryption services (N) An OSI protocol (IS0 11577) for end-to-end encryption services
at the top of OSIRM layer 3. NLSP is derived from SP3 but is more at the top of OSIRM Layer 3. NLSP is derived from SP3 but is more
complex. (Compare: IPsec.) complex. (Compare: IPsec.)
$ Network Substrate Layer
(I) Synonym for "Network Hardware Layer".
$ network weaving $ network weaving
(I) A penetration technique in which an intruder avoids detection (I) A penetration technique in which an intruder avoids detection
and traceback by using multiple linked communication networks to and traceback by using multiple linked communication networks to
access and attack a system. [C4009] access and attack a system. [C4009]
$ NIAP $ NIAP
(N) See: National Information Assurance Partnership. (N) See: National Information Assurance Partnership.
$ nibble $ nibble
(D) Half of a byte (i.e., usually, 4 bits). (D) Half of a byte (i.e., usually, 4 bits).
Deprecated Term: To ensure international understanding, ISDs Deprecated Term: To avoid international misunderstanding, ISDs
SHOULD NOT use this term; instead, state the size of the block SHOULD NOT use this term; instead, state the size of the block
explicitly (e.g., "4-bit block"). (See: (Deprecated Usage under) explicitly (e.g., "4-bit block"). (See: Deprecated Usage under
Green Book.) "Green Book".)
$ NIPRNET $ NIPRNET
(O) The U.S. DoD~Os common-use Non-Classified Internet Protocol (O) The U.S. DoD's common-use Non-Classified Internet Protocol
Router Network; the part of the Internet that is wholly controlled Router Network; the part of the Internet that is wholly controlled
by the U.S. DoD and is used for official DoD business. by the U.S. DoD and is used for official DoD business.
$ NIST $ NIST
(N) See: National Institute of Standards and Technology. (N) See: National Institute of Standards and Technology.
$ NLSP $ NLSP
(N) See: Network Layer Security Protocol (N) See: Network Layer Security Protocol
$ no-lone zone $ no-lone zone
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exchanged by a protocol, usually for the purpose of guaranteeing exchanged by a protocol, usually for the purpose of guaranteeing
liveness and thus detecting and protecting against replay attacks. liveness and thus detecting and protecting against replay attacks.
$ non-critical $ non-critical
See: critical. See: critical.
$ non-repudiation service $ non-repudiation service
1. (I) A security service that provide protection against false 1. (I) A security service that provide protection against false
denial of involvement in a communication. (See: repudiation, time denial of involvement in a communication. (See: repudiation, time
stamp.) stamp.)
2. (O) "Assurance [that] the sender of data is provided with proof
2. (D) "Assurance [that] the sender of data is provided with proof
of delivery and the recipient is provided with proof of the of delivery and the recipient is provided with proof of the
sender's identity, so neither can later deny having processed the sender's identity, so neither can later deny having processed the
data." [NS4009] data." [NS4009]
Deprecated Definition: ISDs SHOULD NOT use the "O" definition Deprecated Definition: ISDs SHOULD NOT use this definition because
because it bundles two security services -- non-repudiation with it bundles two security services -- non-repudiation with proof of
proof of origin, and non-repudiation with proof of receipt -- that origin, and non-repudiation with proof of receipt -- that can be
can be provided independently of each other. provided independently of each other.
Usage: ISDs SHOULD distinguish between the technical aspects and Usage: ISDs SHOULD distinguish between the technical aspects and
the legal aspects of a non-repudiation service: the legal aspects of a non-repudiation service:
- "Technical non-repudiation": Refers to the assurance a relying - "Technical non-repudiation": Refers to the assurance a relying
party has that if a public key is used to validate a digital party has that if a public key is used to validate a digital
signature, that signature had to have been made by the signature, then that signature had to have been made by the
corresponding private signature key. [SP32] corresponding private signature key. [SP32]
-"Legal non-repudiation": Refers to how well possession or - "Legal non-repudiation": Refers to how well possession or
control of the private signature key can be established. [SP32] control of the private signature key can be established. [SP32]
Tutorial: Non-repudiation service does not prevent an entity from Tutorial: Non-repudiation service does not prevent an entity from
repudiating a communication. Instead, the service provides repudiating a communication. Instead, the service provides
evidence that can be stored and later presented to a third party evidence that can be stored and later presented to a third party
to resolve disputes that arise if and when a communication is to resolve disputes that arise if and when a communication is
repudiated by one of the entities involved. repudiated by one of the entities involved.
Ford describes the six phases of a complete non-repudiation Ford describes the six phases of a complete non-repudiation
service and uses "critical action" to refer to the act of service and uses "critical action" to refer to the act of
communication that is the subject of the service [For94, For97]: communication that is the subject of the service [For94, For97]:
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+-------------------+ +-------------------+
Phase / Explanation Phase / Explanation
------------------- -------------------
1. Request service: Before the critical action, the service 1. Request service: Before the critical action, the service
requester asks, either implicitly or explicitly, to have requester asks, either implicitly or explicitly, to have
evidence of the action be generated. evidence of the action be generated.
2. Generate evidence: When the critical action occurs, evidence is 2. Generate evidence: When the critical action occurs, evidence is
generated by a process involving the potential repudiator and generated by a process involving the potential repudiator and
possibly also a trusted third party. possibly also a trusted third party.
3. Transfer evidence: The evidence is transferred to the requester 3. Transfer evidence: The evidence is transferred to the requester
or stored by a third party, for later use (if needed.) or stored by a third party, for later use (if needed.)
4. Verify evidence: The entity that holds the evidence tests it to 4. Verify evidence: The entity that holds the evidence tests it to
be sure that it will suffice if a dispute arises. be sure that it will suffice if a dispute arises.
5. Retain evidence: The evidence is retained for possible future 5. Retain evidence: The evidence is retained for possible future
retrieval and use. retrieval and use.
6. Resolve dispute: In this phase, which occurs only if the 6. Resolve dispute: In this phase, which occurs only if the
critical action is repudiated, the evidence is retrieved from critical action is repudiated, the evidence is retrieved from
storage, presented, and verified to resolve the dispute. storage, presented, and verified to resolve the dispute.
$ non-repudiation with proof of origin $ non-repudiation with proof of origin
(I) A security service that provides the recipient of data with (I) A security service that provides the recipient of data with
evidence that proves the origin of the data, and thus protects the evidence that proves the origin of the data, and thus protects the
recipient against an attempt by the originator to falsely deny recipient against an attempt by the originator to falsely deny
sending the data. This service can be viewed as a strong version sending the data. (See: non-repudiation service.)
of data origin authentication service, in that it proves
authenticity to a third party. (See: non-repudiation service.) Tutorial: This service is a strong version of data origin
authentication service. This service can not only verify the
identity of a system entity that is the original source of
received data; it can also provide proof of that identity to a
third party.
$ non-repudiation with proof of receipt $ non-repudiation with proof of receipt
(I) A security service that provides the originator of data with (I) A security service that provides the originator of data with
evidence that proves the data was received as addressed, and thus evidence that proves the data was received as addressed, and thus
protects the originator against an attempt by the recipient to protects the originator against an attempt by the recipient to
falsely deny receiving the data. (See: non-repudiation service.) falsely deny receiving the data. (See: non-repudiation service.)
$ non-volatile media $ non-volatile media
(I) Storage media that, once written into, provide stable storage (I) Storage media that, once written into, provide stable storage
of information without an external power supply. (Compare: of information without an external power supply. (Compare:
volatile media, permanent storage.) permanent storage, volatile media.)
$ NORA $ NORA
(O) See: no-PIN ORA. (O) See: no-PIN ORA.
$ notarization $ notarization
(I) Registration of data under the authority or in the care of a (I) Registration of data under the authority or in the care of a
trusted third party, thus making it possible to provide subsequent trusted third party, thus making it possible to provide subsequent
assurance of the accuracy of characteristics claimed for the data, assurance of the accuracy of characteristics claimed for the data,
such as content, origin, time of existence, and delivery. [I7498 such as content, origin, time of existence, and delivery. [I7498
Part 2] (See: digital notary.) Part 2] (See: digital notary.)
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ccitt(2) country(16) US(840) organization(1) gov(101) csor(3)}. ccitt(2) country(16) US(840) organization(1) gov(101) csor(3)}.
The NIST CSOR records PKI objects below the branch {joint-iso-itu- The NIST CSOR records PKI objects below the branch {joint-iso-itu-
t(2) country(16) us(840) organization (1) gov(101) csor(3)}. The t(2) country(16) us(840) organization (1) gov(101) csor(3)}. The
U.S. DoD registers INFOSEC objects below the branch {joint-iso- U.S. DoD registers INFOSEC objects below the branch {joint-iso-
itu-t(2) country(16) us(840) organization(1) gov(101) dod(2) itu-t(2) country(16) us(840) organization(1) gov(101) dod(2)
infosec(1)}. infosec(1)}.
The IETF's Public-Key Infrastructure (pkix) Working Group The IETF's Public-Key Infrastructure (pkix) Working Group
registers PKI objects below the branch {iso(1) identified- registers PKI objects below the branch {iso(1) identified-
organization(3) dod(6) internet(1) security(5) mechanisms(5) organization(3) dod(6) internet(1) security(5) mechanisms(5)
pkix(7)}. [R2459] pkix(7)}. [R3280]
$ object reuse $ object reuse
(N) /COMPUSEC/ Reassignment and reuse of an area of a storage (N) /COMPUSEC/ Reassignment and reuse of an area of a storage
medium (e.g., random-access memory, floppy disk, magnetic tape) medium (e.g., random-access memory, floppy disk, magnetic tape)
that once contained sensitive data objects. Before being that once contained sensitive data objects. Before being
reassigned for use by a new subject, the area must erased or, in reassigned for use by a new subject, the area needs to be erased
some cases, purged. [NCS04] or, in some cases, purged. [NCS04]
$ obstruction $ obstruction
(I) A type of threat action that interrupts delivery of system (I) A type of threat action that interrupts delivery of system
services by hindering system operations. (See: disruption.) services by hindering system operations. (See: disruption.)
Tutorial: This type includes the following subtypes: Tutorial: This type includes the following subtypes:
- "Interference": Disruption of system operations by blocking - "Interference": Disruption of system operations by blocking
communications or user data or control information. (See: communication of user data or control information. (See:
jamming.) jamming.)
- "Overload": Hindrance of system operation by placing excess - "Overload": Hindrance of system operation by placing excess
burden on the performance capabilities of a system component. burden on the performance capabilities of a system component.
(See: flooding.) (See: flooding.)
$ OCSP $ OCSP
(I) See: On-line Certificate Status Protocol. (I) See: On-line Certificate Status Protocol.
$ octet $ octet
(I) A data unit of eight bits. (Compare: byte.) (I) A data unit of eight bits. (Compare: byte.)
Usage: This term is used in networking (especially in OSI Usage: This term is used in networking (especially in OSI
standards) in preference to "byte", because some systems use standards) in preference to "byte", because some systems use
"byte" for data storage units of a size other than eight bits. "byte" for data storage units of a size other than eight bits.
$ OFB $ OFB
(N) See: output feedback. (N) See: output feedback.
$ off-line attack $ off-line attack
(I) See: (secondary definition under) attack. (I) See: secondary definition under "attack".
$ ohnosecond $ ohnosecond
(D) That minuscule fraction of time in which you realize that your (D) That minuscule fraction of time in which you realize that your
private key has been compromised. private key has been compromised.
Deprecated Usage: This is a joke for English speakers. (See: Deprecated Usage: This is a joke for English speakers. (See:
(Deprecated Usage under) Green Book.) Deprecated Usage under "Green Book".)
$ OID $ OID
(N) See: object identifier. (N) See: object identifier.
$ On-line Certificate Status Protocol (OCSP) $ On-line Certificate Status Protocol (OCSP)
(I) An Internet protocol [R2560] used by a client to obtain from a (I) An Internet protocol [R2560] used by a client to obtain from a
server the validity status and other information concerning a server the validity status and other information about a digital
digital certificate. certificate.
Tutorial: In some applications, such as those involving high-value Tutorial: In some applications, such as those involving high-value
commercial transactions, it may be necessary either (a) to obtain commercial transactions, it may be necessary either (a) to obtain
certificate revocation status that is more timely than is possible certificate revocation status that is more timely than is possible
with CRLs or (b) to obtain other kinds of status information. OCSP with CRLs or (b) to obtain other kinds of status information. OCSP
may be used to determine the current revocation status of a may be used to determine the current revocation status of a
digital certificate, in lieu of or as a supplement to checking digital certificate, in lieu of or as a supplement to checking
against a periodic CRL. An OCSP client issues a status request to against a periodic CRL. An OCSP client issues a status request to
an OCSP server and suspends acceptance of the certificate in an OCSP server and suspends acceptance of the certificate in
question until the server provides a response. question until the server provides a response.
$ one-time pad $ one-time pad
1. (N) A manual encryption system in the form of a paper pad for 1. (N) A manual encryption system in the form of a paper pad for
one-time use. one-time use.
2. (I) An encryption algorithm in which the key is a random 2. (I) An encryption algorithm in which the key is a random
sequence of symbols and each symbol is used for encryption only sequence of symbols and each symbol is used for encryption only
one time -- to encrypt only one plaintext symbol to produce only one time -- i.e., used to encrypt only one plaintext symbol and
one ciphertext symbol -- and a copy of the key is used similarly thus produce only one ciphertext symbol -- and a copy of the key
for decryption. is used similarly for decryption.
Tutorial: To ensure one-time use, the copy of the key used for Tutorial: To ensure one-time use, the copy of the key used for
encryption is destroyed after use, as is the copy used for encryption is destroyed after use, as is the copy used for
decryption. This is the only encryption algorithm that is truly decryption. This is the only encryption algorithm that is truly
unbreakable, even given unlimited resources for cryptanalysis unbreakable, even given unlimited resources for cryptanalysis
[Schn], but key management costs and synchronization problems make [Schn], but key management costs and synchronization problems make
it impractical except in special situations. it impractical except in special situations.
$ one-time password, One-Time Password (OTP) $ one-time password, One-Time Password (OTP)
1. (I) /not capitalized/ A "one-time password" is a simple 1. (I) /not capitalized/ A "one-time password" is a simple
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constant size; and sends the padded onion to that next router. constant size; and sends the padded onion to that next router.
$ open security environment $ open security environment
(O) /U.S. DoD/ A system environment that meets at least one of the (O) /U.S. DoD/ A system environment that meets at least one of the
following two conditions: (a) Application developers (including following two conditions: (a) Application developers (including
maintainers) do not have sufficient clearance or authorization to maintainers) do not have sufficient clearance or authorization to
provide an acceptable presumption that they have not introduced provide an acceptable presumption that they have not introduced
malicious logic. (b) Configuration control does not provide malicious logic. (b) Configuration control does not provide
sufficient assurance that applications and the equipment are sufficient assurance that applications and the equipment are
protected against the introduction of malicious logic prior to and protected against the introduction of malicious logic prior to and
during the operation of system applications. [NCS04] (See: (first during the operation of system applications. [NCS04] (See: "first
law under) Courtney's laws. Compare: closed security environment.) law" under "Courtney's laws". Compare: closed security
environment.)
$ open storage $ open storage
(N) /U.S. Government/ "Storage of classified information within an (N) /U.S. Government/ "Storage of classified information within an
accredited facility, but not in General Services Administration accredited facility, but not in General Services Administration
approved secure containers, while the facility is unoccupied by approved secure containers, while the facility is unoccupied by
authorized personnel." [C4009] authorized personnel." [C4009]
$ Open Systems Interconnection (OSI) Reference Model (OSIRM) $ Open Systems Interconnection (OSI) Reference Model (OSIRM)
(N) A joint ISO/ITU-T standard [I7498 Part 1] for a seven-layer, (N) A joint ISO/ITU-T standard [I7498 Part 1] for a seven-layer,
architectural communication framework for interconnection of architectural communication framework for interconnection of
computers in networks. computers in networks. (See: OSIRM Security Architecture. Compare:
Internet Protocol Suite.)
Tutorial: OSIRM-based standards include communication protocols Tutorial: OSIRM-based standards include communication protocols
that are mostly incompatible with the IPS, but also include that are mostly incompatible with the IPS, but also include
security models, such as X.509, that are used in the Internet. security models, such as X.509, that are used in the Internet.
The OSIRM layers, from highest to lowest, are (7) Application, (6) The OSIRM layers, from highest to lowest, are (7) Application, (6)
Presentation, (5) Session, (4) Transport, (3) Network, (2) Data Presentation, (5) Session, (4) Transport, (3) Network, (2) Data
Link, and (1) Physical. Link, and (1) Physical.
Usage: In other Glossary entries, OSIRM layers are referred to by Usage: This Glossary refers to OSIRM layers by number to avoid
number to avoid confusing them with IPS layers, which are referred confusing them with IPS layers, which are referred to by name.
to by name.
Some unknown person described how the OSIRM layers correspond to Some unknown person described how the OSIRM layers correspond to
the seven deadly sins: the seven deadly sins:
7. Wrath: Application is always angry at the mess it sees below 7. Wrath: Application is always angry at the mess it sees below
itself. (Hey! Who is it to be pointing fingers?) itself. (Hey! Who is it to be pointing fingers?)
6. Sloth: Presentation is too lazy to do anything productive by 6. Sloth: Presentation is too lazy to do anything productive by
itself. itself.
5. Lust: Session is always craving and demanding what truly 5. Lust: Session is always craving and demanding what truly
belongs to Application's functionality. belongs to Application's functionality.
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attention. attention.
1. Bashful: Physical quietly does its work, unnoticed by the 1. Bashful: Physical quietly does its work, unnoticed by the
others. others.
$ operational integrity $ operational integrity
(I) Synonym for "system integrity"; this synonym emphasizes the (I) Synonym for "system integrity"; this synonym emphasizes the
actual performance of system functions rather than just the actual performance of system functions rather than just the
ability to perform them. ability to perform them.
$ operational security $ operational security
(D) Synonym for "administrative security". (Compare: OPSEC.) 1. (I) System capabilities, or performance of system functions,
that are needed either (a) to securely manage a system or (b) to
manage security features of a system. (Compare: operations
security (OPSEC).)
Usage: ISDs that use this term SHOULD state a definition because
(a) the definition provide here is general and vauge and (b) the
term could easily be confused with "operations security", which is
a different concept.
Tutorial: For example, in the context of an Internet service
provider, the term could refer to capabilities to manage network
devices in the event of attacks, simplify troubleshooting, keep
track of events that affect system integrity, help analyze sources
of attacks, and provide administrators with control over network
addresses and protocols to help mitigate the most common attacks
and exploits. [R3871]
2. (D) Synonym for "administrative security".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "administrative security". Any type of security may affect for "administrative security". Any type of security may affect
system operations; therefore, the term may be misleading. Instead, system operations; therefore, the term may be misleading. Instead,
use "administrative security", "communication security", "computer use "administrative security", "communication security", "computer
security", "emanations security", "personnel security", "physical security", "emanations security", "personnel security", "physical
security", or whatever specific type is meant. (Compare: OPSEC. security", or whatever specific type is meant. (See: security
See: security architecture.) architecture. Compare: operational integrity, OPSEC.)
$ operations security (OPSEC) $ operations security (OPSEC)
(I) A process to identify, control, and protect evidence of the (I) A process to identify, control, and protect evidence of the
planning and execution of sensitive activities and operations, and planning and execution of sensitive activities and operations, and
thereby prevent potential adversaries from gaining knowledge of thereby prevent potential adversaries from gaining knowledge of
capabilities and intentions. (See: communications cover. Compare: capabilities and intentions. (See: communications cover. Compare:
operational security.) operational security.)
$ operator $ operator
(I) A person who has been authorized to direct selected functions (I) A person who has been authorized to direct selected functions
of a system. (Compare: manager.) of a system. (Compare: manager.)
Usage: A system operator may or may not be treated as a "user"; Usage: ISDs that use this term SHOULD state a definition for it
therefore, ISDs that use this term SHOULD state a definition for because a system operator may or may not be treated as a "user".
it.
$ OPSEC $ OPSEC
(I) See: operations security. 1. (I) Abbreviation for "operations security".
2. (D) Abbreviation for "operational security".
Deprecated Usage: ISDs SHOULD NOT use this abbreviation for
"operational security" (as defined in this Glossary), because its
use for "operations security" has been well established for many
years, particular in the military community.
$ ORA $ ORA
See: organizational registration authority. See: organizational registration authority.
$ Orange Book $ Orange Book
(D) Synonym for "Trusted Computer System Evaluation Criteria" (D) /slang/ Synonym for "Trusted Computer System Evaluation
[CSC001, DoD1]. Criteria" [CSC001, DoD1].
Deprecated Usage: ISDs SHOULD NOT use this term as a synonym for Deprecated Usage: ISDs SHOULD NOT use this term as a synonym for
"Trusted Computer System Evaluation Criteria" [CSC001, DoD1]. "Trusted Computer System Evaluation Criteria" [CSC001, DoD1].
Instead, use the full, proper name of the document or, in Instead, use the full, proper name of the document or, in
subsequent references, the abbreviation "TCSEC". (See: (Deprecated subsequent references, the abbreviation "TCSEC". (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ organizational certificate $ organizational certificate
(I) A X.509 certificate in which the "subject" field contains the (I) An X.509 certificate in which the "subject" field contains the
name of an institution or set (e.g., a business, government, name of an institution or set (e.g., a business, government,
school, labor union, club, ethnic group, nationality, system, or school, labor union, club, ethnic group, nationality, system, or
group of individuals playing the same role), rather than the name group of individuals playing the same role), rather than the name
of an individual person or device. (Compare: persona certificate, of an individual person or device. (Compare: persona certificate,
role certificate.) role certificate.)
Tutorial: Such a certificate might be issued for one of the Tutorial: Such a certificate might be issued for one of the
following purposes: following purposes:
- To enable an individual to prove membership in the - To enable an individual to prove membership in the
organization. organization.
- To enable an individual to represent the organization, i.e., to - To enable an individual to represent the organization, i.e., to
act in its name and with it powers or permissions. act in its name and with it powers or permissions.
(O) /MISSI/ A type of MISSI X.509 public-key certificate that is (O) /MISSI/ A type of MISSI X.509 public-key certificate that is
issued to support organizational message handling for the U.S. issued to support organizational message handling for the U.S.
DoD's Defense Message System. DoD's Defense Message System.
$ organizational registration authority (ORA) $ organizational registration authority (ORA)
1. (I) /PKI/ An RA for an organization. 1. (I) /PKI/ An RA for an organization.
2. (O) /MISSI/ An end entity that (a) assists a PCA, CA, or SCA to 2. (O) /MISSI/ An end entity that (a) assists a PCA, CA, or SCA to
register other end entities, by gathering, verifying, and entering register other end entities, by gathering, verifying, and entering
data and forwarding it to the signing authority and (b) may also data and forwarding it to the signing authority and (b) may also
assist with card management functions. An ORA is a local assist with card management functions. An ORA is a local
administrative authority, and the term refers both to the role and administrative authority, and the term refers both to the role and
to the person who plays that role. An ORA does not sign to the person who plays that role. An ORA does not sign
certificates, CRLs, or CKLs. (See: no-PIN ORA, SSO-PIN ORA, user- certificates, CRLs, or CKLs. (See: no-PIN ORA, SSO-PIN ORA, user-
PIN ORA.) PIN ORA.)
$ origin authentication $ origin authentication
Deprecated Term: ISDs SHOULD NOT use this term; it looks like (D) Synonym for "data origin authentication". (See:
authentication, data origin authentication.)
Deprecated Term: ISDs SHOULD NOT use this term; it suggests
careless use of the internationally standardized term "data origin careless use of the internationally standardized term "data origin
authentication", and also could be confused with "peer entity authentication" and also could be confused with "peer entity
authentication." (See: authentication.) authentication."
$ origin authenticity $ origin authenticity
Deprecated Term: ISDs SHOULD NOT use this term; it looks like (D) Synonym for "data origin authentication". (See: authenticity,
data origin authentication.)
Deprecated Term: ISDs SHOULD NOT use this term; it suggests
careless use of the internationally standardized term "data origin careless use of the internationally standardized term "data origin
authentication", and mixes concepts in a potentially misleading authentication" and mixes concepts in a potentially misleading
way. (See: authenticity, origin authentication.) way.
$ OSI $ OSI, OSIRM
$ OSIRM
(N) See: Open Systems Interconnection Reference Model. (N) See: Open Systems Interconnection Reference Model.
$ OSIRM Security Architecture
(N) The part of the OSIRM [I7498-2] that specifies the security
services and security mechanisms that can be applied to protect
communications between two systems. (See: security architecture.)
Tutorial: This part of the OSIRM includes an allocation of
security services to protocol layers. The following table show
which security services (see definitions in this Glossary) are
permitted by the OSIRM in each of its layer. (Also, an application
process that operates above the Application Layer may itself
provide security services.) Similarly, the table suggests which
services are suitable for each IPS layer. However, explaining and
justifying these allocations is beyond the scope of this Glossary.
Legend for Table Entries:
O = Yes, [IS7498-2] permits the service in this OSIRM layer.
I = Yes, the service can be incorporated in this IPS layer.
IPS Protocol Layers +-----------------------------------------+
|Network| Net |In-| Trans | Application |
| H/W |Inter|ter| -port | |
| |-face|net| | |
OSIRM Protocol Layers +-----------------------------------------+
| 1 | 2 | 3 | 4 | 5 | 6 | 7 # |
Confidentiality +-----------------------------------------+
- Datagram | O I | O I | O I | O I | | O * | O I |
- Selective Field | | | I | | | O * | O I |
- Traffic Flow | O | | O | | | | O |
-- Full | I | | | | | | |
-- Partial | | I | I | | | | I |
Integrity +-----------------------------------------+
- Datagram | I | I | O I | O I | | | O I |
- Selective Field | | | I | | | | O I |
- Stream | | | O I | O I | | | O I |
Authentication +-----------------------------------------+
- Peer Entity | | I | O I | O I | | | O I |
- Data Origin | | I | O I | O I | | | O I |
Access Control +-----------------------------------------+
- type as appropriate | | I | O I | O I | | | O I |
Non-Repudiation +-----------------------------------------+
- of Origin | | | | | | | O I |
- of Receipt | | | | | | | O I |
+-----------------------------------------+
$ OTAR $ OTAR
(N) See: over-the-air rekeying. (N) See: over-the-air rekeying.
$ OTP $ OTP
(I) See: One-Time Password. (I) See: One-Time Password.
$ out of band $ out-of-band
1a. (I) Transfer of information using a channel that is outside (I) /adjective, adverb/ Information transfer using a channel or
(i.e., separate from) the main or normal channel. method that is outside (i.e., separate from or different from) the
main channel or normal method.
1b. (I) Transfer of information using a means or method that
differs from the main or normal method of communication.(See:
covert channel.)
Tutorial: Out-of-band mechanisms are often used to distribute Tutorial: Out-of-band mechanisms are often used to distribute
shared secrets (e.g., a symmetric key) or other sensitive shared secrets (e.g., a symmetric key) or other sensitive
information items (e.g., a root key) that are needed to initialize information items (e.g., a root key) that are needed to initialize
or otherwise enable the operation of cryptography or other or otherwise enable the operation of cryptography or other
security mechanisms. Example: Using postal mail to distribute security mechanisms. Example: Using postal mail to distribute
printed or magnetic media containing symmetric cryptographic keys printed or magnetic media containing symmetric cryptographic keys
for use in Internet encryption devices. (See: key distribution.) for use in Internet encryption devices. (See: key distribution.)
$ output feedback (OFB) $ output feedback (OFB)
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block length. block length.
Tutorial: This mode operates by directly using the algorithm's Tutorial: This mode operates by directly using the algorithm's
previously generated output block as the algorithm's next input previously generated output block as the algorithm's next input
block (i.e., by "feeding back" the output block) and combining block (i.e., by "feeding back" the output block) and combining
(exclusive OR-ing) the output block with the next plaintext (exclusive OR-ing) the output block with the next plaintext
segment (of block length or less) to form the next ciphertext segment (of block length or less) to form the next ciphertext
segment. segment.
$ outside attack $ outside attack
(I) See: (secondary definition under) attack. Compare: outsider.) (I) See: secondary definition under "attack". Compare: outsider.)
$ outsider $ outsider
(I) A user (usually a person) that accesses a system from a (I) A user (usually a person) that accesses a system from a
position that is outside the system's security perimeter. position that is outside the system's security perimeter.
(Compare: authorized user, insider, unauthorized user.) (Compare: authorized user, insider, unauthorized user.)
Tutorial: The actions performed by an outsider in accessing the Tutorial: The actions performed by an outsider in accessing the
system may be either authorized or unauthorized; i.e., an outsider system may be either authorized or unauthorized; i.e., an outsider
may act either as an authorized user or as an unauthorized user. may act either as an authorized user or as an unauthorized user.
$ over-the-air rekeying (OTAR) $ over-the-air rekeying (OTAR)
(N) Changing a key in a remote cryptographic device by sending a (N) Changing a key in a remote cryptographic device by sending a
new key directly to the device via a channel that the device is new key directly to the device via a channel that the device is
protecting. [C4009] protecting. [C4009]
$ overload $ overload
(I) See: (secondary definition under) obstruction. (I) /threat action/ See: secondary definition under "obstruction".
$ P1363 $ P1363
(N) See: IEEE P1363. (N) See: IEEE P1363.
$ PAA $ PAA
(O) See: policy approving authority. (O) See: policy approving authority.
$ package $ package
(N) /Common Criteria/ A reusable set of either functional or (N) /Common Criteria/ A reusable set of either functional or
assurance components (e.g. an EAL), combined in a single unit to assurance components (e.g. an EAL), combined in a single unit to
satisfy a set of identified security objectives. satisfy a set of identified security objectives. Example: The
seven EALs defined in Part 3 of the Common Criteria are predefined
assurance packages. (Compare: protection profile.)
Tutorial: A package is a combination of security requirement Tutorial: A package is a combination of security requirement
components and is intended to be reusable in the construction of components and is intended to be reusable in the construction of
either more complex packages or protection profiles and security either more complex packages or protection profiles and security
targets. A package expresses a set of either functional or targets. A package expresses a set of either functional or
assurance requirements that meet some particular need, expressed assurance requirements that meet some particular need, expressed
as a set of security objectives. Example: The seven EALs defined as a set of security objectives.
in Part 3 of the Common Criteria are predefined assurance
packages. $ packet
(I) A block of data that is carried from a source to a destination
through a communication channel or, more generally, across a
network. (Compare: datagram, PDU.)
$ packet filter $ packet filter
(I) See: (secondary definition under) filtering router. (I) See: secondary definition under "filtering router".
$ packet monkey $ packet monkey
(D) Someone who floods a system with packets, creating a denial- (D) /slang/ Someone who floods a system with packets, creating a
of-service condition for the system's users.(See: cracker.) denial-of-service condition for the system's users. (See:
cracker.)
Deprecated Term: To avoid international misunderstanding, ISDs
SHOULD NOT use this term. (See: Deprecated Usage under "Green
Book".)
$ pagejacking $ pagejacking
(D) A contraction of "Web page hijacking". A masquerade attack in (D) /slang/ A contraction of "Web page hijacking". A masquerade
which the attacker copies (steals) a home page or other material attack in which the attacker copies (steals) a home page or other
from the target server, rehosts the page on a server the attacker material from the target server, rehosts the page on a server the
controls, and causes the rehosted page to be indexed by the major attacker controls, and causes the rehosted page to be indexed by
Web search services, thereby diverting browsers from the target the major Web search services, thereby diverting browsers from the
server to the attacker's server. target server to the attacker's server.
Deprecated Term: ISDs SHOULD NOT use this contraction. The term is Deprecated Term: ISDs SHOULD NOT use this contraction. The term is
not listed in most dictionaries and could confuse international not listed in most dictionaries and could confuse international
readers. (See: (Deprecated Usage under) Green Book.) readers. (See: Deprecated Usage under "Green Book".)
$ PAN $ PAN
(O) See: primary account number. (O) See: primary account number.
$ PAP $ PAP
(I) See: Password Authentication Protocol. (I) See: Password Authentication Protocol.
$ parity bit $ parity bit
(I) A checksum that is computed on a block of bits by computing (I) A checksum that is computed on a block of bits by computing
the binary sum of the individual bits in the block and then the binary sum of the individual bits in the block and then
discarding all but the low-order bit of the sum. discarding all but the low-order bit of the sum. (See: checksum.)
$ partitioned security mode $ partitioned security mode
(N) A mode of operation of an information system, wherein all (N) A mode of system operation wherein all users having access to
users have the clearance, but not necessarily formal access the system have the necessary security clearances for all data
authorization and need-to-know, for all data handled by the handled by the system, but some users might not have either formal
system. This mode is defined in U.S. DoD policy regarding system access approval or need-to-know for all the data. (See: /system
accreditation. [DoD2] operation/ under "mode", formal access approval, need to know,
protection level, security clearance.)
Usage: Usually abbreviated as "partitioned mode". This term was
defined in U.S. Government policy on system accreditation.
$ PASS $ PASS
(N) See: personnel authentication system string. (N) See: personnel authentication system string.
$ passive attack $ passive attack
(I) See: (secondary definition under) attack. (I) See: secondary definition under "attack".
$ passive user
(I) See: secondary definition under "user".
$ passive wiretapping $ passive wiretapping
(I) A wiretapping attack that attempts only to observer (I) A wiretapping attack that attempts only to observe a
communication flow and gain knowledge of the data it contains, but communication flow and gain knowledge of the data it contains, but
does not alter or otherwise affect that flow. (See: wiretapping. does not alter or otherwise affect that flow. (See: wiretapping.
Compare: passive attack, active wiretapping.) Compare: passive attack, active wiretapping.)
$ password $ password
(I) A secret data value, usually a character string, that is (I) A secret data value, usually a character string, that is
presented to a system by a user to authenticate the user's presented to a system by a user to authenticate the user's
identity. (See: challenge-response, PIN, simple authentication.) identity. (See: authentication information, challenge-response,
PIN, simple authentication.)
(O) "A character string used to authenticate an identity." [CSC2] (O) "A character string used to authenticate an identity." [CSC2]
(O) "A string of characters (letters, numbers, and other symbols) (O) "A string of characters (letters, numbers, and other symbols)
used to authenticate an identity or to verify access used to authenticate an identity or to verify access
authorization." [FP140] authorization." [FP140]
(O) "A secret that a claimant memorizes and uses to authenticate (O) "A secret that a claimant memorizes and uses to authenticate
his or her identity. Passwords are typically character strings." his or her identity. Passwords are typically character strings."
[SP63] [SP63]
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passwords in cleartext form is inadequate. (See: one-time passwords in cleartext form is inadequate. (See: one-time
password, strong authentication.) password, strong authentication.)
$ Password Authentication Protocol (PAP) $ Password Authentication Protocol (PAP)
(I) A simple authentication mechanism in PPP. In PAP, a user (I) A simple authentication mechanism in PPP. In PAP, a user
identifier and password are transmitted in cleartext form. [R1334] identifier and password are transmitted in cleartext form. [R1334]
(See: CHAP.) (See: CHAP.)
$ password sniffing $ password sniffing
(I) Passive wiretapping, usually on a LAN, to gain knowledge of (I) Passive wiretapping, usually on a LAN, to gain knowledge of
passwords. (See: (Deprecated Usage note under) sniffing.) passwords. (See: Deprecated Usage under "sniffing".)
$ path discovery $ path discovery
(I) For a digital certificate, the process of finding a set of (I) For a digital certificate, the process of finding a set of
public-key certificates that comprise a certification path from a public-key certificates that comprise a certification path from a
trusted key to that specific certificate. trusted key to that specific certificate.
$ path validation $ path validation
(I) The process of validating (a) all of the digital certificates (I) The process of validating (a) all of the digital certificates
in a certification path and (b) the required relationships between in a certification path and (b) the required relationships between
those certificates, thus validating the contents of the last those certificates, thus validating the contents of the last
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Tutorial: The international PC Card Standard defines a non- Tutorial: The international PC Card Standard defines a non-
proprietary form factor in three sizes -- Types I, II and III -- proprietary form factor in three sizes -- Types I, II and III --
each of which have a 68-pin interface between the card and the each of which have a 68-pin interface between the card and the
socket into which it plugs. All three types have the same length socket into which it plugs. All three types have the same length
and width, roughly the size of a credit card, but differ in their and width, roughly the size of a credit card, but differ in their
thickness from 3.3 to 10.5 mm. Examples include storage modules, thickness from 3.3 to 10.5 mm. Examples include storage modules,
modems, device interface adapters, and cryptographic modules. modems, device interface adapters, and cryptographic modules.
$ PCA $ PCA
Deprecated Term: ISDs SHOULD NOT use this acronym without a (D) Abbreviation of various kinds of "certification authority".
qualifying adjective; that would be ambiguous. (See: Internet (See: Internet policy certification authority, (MISSI) policy
policy certification authority, (MISSI) policy creation authority, creation authority, (SET) payment gateway certification
(SET) payment gateway certification authority.) authority.)
Deprecated Abbreviation: An ISD that uses this abbreviation SHOULD
define it at the point of first use.
$ PCI
(N) See: "protocol control information" under "protocol data
unit".
$ PCMCIA $ PCMCIA
(N) Personal Computer Memory Card International Association, a (N) Personal Computer Memory Card International Association, a
group of manufacturers, developers, and vendors, founded in 1989 group of manufacturers, developers, and vendors, founded in 1989
to standardize plug-in peripheral memory cards for personal to standardize plug-in peripheral memory cards for personal
computers and now extended to deal with any technology that works computers and now extended to deal with any technology that works
in the PC Card form factor. (See: PC card.) in the PC Card form factor. (See: PC card.)
$ PDS $ PDS
(N) See: protective distribution system. (N) See: protective distribution system.
$ PDU
(N) See: protocol data unit.
$ peer entity authentication $ peer entity authentication
(I) "The corroboration that a peer entity in an association is the (I) "The corroboration that a peer entity in an association is the
one claimed." [I7498 Part 2] (See: authentication.) one claimed." [I7498 Part 2] (See: authentication.)
$ peer entity authentication service $ peer entity authentication service
(I) A security service that verifies an identity claimed by or for (I) A security service that verifies an identity claimed by or for
a system entity in an association. (See: authentication, a system entity in an association. (See: authentication,
authentication service.) authentication service.)
Tutorial: This service is used at the establishment of, or at Tutorial: This service is used at the establishment of, or at
times during, an association to confirm the identity of one entity times during, an association to confirm the identity of one entity
to another, thus protecting against a masquerade by the first to another, thus protecting against a masquerade by the first
entity. However, unlike data origin authentication service, this entity. However, unlike data origin authentication service, this
service requires an association to exist between the two entities, service requires an association to exist between the two entities,
and the corroboration provided by the service is valid only at the and the corroboration provided by the service is valid only at the
current time that the service is provided. (See: ("relationship current time that the service is provided. (See: "relationship
between data integrity service and authentication services" under) between data integrity service and authentication services" under
data integrity service). "data integrity service").
$ PEM $ PEM
(I) See: Privacy Enhanced Mail. (I) See: Privacy Enhanced Mail.
$ penetrate $ penetrate
1a. Circumvent a system's security protections. (See: attack, 1a. Circumvent a system's security protections. (See: attack,
break, violation.) break, violation.)
1b. (I) Successfully and repeatedly gain unauthorized access to a 1b. (I) Successfully and repeatedly gain unauthorized access to a
protected system resource. [Huff] protected system resource. [Huff]
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a system by using tools and techniques that are available to a system by using tools and techniques that are available to
adversaries. Testing may be performed under various constraints adversaries. Testing may be performed under various constraints
and conditions, including a specified level of knowledge of the and conditions, including a specified level of knowledge of the
system design and implementation. For a TCSEC evaluation, testers system design and implementation. For a TCSEC evaluation, testers
are assumed to have all system design and implementation are assumed to have all system design and implementation
documentation, including source code, manuals, and circuit documentation, including source code, manuals, and circuit
diagrams, and to work under no greater constraints than those diagrams, and to work under no greater constraints than those
applied to ordinary users. applied to ordinary users.
$ perfect forward secrecy $ perfect forward secrecy
(I) See: (usage discussion under) public-key forward secrecy. (I) See: Usage under "public-key forward secrecy".
$ perimeter $ perimeter
See: security perimeter. See: security perimeter.
$ periods processing $ periods processing
(I) A mode of system operation in which information of different (I) A mode of system operation in which information of different
sensitivities is processed at distinctly different times by the sensitivities is processed at distinctly different times by the
same system, with the system being properly purged or sanitized same system, with the system being properly purged or sanitized
between periods. (See: color change.) between periods. (See: color change.)
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system to the completion of any purging of sensitive data handled system to the completion of any purging of sensitive data handled
by the system during the period. by the system during the period.
$ permanent storage $ permanent storage
(I) Non-volatile media that, once written into, can never be (I) Non-volatile media that, once written into, can never be
completely erased. completely erased.
$ permission $ permission
1a. (I) A synonym for "authorization". (Compare: privilege.) 1a. (I) A synonym for "authorization". (Compare: privilege.)
1b. (I) An authorization or set of authorizations to perform 1b. (N) An authorization or set of authorizations to perform
security-relevant functions in the context of role-based access security-relevant functions in the context of role-based access
control. [ANSI] control. [ANSI]
Tutorial: A permission is a positively-stated authorization for Tutorial: A permission is a positively stated authorization for
access that (a) can be associated with one or more roles and (b) access that (a) can be associated with one or more roles and (b)
enables a user in a role to access a specified set of system enables a user in a role to access a specified set of system
resources by causing a specific set of system actions to be resources by causing a specific set of system actions to be
performed on the resources. performed on the resources.
$ persona certificate $ persona certificate
(I) An X.509 certificate issued to a system entity that wishes to (I) An X.509 certificate issued to a system entity that wishes to
use a persona to conceal its true identity when using PEM or other use a persona to conceal its true identity when using PEM or other
Internet services that depend on PKI support. (See: anonymity.) Internet services that depend on PKI support. (See: anonymity.)
[R1422] [R1422]
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seldom serves as a user identifier, and a PIN's characters are not seldom serves as a user identifier, and a PIN's characters are not
necessarily all numeric. Retail banking applications use 4-digit necessarily all numeric. Retail banking applications use 4-digit
numeric user PINs, but the FORTEZZA PC card uses 12-character numeric user PINs, but the FORTEZZA PC card uses 12-character
alphanumeric SSO PINs. alphanumeric SSO PINs.
Thus, a better name for this concept would have been "personnel Thus, a better name for this concept would have been "personnel
authentication system string" (PASS), in which case an authentication system string" (PASS), in which case an
alphanumeric character string for this purpose would have been alphanumeric character string for this purpose would have been
called, obviously, a "PASSword". called, obviously, a "PASSword".
$ personal information
(I) Information about a particular person, especially information
of an intimate or critical nature, that could cause harm or pain
to that person if disclosed to unauthorized parties. Examples:
medical record, arrest record, credit report, academic transcript,
training report, job application, credit card number, Social
Security number. (See: privacy.)
$ personality $ personality
1. (I) Synonym for "principal". 1. (I) Synonym for "principal".
2. (O) /MISSI/ A set of MISSI X.509 public-key certificates that 2. (O) /MISSI/ A set of MISSI X.509 public-key certificates that
have the same subject DN, together with their associated private have the same subject DN, together with their associated private
keys and usage specifications, that is stored on a FORTEZZA PC keys and usage specifications, that is stored on a FORTEZZA PC
card to support a role played by the card's user. card to support a role played by the card's user.
Tutorial: When a card's user selects a personality to use in a Tutorial: When a card's user selects a personality to use in a
FORTEZZA-aware application, the data determines behavior traits FORTEZZA-aware application, the data determines behavior traits
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label", a user-friendly character string that applications can label", a user-friendly character string that applications can
display to the user for selecting or changing the personality to display to the user for selecting or changing the personality to
be used. For example, a military user's card might contain three be used. For example, a military user's card might contain three
personalities: GENERAL HALFTRACK, COMMANDER FORT SWAMPY, and NEW personalities: GENERAL HALFTRACK, COMMANDER FORT SWAMPY, and NEW
YEAR'S EVE PARTY CHAIRMAN. Each personality includes one or more YEAR'S EVE PARTY CHAIRMAN. Each personality includes one or more
certificates of different types (such as DSA versus RSA), for certificates of different types (such as DSA versus RSA), for
different purposes (such as digital signature versus encryption), different purposes (such as digital signature versus encryption),
or with different authorizations. or with different authorizations.
$ personnel authentication system string (PASS) $ personnel authentication system string (PASS)
(N) See: (Tutorial under) personal identification number. (N) See: Tutorial under "personal identification number".
$ personnel security $ personnel security
(I) Procedures to ensure that persons who access a system have (I) Procedures to ensure that persons who access a system have
proper clearance, authorization, and need-to-know as required by proper clearance, authorization, and need-to-know as required by
the system's security policy. the system's security policy.
$ PGP(trademark) $ PGP(trademark)
(O) See: Pretty Good Privacy(trademark). (O) See: Pretty Good Privacy(trademark).
$ phase 1 negotiation
$ phase 2 negotiation
(I) /ISAKMP/ See: secondary definition under "Internet Security
Association and Key Management Protocol".
$ Photuris $ Photuris
(I) A UDP-based, key establishment protocol for session keys, (I) A UDP-based, key establishment protocol for session keys,
designed for use with the IPsec protocols AH and ESP. Superseded designed for use with the IPsec protocols AH and ESP. Superseded
by IKE. by IKE.
$ phreaking $ phreaking
(D) A contraction of "telephone breaking". An attack on or (D) A contraction of "telephone breaking". An attack on or
penetration of a telephone system or, by extension, any other penetration of a telephone system or, by extension, any other
communication or information system. [Raym] communication or information system. [Raym]
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system. Examples: Fences, walls, and other barriers; locks, safes, system. Examples: Fences, walls, and other barriers; locks, safes,
and vaults; dogs and armed guards; sensors and alarm bells. and vaults; dogs and armed guards; sensors and alarm bells.
[FP031, R1455] [FP031, R1455]
$ piggyback attack $ piggyback attack
(I) A form of active wiretapping in which the attacker gains (I) A form of active wiretapping in which the attacker gains
access to a system via intervals of inactivity in another user's access to a system via intervals of inactivity in another user's
legitimate communication connection. Sometimes called a "between- legitimate communication connection. Sometimes called a "between-
the-lines" attack. (See: hijack attack, man-in-the-middle attack.) the-lines" attack. (See: hijack attack, man-in-the-middle attack.)
Deprecated Usage: This term could confuse international readers; Deprecated Usage: ISDs that use this term SHOULD state a
therefore, ISDs that use it SHOULD state a definition for it. definition for it because the term could confuse international
readers.
$ PIN $ PIN
(I) See: personal identification number. (I) See: personal identification number.
$ ping of death $ ping of death
(D) A denial-of-service attack that sends an improperly large ICMP (D) A denial-of-service attack that sends an improperly large ICMP
echo request packet (a "ping") with the intent of causing the echo request packet (a "ping") with the intent of causing the
destination system to fail. (See: ping sweep, teardrop.) destination system to fail. (See: ping sweep, teardrop.)
Deprecated Term: ISDs SHOULD NOT use this term; instead, use "ping Deprecated Term: ISDs SHOULD NOT use this term; instead, use "ping
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requests for public-key certificates. (See: certification requests for public-key certificates. (See: certification
request.) request.)
Tutorial: A PKCS #10 request contains a DN and a public key, and Tutorial: A PKCS #10 request contains a DN and a public key, and
may contain other attributes, and is signed by the entity making may contain other attributes, and is signed by the entity making
the request. The request is sent to a CA, who converts it to an the request. The request is sent to a CA, who converts it to an
X.509 public-key certificate (or some other form), and returns it, X.509 public-key certificate (or some other form), and returns it,
possibly in PKCS #7 format. possibly in PKCS #7 format.
$ PKCS #11 $ PKCS #11
(N) A standard [PKC11] from the PKCS series; defines a software (N) A standard [PKC11] from the PKCS series; defines CAPI called
CAPI called Cryptoki (an abbreviation of "cryptographic token "Cryptoki" for devices that hold cryptographic information and
interface", pronounced "CRYPTO-key") for devices that hold perform cryptographic functions.
cryptographic information and perform cryptographic functions.
$ PKI $ PKI
(I) See: public-key infrastructure. (I) See: public-key infrastructure.
$ PKIX $ PKIX
1a. (I) A contraction of "Public-Key Infrastructure (X.509)", the 1a. (I) A contraction of "Public-Key Infrastructure (X.509)", the
name of the IETF working group that is specifying an architecture name of the IETF working group that is specifying an architecture
[R3280] and set of protocols [R2510] to provide X.509-based PKI [R3280] and set of protocols [R2510] to provide X.509-based PKI
services for the Internet. services for the Internet.
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environments and a range of usage environments. PKIX specifies (a) environments and a range of usage environments. PKIX specifies (a)
profiles of the v3 X.509 public-key certificate standards and the profiles of the v3 X.509 public-key certificate standards and the
v2 X.509 CRL standards for the Internet, (b) operational protocols v2 X.509 CRL standards for the Internet, (b) operational protocols
used by relying parties to obtain information such as certificates used by relying parties to obtain information such as certificates
or certificate status, (c) management protocols used by system or certificate status, (c) management protocols used by system
entities to exchange information needed for proper management of entities to exchange information needed for proper management of
the PKI, and (d) information about certificate policies and CPSs, the PKI, and (d) information about certificate policies and CPSs,
covering the areas of PKI security not directly addressed in the covering the areas of PKI security not directly addressed in the
rest of PKIX. rest of PKIX.
$ PKIX private extension
(I) PKIX defines an private extension to identify an on-line
verification service supporting the issuing CA.
$ plain text $ plain text
(I) /noun/ Data that is input to and transformed by an encryption (I) /noun/ Data that is input to and transformed by an encryption
process, or that is output from a decryption process. (Compare: process, or that is output from a decryption process. (See:
plaintext.) plaintext. Compare: cipher text, clear text.)
Tutorial: Usually, the plain text that is the input to an Tutorial: Usually, the plain text that is the input to an
encryption operation is clear text. But in some cases, the input encryption operation is clear text, but the input could be cipher
is cipher text that was output from another encryption operation. text that was output from another encryption operation. (See:
(See: superencryption.) superencryption.)
$ plaintext $ plaintext
1a. (I) /adjective/ Referring to plain text. (See: plain text.) 1. (I) /adjective/ Referring to plain text. (See: plain text.
Compare: ciphertext, cleartext.)
1b. (D) /noun/ A synonym for plain text. 2. (D) /noun/ A synonym for plain text.
Deprecated Usage: To avoid ambiguity, ISDs SHOULD differentiate Deprecated Usage: ISDs should not use this term as a synonym for
between the noun phrase "plain text" and adjective "plaintext". "plain text". ISDs SHOULD distinguish between the adjective
"plaintext" and the noun phrase "plain text".
$ PLI $ PLI
(I) See: Private Line Interface. (I) See: Private Line Interface.
$ Point-to-Point Protocol (PPP) $ Point-to-Point Protocol (PPP)
(I) An Internet Standard protocol (RFC 1661) for encapsulation and (I) An Internet Standard protocol (RFC 1661) for encapsulation and
full-duplex transportation of protocol data packets in OSIRM layer full-duplex transportation of protocol data packets in OSIRM Layer
3 over an OSIRM layer 2 link between two peers, and for 3 over an OSIRM Layer 2 link between two peers, and for
multiplexing different layer 3 protocols over the same link. multiplexing different Layer 3 protocols over the same link.
Includes optional negotiation to select and use a peer entity Includes optional negotiation to select and use a peer entity
authentication protocol to authenticate the peers to each other authentication protocol to authenticate the peers to each other
before they exchange layer 3 data. (See: CHAP, EAP, PAP.) before they exchange Layer 3 data. (See: CHAP, EAP, PAP.)
$ Point-to-Point Tunneling Protocol (PPTP) $ Point-to-Point Tunneling Protocol (PPTP)
(I) An Internet client-server protocol (RFC 2637) (originally (I) An Internet client-server protocol (RFC 2637) (originally
developed by Ascend and Microsoft) that enables a dial-up user to developed by Ascend and Microsoft) that enables a dial-up user to
create a virtual extension of the dial-up link across a network by create a virtual extension of the dial-up link across a network by
tunneling PPP over IP. (See: L2TP.) tunneling PPP over IP. (See: L2TP.)
Tutorial: PPP can encapsulate any IPS network layer protocol or Tutorial: PPP can encapsulate any IPS Network Interface Layer
OSIRM layer 3 protocol. Therefore, PPTP does not specify security protocol or OSIRM Layer 3 protocol. Therefore, PPTP does not
services; it depends on protocols above and below it to provide specify security services; it depends on protocols above and below
any needed security. PPTP makes it possible to divorce the it to provide any needed security. PPTP makes it possible to
location of the initial dial-up server (i.e., the PPTP Access divorce the location of the initial dial-up server (i.e., the PPTP
Concentrator, the client, which runs on a special-purpose host) Access Concentrator, the client, which runs on a special-purpose
from the location at which the dial-up protocol (PPP) connection host) from the location at which the dial-up protocol (PPP)
is terminated and access to the network is provided (i.e., at the connection is terminated and access to the network is provided
PPTP Network Server, which runs on a general-purpose host). (i.e., at the PPTP Network Server, which runs on a general-purpose
host).
$ policy $ policy
1a. (I) A plan or course of action that is stated for a system or 1a. (I) A plan or course of action that is stated for a system or
organization and is intended to affect and direct the decisions organization and is intended to affect and direct the decisions
and deeds of that entity's components or members. (See: security and deeds of that entity's components or members. (See: security
policy.) policy.)
1b. (O) A definite goal, course, or method of action to guide and 1b. (O) A definite goal, course, or method of action to guide and
determine present and future decisions, that is implemented or determine present and future decisions, that is implemented or
executed within a particular context, such as within a business executed within a particular context, such as within a business
unit. [R3198] unit. [R3198]
Deprecated Usage: ISDs SHOULD NOT use "policy" as an abbreviation Deprecated Abbreviation: ISDs SHOULD NOT use "policy" as an
for either "security policy" or "certificate policy". Instead, to abbreviation of either "security policy" or "certificate policy".
avoid misunderstanding, use a fully qualified term, at least at Instead, to avoid misunderstanding, use a fully qualified term, at
the point of first usage. least at the point of first usage.
Tutorial: The introduction of new technology to replace Tutorial: The introduction of new technology to replace
traditional systems can result in new systems being deployed traditional systems can result in new systems being deployed
without adequate policy definition and before the implications of without adequate policy definition and before the implications of
the new technology are fully understand. In some cases, it can be the new technology are fully understand. In some cases, it can be
difficult to establish policies for new technology before the difficult to establish policies for new technology before the
technology has been operationally tested and evaluated. Thus, technology has been operationally tested and evaluated. Thus,
policy changes tend to lag behind technological changes, such that policy changes tend to lag behind technological changes, such that
either old policies impede the technical innovation, or the new either old policies impede the technical innovation, or the new
technology is deployed without adequate policies to govern its technology is deployed without adequate policies to govern its
use. use.
When new technology changes the ways that things are done, new When new technology changes the ways that things are done, new
"procedures" must be defined to establish operational guidelines "procedures" must be defined to establish operational guidelines
for using the technology and achieving satisfactory results, and for using the technology and achieving satisfactory results, and
new "practices" must be established for managing new systems and new "practices" must be established for managing new systems and
monitoring results. Practices and procedures are more directly monitoring results. Practices and procedures are more directly
coupled to actual systems and business operations than are coupled to actual systems and business operations than are
polices, which tend to be more abstract. polices, which tend to be more abstract.
- "Practices" define how a system is to be managed and what - "Practices" define how a system is to be managed and what
controls are in place to monitor the system and detect abnormal controls are in place to monitor the system and detect abnormal
behavior or quality problems. Practices are established to behavior or quality problems. Practices are established to
ensure that a system is managed in compliance with stated ensure that a system is managed in compliance with stated
policies. System audits are primarily concerned with whether or policies. System audits are primarily concerned with whether or
not practices are being followed. Auditors evaluate the not practices are being followed. Auditors evaluate the
controls to make sure they conform to accepted industry controls to make sure they conform to accepted industry
standards, and then confirm that controls are in place and that standards, and then confirm that controls are in place and that
control measurements are being gathered. Audit trails are control measurements are being gathered. Audit trails are
examples of control measurements that are recorded as part of examples of control measurements that are recorded as part of
system operations. system operations.
- "Procedures" define how a system is operated, and relate - "Procedures" define how a system is operated, and relate
closely to issues of what technology is used, who the operators closely to issues of what technology is used, who the operators
are, and how the system is deployed physically. Procedures are, and how the system is deployed physically. Procedures
define both normal and abnormal operating circumstances. define both normal and abnormal operating circumstances.
For every control defined by a practice statement, there should be - For every control defined by a practice statement, there should
corresponding procedures to implement the control and provide be corresponding procedures to implement the control and
ongoing measurement of the control parameters. Conversely, provide ongoing measurement of the control parameters.
procedures require management practices to insure consistent and Conversely, procedures require management practices to insure
correct operational behavior. consistent and correct operational behavior.
$ policy approving authority (PAA) $ policy approving authority (PAA)
(O) /MISSI/ The top-level signing authority of a MISSI (O) /MISSI/ The top-level signing authority of a MISSI
certification hierarchy. The term refers both to that certification hierarchy. The term refers both to that
authoritative office or role and to the person who plays that authoritative office or role and to the person who plays that
role. (See: root registry.) role. (See: root registry.)
Tutorial: A PAA registers MISSI PCAs and signs their X.509 public- Tutorial: A PAA registers MISSI PCAs and signs their X.509 public-
key certificates. A PAA issues CRLs but does not issue a CKL. A key certificates. A PAA issues CRLs but does not issue a CKL. A
PAA may issue cross-certificates to other PAAs. PAA may issue cross-certificates to other PAAs.
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office. (See: policy certification authority.) office. (See: policy certification authority.)
Tutorial: A MISSI PCA's certificate is issued by a PAA. The PCA Tutorial: A MISSI PCA's certificate is issued by a PAA. The PCA
registers the CAs in its domain, defines their configurations, and registers the CAs in its domain, defines their configurations, and
issues their X.509 public-key certificates. (The PCA may also issues their X.509 public-key certificates. (The PCA may also
issue certificates for SCAs, ORAs, and other end entities, but a issue certificates for SCAs, ORAs, and other end entities, but a
PCA does not usually do this.) The PCA periodically issues CRLs PCA does not usually do this.) The PCA periodically issues CRLs
and CKLs for its domain. and CKLs for its domain.
$ Policy Management Authority $ Policy Management Authority
(N) Canadian usage: An organization responsible for PKI oversight (O) Canadian usage: An organization responsible for PKI oversight
and policy management in the Government of Canada. and policy management in the Government of Canada.
$ policy mapping $ policy mapping
(I) "Recognizing that, when a CA in one domain certifies a CA in (I) "Recognizing that, when a CA in one domain certifies a CA in
another domain, a particular certificate policy in the second another domain, a particular certificate policy in the second
domain may be considered by the authority of the first domain to domain may be considered by the authority of the first domain to
be equivalent (but not necessarily identical in all respects) to a be equivalent (but not necessarily identical in all respects) to a
particular certificate policy in the first domain." [X509] particular certificate policy in the first domain." [X509]
$ policy rule
(I) A building block of a security policy; it (a) defines a set of
system conditions and (b) specifies a set of system actions that
are to be performed if those conditions occur. [R3198]
$ POP3 $ POP3
(I) See: Post Office Protocol, version 3. (I) See: Post Office Protocol, version 3.
$ POP3 APOP $ POP3 APOP
(I) A POP3 command (i.e., a transaction type, or a protocol- (I) A POP3 command (better described as a transaction type, or
within-a-protocol) by which a POP3 client optionally uses a keyed subprotocol) by which a POP3 client optionally uses a keyed hash
hash (based on MD5) to authenticate itself to a POP3 server and, (based on MD5) to authenticate itself to a POP3 server and,
depending on the server implementation, to protect against replay depending on the server implementation, to protect against replay
attacks. (See: CRAM, POP3 AUTH, IMAP4 AUTHENTICATE.) attacks. (See: CRAM, POP3 AUTH, IMAP4 AUTHENTICATE.)
Tutorial: The server includes a unique timestamp in its greeting Tutorial: The server includes a unique timestamp in its greeting
to the client. The subsequent APOP command sent by the client to to the client. The subsequent APOP command sent by the client to
the server contains the client's name and the hash result of the server contains the client's name and the hash result of
applying MD5 to a string formed from both the timestamp and a applying MD5 to a string formed from both the timestamp and a
shared secret that is known only to the client and the server. shared secret value that is known only to the client and the
APOP was designed to provide an alternative to using POP3's USER server. APOP was designed to provide an alternative to using
and PASS (i.e., password) command pair, in which the client sends POP3's USER and PASS (i.e., password) command pair, in which the
a cleartext password to the server. client sends a cleartext password to the server.
$ POP3 AUTH $ POP3 AUTH
(I) A POP3 command [R1734] (i.e., a transaction type, or a (I) A POP3 command [R1734] (better described as a transaction
protocol-within-a-protocol) by which a POP3 client optionally type, or subprotocol) by which a POP3 client optionally proposes a
proposes a mechanism to a POP3 server to authenticate the client mechanism to a POP3 server to authenticate the client to the
to the server and provide other security services. (See: POP3 server and provide other security services. (See: POP3 APOP, IMAP4
APOP, IMAP4 AUTHENTICATE.) AUTHENTICATE.)
Tutorial: If the server accepts the proposal, the command is Tutorial: If the server accepts the proposal, the command is
followed by performing a challenge-response authentication followed by performing a challenge-response authentication
protocol and, optionally, negotiating a protection mechanism for protocol and, optionally, negotiating a protection mechanism for
subsequent POP3 interactions. The security mechanisms used by POP3 subsequent POP3 interactions. The security mechanisms used by POP3
AUTH are those used by IMAP4. AUTH are those used by IMAP4.
$ port scan $ port scan
(I) An attack that sends client requests to a range of server port (I) An attack that sends client requests to a range of server port
addresses on a host, with the goal of finding an active port and addresses on a host, with the goal of finding an active port and
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client to a server and providing other security services. (See: client to a server and providing other security services. (See:
POP3 APOP, POP3 AUTH.) POP3 APOP, POP3 AUTH.)
$ PPP $ PPP
(I) See: Point-to-Point Protocol. (I) See: Point-to-Point Protocol.
$ PPTP $ PPTP
(I) See: Point-to-Point Tunneling Protocol. (I) See: Point-to-Point Tunneling Protocol.
$ preauthorization $ preauthorization
(I) A CAW capability that enables certification requests to be (N) /PKI/ A CAW feature that enables certification requests to be
automatically validated against data provided in advance to the CA automatically validated against data provided in advance to the CA
by an authorizing entity. by an authorizing entity.
$ precedence $ precedence
(N) A designation assigned to a communication (i.e., packet, (N) A designation assigned to a communication (i.e., packet,
message, data stream, connection, etc.) by the originator to state message, data stream, connection, etc.) by the originator to state
the importance or urgency of that communication versus other the importance or urgency of that communication versus other
communications, and thus indicate to the transmission system the communications, and thus indicate to the transmission system the
relative order of handling, and indicate to the receiver the order relative order of handling, and indicate to the receiver the order
in which the communication is to be noted. [F1037] (See: in which the communication is to be noted. [F1037] (See:
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(O) Trademarks of Network Associates, Inc., referring to a (O) Trademarks of Network Associates, Inc., referring to a
computer program (and related protocols) that uses cryptography to computer program (and related protocols) that uses cryptography to
provide data security for electronic mail and other applications provide data security for electronic mail and other applications
on the Internet. (Compare: MOSS, MSP, PEM, S/MIME.) on the Internet. (Compare: MOSS, MSP, PEM, S/MIME.)
Tutorial: PGP encrypts messages with IDEA in CFB mode, distributes Tutorial: PGP encrypts messages with IDEA in CFB mode, distributes
the IDEA keys by encrypting them with RSA, and creates digital the IDEA keys by encrypting them with RSA, and creates digital
signatures on messages with MD5 and RSA. To establish ownership of signatures on messages with MD5 and RSA. To establish ownership of
public keys, PGP depends on the web of trust. public keys, PGP depends on the web of trust.
$ prevention
(I) See: secondary definition under "security".
$ primary account number (PAN) $ primary account number (PAN)
(O) /SET/ "The assigned number that identifies the card issuer and (O) /SET/ "The assigned number that identifies the card issuer and
cardholder. This account number is composed of an issuer cardholder. This account number is composed of an issuer
identification number, an individual account number identification number, an individual account number
identification, and an accompanying check digit as defined by ISO identification, and an accompanying check digit as defined by ISO
7812-1985." [SET2, IS7812] (See: bank identification number.) 7812-1985." [SET2, IS7812] (See: bank identification number.)
Tutorial: The PAN is embossed, encoded, or both on a magnetic- Tutorial: The PAN is embossed, encoded, or both on a magnetic-
strip-based credit card. The PAN identifies the issuer to which a strip-based credit card. The PAN identifies the issuer to which a
transaction is to be routed and the account to which it is to be transaction is to be routed and the account to which it is to be
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subjects, but each subject is associated with only one principal. subjects, but each subject is associated with only one principal.
(Compare: role, subject, user.) (Compare: role, subject, user.)
(N) /Kerberos/ A uniquely named client or server instance that (N) /Kerberos/ A uniquely named client or server instance that
participates in a network communication. participates in a network communication.
$ privacy $ privacy
1. (I) The right of an entity (normally a person), acting in its 1. (I) The right of an entity (normally a person), acting in its
own behalf, to determine the degree to which it will interact with own behalf, to determine the degree to which it will interact with
its environment, including the degree to which the entity is its environment, including the degree to which the entity is
willing to share information about itself with others. (See: willing to share its personal information with others. (See:
HIPAA, Privacy Act of 1974. Compare: anonymity, data HIPAA, personal information, Privacy Act of 1974. Compare:
confidentiality.) anonymity, data confidentiality.)
2. (O) "The right of individuals to control or influence what 2. (O) "The right of individuals to control or influence what
information related to them may be collected and stored and by information related to them may be collected and stored and by
whom and to whom that information may be disclosed." [I7498 Part whom and to whom that information may be disclosed." [I7498 Part
2] 2]
3. (D) Synonym for "data confidentiality". 3. (D) Synonym for "data confidentiality".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Definition: ISDs SHOULD NOT use this term as a synonym
for "data confidentiality" or "data confidentiality service", for "data confidentiality" or "data confidentiality service",
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Code) that seeks to balance the U.S. Government's need to maintain Code) that seeks to balance the U.S. Government's need to maintain
data about individuals with the rights of individuals to be data about individuals with the rights of individuals to be
protected against unwarranted invasions of their privacy stemming protected against unwarranted invasions of their privacy stemming
from federal agencies' collection, maintenance, use, and from federal agencies' collection, maintenance, use, and
disclosure of personal data. (See: privacy.) disclosure of personal data. (See: privacy.)
Tutorial: In 1974, the U.S. Congress was concerned with the Tutorial: In 1974, the U.S. Congress was concerned with the
potential for abuses that could arise from the Government's potential for abuses that could arise from the Government's
increasing use of computers to store and retrieve personal data. increasing use of computers to store and retrieve personal data.
Therefore, the Act has four basic policy objectives: Therefore, the Act has four basic policy objectives:
- To restrict disclosure of personally identifiable records - To restrict disclosure of personally identifiable records
maintained by Federal agencies. maintained by Federal agencies.
- To grant individuals increased rights of access to Federal - To grant individuals increased rights of access to Federal
agency records maintained on themselves. agency records maintained on themselves.
- To grant individuals the right to seek amendment of agency - To grant individuals the right to seek amendment of agency
records maintained on themselves upon a showing that the records maintained on themselves upon a showing that the
records are not accurate, relevant, timely, or complete. records are not accurate, relevant, timely, or complete.
- To establish a code of "fair information practices" that - To establish a code of "fair information practices" that
requires agencies to comply with statutory norms for requires agencies to comply with statutory norms for
collection, maintenance, and dissemination of records. collection, maintenance, and dissemination of records.
$ Privacy Enhanced Mail (PEM) $ Privacy Enhanced Mail (PEM)
(I) An Internet protocol to provide data confidentiality, data (I) An Internet protocol to provide data confidentiality, data
integrity, and data origin authentication for electronic mail. integrity, and data origin authentication for electronic mail.
[R1421, R1422]. (Compare: MOSS, MSP, PGP, S/MIME.) [R1421, R1422]. (Compare: MOSS, MSP, PGP, S/MIME.)
Tutorial: PEM encrypts messages with DES in CBC mode, provides key
distribution of DES keys by encrypting them with RSA, and signs Tutorial: PEM encrypts messages with DES in CBC mode, provides
distribution for DES keys by encrypting them with RSA, and signs
messages with RSA over either MD2 or MD5. To establish ownership messages with RSA over either MD2 or MD5. To establish ownership
of public keys, PEM uses a certification hierarchy, with X.509 of public keys, PEM uses a certification hierarchy, with X.509
public-key certificates and X.509 CRLs that are signed with RSA public-key certificates and X.509 CRLs that are signed with RSA
and MD2. and MD2.
PEM is designed to be compatible with a wide range of key PEM is designed to be compatible with a wide range of key
management methods, but is limited to specifying security services management methods, but is limited to specifying security services
only for text messages and, like MOSS, has not been widely only for text messages and, like MOSS, has not been widely
implemented in the Internet. implemented in the Internet.
$ private component $ private component
(I) Synonym for "private key". (I) Synonym for "private key".
Deprecated Usage: In most cases, ISDs SHOULD NOT use this term; Deprecated Usage: In most cases, ISDs SHOULD NOT use this term;
instead, to avoid confusing readers, use "private key". However, instead, to avoid confusing readers, use "private key". However,
the term MAY be used when discussing a key pair; e.g., "A key pair the term MAY be used when discussing a key pair; e.g., "A key pair
has a public component and a private component." has a public component and a private component."
$ private extension $ private extension
(I) See: (secondary definition under) extension. (I) See: secondary definition under "extension".
$ private key $ private key
1. (I) The secret component of a pair of cryptographic keys used 1. (I) The secret component of a pair of cryptographic keys used
for asymmetric cryptography. (See: key pair, public key.) for asymmetric cryptography. (See: key pair, public key, secret
key.)
2. (O) In a public key cryptosystem, "that key of a user's key 2. (O) In a public key cryptosystem, "that key of a user's key
pair which is known only by that user." [X509] pair which is known only by that user." [X509]
$ Private Line Interface (PLI) $ Private Line Interface (PLI)
(I) The first end-to-end packet encryption system for a computer (I) The first end-to-end packet encryption system for a computer
network, developed by BBN starting in 1975 for the U.S. DoD, network, developed by BBN starting in 1975 for the U.S. DoD,
incorporating Government-furnished, military-grade COMSEC incorporating Government-furnished, military-grade COMSEC
equipment (TSEC/KG-34). [B1822] (Compare: IPLI.) equipment (TSEC/KG-34). [B1822] (Compare: IPLI.)
$ privilege $ privilege
1a. (I) A synonym for "authorization". (Compare: permission.) 1a. (I) /access control/ A synonym for "authorization". (See
authorization. Compare: permission.)
1b. (I) An authorization or set of authorizations to perform
security-relevant functions in the context of computer operating
systems.
Tutorial: A privilege can be modeled as (a) an action acting upon 1b. (I) /computer platform/ An authorization to perform a
(b) an object that contains (c) attributes that can be constrained security-relevant function in the context of a computer's
by (d) domains. operating system.
$ privilege management infrastructure $ privilege management infrastructure
(O) "The infrastructure able to support the management of (O) "The infrastructure able to support the management of
privileges in support of a comprehensive authorization service and privileges in support of a comprehensive authorization service and
in relationship with a" PKI; i.e., processes concerned with in relationship with a" PKI; i.e., processes concerned with
attribute certificates. [X509] attribute certificates. [X509]
Deprecated Usage: ISDs SHOULD NOT use this term; this definition Deprecated Usage: ISDs SHOULD NOT use this term with this
is vague and there is no consensus on a more specific definition. definition. This definition is vague, and there is no consensus on
a more specific one.
$ privileged process $ privileged process
(I) An computer process that is authorized (and, therefore, (I) An computer process that is authorized (and, therefore,
trusted) to perform some security-relevant functions that ordinary trusted) to perform some security-relevant functions that ordinary
processes are not. (See: privilege, trusted process.) processes are not. (See: privilege, trusted process.)
$ privileged user
(I) An user that has access to system control, monitoring, or
administration functions. (See: privilege, /UNIX/ under "root",
superuser, user.)
Tutorial: Privileged users include the following types:
- Users with near or complete control of a system, who are
authorized to set up and administer user accounts, identifiers,
and authentication information, or are authorized to assign or
change other users' access to system resources.
- Users that are authorized to change control parameters (e.g.,
network addresses, routing tables, processing priorities) on
routers, multiplexers, and other important equipment.
- Users that are authorized to monitor or perform troubleshooting
for a system's security functions, typically using special
tools and features that are not available to ordinary users.
$ probe $ probe
(I) /verb/ To access an information system in an attempt to gather (I) /verb/ To access an information system in an attempt to gather
information about the system for the purpose of circumventing the information about the system for the purpose of circumventing the
system's security measures. system's security measures.
$ procedural security $ procedural security
(I) Synonym for "administrative security". (D) Synonym for "administrative security".
Deprecated Definition: ISDs SHOULD NOT use this term as a synonym Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
for "administrative security". Any type of security may involve "administrative security". The term may be misleading because any
procedures; therefore, the term may be misleading. Instead, use type of security may involve procedures, and procedures may be
either external to the system or internal. Instead, use
"administrative security", "communication security", "computer "administrative security", "communication security", "computer
security", "emanations security", "personnel security", "physical security", "emanations security", "personnel security", "physical
security", or whatever specific type is meant. (See: security security", or whatever specific type is meant. (See: security
architecture.) architecture.)
$ profile $ profile
See: certificate profile, protection profile. See: certificate profile, protection profile.
$ proof-of-possession protocol $ proof-of-possession protocol
(I) A protocol whereby a system entity proves to another that it (I) A protocol whereby a system entity proves to another that it
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$ proprietary $ proprietary
(I) Refers to information (or other property) that is owned by an (I) Refers to information (or other property) that is owned by an
individual or organization and for which the use is restricted by individual or organization and for which the use is restricted by
that entity. that entity.
$ protected checksum $ protected checksum
(I) A checksum that is computed for a data object by means that (I) A checksum that is computed for a data object by means that
protect against active attacks that would attempt to change the protect against active attacks that would attempt to change the
checksum to make it match changes made to the data object. (See: checksum to make it match changes made to the data object. (See:
digital signature, keyed hash, (discussion under) checksum. digital signature, keyed hash, Tutorial under "checksum".)
$ protective packaging $ protective packaging
(N) Packaging techniques for COMSEC material that discourage (N) Packaging techniques for COMSEC material that discourage
penetration, reveal a penetration has occurred or was attempted, penetration, reveal a penetration has occurred or was attempted,
or inhibit viewing or copying of keying material prior to the time or inhibit viewing or copying of keying material prior to the time
it is exposed for use. [C4008] (Compare: QUADRANT. See: tamper it is exposed for use. [C4008] (See: tamper-evident, tamper-
evident, tamper resistant.) resistant. Compare: QUADRANT.)
$ protection authority $ protection authority
(I) See: (secondary definition under) Internet Protocol Security (I) See: secondary definition under "Internet Protocol Security
Option. Option".
$ protection level
(N) /U.S. Government/ An indication of the trust that is needed in
a system's technical ability to enforce security policy for
confidentiality. (Compare: /system operation/ under "mode of
operation".)
Tutorial: An organization's security policy could define
protection levels that are based on (a) the sensitivity of
information handled by a system compared to (b) the authorizations
of users that receive information from the system without manual
intervention and reliable human review. For each level, the policy
could specify security features and assurances that must be
included in any system that was intended to operate at that level.
Example: Given some set of data objects that are classified at one
or more hierarchical levels and in one or more non-hierarchical
categories, the following table defines five protection levels for
systems that would handle that data. Beginning with PL1 and
evolving to PL5, each successive level would require stronger
features and assurances to handle the dataset. (See: clearance,
formal access approval, and need-to-know.)
Lowest Clearance Formal Access Need-To-Know
Among All Users Approval of Users of Users
+-------------------+-------------------+-------------------+
PL5 | Some user has no | [Does not matter.]| [Does not matter.]|
High | clearance at all. | | |
+-------------------+-------------------+-------------------+
PL4 | All are cleared | [Does not matter.]| [Does not matter.]|
| for some data. | | |
+-------------------+-------------------+-------------------+
PL3 | All are cleared | Some not approved | [Does not matter.]|
| for all data. | for all data. | |
+-------------------+-------------------+-------------------+
PL2 | All are cleared | All are approved | Some don't need to|
| for all data. | for all data. | to know all data. |
+-------------------+-------------------+-------------------+
PL1 | All are cleared | All are approved | All have a need |
Low | for all data. | for all data. | to know all data.|
+-------------------+-------------------+-------------------+
Each of these protection levels can be viewed as being equivalent
to one or more modes of system operation defined in this Glossary:
- PL5 is equivalent to multilevel security mode.
- PL4 is equivalent to either multilevel or compartmented
security mode, depending on the details of users' clearances.
- PL3 is equivalent to partitioned security mode.
- PL2 is equivalent to system-high security mode.
- PL1 is equivalent to dedicated security mode.
$ protection profile $ protection profile
(N) /Common Criteria/ An implementation-independent set of (N) /Common Criteria/ An implementation-independent set of
security requirements for a category of targets of evaluation that security requirements for a category of targets of evaluation that
meet specific consumer needs. [CCIB] Example: [IDSAN]. meet specific consumer needs. [CCIB] Example: [IDSAN]. (See:
target of evaluation. Compare: package.)
Tutorial: A protection profile (PP) is intended to be a reusable Tutorial: A protection profile (PP) is the kind of document used
statement of product security needs, which are known to be useful by consumers to specify functional requirements they want in a
and effective, for a set of information technology security product, and a target of evaluation (TOE) is the kind of document
products that could be built. A PP contains a set of security used by vendors to make functional claims about a product.
requirements, preferably taken from the catalogs in Parts 2 and 3
of the Common Criteria, and should include an EAL. A PP could be A PP is intended to be a reusable statement of product security
developed by user communities, product developers, or any other needs, which are known to be useful and effective, for a set of
parties interested in defining a common set of requirements. information technology security products that could be built. A PP
contains a set of security requirements, preferably taken from the
catalogs in Parts 2 and 3 of the Common Criteria, and should
include an EAL. A PP could be developed by user communities,
product developers, or any other parties interested in defining a
common set of requirements.
$ protection ring $ protection ring
(I) One of a hierarchy of privileged operation modes of a system (I) One of a hierarchy of privileged operation modes of a system
that gives certain access rights to processes authorized to that gives certain access rights to processes authorized to
operate in that mode. (See: Multics.) operate in that mode. (See: Multics.)
$ protective distribution system (PDS) $ protective distribution system (PDS)
(N) A wireline or fiber-optic communication system used to (N) A wireline or fiber-optic communication system used to
transmit cleartext classified information through an area of transmit cleartext classified information through an area of
lesser classification or control. [N7003] lesser classification or control. [N7003]
$ protocol $ protocol
1a. (I) A set of rules (i.e., formats and procedures) to implement 1a. (I) A set of rules (i.e., formats and procedures) to implement
and control some type of association (e.g., communication) between and control some type of association (e.g., communication) between
systems. Example: Internet Protocol. systems. Example: Internet Protocol.
1b. (I) A series of ordered computing and communication steps that 1b. (I) A series of ordered computing and communication steps that
are performed by two or more system entities to achieve a joint are performed by two or more system entities to achieve a joint
objective. [A9042] objective. [A9042]
$ protocol control information (PCI)
(N) See: secondary definition under "protocol data unit".
$ protocol data unit (PDU)
(N) A data packet that is defined for peer-to-peer transfers in a
protocol layer.
Tutorial: A PDU consists of two disjoint subsets of data: the SDU
and the PCI. (Although these terms -- PDU, SDU, and PCI --
originated in the OSIRM, they are also useful and permissible in
an IPS context.)
- The "service data unit" (SDU) in a packet is data that the
protocol transfers between peer protocol entities on behalf of
the users of that layer's services. For Layers 1 through 6, the
layer's users are peer protocol entities at a higher layer; for
Layer 7, the users are application entities outside the scope
of the OSIRM.
- The "protocol control information" (PCI) in a packet is data
that peer protocol entities exchange between themselves to
control their joint operation of the layer.
$ protocol suite $ protocol suite
(I) A complementary collection of communication protocols used in (I) A complementary collection of communication protocols used in
a computer network. (See: Internet, OSI.) a computer network. (See: IPS, OSI.)
$ proxy $ proxy
1. (I) A computer process that acts on behalf of a user or client. 1. (I) A computer process that acts on behalf of a user or client.
2. (I) A computer process -- often used as, or as part of, a 2. (I) A computer process -- often used as, or as part of, a
firewall -- that relays a protocol between client and server firewall -- that relays a protocol between client and server
computer systems, by appearing to the client to be the server and computer systems, by appearing to the client to be the server and
appearing to the server to be the client. (See: SOCKS.) appearing to the server to be the client. (See: SOCKS.)
Tutorial: In a firewall, a proxy server usually runs on a bastion Tutorial: In a firewall, a proxy server usually runs on a bastion
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firewall, gets the response, then sends the response back to the firewall, gets the response, then sends the response back to the
client. The proxy may be transparent to the clients, or they may client. The proxy may be transparent to the clients, or they may
need to connect first to the proxy server, and then use that need to connect first to the proxy server, and then use that
association to also initiate a connection to the real server. association to also initiate a connection to the real server.
Proxies are generally preferred over SOCKS for their ability to Proxies are generally preferred over SOCKS for their ability to
perform caching, high-level logging, and access control. A proxy perform caching, high-level logging, and access control. A proxy
can provide security service beyond that which is normally part of can provide security service beyond that which is normally part of
the relayed protocol, such as access control based on peer entity the relayed protocol, such as access control based on peer entity
authentication of clients, or peer entity authentication of authentication of clients, or peer entity authentication of
servers when clients do not have that capability. A proxy at OSIRM servers when clients do not have that ability. A proxy at OSIRM
layer 7 can also provide finer-grained security service than can a Layer 7 can also provide finer-grained security service than can a
filtering router at layer 3. For example, an FTP proxy could filtering router at Layer 3. For example, an FTP proxy could
permit transfers out of, but not into, a protected network. permit transfers out of, but not into, a protected network.
$ proxy certificate $ proxy certificate
(I) An X.509 public-key certificate derived from a end-entity (I) An X.509 public-key certificate derived from a end-entity
certificate, or from another proxy certificate, for the purpose of certificate, or from another proxy certificate, for the purpose of
establishing proxies and delegating authorizations in the context establishing proxies and delegating authorizations in the context
of a PKI-based authentication system. [R3280] of a PKI-based authentication system. [R3280]
Tutorial: A proxy certificate has the following properties: Tutorial: A proxy certificate has the following properties:
- It contains an critical extension that (a) identifies it as a - It contains an critical extension that (a) identifies it as a
proxy certificate and (b) may contain a certification path proxy certificate and (b) may contain a certification path
length constraint and policy constraints. length constraint and policy constraints.
- It contains the public component of a key pair that is distinct - It contains the public component of a key pair that is distinct
from that associated with any other certificate. from that associated with any other certificate.
- It is signed by the private component of a key pair that is - It is signed by the private component of a key pair that is
associated with an end-entity certificate or another proxy associated with an end-entity certificate or another proxy
certificate. certificate.
- Its associated private key can be used to sign only other proxy - Its associated private key can be used to sign only other proxy
certificates (not end-entity certificates). certificates (not end-entity certificates).
- Its "subject" DN is derived from its "issuer" DN and is unique. - Its "subject" DN is derived from its "issuer" DN and is unique.
- Its "issuer" DN is the "subject" DN of an end-entity - Its "issuer" DN is the "subject" DN of an end-entity
certificate or another proxy certificate. certificate or another proxy certificate.
$ pseudorandom $ pseudorandom
(I) A sequence of values that appears to be random (i.e., (I) A sequence of values that appears to be random (i.e.,
unpredictable) but is actually generated by a deterministic unpredictable) but is actually generated by a deterministic
algorithm. (See: compression, random, random number generator.) algorithm. (See: compression, random, random number generator.)
$ pseudorandom number generator $ pseudorandom number generator
See: random number generator. (I) See: secondary definition under "random number generator".
$ public component $ public component
(I) Synonym for "public key". (I) Synonym for "public key".
Deprecated Usage: In most cases, ISDs SHOULD NOT use this term; to Deprecated Usage: In most cases, ISDs SHOULD NOT use this term; to
avoid confusing readers, use "private key" instead. However, the avoid confusing readers, use "private key" instead. However, the
term MAY be used when discussing a key pair; e.g., "A key pair has term MAY be used when discussing a key pair; e.g., "A key pair has
a public component and a private component." a public component and a private component."
$ public key $ public key
1. (I) The publicly-disclosable component of a pair of 1. (I) The publicly disclosable component of a pair of
cryptographic keys used for asymmetric cryptography. (See: key cryptographic keys used for asymmetric cryptography. (See: key
pair, private key.) pair. Compare: private key.)
2. (O) In a public key cryptosystem, "that key of a user's key 2. (O) In a public key cryptosystem, "that key of a user's key
pair which is publicly known." [X509] pair which is publicly known." [X509]
$ public-key certificate $ public-key certificate
1. (I) A digital certificate that binds a system entity's identity 1. (I) A digital certificate that binds a system entity's
to a public key value, and possibly to additional, secondary data identifier to a public key value, and possibly to additional,
items; i.e., a digitally-signed data structure that attests to the secondary data items; i.e., a digitally signed data structure that
ownership of a public key. (See: X.509 public-key certificate.) attests to the ownership of a public key. (See: X.509 public-key
certificate.)
2. (O) "The public key of a user, together with some other 2. (O) "The public key of a user, together with some other
information, rendered unforgeable by encipherment with the private information, rendered unforgeable by encipherment with the private
key of the certification authority which issued it." [X509] key of the certification authority which issued it." [X509]
Tutorial: The digital signature on a public-key certificate is Tutorial: The digital signature on a public-key certificate is
unforgeable. Thus, the certificate can be published, such as by unforgeable. Thus, the certificate can be published, such as by
posting it in a directory, without the directory having to protect posting it in a directory, without the directory having to protect
the certificate's data integrity. the certificate's data integrity.
$ public-key cryptography $ public-key cryptography
(I) The popular synonym for "asymmetric cryptography". (I) Synonym for "asymmetric cryptography".
$ Public-Key Cryptography Standards (PKCS) $ Public-Key Cryptography Standards (PKCS)
(N) A series of specifications published by RSA Laboratories for (N) A series of specifications published by RSA Laboratories for
data structures and algorithm used in basic applications of data structures and algorithms used in basic applications of
asymmetric cryptography. (See: PKCS #5 through PKCS #11.) asymmetric cryptography. (See: PKCS #5 through PKCS #11.)
Tutorial: The PKCS were begun in 1991 in cooperation with industry Tutorial: The PKCS were begun in 1991 in cooperation with industry
and academia, originally including Apple, Digital, Lotus, and academia, originally including Apple, Digital, Lotus,
Microsoft, Northern Telecom, Sun, and MIT. Today, the Microsoft, Northern Telecom, Sun, and MIT. Today, the
specifications are widely used, but they are not sanctioned by an specifications are widely used, but they are not sanctioned by an
official standards organization, such as ANSI, ITU-T, or IETF. RSA official standards organization, such as ANSI, ITU-T, or IETF. RSA
Laboratories retains sole decision-making authority over the PKCS. Laboratories retains sole decision-making authority over the PKCS.
$ public-key forward secrecy (PFS) $ public-key forward secrecy (PFS)
(I) For a key agreement protocol based on asymmetric cryptography, (I) For a key-agreement protocol based on asymmetric cryptography,
the property that ensures that a session key derived from a set of the property that ensures that a session key derived from a set of
long-term public and private keys will not be compromised if one long-term public and private keys will not be compromised if one
of the private keys is compromised in the future. of the private keys is compromised in the future.
Usage: Some existing RFCs use the term "perfect forward secrecy" Usage: Some existing RFCs use the term "perfect forward secrecy"
but either do not define it or do not define it precisely. While but either do not define it or do not define it precisely. While
preparing this Glossary, we tried to find a good definition for preparing this Glossary, we tried to find a good definition for
that term, but found this to be a muddled area. Experts did not that term, but found this to be a muddled area. Experts did not
agree. For all practical purposes, the literature defines "perfect agree. For all practical purposes, the literature defines "perfect
forward secrecy" by stating the Diffie-Hellman algorithm. The term forward secrecy" by stating the Diffie-Hellman algorithm. The term
"public-key forward secrecy" (suggested by Hilarie Orman) and the "public-key forward secrecy" (suggested by Hilarie Orman) and the
"I" definition stated for it here were crafted to be compatible "I" definition stated for it here were crafted to be compatible
with current Internet documents, yet be narrow and leave room for with current Internet documents, yet be narrow and leave room for
improved terminology. improved terminology.
Challenge to the Internet security community: We need a taxonomy Challenge to the Internet security community: We need a taxonomy
-- a family of mutually exclusive and collectively exhaustive of terms and definitions to cover the basic properties discussed
terms and definitions to cover the basic properties discussed here here for the full range of cryptographic algorithms and protocols
-- for the full range of cryptographic algorithms and protocols
used in Internet Standards: used in Internet Standards:
Involvement of session keys vs. long-term keys: Experts disagree Involvement of session keys vs. long-term keys: Experts disagree
about the basic ideas involved: about the basic ideas involved:
- One concept of "forward secrecy" is that, given observations of - One concept of "forward secrecy" is that, given observations of
the operation of a key establishment protocol up to time t, and the operation of a key establishment protocol up to time t, and
given some of the session keys derived from those protocol given some of the session keys derived from those protocol
runs, you cannot derive unknown past session keys or future runs, you cannot derive unknown past session keys or future
session keys. session keys.
- A related property is that, given observations of the protocol - A related property is that, given observations of the protocol
and knowledge of the derived session keys, you cannot derive and knowledge of the derived session keys, you cannot derive
one or more of the long-term private keys. one or more of the long-term private keys.
- The "I" definition presented above involves a third concept of - The "I" definition presented above involves a third concept of
"forward secrecy" that refers to the effect of the compromise "forward secrecy" that refers to the effect of the compromise
of long-term keys. of long-term keys.
- All three concepts involve the idea that a compromise of "this" - All three concepts involve the idea that a compromise of "this"
encryption key is not supposed to compromise the "next" one. encryption key is not supposed to compromise the "next" one.
There also is the idea that compromise of a single key will There also is the idea that compromise of a single key will
compromise only the data protected by the single key. In compromise only the data protected by the single key. In
Internet literature, the focus has been on protection against Internet literature, the focus has been on protection against
decryption of back traffic in the event of a compromise of decryption of back traffic in the event of a compromise of
secret key material held by one or both parties to a secret key material held by one or both parties to a
communication. communication.
Forward vs. backward: Experts are unhappy with the word "forward", Forward vs. backward: Experts are unhappy with the word "forward",
because compromise of "this" encryption key also is not supposed because compromise of "this" encryption key also is not supposed
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approve or coordinate CPSs, which are security policies under approve or coordinate CPSs, which are security policies under
which components of a PKI operate. which components of a PKI operate.
A number of other servers and agents may support the core PKI, and A number of other servers and agents may support the core PKI, and
PKI clients may obtain services from them. The full range of such PKI clients may obtain services from them. The full range of such
services is not yet fully understood and is evolving, but services is not yet fully understood and is evolving, but
supporting roles may include archive agent, certified delivery supporting roles may include archive agent, certified delivery
agent, confirmation agent, digital notary, directory, key escrow agent, confirmation agent, digital notary, directory, key escrow
agent, key generation agent, naming agent who ensures that issuers agent, key generation agent, naming agent who ensures that issuers
and subjects have unique identifiers within the PKI, repository, and subjects have unique identifiers within the PKI, repository,
ticket-granting agent, and time stamp agent. ticket-granting agent, and time-stamp agent.
$ purge $ purge
(I) Use degaussing or other means to render (magnetically) stored (I) Use degaussing or other means to render (magnetically) stored
data unusable and unrecoverable by any means, including laboratory data unusable and unrecoverable by any means, including laboratory
methods. [C4009] (See: zeroize. Compare: erase, sanitize.) methods. [C4009] (See: zeroize. Compare: erase, sanitize.)
$ QUADRANT $ QUADRANT
(O) /U.S. Government/ Short name for technology and methods that (O) /U.S. Government/ Short name for technology and methods that
protect cryptographic equipment by making the equipment tamper- protect cryptographic equipment by making the equipment tamper-
resistant. [C4009] (Compare: protective packaging, TEMPEST.) resistant. [C4009] (Compare: protective packaging, TEMPEST.)
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Tutorial: Equipment cannot be made completely tamper-proof, but it Tutorial: Equipment cannot be made completely tamper-proof, but it
can be made tamper-resistant or tamper-evident. can be made tamper-resistant or tamper-evident.
$ qualified certificate $ qualified certificate
(I) A public-key certificate that has the primary purpose of (I) A public-key certificate that has the primary purpose of
identifying a person with a high level of assurance, where the identifying a person with a high level of assurance, where the
certificate meets some qualification requirements defined by an certificate meets some qualification requirements defined by an
applicable legal framework, such as the European Directive on applicable legal framework, such as the European Directive on
Electronic Signature [EU-ESDIR]. [R3739]. Electronic Signature [EU-ESDIR]. [R3739].
$ quick mode
(I) See: /IKE/ under "mode".
$ RA $ RA
(I) See: registration authority. (I) See: registration authority.
$ RA domains $ RA domains
(I) A capability of a CAW that allows a CA to divide the (I) A feature of a CAW that allows a CA to divide the
responsibility for certificate requests among multiple RAs. responsibility for certificate requests among multiple RAs.
Tutorial: This capability might be used to restrict access to Tutorial: This ability might be used to restrict access to private
private authorization data that is provided with a certificate authorization data that is provided with a certificate request,
request, and to distribute the responsibility to review and and to distribute the responsibility to review and approve
approve certificate requests in high volume environments. RA certificate requests in high volume environments. RA domains might
domains might segregate certificate requests according to an segregate certificate requests according to an attribute of the
attribute of the certificate subject, such as an organizational certificate subject, such as an organizational unit.
unit.
$ RADIUS $ RADIUS
(I) See: Remote Authentication Dial-In User Service. (I) See: Remote Authentication Dial-In User Service.
$ Rainbow Series $ Rainbow Series
(O) A set of more than 30 technical and policy documents with (O) /COMPUSEC/ A set of more than 30 technical and policy
colored covers, issued by the NCSC, that discuss in detail the documents with colored covers, issued by the NCSC, that discuss in
TCSEC and provide guidance for meeting and applying the criteria. detail the TCSEC and provide guidance for meeting and applying the
(See: Green Book, Orange Book, Red Book, Yellow Book.) criteria. (See: Green Book, Orange Book, Red Book, Yellow Book.)
$ random $ random
(I) In essence, "random" means "unpredictable". [SP22, Knut, (I) In essence, "random" means "unpredictable". [SP22, Knut,
R1750] (See: cryptographic key, pseudorandom.) R1750] (See: cryptographic key, pseudorandom.)
- "Random sequence": A sequence in which each successive value is - "Random sequence": A sequence in which each successive value is
obtained merely by chance and does not depend on the preceding obtained merely by chance and does not depend on the preceding
values of the sequence. In a random sequence of bits, each bit values of the sequence. In a random sequence of bits, each bit
is unpredictable; i.e., (a) the probability of each bit being a is unpredictable; i.e., (a) the probability of each bit being a
"0" or "1" is 1/2, and (b) the value of each bit is independent "0" or "1" is 1/2, and (b) the value of each bit is independent
of any other bit in the sequence. of any other bit in the sequence.
- "Random value": A individual value that is unpredictable; i.e., - "Random value": A individual value that is unpredictable; i.e.,
each value in the total population of possibilities has equal each value in the total population of possibilities has equal
probability of being selected. probability of being selected.
$ random number generator $ random number generator
(I) A process that is invoked to generate a random sequence of (I) A process that is invoked to generate a random sequence of
values (usually a sequence of bits) or an individual random value. values (usually a sequence of bits) or an individual random value.
Tutorial: There are two basic types of generators. [SP22] Tutorial: There are two basic types of generators. [SP22]
- (True) random number generator: Uses one or more non- - "(True) random number generator": It uses one or more non-
deterministic bit sources (usually physical phenomena; e.g., deterministic bit sources (e.g., electrical circuit noise,
electrical circuit noise, timing of user processes such as key timing of human processes such as key strokes or mouse
strokes or mouse movements, semiconductor quantum effects) and movements, semiconductor quantum effects, and other physical
some processing function that formats the bits; and outputs an phenomena) and a processing function that formats the bits, and
sequence of values that is unpredictable and uniformly it outputs a sequence of values that is unpredictable and
distributed. uniformly distributed.
- Pseudorandom number generator: Uses a deterministic - "Pseudorandom number generator": It uses a deterministic
computational process (usually implemented by software) that computational process (usually implemented by software) that
has one or more inputs called "seeds"; and outputs a sequence has one or more inputs called "seeds", and it outputs a
of values that appears to be random according to specified sequence of values that appears to be random according to
statistical tests. specified statistical tests.
$ RBAC $ RBAC
(N) See: role-based access control, rule-based access control. (N) See: role-based access control, rule-based access control.
Deprecated Usage: This abbreviation is ambiguous; therefore, ISDs Deprecated Usage: ISDs that use this term SHOULD state a
that use it SHOULD state a definition for it. definition for it because the abbreviation is ambiguous.
$ RC2, RC4, RC6 $ RC2, RC4, RC6
(N) See: Rivest Cipher #2, #4, #6. (N) See: Rivest Cipher #2, #4, #6.
$ read $ read
(I) A fundamental operation in an information system that results (I) A fundamental operation in an information system that results
only in the flow of information from an object to a subject. (See: only in the flow of information from an object to a subject. (See:
access mode.) access mode.)
$ realm $ realm
(O) /Kerberos/ The domain of authority of a Kerberos server (O) /Kerberos/ The domain of authority of a Kerberos server
(consisting of an authentication server and a ticket-granting (consisting of an authentication server and a ticket-granting
server), including the Kerberized clients and the Kerberized server), including the Kerberized clients and the Kerberized
application servers application servers. (See: domain.)
$ recovery $ recovery
1. (I) /cryptography/ The process of learning or obtaining 1. (I) /cryptography/ The process of learning or obtaining
cryptographic data or plain text through cryptanalysis. (See: key cryptographic data or plain text through cryptanalysis. (See: key
recovery, data recovery.) recovery, data recovery.)
2a. (I) /system integrity/ The process of restoring a secure state 2a. (I) /system integrity/ The process of restoring a secure state
in a system after there has been an accidental failure or a in a system after there has been an accidental failure or a
successful attack. (See: system integrity.) successful attack. (See: secondary definition under "security",
system integrity.)
2b. (I) /system integrity/ The process of restoring an information 2b. (I) /system integrity/ The process of restoring an information
system's assets and operation following damage or destruction. system's assets and operation following damage or destruction.
(See: contingency plan.) (See: contingency plan.)
$ RED $ RED
1. (I) Designation for data that consists only of clear text, and 1. (I) Designation for data that consists only of clear text, and
for information system equipment items and facilities that handle for information system equipment items and facilities that handle
only clear text. Example: "RED key". (Compare: BLACK. See: color only clear text. Example: "RED key". (See: color change, RED/BLACK
change, RED/BLACK separation.) separation. Compare: BLACK.)
Derivation: From the practice of marking equipment with colors to Derivation: From the practice of marking equipment with colors to
prevent operational errors. prevent operational errors.
2. (O) /U.S. Government/ Designation applied to information 2. (O) /U.S. Government/ Designation applied to information
systems, and to associated areas, circuits, components, and systems, and to associated areas, circuits, components, and
equipment, "in which unencrypted national security information is equipment, "in which unencrypted national security information is
being processed." [C4009] being processed." [C4009]
$ RED/BLACK separation $ RED/BLACK separation
(I) An architectural concept for cryptographic systems that (I) An architectural concept for cryptographic systems that
strictly separates the parts of a system that handle plain text strictly separates the parts of a system that handle plain text
(i.e., RED information) from the parts that handle cipher text (i.e., RED information) from the parts that handle cipher text
(i.e., BLACK information). (See: BLACK, RED.) (i.e., BLACK information). (See: BLACK, RED.)
$ Red Book $ Red Book
(D) Synonym for "Trusted Network Interpretation of the Trusted (D) /slang/ Synonym for "Trusted Network Interpretation of the
Computer System Evaluation Criteria" [NCS05]. Trusted Computer System Evaluation Criteria" [NCS05].
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term. Instead, use the
"Trusted Network Interpretation of the Trusted Computer System full proper name of the document or, in subsequent references, a
Evaluation Criteria". Instead, use the full proper name of the more conventional abbreviation, e.g., TNI-TCSEC. (See: TCSEC,
document or, in subsequent references, a more conventional Rainbow Series, Deprecated Usage under "Green Book".)
abbreviation. (See: TCSEC, Rainbow Series, (Deprecated Usage
under) Green Book.)
$ RED key $ RED key
(I) A key that is usable in its present form without any (I) A cleartext key, which is usable in its present form (i.e., it
additional decryption. (Compare: BLACK key. See: RED.) does not need to be decrypted before being used). (See: RED.
Compare: BLACK key.)
$ reference monitor $ reference monitor
(I) "An access control concept that refers to an abstract machine (I) "An access control concept that refers to an abstract machine
that mediates all accesses to objects by subjects." [NCS04] (See: that mediates all accesses to objects by subjects." [NCS04] (See:
security kernel.) security kernel.)
Tutorial: This concept was described in the Anderson report. A Tutorial: This concept was described in the Anderson report. A
reference monitor should be (a) complete (i.e., it mediates every reference monitor should be (a) complete (i.e., it mediates every
access), (b) isolated (i.e., it cannot be modified by other system access), (b) isolated (i.e., it cannot be modified by other system
entities), and (c) verifiable (i.e., small enough to be subjected entities), and (c) verifiable (i.e., small enough to be subjected
to analysis and tests to ensure that it is correct). to analysis and tests to ensure that it is correct).
$ reflection attack $ reflection attack
(I) An attack in which a valid data transmission is maliciously or (I) An attack in which a valid data transmission is maliciously or
fraudulently retransmitted, either by an adversary who intercepts fraudulently retransmitted, either by an adversary who intercepts
the data or by its originator. (Compare: replay attack.) the data or by its originator. (Compare: replay attack.)
$ registered user
(I) A system entity that is authorized to receive a system's
products and services or otherwise access system resources. (See:
registration, user.)
$ registration $ registration
1. (I) A system process that (a) initializes an identity in the 1. (I) /information system/ A system process that (a) initializes
system, (b) establishes an identifier for that identity, (c) may an identity (of a system entity) in the system, (b) establishes an
associate authentication information with that identifier, and (d) identifier for that identity, (c) may associate authentication
may issue an identifier credential (depending on the type of information with that identifier, and (d) may issue an identifier
authentication mechanism being used). (See: authentication credential (depending on the type of authentication mechanism
information, credential, identifier, identity.) being used). (See: authentication information, credential,
identifier, identity, identity proofing.)
2. (I) /PKI/ An administrative act or process whereby an entity's 2. (I) /PKI/ An administrative act or process whereby an entity's
name and other attributes are established for the first time at a name and other attributes are established for the first time at a
CA, prior to the CA issuing a digital certificate that has the CA, prior to the CA issuing a digital certificate that has the
entity's name as the subject. (See: registration authority.) entity's name as the subject. (See: registration authority.)
Tutorial: Registration may be accomplished either directly, by the Tutorial: Registration may be accomplished either directly, by the
CA, or indirectly, by a separate RA. An entity is presented to the CA, or indirectly, by a separate RA. An entity is presented to the
CA or RA, and the authority either records the name(s) claimed for CA or RA, and the authority either records the name(s) claimed for
the entity or assigns the entity's name(s). The authority also the entity or assigns the entity's name(s). The authority also
determines and records other attributes of the entity that are to determines and records other attributes of the entity that are to
be bound in a certificate (such as a public key or authorizations) be bound in a certificate (such as a public key or authorizations)
or maintained in the authority's database (such as street address or maintained in the authority's database (such as street address
and telephone number). The authority is responsible, possibly and telephone number). The authority is responsible, possibly
assisted by an RA, for verifying the entity's identity and vetting assisted by an RA, for verifying the entity's identity and vetting
the other attributes, in accordance with the CA's CPS. the other attributes, in accordance with the CA's CPS.
Among the registration issues that a CPS may address are the Among the registration issues that a CPS may address are the
following [R2527]: following [R3647]:
- How a claimed identity and other attributes are verified. - How a claimed identity and other attributes are verified.
- How organization affiliation or representation is verified. - How organization affiliation or representation is verified.
- What forms of names are permitted, such as X.500 DN, domain - What forms of names are permitted, such as X.500 DN, domain
name, or IP address. name, or IP address.
- Whether names are required to be meaningful or unique, and - Whether names are required to be meaningful or unique, and
within what domain. within what domain.
- How naming disputes are resolved, including the role of - How naming disputes are resolved, including the role of
trademarks. trademarks.
- Whether certificates are issued to entities that are not - Whether certificates are issued to entities that are not
persons. persons.
- Whether a person is required to appear before the CA or RA, or - Whether a person is required to appear before the CA or RA, or
can instead be represented by an agent. can instead be represented by an agent.
- Whether and how an entity proves possession of the private key - Whether and how an entity proves possession of the private key
matching a public key. matching a public key.
$ registration authority (RA) $ registration authority (RA)
1. (I) An optional PKI entity (separate from the CAs) that does 1. (I) An optional PKI entity (separate from the CAs) that does
not sign either digital certificates or CRLs but has not sign either digital certificates or CRLs but has
responsibility for recording or verifying some or all of the responsibility for recording or verifying some or all of the
information (particularly the identities of subjects) needed by a information (particularly the identities of subjects) needed by a
CA to issue certificates and CRLs and to perform other certificate CA to issue certificates and CRLs and to perform other certificate
management functions. (See: ORA, registration.) management functions. (See: ORA, registration.)
skipping to change at page 200, line 15 skipping to change at page 214, line 21
revocation reporting. [R2510] revocation reporting. [R2510]
Tutorial: Sometimes, a CA may perform all certificate management Tutorial: Sometimes, a CA may perform all certificate management
functions for all end users for which the CA signs certificates. functions for all end users for which the CA signs certificates.
Other times, such as in a large or geographically dispersed Other times, such as in a large or geographically dispersed
community, it may be necessary or desirable to offload secondary community, it may be necessary or desirable to offload secondary
CA functions and delegate them to an assistant, while the CA CA functions and delegate them to an assistant, while the CA
retains the primary functions (signing certificates and CRLs). The retains the primary functions (signing certificates and CRLs). The
tasks that are delegated to an RA by a CA may include personal tasks that are delegated to an RA by a CA may include personal
authentication, name assignment, token distribution, revocation authentication, name assignment, token distribution, revocation
reporting, key generation, and archiving. An RA is an optional PKI reporting, key generation, and archiving.
component, separate from the CA, that is assigned secondary
functions. The duties assigned to RAs vary from case to case but An RA is an optional PKI entity, separate from the CA, that is
may include the following: assigned secondary functions. The duties assigned to RAs vary from
- Verifying a subject's identity, i.e., performing personal case to case but may include the following:
- Verifying a subject's identity, i.e., performing personal
authentication functions. authentication functions.
- Assigning a name to a subject. (See: distinguished name.) - Assigning a name to a subject. (See: distinguished name.)
- Verifying that a subject is entitled to have the attributes - Verifying that a subject is entitled to have the attributes
requested for a certificate. requested for a certificate.
- Verifying that a subject possesses the private key that matches - Verifying that a subject possesses the private key that matches
the public key requested for a certificate. the public key requested for a certificate.
- Performing functions beyond mere registration, such as - Performing functions beyond mere registration, such as
generating key pairs, distributing tokens, and handling generating key pairs, distributing tokens, handling revocation
revocation reports. (Such functions may be assigned to a PKI reports, and archiving data. (Such functions may be assigned to
component that is separate from both the CA and the RA.) a PKI component that is separate from both the CA and the RA.)
3. (O) /SET/ "An independent third-party organization that 3. (O) /SET/ "An independent third-party organization that
processes payment card applications for multiple payment card processes payment card applications for multiple payment card
brands and forwards applications to the appropriate financial brands and forwards applications to the appropriate financial
institutions." [SET2] institutions." [SET2]
$ regrade $ regrade
(I) Deliberately change the classification level of information in (I) Deliberately change the security level (especially the
an authorized manner. (See: downgrade, upgrade.) hierarchical classification level) of information in an authorized
manner. (See: downgrade, upgrade.)
$ rekey $ rekey
(I) Change the value of a cryptographic key that is being used in (I) Change the value of a cryptographic key that is being used in
an application of a cryptographic system. (See: certificate an application of a cryptographic system. (See: certificate
rekey.) rekey.)
Tutorial: Rekey is required at the end of a cryptoperiod or key Tutorial: Rekey is required at the end of a cryptoperiod or key
lifetime. lifetime.
$ reliability $ reliability
skipping to change at page 201, line 20 skipping to change at page 215, line 29
Usage: Used in a legal context to mean a recipient of a Usage: Used in a legal context to mean a recipient of a
certificate who acts in reliance on that certificate. (See: ABA certificate who acts in reliance on that certificate. (See: ABA
Guidelines.) Guidelines.)
$ remanence $ remanence
(I) Residual information that can be recovered from a storage (I) Residual information that can be recovered from a storage
medium after clearing. (See: clear, magnetic remanence, purge.) medium after clearing. (See: clear, magnetic remanence, purge.)
$ Remote Authentication Dial-In User Service (RADIUS) $ Remote Authentication Dial-In User Service (RADIUS)
(I) An Internet protocol [R2138] for carrying dial-in users' (I) An Internet protocol [R2865] for carrying dial-in users'
authentication information and configuration information between a authentication information and configuration information between a
shared, centralized authentication server (the RADIUS server) and shared, centralized authentication server (the RADIUS server) and
a network access server (the RADIUS client) that needs to a network access server (the RADIUS client) that needs to
authenticate the users of its network access ports. (See: TACACS.) authenticate the users of its network access ports. (See: TACACS.)
Tutorial: A user of the RADIUS client presents authentication Tutorial: A user of the RADIUS client presents authentication
information to the client, and the client passes that information information to the client, and the client passes that information
to the RADIUS server. The server authenticates the client using a to the RADIUS server. The server authenticates the client using a
shared secret value, then checks the user's authentication shared secret value, then checks the user's authentication
information, and finally returns to the client all authorization information, and finally returns to the client all authorization
and configuration information needed by the client to deliver and configuration information needed by the client to deliver
service to the user. service to the user.
$ renew $ renew
See: certificate renewal. See: certificate renewal.
$ replay attack $ replay attack
(I) An attack in which a valid data transmission is maliciously or (I) An attack in which a valid data transmission is maliciously or
fraudulently repeated, either by the originator or by an adversary fraudulently repeated, either by the originator or by an adversary
who intercepts the data and retransmits it, possibly as part of a who intercepts the data and retransmits it, possibly as part of a
masquerade attack. (See: active wiretapping. Compare: reflection masquerade attack. (See: active wiretapping, liveness. Compare:
attack.) reflection attack.)
$ reordering
(I) /packet/ See: secondary definition under "stream integrity
service".
$ repository $ repository
1. (I) A system for storing and distributing digital certificates 1. (I) A system for storing and distributing digital certificates
and related information (including CRLs, CPSs, and certificate and related information (including CRLs, CPSs, and certificate
policies) to certificate users. (See: archive, directory.) policies) to certificate users. (Compare: archive, directory.)
2. (O) "A trustworthy system for storing and retrieving 2. (O) "A trustworthy system for storing and retrieving
certificates or other information relevant to certificates." [ABA] certificates or other information relevant to certificates." [ABA]
Tutorial: A certificate is published to those who might need it by Tutorial: A certificate is published to those who might need it by
putting it in a repository. The repository usually is a publicly putting it in a repository. The repository usually is a publicly
accessible, on-line server. In the Federal Public-key accessible, on-line server. In the FPKI, for example, the expected
Infrastructure, for example, the expected repository is a repository is a directory that uses LDAP, but also may be an X.500
directory that uses LDAP, but also may be the X.500 Directory that Directory that uses DAP, or an HTTP server, or an FTP server that
uses DAP, or an HTTP server, or an FTP server that permits permits anonymous login.
anonymous login.
$ repudiation $ repudiation
1. (I) Denial by a system entity that was involved in an 1. (I) Denial by a system entity that was involved in an
association (especially an association that transfers information) association (especially an association that transfers information)
of having participated in the relationship. (See: accountability, of having participated in the relationship. (See: accountability,
non-repudiation service.) non-repudiation service.)
2. (I) A type of threat action whereby an entity deceives another 2. (I) A type of threat action whereby an entity deceives another
by falsely denying responsibility for an act. (See: deception.) by falsely denying responsibility for an act. (See: deception.)
Usage: This type of threat action includes the following subtypes: Usage: This type of threat action includes the following subtypes:
- False denial of origin: Action whereby an originator denies - False denial of origin: Action whereby an originator denies
responsibility for sending data. responsibility for sending data.
- False denial of receipt: Action whereby a recipient denies - False denial of receipt: Action whereby a recipient denies
receiving and possessing data. receiving and possessing data.
3. (O) /OSIRM/ "Denial by one of the entities involved in a 3. (O) /OSIRM/ "Denial by one of the entities involved in a
communication of having participated in all or part of the communication of having participated in all or part of the
communication." [I7498 Part 2] communication." [I7498 Part 2]
$ Request for Comment (RFC) $ Request for Comment (RFC)
(I) One of the documents in the archival series that is the 1. (I) One of the documents in the archival series that is the
official channel for ISDs and other publications of the Internet official channel for ISDs and other publications of the Internet
Engineering Steering Group, the Internet Architecture Board, and Engineering Steering Group, the Internet Architecture Board, and
the Internet community in general. [R2026, R2223] (See: Internet the Internet community in general. (RFC 2026, 2223) (See: Internet
Standard.) Standard.)
Deprecated Usage: This term is NOT a synonym for "Internet 2. (D) A popularly misused synonym for a document on the Internet
Standard". Standards Track, i.e., an Internet Standard, Draft Standard, or
Proposed Standard. (See: Internet Standard.)
Deprecated Definition: This term SHOULD NOT be used as a synonym
for a document on the Internet Standards Track because many other
types of documents also are published as RFCs.
$ residual risk $ residual risk
(I) The portion of an original risk or set of risks that remains (I) The portion of an original risk or set of risks that remains
after countermeasures have been applied. (Compare: acceptable after countermeasures have been applied. (Compare: acceptable
risk, risk analysis.) risk, risk analysis.)
$ restore $ restore
See: card restore. See: card restore.
$ revocation $ revocation
skipping to change at page 203, line 20 skipping to change at page 217, line 36
$ revocation list $ revocation list
See: certificate revocation list. See: certificate revocation list.
$ revoke $ revoke
(I) See: certificate revocation. (I) See: certificate revocation.
$ RFC $ RFC
(I) See: Request for Comment. (I) See: Request for Comment.
$ Rijndael $ Rijndael
(I) A block cipher, designed by Joan Daemen and Vincent Rijmen as (N) A symmetric, block cipher that was designed by Joan Daemen and
a candidate algorithm for the AES. [Daem] Vincent Rijmen as a candidate for the AES, and that won that
competition. [Daem] (See: Advanced Encryption Standard.)
$ risk $ risk
1. (I) An expectation of loss expressed as the probability that a 1. (I) An expectation of loss expressed as the probability that a
particular threat will exploit a particular vulnerability with a particular threat will exploit a particular vulnerability with a
particular harmful result. particular harmful result.
2. (O) /SET/ "The possibility of loss because of one or more 2. (O) /SET/ "The possibility of loss because of one or more
threats to information (not to be confused with financial or threats to information (not to be confused with financial or
business risk)." [SET2] business risk)." [SET2]
Tutorial: There are four basic ways to deal with a risk [SP30]:
- "Risk avoidance": Eliminate the risk by either countering the
threat or removing the vulnerability. (Compare: "avoidance"
under "security".)
- "Risk transference": Shift the risk to another system or
entity; e.g., buy insurance to compensate for potential loss.
- "Risk limitation": Limit the risk by implementing controls that
minimize resulting loss.
- "Risk assumption": Accept the potential for loss and continue
operating the system.
$ risk analysis $ risk analysis
(I) An assessment process that systematically (a) identifies (I) An assessment process that systematically (a) identifies
valuable system resources and threats to those resources, (b) valuable system resources and threats to those resources, (b)
quantifies loss exposures (i.e., loss potential) based on quantifies loss exposures (i.e., loss potential) based on
estimated frequencies and costs of occurrence, and (c) estimated frequencies and costs of occurrence, and (c)
(optionally) recommends how to allocate resources to (optionally) recommends how to allocate available resources to
countermeasures so as to minimize total exposure. (See: risk countermeasures so as to minimize total exposure. (See: risk
management.) management, business case analysis. Compare: threat analysis.)
Tutorial: There are four basic options for dealing with a risk Tutorial: Usually, it is financially and technically infeasible to
[SP30]: avoid or transfer all risks (see: "first corollary" of "second
- Risk avoidance: Eliminate the risk either by countering the law" under "Courtney's laws"), and some residual risks will
threat or removing the vulnerability. remain, even after all available countermeasures have been
- Risk transference: Shift the risk to another system or system deployed (see: "second corollary" of "second law" under
entity, such as by buying insurance to compensate for loss. "Courtney's laws"). Thus, a risk analysis typically lists risks in
- Risk limitation: Limit the risk by implementing controls that order of cost and criticality, thereby determining where
minimize the resulting loss. countermeasures should be applied first. [FP031, R2196]
- Risk assumption: Accept the potential for loss and continue
operating the system.
Usually, it is financially and technically infeasible to avoid or In some contexts, it is infeasible or inadvisable to attempt a
transfer all risks (see: (first corollary of second law under) complete or quantitative risk analysis because needed data, time,
Courtney's laws), and so some residual risk will remain, even and expertise are not available. Instead, basic answers to
after all available countermeasures have been deployed (see: questions about threats and risks may be already built into
institutional security policies. For example, U.S. DoD policies
for data confidentiality "do not explicitly itemize the range of
expected threats" but instead "reflect an operational approach ...
by stating the particular management controls that must be used to
achieve [confidentiality] ... Thus, they avoid listing threats,
which would represent a severe risk in itself, and avoid the risk
of poor security design implicit in taking a fresh approach to
each new problem". [NRC91]
(second corollary of second law under) Courtney's laws). Thus, a $ risk assumption
risk analysis typically lists risks in order of cost and (I) See: secondary definition under "risk".
criticality, thereby determining where countermeasures should be
applied first. [FP031, R2196]
In some contexts, it is infeasible to do a risk analysis because $ risk avoidance
needed data and resources are not available, or it is inadvisable. (I) See: secondary definition under "risk".
Instead, answers to questions about threats and risks may be
already built into basic institutional security policies. For $ risk limitation
example, U.S. DoD policies for data confidentiality "do not (I) See: secondary definition under "risk".
explicitly itemize the range of expected threats" but instead
"reflect an operational approach ... by stating the particular
management controls that must be used to achieve [confidentiality]
severe risk in itself, and avoid the risk of poor security design
implicit in taking a fresh approach to each new problem". [NRC91]
$ risk management $ risk management
1. (I) The process of identifying, measuring, and controlling 1. (I) The process of identifying, measuring, and controlling
(i.e., mitigating) risks in information systems so as to reduce (i.e., mitigating) risks in information systems so as to reduce
the risks to a level commensurate with the value of the assets the risks to a level commensurate with the value of the assets
protected. (See: risk analysis.) protected. (See: risk analysis.)
2. (I) The process of controlling uncertain events that may affect 2. (I) The process of controlling uncertain events that may affect
information system resources. information system resources.
3. (O) "The total process of identifying, controlling, and 3. (O) "The total process of identifying, controlling, and
mitigating information system-Drelated risks. It includes risk mitigating information system- Drelated risks. It includes risk
assessment; cost-benefit analysis; and the selection, assessment; cost-benefit analysis; and the selection,
implementation, test, and security evaluation of safeguards. This implementation, test, and security evaluation of safeguards. This
overall system security review considers both effectiveness and overall system security review considers both effectiveness and
efficiency, including impact on the mission and constraints due to efficiency, including impact on the mission and constraints due to
policy, regulations, and laws." [SP30] policy, regulations, and laws." [SP30]
$ risk transference
(I) See: secondary definition under "risk".
$ Rivest Cipher #2 (RC2) $ Rivest Cipher #2 (RC2)
(N) A proprietary, variable-key-length block cipher invented by (N) A proprietary, variable-key-length block cipher invented by
Ron Rivest for RSA Data Security, Inc. Ron Rivest for RSA Data Security, Inc.
$ Rivest Cipher #4 (RC4) $ Rivest Cipher #4 (RC4)
(N) A proprietary, variable-key-length stream cipher invented by (N) A proprietary, variable-key-length stream cipher invented by
Ron Rivest for RSA Data Security, Inc. Ron Rivest for RSA Data Security, Inc.
$ Rivest Cipher #6 (RC6) $ Rivest Cipher #6 (RC6)
(N) A block cipher with 128-bit or higher key size; invented by (N) A symmetric, block cipher with 128-bit or longer key length,
Ron Rivest for RSA Data Security, Inc. A finalist in the developed by Ron Rivest for RSA Data Security, Inc. as a candidate
competition for AES. for the AES.
$ Rivest-Shamir-Adleman (RSA) $ Rivest-Shamir-Adleman (RSA)
(N) An algorithm for asymmetric cryptography, invented in 1977 by (N) An algorithm for asymmetric cryptography, invented in 1977 by
Ron Rivest, Adi Shamir, and Leonard Adleman [RSA78]. Ron Rivest, Adi Shamir, and Leonard Adleman [RSA78].
Tutorial: RSA uses exponentiation modulo the product of two large Tutorial: RSA uses exponentiation modulo the product of two large
prime numbers. The difficulty of breaking RSA is believed to be prime numbers. The difficulty of breaking RSA is believed to be
equivalent to the difficulty of factoring integers that are the equivalent to the difficulty of factoring integers that are the
product of two large prime numbers of approximately equal size. product of two large prime numbers of approximately equal size.
skipping to change at page 205, line 48 skipping to change at page 220, line 27
private key to get s. She sends m and s. Bob receives m' and s', private key to get s. She sends m and s. Bob receives m' and s',
either of which might have been changed from the m and s that either of which might have been changed from the m and s that
Alice sent. To test this, he decrypts s' with Alice's public key Alice sent. To test this, he decrypts s' with Alice's public key
to get v'. He then computes h(m') = v". If v' equals v", Bob is to get v'. He then computes h(m') = v". If v' equals v", Bob is
assured that m' is the same m that Alice sent. assured that m' is the same m that Alice sent.
$ robustness $ robustness
(N) See: level of robustness. (N) See: level of robustness.
$ role $ role
1. (I) A job function (or a job title that implies a set of 1. (I) A job function (or a job title that implies a function) to
functions) to which people or other system entities are assigned, which people or other system entities may be assigned in a system.
within an organization or other system. (Compare: duty, billet, (See: role-based access control. Compare: duty, billet, principal,
principal, user. See: role-based access control.) user.)
2. (O) /Common Criteria/ A pre-defined set of rules establishing 2. (O) /Common Criteria/ A pre-defined set of rules establishing
the allowed interactions between a user and the TOE. the allowed interactions between a user and the TOE.
$ role-based access control $ role-based access control
(I) A form of identity-based access control wherein the system (I) A form of identity-based access control wherein the system
entities that are identified and controlled are functional entities that are identified and controlled are functional
positions in an organization or process. [Sand] (See: positions in an organization or process. [Sand] (See:
authorization, constraint, identity, principal, role.) authorization, constraint, identity, principal, role.)
Tutorial: Administrators assign permissions to roles as needed to Tutorial: Administrators assign permissions to roles as needed to
perform functions in the system. Administrators separately assign perform functions in the system. Administrators separately assign
user identities to roles. When a user accesses the system in an user identities to roles. When a user accesses the system in an
identity (for which the user has been registered) and initiates a identity (for which the user has been registered) and initiates a
session using a role (to which the user has been assigned), then session using a role (to which the user has been assigned), then
the permissions that have been assigned to the role are available the permissions that have been assigned to the role are available
to be exercised by the user. to be exercised by the user.
The following diagram shows that role-based access control The following diagram shows that role-based access control
involves five types relationships. Administrators assign (a) involves five different relationships: (1) administrators assign
identities to roles, (b) permissions to roles, and (c) roles to identities to roles, (2) administrators assign permissions to
roles; and users select (d) identities in sessions, and (e) roles roles, (3) administrators assign roles to roles, (4) users select
in sessions. Security policies may define constraints on these identities in sessions, and (5) users select roles in sessions.
assignments and selections. Security policies may define constraints on these assignments and
selections.
(c) Permission Inheritance Assignments (i.e., Role Hierarchy) (3) Permission Inheritance Assignments (i.e., Role Hierarchy)
[Constraints] [Constraints]
+=====+ +=====+
| | | |
(a) Identity v v (b) Permission (1) Identity v v (2) Permission
+----------+ Assignments +-------+ Assignments +----------+ +----------+ Assignments +-------+ Assignments +----------+
|Identities|<=============>| Roles |<=============>|Permissions| |Identities|<=============>| Roles |<=============>|Permissions|
+----------+ [Constraints] +-------+ [Constraints] +----------+ +----------+ [Constraints] +-------+ [Constraints] +----------+
| | ^ ^ | | ^ ^
| | +-----------+ | | +---------------------+ | | +-----------+ | | +---------------------+
| | | +-------+ | | | | Legend | | | | +-------+ | | | | Legend |
| +====>|Session|=====+ | | | | +====>|Session|=====+ | | |
| | +-------+ | | | One-to-One | | | +-------+ | | | One-to-One |
| | ... | | | =================== | | | ... | | | =================== |
| | +-------+ | | | | | | +-------+ | | | |
+========>|Session|=========+ | One-to-Many | +========>|Session|=========+ | One-to-Many |
(d) Identity | +-------+ | (e) Role | ==================> | (4) Identity | +-------+ | (5) Role | ==================> |
Selections | | Selections | | Selections | | Selections | |
[Constraints]| Access |[Constraints] | Many-to-Many | [Constraints]| Access |[Constraints] | Many-to-Many |
| Sessions | | <=================> | | Sessions | | <=================> |
+-----------+ +---------------------+ +-----------+ +---------------------+
$ role certificate $ role certificate
(I) An organizational certificate that is issued to a system (I) An organizational certificate that is issued to a system
entity that is a member of the set of users that have identities entity that is a member of the set of users that have identities
that are assigned to a particular role. (See: role-based access that are assigned to the same role. (See: role-based access
control.) control.)
$ root $ root, root CA
1. (I) A CA that is directly trusted by an end entity. 1. (I) /PKI/ A CA that is directly trusted by an end entity. (See:
trust anchor, trusted CA.)
2. (I) /hierarchical PKI/ The CA that is the highest level (most 2. (I) /hierarchical PKI/ The CA that is the highest level (most
trusted) CA in a certification hierarchy; i.e., the authority upon trusted) CA in a certification hierarchy; i.e., the authority upon
whose public key all certificate users base their validation of whose public key all certificate users base their validation of
certificates, CRLs, certification paths, and other constructs. certificates, CRLs, certification paths, and other constructs.
(See: top CA.) (See: top CA.)
Tutorial: The root CA in a certification hierarchy issues public- Tutorial: The root CA in a certification hierarchy issues public-
key certificates to one or more additional CAs that form the key certificates to one or more additional CAs that form the
second highest level. Each of these CAs may issue certificates to second highest level. Each of these CAs may issue certificates to
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securely distributed to all certificate users in a way that does securely distributed to all certificate users in a way that does
not depend on the PKI's certification relationships, i.e., by an not depend on the PKI's certification relationships, i.e., by an
out-of-band procedure. The root's public key may be distributed out-of-band procedure. The root's public key may be distributed
simply as a numerical value, but typically is distributed in a simply as a numerical value, but typically is distributed in a
self-signed certificate in which the root is the subject. The self-signed certificate in which the root is the subject. The
root's certificate is signed by the root itself because there is root's certificate is signed by the root itself because there is
no higher authority in a certification hierarchy. The root's no higher authority in a certification hierarchy. The root's
certificate is then the first certificate in every certification certificate is then the first certificate in every certification
path. path.
3. (O) /MISSI/ A name previously used for a MISSI policy creation 3. (I) /DNS/ The base of the tree structure that defines the name
space for the Internet DNS. (See: domain name.)
4. (O) /MISSI/ A name previously used for a MISSI policy creation
authority, which is not a root as defined above for general usage, authority, which is not a root as defined above for general usage,
but is a CA at the second level of the MISSI hierarchy, but is a CA at the second level of the MISSI hierarchy,
immediately subordinate to a MISSI policy approving authority. immediately subordinate to a MISSI policy approving authority.
4. (O) /UNIX/ A user account (also called "superuser") that has 5. (O) /UNIX/ A user account (also called "superuser") that has
all privileges (including all security-related privileges) and all privileges (including all security-related privileges) and
thus can manage the system and its other user accounts. thus can manage the system and its other user accounts.
5. (O) /DNS/ The base of the tree structure that defines the name
space for the Internet DNS. (See: domain name.)
$ root certificate $ root certificate
1. (I) A certificate for which the subject is a root. 1. (I) /PKI/ A certificate for which the subject is a root. (See:
trust anchor certificate, trusted certificate.)
2. (I) /hierarchical PKI/ The self-signed public-key certificate 2. (I) /hierarchical PKI/ The self-signed public-key certificate
at the top of a certification hierarchy. at the top of a certification hierarchy.
$ root key $ root key
(I) A public key for which the matching private key is held by a (I) /PKI/ A public key for which the matching private key is held
root. by a root. (See: trust anchor key, trusted key.)
$ root registry $ root registry
(O) /MISSI/ A name previously used for a MISSI PAA. (O) /MISSI/ A name previously used for a MISSI PAA.
$ ROT13 $ ROT13
(I) See: Caeser cipher. (I) See: secondary definition under "Caesar cipher".
$ router $ router
1. (I) /IP/ A networked computer that forwards IP packets that are 1a. (I) /IP/ A networked computer that forwards IP packets that
not addressed to the computer itself. (Compare: host.) are not addressed to the computer itself. (Compare: host.)
2. (I) /OSIRM/ A computer that is a gateway between two networks
at OSIRM layer 3 and that relays and directs data packets through 1b. (I) /IPS/ A gateway that operates in the IPS Internet Layer to
that internetwork. The most common form of router operates on IP connect two or more subnetworks.
packets. (Compare: bridge, proxy.)
1c. (N) /OSIRM/ A computer that is a gateway between two networks
at OSIRM Layer 3 and that relays and directs data packets through
that internetwork. (Compare: bridge, proxy.)
$ RSA $ RSA
(N) See: Rivest-Shamir-Adleman. (N) See: Rivest-Shamir-Adleman.
$ rule $ rule
See: security rule. See: policy rule.
$ rule-based security policy $ rule-based security policy
(I) "A security policy based on global rules imposed for all (I) "A security policy based on global rules [i.e., policy rules]
users. These rules usually rely on comparison of the sensitivity imposed for all users. These rules usually rely on comparison of
of the resource being accessed and the possession of corresponding the sensitivity of the resource being accessed and the possession
attributes of users, a group of users, or entities acting on of corresponding attributes of users, a group of users, or
behalf of users." [I7498 Part 2] (Compare: identity-based security entities acting on behalf of users." [I7498 Part 2] (Compare:
policy, RBAC.) identity-based security policy, policy rule, RBAC.)
$ rules of behavior $ rules of behavior
(I) A body of security policy that has been established and (I) A body of security policy that has been established and
implemented concerning the responsibilities and expected behavior implemented concerning the responsibilities and expected behavior
of entities that have access to a system. (Compare: [R1281].) of entities that have access to a system. (Compare: [R1281].)
Tutorial: For persons employed by a corporation or government, the Tutorial: For persons employed by a corporation or government, the
rules might cover such matters as working at home, remote access, rules might cover such matters as working at home, remote access,
use of the Internet, use of copyrighted works, use of system use of the Internet, use of copyrighted works, use of system
resources for unofficial purpose, assignment and limitation of resources for unofficial purpose, assignment and limitation of
skipping to change at page 209, line 46 skipping to change at page 224, line 30
$ SAML $ SAML
(N) See: Security Assertion Markup Language (SAML). (N) See: Security Assertion Markup Language (SAML).
$ sandbox $ sandbox
(I) A restricted, controlled execution environment that prevents (I) A restricted, controlled execution environment that prevents
potentially malicious software, such as mobile code, from potentially malicious software, such as mobile code, from
accessing any system resources except those for which the software accessing any system resources except those for which the software
is authorized. is authorized.
$ sanitize $ sanitize
(I) Delete sensitive data from a file, a device, or a system; or 1. (I) Delete sensitive data from a file, device, or system.
modify data so as to be able to downgrade its classification
level. 2. (I) Modify data so as to be able either (a) to completely
declassify it or (b) to downgrade it to a lower security level.
$ SAP $ SAP
(O) See: special access program. (O) See: special access program.
$ SASL $ SASL
(I) See: Simple Authentication and Security Layer. (I) See: Simple Authentication and Security Layer.
$ SCA $ SCA
(I) See: subordinate certification authority. (I) See: subordinate certification authority.
$ scavenging $ scavenging
(I) See: (secondary definition under) threat consequence. (I) See: secondary definition under "threat consequence".
$ SCI $ SCI
(O) See: sensitive compartmented information. (O) See: sensitive compartmented information.
$ SCIF $ SCIF
(O) See: sensitive compartmented information facility. (O) See: sensitive compartmented information facility.
$ SCOMP $ SCOMP
(N) Secure COMmunications Processor; an enhanced, MLS version of (N) Secure COMmunications Processor; an enhanced, MLS version of
the Honeywell Level 6 minicomputer. It was the first system to be the Honeywell Level 6 minicomputer. It was the first system to be
rated in TCSEC Class A1. (See: KSOS.) rated in TCSEC Class A1. (See: KSOS.)
$ screen room $ screen room
(I) /slang/ Synonym for "shielded enclosure". (D) /slang/ Synonym for "shielded enclosure" in the context of
electromagnetic emanations. (See: EMSEC, TEMPEST.)
Deprecated Term: To avoid international misunderstanding, ISDs
SHOULD NOT use this term.
$ screening router $ screening router
(I) Synonym for "filtering router". (I) Synonym for "filtering router".
$ script kiddy $ script kiddy
(D) /slang/ A cracker who is able to use existing attack (D) /slang/ A cracker who is able to use existing attack
techniques (i.e., to read scripts) and execute existing attack techniques (i.e., to read scripts) and execute existing attack
software, but is unable to invent new exploits or manufacture the software, but is unable to invent new exploits or manufacture the
tools to perform them; pejoratively, an immature or novice tools to perform them; pejoratively, an immature or novice
cracker. (See: packet monkey.) cracker.
Deprecated Term: It is likely that other cultures have different Deprecated Term: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ SDE $ SDE
(N) See: Secure Data Exchange. (N) See: Secure Data Exchange.
$ SDNS $ SDNS
(O) See: Secure Data Network System. (O) See: Secure Data Network System.
$ SDU
(N) See: "service data unit" under "protocol data unit".
$ seal $ seal
1. (I) To use asymmetric cryptography to encrypt plain text with a 1. (I) To use asymmetric cryptography to encrypt plain text with a
public key in such a way that only the holder of the matching public key in such a way that only the holder of the matching
private key can learn what was the plain text. [Chau] private key can learn what was the plain text. [Chau]
Usage: The definition is not widely known; therefore, ISDs that Usage: ISDs that use this term SHOULD state a definition for it
use this term SHOULD state a definition for it. because this definition is not widely known.
Tutorial: The definition does *not* say "only the holder of the Tutorial: The definition does *not* say "only the holder of the
matching private key can decrypt the ciphertext to learn what was matching private key can decrypt the ciphertext to learn what was
the plaintext"; sealing is stronger than that. If Alice simply the plaintext"; sealing is stronger than that. If Alice simply
encrypts a plaintext P with a public key K to produce ciphertext C encrypts a plaintext P with a public key K to produce ciphertext C
= K(P), then if Bob guesses that P = X, Bob could verify the guess = K(P), then if Bob guesses that P = X, Bob could verify the guess
by checking whether K(P) = K(X). To "seal" P and block Bob's by checking whether K(P) = K(X). To "seal" P and block Bob's
guessing attack, Alice could attach a long string R of random bits guessing attack, Alice could attach a long string R of random bits
to P before encrypting to produce C = K(P,R); if Bob guesses that to P before encrypting to produce C = K(P,R); if Bob guesses that
P = X, Bob can only test the guess by also guessing R. P = X, Bob can only test the guess by also guessing R.
2. (D) To use cryptography to provide data integrity service for a 2. (D) To use cryptography to provide data integrity service for a
data object. (See: sign.) data object. (See: sign.)
Deprecated Definition: ISDs SHOULD NOT use this term with this Deprecated Definition: ISDs SHOULD NOT use this term with this
definition. Instead, use a term that is more specific with regard definition. Instead, use a term that is more specific with regard
to the mechanism(s) used to provide the data integrity service; to the mechanism used to provide the data integrity service; e.g.,
e.g., use "sign" when the mechanism is digital signature. use "sign" when the mechanism is digital signature.
$ secret $ secret
1a. (I) /adjective/ The condition of information being protected 1a. (I) /adjective/ The condition of information being protected
from being known by any system entities except those that are from being known by any system entities except those that are
intended to know it. intended to know it.
1b. (I) /noun/ An item of information that is protected thusly. 1b. (I) /noun/ An item of information that is protected thusly.
Usage: This term applies to symmetric keys, private keys, and Usage: This term applies to symmetric keys, private keys, and
passwords. passwords.
$ secret key
(D) A key that is kept secret or needs to be kept secret.
Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts
in a potentially misleading way. In the context of asymmetric
cryptography, ISDs SHOULD use "private key". In the context of
symmetric cryptography, the adjective "secret" is unnecessary
because all keys must be kept secret.
$ secret-key cryptography $ secret-key cryptography
(D) Synonym for "symmetric cryptography". (D) Synonym for "symmetric cryptography".
Deprecated Term: ISDs SHOULD NOT use this term; it could be Deprecated Term: ISDs SHOULD NOT use this term; it could be
confused with asymmetric cryptography, in which the private key is confused with asymmetric cryptography, in which the private key is
secret. kept secret.
Derivation: Symmetric cryptography is sometimes called "secret-key Derivation: Symmetric cryptography is sometimes called "secret-key
cryptography" because entities that share the key, such as the cryptography" because entities that share the key, such as the
originator and the recipient of a message, need to keep the key originator and the recipient of a message, need to keep the key
secret from other entities. secret from other entities.
$ Secure BGP (S-BGP) $ Secure BGP (S-BGP)
(I) A project of BBN Technologies, sponsored by the U.S. DoD's (I) A project of BBN Technologies, sponsored by the U.S. DoD's
Defense Advanced Research Projects Agency, to design and Defense Advanced Research Projects Agency, to design and
demonstrate an architecture to secure the Border Gateway Protocol demonstrate an architecture to secure the Border Gateway Protocol
(RFC 1771) and to promote deployment of that architecture in the (RFC 1771) and to promote deployment of that architecture in the
Internet. Internet.
Tutorial: S-BGP incorporates three security mechanisms: Tutorial: S-BGP incorporates three security mechanisms:
- A PKI supports authentication of ownership of IP address - A PKI supports authentication of ownership of IP address
blocks, autonomous system (AS) numbers, an AS's identity, and a blocks, autonomous system (AS) numbers, an AS's identity, and a
BGP router's identity and its authorization to represent an AS. BGP router's identity and its authorization to represent an AS.
This PKI parallels and takes advantage of the Internet's This PKI parallels and takes advantage of the Internet's
existing IP address and AS number assignment system. existing IP address and AS number assignment system.
- A new, optional, BGP transitive path attribute carries digital
- A new, optional, BGP transitive path attribute carries digital
signatures (in "attestations") covering the routing information signatures (in "attestations") covering the routing information
in a BGP UPDATE. These signatures along with certificates from in a BGP UPDATE. These signatures along with certificates from
the S-BGP PKI enable the receiver of a BGP routing UPDATE to the S-BGP PKI enable the receiver of a BGP routing UPDATE to
verify the address prefixes and path information that it validate the attribute and gain trust in the address prefixes
contains. and path information that it contains.
- IPsec provides data and partial sequence integrity, and enables - IPsec provides data and partial sequence integrity, and enables
BGP routers to authenticate each other for exchanges of BGP BGP routers to authenticate each other for exchanges of BGP
control traffic. control traffic.
$ Secure Data Exchange (SDE) $ Secure Data Exchange (SDE)
(N) A LAN security protocol defined by the IEEE 802.10 standard. (N) A LAN security protocol defined by the IEEE 802.10 standard.
$ Secure Data Network System (SDNS) $ Secure Data Network System (SDNS)
(O) An NSA program that developed security protocols for (O) An NSA program that developed security protocols for
electronic mail (see: MSP), OSIRM layer 3 (see: SP3), OSIRM layer electronic mail (see: MSP), OSIRM Layer 3 (see: SP3), OSIRM Layer
4 (see: SP4), and key management (see: KMP). 4 (see: SP4), and key establishment (see: KMP).
$ Secure Hash Algorithm (SHA) $ Secure Hash Algorithm (SHA)
(N) A cryptographic hash function (specified in SHS) that produces (N) A cryptographic hash function (specified in SHS) that produces
a 160-bit output (hash result) for input data of any length < a 160-bit output (hash result) for input data of any length <
2**64 bits. 2**64 bits.
$ Secure Hash Standard (SHS) $ Secure Hash Standard (SHS)
(N) The U.S. Government standard [FP180] that specifies SHA. (N) The U.S. Government standard [FP180] that specifies SHA.
$ Secure Hypertext Transfer Protocol (S-HTTP) $ Secure Hypertext Transfer Protocol (S-HTTP)
(I) A Internet protocol (RFC 2660) for providing client-server (I) A Internet protocol [R2660] for providing client-server
security services for HTTP communications. (Compare: https.) security services for HTTP communications. (Compare: https.)
Tutorial: S-HTTP was originally specified by CommerceNet, a Tutorial: S-HTTP was originally specified by CommerceNet, a
coalition of businesses interested in developing the Internet for coalition of businesses interested in developing the Internet for
commercial uses. Several message formats may be incorporated into commercial uses. Several message formats may be incorporated into
S-HTTP clients and servers, particularly CMS and MOSS. S-HTTP S-HTTP clients and servers, particularly CMS and MOSS. S-HTTP
supports choice of security policies, key management mechanisms, supports choice of security policies, key management mechanisms,
and cryptographic algorithms through option negotiation between and cryptographic algorithms through option negotiation between
parties for each transaction. S-HTTP supports modes of operation parties for each transaction. S-HTTP supports modes of operation
for both asymmetric and symmetric cryptography. S-HTTP attempts to for both asymmetric and symmetric cryptography. S-HTTP attempts to
avoid presuming a particular trust model, but it attempts to avoid presuming a particular trust model, but it attempts to
facilitate multiply-rooted hierarchical trust and anticipates that facilitate multiply rooted, hierarchical trust and anticipates
principals may have many public-key certificates. that principals may have many public-key certificates.
$ Secure/MIME (S/MIME) $ Secure/MIME (S/MIME)
(I) Secure/Multipurpose Internet Mail Extensions, an Internet (I) Secure/Multipurpose Internet Mail Extensions, an Internet
protocol (RFC 3851) to provide encryption and digital signatures protocol [R3851] to provide encryption and digital signatures for
for Internet mail messages. Internet mail messages.
$ secure multicast $ secure multicast
(I) Refers generally to providing security services for multicast (I) Refers generally to providing security services for multicast
groups of various types (e.g., 1-to-N and M-to-N) and to classes groups of various types (e.g., 1-to-N and M-to-N) and to classes
of protocols used to protect multicast packets. of protocols used to protect multicast packets.
Tutorial: Multicast applications include video broadcast and Tutorial: Multicast applications include video broadcast and
multicast file transfer, and many of these applications require multicast file transfer, and many of these applications require
network security services. The Multicast Security Reference network security services. The Multicast Security Reference
Framework [R3740] covers three functional areas: Framework [R3740] covers three functional areas:
- Multicast data handling: Security-related treatment of - Multicast data handling: Security-related treatment of
multicast data by the sender and the receiver. multicast data by the sender and the receiver.
- Group key management: Secure distribution and refreshment of - Group key management: Secure distribution and refreshment of
keying material. (See: Group Domain of Interpretation.) keying material. (See: Group Domain of Interpretation.)
- Multicast security policy: Policy translation and - Multicast security policy: Policy translation and
interpretation across the multiple administrative domains that interpretation across the multiple administrative domains that
typically are spanned by a multicast application. typically are spanned by a multicast application.
$ Secure Shell(trademark) (SSH(trademark)) $ Secure Shell(trademark) (SSH(trademark))
(N) Trademarks of SSH Communications Security Corp. that refer to (N) Trademarks of SSH Communications Security Corp. that refer to
a protocol for secure remote login and other secure network a protocol for secure remote login and other secure network
services. services.
Tutorial: SSH has three main parts: Tutorial: SSH has three main parts:
- Transport layer protocol: Provides server authentication, - Transport layer protocol: Provides server authentication,
confidentiality, and integrity; and can optionally provide confidentiality, and integrity; and can optionally provide
compression. This layer typically runs over a TCP/IP compression. This layer typically runs over a TCP connection,
connection, but might also run on top of any other reliable but might also run on top of any other reliable data stream.
data stream. - User authentication protocol: Authenticates the client-side
- User authentication protocol: Authenticates the client-side
user to the server. It runs over the transport layer protocol. user to the server. It runs over the transport layer protocol.
- Connection protocol: Multiplexes the encrypted tunnel into - Connection protocol: Multiplexes the encrypted tunnel into
several logical channels. It runs over the user authentication several logical channels. It runs over the user authentication
protocol. protocol.
$ Secure Sockets Layer (SSL) $ Secure Sockets Layer (SSL)
(N) An Internet protocol (originally developed by Netscape (N) An Internet protocol (originally developed by Netscape
Communications, Inc.) that uses connection-oriented end-to-end Communications, Inc.) that uses connection-oriented end-to-end
encryption to provide data confidentiality service and data encryption to provide data confidentiality service and data
integrity service for traffic between a client (often a web integrity service for traffic between a client (often a web
browser) and a server, and that can optionally provide peer entity browser) and a server, and that can optionally provide peer entity
authentication between the client and the server. (See: Transport authentication between the client and the server. (See: Transport
Layer Security.) Layer Security.)
Tutorial: The name misleadingly suggests that SSL is situated in Tutorial: SSL has two layers; SSL's lower layer, the SSL Record
the IPS transport layer, but SSL is layered above a reliable Protocol, is layered on top of an IPS Transport-Layer protocol and
transport protocol (usually TCP) and below an application protocol encapsulates protocols that run in the upper layer. The upper
(often HTTP). SSL is independent of the application it layer protocols are the three SSL management protocols -- SSL
encapsulates, and any higher level protocol can layer on top of Handshake Protocol, SSL Change Cipher Spec Protocol, or SSL Alert
SSL transparently. However, many Internet applications might be Protocol -- and some Application-Layer protocol (e.g., HTTP).
better served by IPsec.
SSL has two layers: (a) SSL's lower layer, the SSL Record The SSL management protocols provide asymmetric cryptography for
Protocol, is layered on top of the transport protocol and server authentication (verifying the server's identity to the
encapsulates higher level protocols. One such encapsulated client) and optional client authentication (verifying the client's
protocol is SSL Handshake Protocol. (b) SSL's upper layer provides identity to the server), and also enable them, before the
asymmetric cryptography for server authentication (verifying the application protocol transmits or receives data, to negotiate a
server's identity to the client) and optional client symmetric encryption algorithm and secret session key (to use for
authentication (verifying the client's identity to the server), data confidentiality service) and a keyed hash (to use for data
and also enables them, before the application protocol transmits integrity service).
or receives data, to negotiate a symmetric encryption algorithm
and secret session key (to use for data confidentiality service) SSL is independent of the application it encapsulates, and any
and a keyed hash (to use for data integrity service). application can layer on top of SSL transparently. However, many
Internet applications might be better served by IPsec.
$ secure state $ secure state
1a. (I) A system condition in which the system is in conformance 1a. (I) A system condition in which the system is in conformance
with the applicable security policy. (Compare: clean system, with the applicable security policy. (Compare: clean system,
transaction.) transaction.)
1b. (I) /formal model/ A system condition in which no subject can 1b. (I) /formal model/ A system condition in which no subject can
access any object in an unauthorized manner. (See: (secondary access any object in an unauthorized manner. (See: secondary
definition under) Bell-LaPadula model.) definition under "Bell-LaPadula model".)
$ security $ security
1a. (I) A system condition that results from the establishment and 1a. (I) A system condition that results from the establishment and
maintenance of measures to protect the system. maintenance of measures to protect the system.
1b. (I) A system condition in which system resources are free from 1b. (I) A system condition in which system resources are free from
unauthorized access and from unauthorized or accidental change, unauthorized access and from unauthorized or accidental change,
destruction, or loss. (Compare: safety.) destruction, or loss. (Compare: safety.)
2. (I) Measures taken to protect a system. 2. (I) Measures taken to protect a system.
Tutorial: Providing a condition of system security may involve the Tutorial: Parker suggests that providing a condition of system
following six basic functions [Park]: security may involve the following six basic functions [Park];
- "Avoidance": Reducing a risk by either reducing the value of however, these functions overlap to some extent:
the potential loss or reducing the probability that the loss - "Deterrence": Reducing an intelligent threat by discouraging
will occur. (See: risk, risk analysis.)
- "Deterrence": Reducing an intelligent threat by discouraging
action, such as by fear or doubt. (See: attack, threat action.) action, such as by fear or doubt. (See: attack, threat action.)
- "Prevention": Impeding a security violation by using a - "Avoidance": Reducing a risk by either reducing the value of
the potential loss or reducing the probability that the loss
will occur. (See: risk analysis. Compare: "risk avoidance"
under "risk".)
- "Prevention": Impeding a security violation by using a
countermeasure. countermeasure.
- "Detection": Determining that a security violation is - "Detection": Determining that a security violation is
impending, is in progress, or has recently occurred, and thus impending, is in progress, or has recently occurred, and thus
make it possible to reduce the potential loss. (See: intrusion make it possible to reduce the potential loss. (See: intrusion
detection.) detection.)
- "Recovery": Restoring a normal state of system operation by - "Recovery": Restoring a normal state of system operation by
compensating for a security violation, possibly by eliminating compensating for a security violation, possibly by eliminating
or repairing its effects. (See: contingency plan.) or repairing its effects. (See: contingency plan, main entry
- "Correction": Changing a security architecture to eliminate or for "recovery".)
- "Correction": Changing a security architecture to eliminate or
reduce the risk of reoccurrence of a security violation or reduce the risk of reoccurrence of a security violation or
threat consequence. threat consequence, such as by eliminating a vulnerability.
$ security architecture $ security architecture
(I) A plan and set of principles that describe (a) the security (I) A plan and set of principles that describe (a) the security
services that a system is required to provide to meet the needs of services that a system is required to provide to meet the needs of
its users, (b) the system components required to implement the its users, (b) the system components required to implement the
services, and (c) the performance levels required in the services, and (c) the performance levels required in the
components to deal with the threat environment. (See: defense in components to deal with the threat environment (e.g., [R2179]).
depth, IATF, (Tutorial under) security policy. Compare: system (See: defense in depth, IATF, security controls, Tutorial under
architecture.) "security policy". Compare: OSIRM System Architecture.)
Tutorial: A security architecture is the result of applying the Tutorial: A security architecture is the result of applying the
system engineering process. A complete system security system engineering process. A complete system security
architecture includes administrative security, communication architecture includes administrative security, communication
security, computer security, emanations security, personnel security, computer security, emanations security, personnel
security, and physical security (e.g., see: [R2179]). A complete security, and physical security. A complete security architecture
security architecture needs to deal with both intentional, needs to deal with both intentional, intelligent threats and
intelligent threats and accidental threats. accidental threats.
$ Security Assertion Markup Language (SAML) $ Security Assertion Markup Language (SAML)
(N) A protocol consisting of XML-based request and response (N) A protocol consisting of XML-based request and response
message formats for exchanging security information, expressed in message formats for exchanging security information, expressed in
the form of assertions about subjects, between online business the form of assertions about subjects, between online business
partners. [SAML] partners. [SAML]
$ security association $ security association
1. (I) A relationship established between two or more entities to 1. (I) A relationship established between two or more entities to
enable them to protect data they exchange. (See: association, enable them to protect data they exchange. (See: association,
ISAKMP, SAD. Compare: session.) ISAKMP, SAD. Compare: session.)
Tutorial: The relationship is represented by a set of data that is Tutorial: The relationship is represented by a set of data that is
shared between the entities and is agreed upon and considered a shared between the entities and is agreed upon and considered a
contract between them. The data describes how the associated contract between them. The data describes how the associated
entities jointly use security services. The relationship is used entities jointly use security services. The relationship is used
to negotiate characteristics of security mechanisms, but the to negotiate characteristics of security mechanisms, but the
relationship is usually understood to exclude the mechanisms relationship is usually understood to exclude the mechanisms
themselves. themselves.
2. (O) "A set of policy and cryptographic keys that provide 2. (I) /IPsec/ A simplex (uni-directional) logical connection
security services to network traffic that matches that policy".
[R3740] (See: cryptographic association, group security
association.)
3. (O) /IPsec/ A simplex (uni-directional) logical connection
created for security purposes and implemented with either AH or created for security purposes and implemented with either AH or
ESP (but not both). The security services offered by a security ESP (but not both). The security services offered by a security
association depend on the protocol (AH or ESP), the IPsec mode association depend on the protocol (AH or ESP), the IPsec mode
(transport or tunnel), the endpoints, and the election of optional (transport or tunnel), the endpoints, and the election of optional
services within the protocol. A security association is identified services within the protocol. A security association is identified
by a triple consisting of (a) a destination IP address, (b) a by a triple consisting of (a) a destination IP address, (b) a
protocol (AH or ESP) identifier, and (c) a Security Parameter protocol (AH or ESP) identifier, and (c) a Security Parameter
Index. Index.
3. (O) "A set of policy and cryptographic keys that provide
security services to network traffic that matches that policy".
[R3740] (See: cryptographic association, group security
association.)
4. (O) "The totality of communications and security mechanisms and 4. (O) "The totality of communications and security mechanisms and
functions (e.g., communications protocols, security protocols, functions (e.g., communications protocols, security protocols,
security mechanisms and functions) that securely binds together security mechanisms and functions) that securely binds together
two security contexts in different end systems or relay systems two security contexts in different end systems or relay systems
supporting the same information domain." [DGSA] supporting the same information domain." [DGSA]
$ Security Association Database (SAD) $ Security Association Database (SAD)
(I) In an IPsec implementation operating in a network node, a (I) /IPsec/ In an IPsec implementation that operates in a network
database that contains parameters to describe the status and node, a database that contains parameters to describe the status
operation of each of the active security associations that the and operation of each of the active security associations that the
node has established with other nodes. Separate inbound and node has established with other nodes. Separate inbound and
outbound SADs are needed because of the directionality of IPsec outbound SADs are needed because of the directionality of IPsec
security associations. [R2401] (Compare: SPD.) security associations. [R2401] (Compare: SPD.)
$ security association identifier (SAID) $ security association identifier (SAID)
(I) A data field in a security protocol (such as NLSP or SDE), (I) A data field in a security protocol (such as NLSP or SDE),
used to identify the security association to which a protocol data used to identify the security association to which a PDU is bound.
unit is bound. The SAID value is usually used to select a key for The SAID value is usually used to select a key for decryption or
decryption or authentication at the destination. (See: Security authentication at the destination. (See: Security Parameter
Parameter Index.) Index.)
$ security assurance $ security assurance
1. (I) An attribute of an information system that provides grounds 1. (I) An attribute of an information system that provides grounds
for having confidence that the system operates such that the for having confidence that the system operates such that the
system security policy is enforced. (Compare: trust.) system's security policy is enforced. (Compare: trust.)
2. (I) A procedure that ensures a system is developed and operated 2. (I) A procedure that ensures a system is developed and operated
as intended by the system's security policy. as intended by the system's security policy.
3. (D) "The degree of confidence one has that the security 3. (D) "The degree of confidence one has that the security
controls operate correctly and protect the system as intended." controls operate correctly and protect the system as intended."
[SP12] [SP12]
Deprecated Definition: ISDs SHOULD NOT use definition 3; it is a Deprecated Definition: ISDs SHOULD NOT use definition 3; it is a
definition for "assurance level" rather than for "assurance". definition for "assurance level" rather than for "assurance".
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of confidence in the vetting process used to establish the of confidence in the vetting process used to establish the
identity of the individual to whom the [identity] credential was identity of the individual to whom the [identity] credential was
issued" and (b) "the degree of confidence that the individual who issued" and (b) "the degree of confidence that the individual who
uses the credential is the individual to whom the credential was uses the credential is the individual to whom the credential was
issued". [M0404] issued". [M0404]
Deprecated Definition: ISDs SHOULD NOT use definition 4; it mixes Deprecated Definition: ISDs SHOULD NOT use definition 4; it mixes
concepts in a potentially misleading way. Part "a" is a definition concepts in a potentially misleading way. Part "a" is a definition
for "assurance level" (rather than "security assurance") of an for "assurance level" (rather than "security assurance") of an
identity registration process; and part "b" is a definition for identity registration process; and part "b" is a definition for
"assurance level" (rather than "security assurance") of such a "assurance level" (rather than "security assurance") of an
process. Also, the processes of registration and authentication identity authentication process. Also, the processes of
should be defined and designed separately to ensure clarity in registration and authentication should be defined and designed
certification. separately to ensure clarity in certification.
$ security audit $ security audit
(I) An independent review and examination of a system's records (I) An independent review and examination of a system's records
and activities to determine the adequacy of system controls, and activities to determine the adequacy of system controls,
ensure compliance with established security policy and procedures, ensure compliance with established security policy and procedures,
detect breaches in security services, and recommend any changes detect breaches in security services, and recommend any changes
that are indicated for countermeasures. [I7498 Part 2, NCS01] that are indicated for countermeasures. [I7498 Part 2, NCS01]
(Compare: accounting, intrusion detection.) (Compare: accounting, intrusion detection.)
Tutorial: The basic audit objective is to establish accountability Tutorial: The basic audit objective is to establish accountability
for system entities that initiate or participate in security- for system entities that initiate or participate in security-
relevant events and actions. Thus, means are needed to generate relevant events and actions. Thus, means are needed to generate
and record a security audit trail and to review and analyze the and record a security audit trail and to review and analyze the
audit trail to discover and investigate attacks and security audit trail to discover and investigate security violations.
compromises.
$ security audit trail $ security audit trail
(I) A chronological record of system activities that is sufficient (I) A chronological record of system activities that is sufficient
to enable the reconstruction and examination of the sequence of to enable the reconstruction and examination of the sequence of
environments and activities surrounding or leading to an environments and activities surrounding or leading to an
operation, procedure, or event in a security-relevant transaction operation, procedure, or event in a security-relevant transaction
from inception to final results. [NCS04] (See: security audit.) from inception to final results. [NCS04] (See: security audit.)
$ security by obscurity $ security by obscurity
(O) Attempting to maintain or increase security of a system by (O) Attempting to maintain or increase security of a system by
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will be lost or stolen and, therefore, that the algorithms will be will be lost or stolen and, therefore, that the algorithms will be
reverse engineered and become known to the adversary. Thus, one reverse engineered and become known to the adversary. Thus, one
should rely only on algorithms and protocols that are strong should rely only on algorithms and protocols that are strong
enough to have been published widely, and have been peer reviewed enough to have been published widely, and have been peer reviewed
for long enough that their flaws have been found and removed. For for long enough that their flaws have been found and removed. For
example, NIST used a long, public process to select AES to replace example, NIST used a long, public process to select AES to replace
DES. DES.
In computer and network security, the principle of "no security by In computer and network security, the principle of "no security by
obscurity" also applies to security mechanisms other than obscurity" also applies to security mechanisms other than
cryptography. For example, if a protocol for access control, or cryptography. For example, if the design and implementation of a
for identification and authentication, is really good, than protocol for access control are strong, than reading the
reading the protocol's source code should not enable you to find a protocol's source code should not enable you to find a way to
way to evade the protection and penetrate the system. evade the protection and penetrate the system.
$ security class $ security class
(D) Synonym for "security level". (D) Synonym for "security level".
Deprecated Term: ISDs SHOULD NOT use this term. Instead, use Deprecated Term: ISDs SHOULD NOT use this term. Instead, use
"security level", which is more widely established and understood. "security level", which is more widely established and understood.
$ security clearance $ security clearance
(I) A determination that a person is eligible, under the standards (I) A determination that a person is eligible, under the standards
of a specific security policy, for authorization to access of a specific security policy, for authorization to access
sensitive information or other system resources. (See: clearance sensitive information or other system resources. (See: clearance
level.) level.)
$ security compromise $ security compromise
(I) A security violation in which a system resource is exposed, or (I) A security violation in which a system resource is exposed, or
is potentially exposed, to unauthorized access. (Compare: data is potentially exposed, to unauthorized access. (Compare: data
compromise, exposure, violation.) compromise, exposure, violation.)
$ security controls
(N) The management, operational, and technical controls
(safeguards or countermeasures) prescribed for an information
system which, taken together, satisfy the specified security
requirements and adequately protect the confidentiality,
integrity, and availability of the system and its information.
[FP199] (See: security architecture.)
$ security doctrine $ security doctrine
1. (I) A specified set of procedures or practices that direct or 1. (I) A specified set of procedures or practices that direct or
provide guidance for how to comply with security policy. (Compare: provide guidance for how to comply with security policy. (Compare:
security mechanism, security policy.) security mechanism, security policy.)
Tutorial: Security policy and security doctrine are relative Tutorial: Security policy and security doctrine are closely
terms: policy deals mainly with strategy, and doctrine deals with related. However, policy deals mainly with strategy, and doctrine
tactics. deals with tactics.
Security doctrine is often understood to refer mainly to Security doctrine is often understood to refer mainly to
administrative security, personnel security, and physical administrative security, personnel security, and physical
security. For example, security mechanisms and devices that security. For example, security mechanisms and devices that
implement them are normally designed to operate in a limited range implement them are normally designed to operate in a limited range
of environmental and administrative conditions, and these of environmental and administrative conditions, and these
conditions must be met to complement and ensure the technical conditions must be met to complement and ensure the technical
protection afforded by the hardware, firmware, and software in the protection afforded by the hardware, firmware, and software in the
devices. Security doctrine specifies how to achieve those devices. Security doctrine specifies how to achieve those
conditions. (See: (first law under) Courtney's laws.) conditions. (See: "first law" under "Courtney's laws".)
$ security domain $ security domain
(I) See: domain. (I) See: domain.
$ security environment $ security environment
(I) The set of external entities, procedures, and conditions that (I) The set of external entities, procedures, and conditions that
affect secure development, operation, and maintenance of a system. affect secure development, operation, and maintenance of a system.
(See: (first law under) Courtney's laws.) (See: "first law" under "Courtney's laws".)
$ security event $ security event
(I) A occurrence in a system that is relevant to the security of (I) An occurrence in a system that is relevant to the security of
the system. (See: security incident.) the system. (See: security incident.)
Tutorial: The term covers both events that are security incidents Tutorial: The term covers both events that are security incidents
and those that are not. In a CA workstation, for example, a list and those that are not. In a CA workstation, for example, a list
of security events might include the following: of security events might include the following:
- Logging the operator in or out. - Logging an operator into or out of the system.
- Performing a cryptographic operation, e.g., signing a digital - Performing a cryptographic operation, e.g., signing a digital
certificate or CRL. certificate or CRL.
- Performing a cryptographic card operation: creation, insertion, - Performing a cryptographic card operation: creation, insertion,
removal, or backup. removal, or backup.
- Performing a digital certificate lifecycle operation: rekey, - Performing a digital certificate lifecycle operation: rekey,
renewal, revocation, or update. renewal, revocation, or update.
- Posting information to an X.500 Directory.
- Receiving a key compromise notification. - Posting a digital certificate to an X.500 Directory.
- Receiving an improper certification request. - Receiving a key compromise notification.
- Detecting an alarm condition reported by a cryptographic - Receiving an improper certification request.
- Detecting an alarm condition reported by a cryptographic
module. module.
- Failing a built-in hardware self-test or a software system - Failing a built-in hardware self-test or a software system
integrity check. integrity check.
$ security fault analysis $ security fault analysis
(I) A security analysis, usually performed on hardware at a logic (I) A security analysis, usually performed on hardware at the
gate level, gate-by-gate, to determine the security properties of level of gate logic, gate-by-gate, to determine the security
a device when a hardware fault is encountered. properties of a device when a hardware fault is encountered.
$ security gateway $ security gateway
1. (I) An internetwork gateway that separates trusted (or 1. (I) An internetwork gateway that separates trusted (or
relatively more trusted) hosts on one side from untrusted (or less relatively more trusted) hosts on one side from untrusted (or less
trusted) hosts on the other side. (See: firewall and guard.) trusted) hosts on the other side. (See: firewall and guard.)
2. (O) /IPsec/ "An intermediate system that implements IPsec 2. (O) /IPsec/ "An intermediate system that implements IPsec
protocols." [R2401] protocols." [R2401]
Tutorial: IPsec's AH or ESP can be implemented on a gateway Tutorial: IPsec's AH or ESP can be implemented on a gateway
between a protected network and an unprotected network, in order between a protected network and an unprotected network, in order
to provide security services to the protected network's hosts when to provide security services to the protected network's hosts when
they communicate across the unprotected network to other hosts and they communicate across the unprotected network to other hosts and
gateways. gateways.
$ security incident $ security incident
1. (I) A security event that involves a security violation. (See: 1. (I) A security event that involves a security violation. (See:
CERT, GRIP, security event, security intrusion. See: security CERT, GRIP, security event, security intrusion, security
violation.) violation.)
Tutorial: In other words, a security-relevant system event in Tutorial: In other words, a security-relevant system event in
which the system's security policy is disobeyed or otherwise which the system's security policy is disobeyed or otherwise
breached. breached.
2. (O) "Any adverse event [that] compromises some aspect of 2. (D) "Any adverse event [that] compromises some aspect of
computer or network security." [R2350] computer or network security." [R2350]
Deprecated Definition: ISDs SHOULD NOT use this "O" definition, Deprecated Definition: ISDs SHOULD NOT use this definition,
because (a) a security incident may occur without actually being because (a) a security incident may occur without actually being
harmful (i.e., adverse) and (b) this Glossary defines "compromise" harmful (i.e., adverse) and (b) this Glossary defines "compromise"
more narrowly in relation to unauthorized access. more narrowly in relation to unauthorized access.
3. (O) "A violation or imminent threat of violation of computer 3. (D) "A violation or imminent threat of violation of computer
security policies, acceptable use policies, or standard computer security policies, acceptable use policies, or standard computer
security practices." [SP61] security practices." [SP61]
Deprecated Definition: ISDs SHOULD NOT use this "O" definition, Deprecated Definition: ISDs SHOULD NOT use this definition because
because mixes concepts in way that does not agree with common mixes concepts in way that does not agree with common usage; a
usage; a security incident is commonly thought of as involving a security incident is commonly thought of as involving a
realization of a threat (see: threat action), not just a threat. realization of a threat (see: threat action), not just a threat.
$ security intrusion $ security intrusion
(I) A security event, or a combination of multiple security (I) A security event, or a combination of multiple security
events, that constitutes a security incident in which an intruder events, that constitutes a security incident in which an intruder
gains, or attempts to gain, access to a system (or system gains, or attempts to gain, access to a system or system resource
resource) without having authorization to do so. without having authorization to do so.
$ security kernel $ security kernel
(I) "The hardware, firmware, and software elements of a trusted (I) "The hardware, firmware, and software elements of a trusted
computing base that implement the reference monitor concept. It computing base that implement the reference monitor concept. It
must mediate all accesses, be protected from modification, and be must mediate all accesses, be protected from modification, and be
verifiable as correct." [NCS04] (See: kernel, TCB.) verifiable as correct." [NCS04] (See: kernel, TCB.)
Tutorial: A security kernel is an implementation of a reference Tutorial: A security kernel is an implementation of a reference
monitor for a given hardware base. [Huff] monitor for a given hardware base. [Huff]
$ security label $ security label
(I) An item of meta-data that designates the value of one or more (I) An item of meta-data that designates the value of one or more
security-relevant attributes (e.g., security level) of a system security-relevant attributes (e.g., security level) of a system
resource. (Compare: security marking. See: [R1457].) resource. (See: [R1457]. Compare: security marking.)
Deprecated usage: To avoid confusion, ISDs SHOULD NOT use Deprecated usage: To avoid confusion, ISDs SHOULD NOT use
"security label" for "security marking", or vice versa, even "security label" for "security marking", or vice versa, even
though that is commonly done (including in some national and though that is commonly done (including in some national and
international standards that should know better). international standards that should know better).
Tutorial: Humans and automated security mechanisms use a security Tutorial: Humans and automated security mechanisms use a security
label of a system resource to determine, according to applicable label of a system resource to determine, according to applicable
security policy, how to control access to the resource (and they security policy, how to control access to the resource (and they
affix appropriate, matching security markings to physical affix appropriate, matching security markings to physical
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implicit label that is determined at the time the connection is implicit label that is determined at the time the connection is
established. established.
Both classified and unclassified system resources may require a Both classified and unclassified system resources may require a
security label. (See: FOUO.) security label. (See: FOUO.)
$ security level $ security level
(I) The combination of a hierarchical classification level and a (I) The combination of a hierarchical classification level and a
set of non-hierarchical category designations that represents how set of non-hierarchical category designations that represents how
sensitive a specified type or item of information is. (See: sensitive a specified type or item of information is. (See:
(Deprecated Usage note under) classification level, dominate,
lattice model.)
Usage: The term is usually understood to refer to sensitivity to dominate, lattice model. Compare: classification level.)
disclosure, but also is used in many other ways and could easily
be misunderstood; therefore, ISDs that use this term SHOULD state Usage: ISDs that use this term SHOULD state a definition for it.
a definition for it. The term is usually understood to involve sensitivity to
disclosure, but it also is used in many other ways and could
easily be misunderstood.
$ Security Level field $ Security Level field
(I) A 16-bit field (the "S field") that specifies a security level (I) A 16-bit field that specifies a security level value in the
value in the security option (option type 130) of version 4 IP's security option (option type 130) of version 4 IP's datagram
datagram header format. header format.
Deprecated Abbreviation: ISDs SHOULD NOT use the abbreviation "S Deprecated Abbreviation: ISDs SHOULD NOT use the abbreviation "S
field", which is potentially ambiguous. Instead, use "Security field", which is potentially ambiguous.
Level field".
$ security management infrastructure (SMI) $ security management infrastructure (SMI)
(I) System components and activities that support security policy (I) System components and activities that support security policy
by monitoring and controlling security services and mechanisms, by monitoring and controlling security services and mechanisms,
distributing security information, and reporting security events. distributing security information, and reporting security events.
Tutorial: The associated functions are as follows [I7498-4]: Tutorial: The associated functions are as follows [I7498-4]:
- Controlling (granting or restricting) access to system - Controlling (granting or restricting) access to system
resources: This includes verifying authorizations and resources: This includes verifying authorizations and
identities, controlling access to sensitive security data, and identities, controlling access to sensitive security data, and
modifying access priorities and procedures in the event of modifying access priorities and procedures in the event of
attacks. attacks.
- Retrieving (gathering) and archiving (storing) security - Retrieving (gathering) and archiving (storing) security
information: This includes logging security events and information: This includes logging security events and
analyzing the log, monitoring and profiling usage, and analyzing the log, monitoring and profiling usage, and
reporting security violations. reporting security violations.
- Managing and controlling the encryption process: This includes - Managing and controlling the encryption process: This includes
performing the functions of key management and reporting on key performing the functions of key management and reporting on key
management problems. (See: PKI.) management problems. (See: PKI.)
$ security marking $ security marking
(I) A physical marking that is bound to an instance of a system (I) A physical marking that is bound to an instance of a system
resource and that represents a security label of the resource, resource and that represents a security label of the resource,
i.e., that names or designates the value of one or more security- i.e., that names or designates the value of one or more security-
relevant attributes of the resource. (Compare: security label.) relevant attributes of the resource. (Compare: security label.)
Tutorial: A security label may be represented by various Tutorial: A security label may be represented by various
equivalent markings depending on the physical form taken by the equivalent markings depending on the physical form taken by the
labeled resource. For example, a document could have a marking labeled resource. For example, a document could have a marking
composed of a bit pattern [FP188] when the document is stored composed of a bit pattern [FP188] when the document is stored
electronically as a file in a computer, and also a marking of electronically as a file in a computer, and also a marking of
printed alphabetic characters when the document is in paper form. printed alphabetic characters when the document is in paper form.
$ security mechanism $ security mechanism
(I) A process (or a device incorporating such a process) that can (I) A process (or a device incorporating such a process) that can
be used in a system to implement a security service that is be used in a system to implement a security service that is
provided by or within the system. (See: (discussion under) provided by or within the system. (See: Tutorial under "security
security policy. Compare: security doctrine.) policy". Compare: security doctrine.)
Usage: Usually understood to refer primarily to components of Usage: Usually understood to refer primarily to components of
communication security, computer security, and emanation security. communication security, computer security, and emanation security.
Examples: Authentication exchange, checksum, digital signature, Examples: Authentication exchange, checksum, digital signature,
encryption, and traffic padding. encryption, and traffic padding.
$ security model $ security model
(I) A schematic description of a set of entities and relationships (I) A schematic description of a set of entities and relationships
by which a specified set of security services are provided by or by which a specified set of security services are provided by or
within a system. Example: Bell-LaPadula model. (See: (discussion within a system. Example: Bell-LaPadula model, OSIRM . (See:
under) security policy.) Tutorial under "security policy".)
$ security parameters index (SPI) $ security parameters index (SPI)
(I) /IPsec/ A 32-bit identifier used to distinguish among security (I) /IPsec/ A 32-bit identifier used to distinguish among security
associations that terminate at the same destination (IP address) associations that terminate at the same destination (IP address)
and use the same security protocol (AH or ESP). Carried in AH and and use the same security protocol (AH or ESP). Carried in AH and
ESP to enable the receiving system to determine under which ESP to enable the receiving system to determine under which
security association to process a received packet. security association to process a received packet.
(I) /mobile IP/ A 32-bit index identifying a security association (I) /mobile IP/ A 32-bit index identifying a security association
between a pair of nodes, from among the collection of associations from among the collection of associations that are available
between them that are available for application to mobile IP between a pair of nodes, for application to mobile IP protocol
protocol messages that they exchange. messages that the nodes exchange.
$ security perimeter $ security perimeter
(I) A physical or logical boundary that is defined for a domain or (I) A physical or logical boundary that is defined for a domain or
enclave and within which a particular security policy or security enclave and within which a particular security policy or security
architecture applies. (See: insider, outsider.) architecture applies. (See: insider, outsider.)
$ security policy $ security policy
1a. (I) A set of security principles or rules that direct how a 1. (I) A definite goal, course, or method of action to guide and
system or organization provides security services to protect determine present and future decisions concerning security in a
system. [R3198]
2a. (I) A set of policy rules (or principles) that direct how a
system (or an organization) provides security services to protect
sensitive and critical system resources. (See: identity-based sensitive and critical system resources. (See: identity-based
security policy, policy rule, rule-based security policy, rules of security policy, policy rule, rule-based security policy, rules of
behavior. Compare: security architecture, security doctrine, behavior. Compare: security architecture, security doctrine,
security mechanism, security model, [R1281].) security mechanism, security model, [R1281].)
1b. (O) /X.509/ A set of security rules laid down by an authority 2b. (O) A set of rules to administer, manage, and control access
to govern the use and provision of security services and to network resources. [R3060, R3198]
facilities.
2. (O) /Common Criteria/ A set of rules that regulate how assets 2c. (O) /X.509/ A set of rules laid down by an authority to govern
the use and provision of security services and facilities.
2d. (O) /Common Criteria/ A set of rules that regulate how assets
are managed, protected, and distributed within a TOE. are managed, protected, and distributed within a TOE.
Tutorial: Ravi Sandhu notes that security policy is one of four Tutorial: Ravi Sandhu suggests that security policy is one of four
layers of the security engineering process (as shown in the layers of the security engineering process (as shown in the
following diagram). Each layer provides a different view of following diagram). Each layer provides a different view of
security, ranging from what services are needed to how services security, ranging from what services are needed to how services
are implemented. From a security architect~Os perspective, a are implemented.
security policy is the requirements specification for designing an
adequately secure system.
What Security Services Should Be Provided? What Security Services
^ Should Be Provided? +- - - - - - - - - - - - -+
| + - - - - - - - - - - - + ^ +- - - - - - - - - - - -| Mission Functions View |
| | Security Policy | | | Security Policy |- - - - - - - - - - - - -+
| + - - - - - - - - - - - + + - - - - - - - - - - - - - - + | +- - - - - - - - - - - -| Domain Practices View |
| | Security Model | | A "top-level specification" | | | Security Model |- - - - - - - - - - - - -+
| + - - - - - - - - - - - + <- | is at a level below "model" | | +- - - - - - - - - - - -| Enclave Services View |
| | Security Architecture | | but above "architecture". | | | Security Architecture |- - - - - - - - - - - - -+
| + - - - - - - - - - - - + + - - - - - - - - - - - - - - + | +- - - - - - - - - - - -| Agent Mechanisms View |
| | Security Mechanism | | | Security Mechanism |- - - - - - - - - - - - -+
| + - - - - - - - - - - - + v +- - - - - - - - - - - -| Platform Devices View |
v How Are Security +- - - - - - - - - - - - -+
How Are Security Services Implemented? Services Implemented?
Rob Shirey suggests that another way to think about Sandhu's We suggest that each of Sandhu's four layers is a mapping between
layers is to say that statements of security policy vary in their two points of view that differ in their degree of abstraction,
degree of abstraction according to the perspectives of the according to the perspectives of various participants in system
participants in system design, development, and operation design, development, and operation activities, as follows:.
activities: - Mission functions view: The perspective of a user of system
- Mission functions view: Has perspective of user of information resources. States time-phased protection needs for resources
system resources. States time-phased protection needs for and identifies sensitive and critical resources -- networks,
system resources and identifies sensitive and critical hosts, applications, and databases. Independent of rules and
resources -- networks, hosts, applications, and databases. practices used to achieve protection.
Independent of rules and practices used to achieve protection. - Domain practices view: The perspective of an enterprise manager
- Domain practices view: Has perspective of enterprise manager
who sets protection standards for resources. States rules and who sets protection standards for resources. States rules and
practices for protection. Identifies domain members; i.e., practices for protection. Identifies domain members; i.e.,
entities (users/providers) and resources (including data entities (users/providers) and resources (including data
objects). Independent of system topology. Not required to be objects). Independent of system topology. Not required to be
hierarchical. hierarchical.
- Enclave services view: Has perspective of system designer who - Enclave services view: The perspective of a system designer who
allocates security functions to major components. Assigns allocates security functions to major components. Assigns
security services to system topology structures and their security services to system topology structures and their
contents. Independent of security mechanisms. Hierarchical contents. Independent of security mechanisms. Hierarchical
across all domains. across all domains.
- Agent mechanisms view: Has perspective of system engineer who - Agent mechanisms view: The perspective of a system engineer who
specifies security mechanisms to implement security services. specifies security mechanisms to implement security services.
Specifies mechanisms to be used by protocol, database, and Specifies mechanisms to be used by protocol, database, and
application engines. Independent of type and manufacture of application engines. Independent of type and manufacture of
platforms and other physical devices. platforms and other physical devices.
- Platform devices view: Has perspective of as-built description - Platform devices view: The perspective of an as-built
of the system in operation. Specifies exactly how to build or description of the system in operation. Specifies exactly how
assemble the system, and also specifies procedures for to build or assemble the system, and also specifies procedures
operating the system. for operating the system.
$ Security Policy Database (SPD) $ Security Policy Database (SPD)
(I) In an IPsec implementation operating in a network node, a (I) /IPsec/ In an IPsec implementation operating in a network
database that contains parameters that specify policies set by a node, a database that contains parameters that specify policies
user or administrator to determine what IPsec services, if any, set by a user or administrator to determine what IPsec services,
are to be provided to IP datagrams sent or received by the node, if any, are to be provided to IP datagrams sent or received by the
and in what fashion they are provided. For each datagram, the SPD node, and in what fashion they are provided. For each datagram,
specifies one of three choices: discard the datagram, apply IPsec the SPD specifies one of three choices: discard the datagram,
services (e.g., AH or ESP), or bypass IPsec. Separate inbound and apply IPsec services (e.g., AH or ESP), or bypass IPsec. Separate
outbound SPDs are needed because of the directionality of IPsec inbound and outbound SPDs are needed because of the directionality
security associations. [R2401] (Compare: SAD.) of IPsec security associations. [R2401] (Compare: SAD.)
$ Security Protocol 3 (SP3) $ Security Protocol 3 (SP3)
(O) A protocol [SDNS3] developed by SDNS to provide connectionless (O) A protocol [SDNS3] developed by SDNS to provide connectionless
data security at the top of OSIRM layer 3. (Compare: IPsec, NLSP.) data security at the top of OSIRM Layer 3. (Compare: IPsec, NLSP.)
$ Security Protocol 4 (SP4) $ Security Protocol 4 (SP4)
(O) A protocol [SDNS4] developed by SDNS to provide either (O) A protocol [SDNS4] developed by SDNS to provide either
connectionless or end-to-end connection-oriented data security at connectionless or end-to-end connection-oriented data security at
the bottom of OSIRM layer 4. (See: TLSP.) the bottom of OSIRM Layer 4. (See: TLSP.)
$ security-relevant event $ security-relevant event
(D) See: security event. (D) See: security event.
$ security rule
(I) A building block of a security policy; it defines (a) a set of
system conditions and (b) a set of system actions that are to be
performed if those conditions occur. [R3198]
$ security service $ security service
1. (I) A processing or communication service that is provided by a 1. (I) A processing or communication service that is provided by a
system to give a specific kind of protection to system resources. system to give a specific kind of protection to system resources.
(See: access control service, audit service, availability service, (See: access control service, audit service, availability service,
data confidentiality service, data integrity service, data origin data confidentiality service, data integrity service, data origin
authentication service, non-repudiation service, peer entity authentication service, non-repudiation service, peer entity
authentication service, system integrity service.) authentication service, system integrity service.)
Tutorial: Security services implement security policies, and are Tutorial: Security services implement security policies, and are
implemented by security mechanisms. implemented by security mechanisms.
2. (O) "A service, provided by a layer of communicating open 2. (O) "A service, provided by a layer of communicating open
systems, which ensures adequate security of the systems or the systems, which ensures adequate security of the systems or the
data transfers." [I7498 Part 2] data transfers." [I7498 Part 2]
$ security situation $ security situation
(I) ISAKMP usage: The set of all security-relevant information -- (I) /ISAKMP/ The set of all security-relevant information -- e.g.,
e.g., network addresses, security classifications, manner of network addresses, security classifications, manner of operation
operation (normal or emergency) -- that is needed to decide the (normal or emergency) -- that is needed to decide the security
security services that are required to protect the association services that are required to protect the association that is
that is being negotiated. being negotiated.
$ security target $ security target
(N) /Common Criteria/ A set of security requirements and (N) /Common Criteria/ A set of security requirements and
specifications to be used as the basis for evaluation of an specifications to be used as the basis for evaluation of an
identified TOE. identified TOE.
Tutorial: An security target (ST) is a statement of security Tutorial: An security target (ST) is a statement of security
claims for a particular information technology security product or claims for a particular information technology security product or
system, and is the basis for agreement among all parties as to system, and is the basis for agreement among all parties as to
what security the product or system offers. An ST parallels the what security the product or system offers. An ST parallels the
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$ security token $ security token
(I) See: token. (I) See: token.
$ security violation $ security violation
(I) An act or event that disobeys or otherwise breaches security (I) An act or event that disobeys or otherwise breaches security
policy. (See: compromise, penetration, security incident.) policy. (See: compromise, penetration, security incident.)
$ seed $ seed
(I) A value that is an input to a pseudorandom number generator. (I) A value that is an input to a pseudorandom number generator.
$ selective-field confidentiality
(I) A data confidentiality service that preserves confidentiality
for one or more parts (i.e., fields) of each packet. (See:
selective-field integrity.)
Tutorial: Data confidentiality service usually is applied to
entire SDUs, but some situations might require protection of only
part of each packet. For example, when Alice uses a debit card at
an automated teller machine (ATM), perhaps only her personal
identification number (PIN) is enciphered for confidentiality when
her transaction request is transmitted from the ATM to her bank's
computer.
In any given operational situation, there could be many different
reasons for using selective field confidentiality. In the ATM
example, there are at least four possibilities: The service may
provide a fail-safe mode of operation, ensuring that the bank can
still process transactions (although with some risk) even when the
encryption system fails. It may make messages easier to work with
when doing system fault isolation. It may avoid problems with laws
that prevent shipping enciphered data across international
borders. It may improve efficiency by reducing processing load at
a central computer site.
$ selective-field integrity
(I) A data integrity service that preserves integrity for one or
more parts (i.e., fields) of each packet. (See: selective-field
confidentiality.)
Tutorial: Data integrity service may be implemented in a protocol
to protect the SDU part of packets, the PCI part, or both.
- SDU protection: When service is provided for SDUs, it usually
is applied to entire SDUs, but it might be applied only to
parts of SDUs in some situations. For example, an IPS
Application-Layer protocol might need protection of only part
of each packet, and this might enable faster processing.
- PCI protection: To prevent active wiretapping, it might be
desirable to apply data integrity service to the entire PCI,
but some PCI fields in some protocols need to be mutable in
transit. For example, the "Time to Live" field in IPv4 is
changed each time a packet passes through a router in the
Internet Layer. Thus, the value that the field will have when
the packet arrives at its destination is not predictable by the
sender and cannot be included in a checksum computed by the
sender. (See: Authentication Header.)
$ self-signed certificate $ self-signed certificate
(I) A public-key certificate for which the public key bound by the (I) A public-key certificate for which the public key bound by the
certificate and the private key used to sign the certificate are certificate and the private key used to sign the certificate are
components of the same key pair, which belongs to the signer. components of the same key pair, which belongs to the signer.
(Compare: root certificate.) (Compare: root certificate.)
Tutorial: In a self-signed X.509 public-key certificate, the Tutorial: In a self-signed X.509 public-key certificate, the
issuer's DN is the same as the subject's DN. issuer's DN is the same as the subject's DN.
$ semantic security $ semantic security
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of the notion that the algorithm not only hides the plain text but of the notion that the algorithm not only hides the plain text but
also reveals no partial information about the plain text; i.e., also reveals no partial information about the plain text; i.e.,
whatever is computable about the plain text when given the cipher whatever is computable about the plain text when given the cipher
text, is also computable without the cipher text. (Compare: text, is also computable without the cipher text. (Compare:
indistinguishability.) indistinguishability.)
$ semiformal $ semiformal
(I) Expressed in a restricted syntax language with defined (I) Expressed in a restricted syntax language with defined
semantics. [CCIB] (Compare: formal, informal.) semantics. [CCIB] (Compare: formal, informal.)
$ sensitive
(I) A condition of a system resource such that the loss of some
specified property of that resource, such as confidentiality or
integrity, would adversely affect the interests or business of its
owner or user. (See: sensitive information. Compare: critical.)
$ sensitive compartmented information (SCI) $ sensitive compartmented information (SCI)
(O) /U.S. Government/ Classified information concerning or derived (O) /U.S. Government/ Classified information concerning or derived
from intelligence sources, methods, or analytical processes, which from intelligence sources, methods, or analytical processes, which
is required to be handled within formal control systems is required to be handled within formal control systems
established by the Director of Central Intelligence. [DC6/9] (See: established by the Director of Central Intelligence. [DC6/9] (See:
SCIF) compartment, SCIF)
$ sensitive compartmented information facility (SCIF) $ sensitive compartmented information facility (SCIF)
(O) /U.S. Government/ An accredited area, room, group of rooms, (O) /U.S. Government/ An accredited area, room, group of rooms,
building, or installation where SCI may be stored, used, building, or installation where SCI may be stored, used,
discussed, or electronically processed. [DC6/9] discussed, or electronically processed. [DC6/9] (See: SCI.
Compare: shielded enclosure.)
$ sensitive information $ sensitive information
(I) Information for which (a) disclosure, (b) alteration, or (c) (I) Information for which (a) disclosure, (b) alteration, or (c)
destruction or loss could adversely affect the interests or destruction or loss could adversely affect the interests or
business of its owner or user. (See: data confidentiality, data business of its owner or user. (See: data confidentiality, data
integrity. Compare: classified, critical.) integrity, sensitive. Compare: classified, critical.)
(O) /U.S. Government/ Information for which (a) loss, (b) misuse, (O) /U.S. Government/ Information for which (a) loss, (b) misuse,
(c) unauthorized access, or (d) unauthorized modification could (c) unauthorized access, or (d) unauthorized modification could
adversely affect the national interest or the conduct of federal adversely affect the national interest or the conduct of federal
programs, or the privacy to which individuals are entitled under programs, or the privacy to which individuals are entitled under
the Privacy Act of 1974, but that has not been specifically the Privacy Act of 1974, but that has not been specifically
authorized under criteria established by an Executive Order or an authorized under criteria established by an Executive Order or an
Act of Congress to be kept classified in the interest of national Act of Congress to be kept classified in the interest of national
defense or foreign policy. defense or foreign policy.
Tutorial: Systems that are not U.S. national security systems, but Tutorial: Systems that are not U.S. national security systems, but
contain sensitive U.S. Federal Government information, must be contain sensitive U.S. Federal Government information, must be
protected according to the Computer Security Act of 1987 (Public protected according to the Computer Security Act of 1987 (Public
Law 100-235). Law 100-235).
$ sensitivity label $ sensitivity label
(D) Synonym for "classification label". (D) Synonym for "classification label".
Deprecated term: ISDs should not use this term because the Deprecated term: ISDs SHOULD NOT use this term because the
definition of "sensitive" involves not only data confidentiality, definition of "sensitive" involves not only data confidentiality,
but also data integrity. but also data integrity.
$ sensitivity level $ sensitivity level
(D) Synonym for "classification level". (D) Synonym for "classification level".
Deprecated term: ISDs should not use this term because the Deprecated term: ISDs SHOULD NOT use this term because the
definition of "sensitive" involves not only data confidentiality, definition of "sensitive" involves not only data confidentiality,
but also data integrity. but also data integrity.
$ separation of duties $ separation of duties
(I) The practice of dividing the steps in a system function among (I) The practice of dividing the steps in a system process among
different individual entities (i.e., different users or different different individual entities (i.e., different users or different
roles) so as to keep a single entity from subverting the process. roles) so as to prevent a single entity acting alone from being
Sometimes called "separation of privilege". (See: administrative able to subvert the process. Usage: a.k.a. "separation of
security, dual control.) privilege". (See: administrative security, dual control.)
$ serial number $ serial number
See: certificate serial number. See: certificate serial number.
$ Serpent
(O) A symmetric, 128-bit block cipher designed by Ross Anderson,
Eli Biham, and Lars Knudsen as a candidate for the AES.
$ server $ server
(I) A system entity that provides a service in response to (I) A system entity that provides a service in response to
requests from other system entities called clients. requests from other system entities called clients.
$ service data unit (SDU)
(N) See: secondary definition under "protocol data unit".
$ session $ session
1a. (I) /computer usage/ A continuous period of time, usually 1a. (I) /computer usage/ A continuous period of time, usually
initiated by a login, during which a user accesses a computer initiated by a login, during which a user accesses a computer
system. system.
1b. (I) /computer activity/ The set of transactions or other 1b. (I) /computer activity/ The set of transactions or other
computer activities that are performed by or for a user during a computer activities that are performed by or for a user during a
period of computer usage. period of computer usage.
2. (I) /access control/ A temporary mapping of a principal to one 2. (I) /access control/ A temporary mapping of a principal to one
or more roles. (See: role-based access control.) or more roles. (See: role-based access control.)
Tutorial: A user establishes a session as a principal and Tutorial: A user establishes a session as a principal and
activates some subset of roles to which the principal has been activates some subset of roles to which the principal has been
assigned. The authorizations available to the principal in the assigned. The authorizations available to the principal in the
session are the union of permissions from all the roles activated session are the union of the permissions of all the roles
in the session. Each session is associated with a single principal activated in the session. Each session is associated with a single
and, therefore, with a single user. A principal may have multiple, principal and, therefore, with a single user. A principal may have
concurrent sessions and may activate a different set of roles in multiple, concurrent sessions and may activate a different set of
each session. roles in each session.
3. (I) /computer network/ A persistent but (normally) temporary 3. (I) /computer network/ A persistent but (normally) temporary
association between a user agent (typically a client) and a second association between a user agent (typically a client) and a second
process (typically a server). The association may persist across process (typically a server). The association may persist across
multiple exchanges of data, including multiple connections. multiple exchanges of data, including multiple connections.
(Compare: security association.) (Compare: security association.)
$ session key $ session key
(I) In the context of symmetric encryption, a key that is (I) In the context of symmetric encryption, a key that is
temporary or is used for a relatively short period of time. (See: temporary or is used for a relatively short period of time. (See:
ephemeral key, KDC, session. Compare: master key.) ephemeral, KDC, session. Compare: master key.)
Tutorial: A session key is used for a defined period of Tutorial: A session key is used for a defined period of
communication between two system entities or components, such as communication between two system entities or components, such as
for the duration of a single connection or transaction set; or the for the duration of a single connection or transaction set; or the
key is used in an application that protects relatively large key is used in an application that protects relatively large
amounts of data and, therefore, needs to be rekeyed frequently. amounts of data and, therefore, needs to be rekeyed frequently.
$ SET $ SET(trademark)
(O) See: SET Secure Electronic Transaction(trademark). (O) See: SET Secure Electronic Transaction(trademark).
$ SET private extension $ SET private extension
(O) One of the private extensions defined by SET for X.509 (O) One of the private extensions defined by SET for X.509
certificates. Carries information about hashed root key, certificates. Carries information about hashed root key,
certificate type, merchant data, cardholder certificate certificate type, merchant data, cardholder certificate
requirements, encryption support for tunneling, or message support requirements, encryption support for tunneling, or message support
for payment instructions. for payment instructions.
$ SET qualifier $ SET qualifier
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confidentiality of transaction information, payment integrity, and confidentiality of transaction information, payment integrity, and
authentication of transaction participants for payment card authentication of transaction participants for payment card
transactions over unsecured networks, such as the Internet. [SET1] transactions over unsecured networks, such as the Internet. [SET1]
(See: acquirer, brand, cardholder, dual signature, electronic (See: acquirer, brand, cardholder, dual signature, electronic
commerce, IOTP, issuer, merchant, payment gateway, third party.) commerce, IOTP, issuer, merchant, payment gateway, third party.)
Tutorial: This term and acronym are trademarks of SETCo. Tutorial: This term and acronym are trademarks of SETCo.
MasterCard and Visa announced the SET standard on 1 February 1996. MasterCard and Visa announced the SET standard on 1 February 1996.
$ SETCo $ SETCo
(O) Abbreviation for "SET Secure Electronic Transaction LLC", (O) Abbreviation of "SET Secure Electronic Transaction LLC",
formed on 19 December 1997 by MasterCard and Visa for the purpose formed on 19 December 1997 by MasterCard and Visa for the purpose
of implementing the SET Secure Electronic Transaction" standard. of implementing the SET Secure Electronic Transaction(trademark)
A memorandum of understanding adds American Express and JCB Credit standard. A later memorandum of understanding added American
Card Company as co-owners of SETCo. Express and JCB Credit Card Company as co-owners of SETCo.
$ SHA, SHA-1, SHA-2 $ SHA, SHA-1, SHA-2
(N) See: Secure Hash Algorithm. (N) See: Secure Hash Algorithm.
$ shared identity $ shared identity
(I) See: (secondary definition under) identity. (I) See: secondary definition under "identity".
$ shared secret $ shared secret
(D) A synonym for "cryptographic key" or "password". (D) A synonym for "cryptographic key" or "password".
Deprecated Usage: The term is used in many ways and could easily Deprecated Usage: ISDs that use this term SHOULD state a
be misunderstood; therefore, ISDs that use this term SHOULD state definition for it because the term is used in many ways and could
a definition for it. easily be misunderstood.
$ shielded enclosure $ shielded enclosure
(O) "Room or container designed to attenuate electromagnetic (O) "Room or container designed to attenuate electromagnetic
radiation." [C4009] (See: emanation.) radiation." [C4009] (See: emanation. Compare: SCIF.)
$ short title $ short title
(O) "Identifying combination of letters and numbers assigned to (O) "Identifying combination of letters and numbers assigned to
certain items of COMSEC material to facilitate handling, certain items of COMSEC material to facilitate handling,
accounting, and controlling." [C4009] (Compare: KMID, long title.) accounting, and controlling." [C4009] (Compare: KMID, long title.)
$ SHS $ SHS
(N) See: Secure Hash Standard. (N) See: Secure Hash Standard.
$ sign $ sign
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data. (See: emanation. Compare: traffic analysis.) data. (See: emanation. Compare: traffic analysis.)
$ signal intelligence $ signal intelligence
(I) The science and practice of extracting information from (I) The science and practice of extracting information from
signals. (See: signal security.) signals. (See: signal security.)
$ signal security $ signal security
(N) (I) The science and practice of protecting signals. (See: (N) (I) The science and practice of protecting signals. (See:
cryptology, security.) cryptology, security.)
Tutorial: The term "signal" denotes communication in almost any Tutorial: The term "signal" denotes (a) communication in almost
form and also impulses emitted for other purposes, such as radar. any form and also (b) emanations for other purposes, such as
Signal security is opposed by signal intelligence, and each radar. Signal security is opposed by signal intelligence, and each
discipline includes opposed sub-disciplines as follows [Kahn]: discipline includes opposed sub-disciplines as follows [Kahn]:
Signal Security Signal Intelligence Signal Security Signal Intelligence
------------------------------ --------------------------------- ------------------------------ ---------------------------------
1. Communication Security 1. Communication Intelligence 1. Communication Security 1. Communication Intelligence
1a. Cryptography 1a. Cryptanalysis 1a. Cryptography 1a. Cryptanalysis
1b. Traffic Security 1b. Traffic Analysis 1b. Traffic Security 1b. Traffic Analysis
1c. Steganography 1c. Detection and Interception 1c. Steganography 1c. Detection and Interception
2. Electronic Security 2. Electronic Intelligence 2. Electronic Security 2. Electronic Intelligence
2a. Emission Security 2a. Electronic Reconnaissance 2a. Emission Security 2a. Electronic Reconnaissance
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service to connection-based protocols. service to connection-based protocols.
Tutorial: To use SASL, a protocol includes a command for Tutorial: To use SASL, a protocol includes a command for
authenticating a user to a server and for optionally negotiating authenticating a user to a server and for optionally negotiating
protection of subsequent protocol interactions. The command names protection of subsequent protocol interactions. The command names
a registered security mechanism. SASL mechanisms include Kerberos, a registered security mechanism. SASL mechanisms include Kerberos,
GSSAPI, S/KEY, and others. Some protocols that use SASL are IMAP4 GSSAPI, S/KEY, and others. Some protocols that use SASL are IMAP4
and POP3. and POP3.
$ Simple Key Management for Internet Protocols (SKIP) $ Simple Key Management for Internet Protocols (SKIP)
(I) A key distribution protocol that uses hybrid encryption to (I) A key-distribution protocol that uses hybrid encryption to
convey session keys that are used to encrypt data in IP packets. convey session keys that are used to encrypt data in IP packets.
Tutorial: SKIP was designed by Ashar Aziz and Whitfield Diffie at Tutorial: SKIP was designed by Ashar Aziz and Whitfield Diffie at
Sun Microsystems and proposed as the standard key management Sun Microsystems and proposed as the standard key management
protocol for IPsec, but IKE was chosen instead. Although IKE is protocol for IPsec, but IKE was chosen instead. Although IKE is
mandatory for an IPsec implementation, the use of SKIP is not mandatory for an IPsec implementation, the use of SKIP is not
excluded. excluded.
SKIP uses the Diffie-Hellman algorithm (or could use another key SKIP uses the Diffie-Hellman algorithm (or could use another key-
agreement algorithm) to generate a key-encrypting key for use agreement algorithm) to generate a key-encrypting key for use
between two entities. A session key is used with a symmetric between two entities. A session key is used with a symmetric
algorithm to encrypt data in one or more IP packets that are to be algorithm to encrypt data in one or more IP packets that are to be
sent from one entity to the other. A symmetric KEK is established sent from one entity to the other. A symmetric KEK is established
and used to encrypt the session key, and the encrypted session key and used to encrypt the session key, and the encrypted session key
is placed in a SKIP header that is added to each IP packet that is is placed in a SKIP header that is added to each IP packet that is
encrypted with that session key. encrypted with that session key.
$ Simple Mail Transfer Protocol (SMTP) $ Simple Mail Transfer Protocol (SMTP)
(I) A TCP-based, application-level, Internet Standard protocol (I) A TCP-based, Application-Layer, Internet Standard protocol
(RFC 821) for moving electronic mail messages from one computer to (RFC 821) for moving electronic mail messages from one computer to
another. another.
$ Simple Network Management Protocol (SNMP) $ Simple Network Management Protocol (SNMP)
(I) A TCP-based, application-level, Internet Standard protocol (I) A TCP-based, Application-Layer, Internet Standard protocol
[R2570, R2574] for conveying management information between [R3410, R3414] for conveying management information between system
managers and agents. components that act as managers and agents.
$ Simple Public Key Infrastructure (SPKI) $ Simple Public Key Infrastructure (SPKI)
(I) A set of experimental concepts (RFCs 2692, 2693) that were (I) A set of experimental concepts (RFCs 2692, 2693) that were
proposed as alternatives to the concepts standardized in PKIX. proposed as alternatives to the concepts standardized in PKIX.
$ simple security property $ simple security property
(N) /formal model/ Property of a system whereby a subject has (N) /formal model/ Property of a system whereby a subject has
read access to an object only if the clearance of the subject read access to an object only if the clearance of the subject
dominates the classification of the object. See: Bell-LaPadula dominates the classification of the object. See: Bell-LaPadula
model. model.
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Tutorial: In a single sign-on system, a user typically logs in Tutorial: In a single sign-on system, a user typically logs in
just once, and then is transparently granted access to a set of just once, and then is transparently granted access to a set of
system resources with no further login being required (unless, of system resources with no further login being required (unless, of
course, the user logs out). Such a system has the advantages of course, the user logs out). Such a system has the advantages of
being user friendly and enabling authentication to be managed being user friendly and enabling authentication to be managed
consistently across an entire enterprise. Such a system also has consistently across an entire enterprise. Such a system also has
the disadvantage of requiring all hosts and applications to trust the disadvantage of requiring all hosts and applications to trust
the same authentication information. the same authentication information.
$ singular identity $ singular identity
(I) See: (secondary definition under) identity. (I) See: secondary definition under "identity".
$ site $ site
(I) A facility--i.e., a physical space, room, or building together (I) A facility -- i.e., a physical space, room, or building
with its physical, personnel, administrative, and other together with its physical, personnel, administrative, and other
safeguards--in which system functions are performed. (See: node.) safeguards -- in which system functions are performed. (See:
node.)
$ situation $ situation
See: security situation. (I) See: security situation.
$ SKEME $ SKEME
(I) A key distribution protocol from which features were adapted (I) A key-distribution protocol from which features were adapted
for IKE. [SKEME] for IKE. [SKEME]
$ SKIP $ SKIP
(I) See: Simple Key-management for IP. (I) See: Simple Key Management for Internet Protocols.
$ SKIPJACK $ SKIPJACK
(N) A type 2 block cipher [SKIP, R2773] with a block size of 64 (N) A type 2, 64-bit block cipher [SKIP, R2773] with a key size of
bits and a key size of 80 bits. (See: CAPSTONE, CLIPPER, FORTEZZA, 80 bits. (See: CAPSTONE, CLIPPER, FORTEZZA, Key Exchange
Key Exchange Algorithm.) Algorithm.)
Tutorial: SKIPJACK was developed by NSA and formerly classified at Tutorial: SKIPJACK was developed by NSA and formerly classified at
the U.S. DoD "Secret" level. On 23 June 1998, NSA announced that the U.S. DoD "Secret" level. On 23 June 1998, NSA announced that
SKIPJACK had been declassified. SKIPJACK had been declassified.
$ slot $ slot
(O) /MISSI/ One of the FORTEZZA PC card storage areas that are (O) /MISSI/ One of the FORTEZZA PC card storage areas that are
each able to hold an X.509 certificate plus other data, such as each able to hold an X.509 certificate plus other data, including
the private key that is associated with a public-key certificate. the private key that is associated with a public-key certificate.
$ smart card $ smart card
(I) A credit-card sized device containing one or more integrated (I) A credit-card sized device containing one or more integrated
circuit chips, which perform the functions of a computer's central circuit chips, which perform the functions of a computer's central
processor, memory, and input/output interface. (See: PC card.) processor, memory, and input/output interface. (See: PC card,
smart token.)
Usage: Sometimes this term is used rather strictly to mean a card Usage: Sometimes this term is used rather strictly to mean a card
that closely conforms to the dimensions and appearance of the kind that closely conforms to the dimensions and appearance of the kind
of plastic credit card issued by banks and merchants. At other of plastic credit card issued by banks and merchants. At other
times, the term is used loosely to include cards that are larger times, the term is used loosely to include cards that are larger
than credit cards, especially cards that are thicker, such as PC than credit cards, especially cards that are thicker, such as PC
cards. cards.
Tutorial: A "smart token" is a device that conforms to the
definition of smart card except that rather than having standard
credit card dimensions, the token is packaged in some other form,
such as a dog tag or door key shape.
$ smart token $ smart token
See: (secondary definition under) smart card. (I) A device that conforms to the definition of "smart card"
except that rather than having the standard dimensions of a credit
card, the token is packaged in some other form, such as a military
dog tag or a door key. (See: smart card, cryptographic token.)
$ SMI $ SMI
(I) See: security management infrastructure. (I) See: security management infrastructure.
$ SMTP $ SMTP
(I) See: Simple Mail Transfer Protocol. (I) See: Simple Mail Transfer Protocol.
$ smurf attack $ smurf attack
(D) A denial-of-service attack that uses IP broadcast addressing (D) /slang/ A denial-of-service attack that uses IP broadcast
to send ICMP ping packets with the intent of flooding a system. addressing to send ICMP ping packets with the intent of flooding a
(See: ICMP flood.) system. (See: ICMP flood.)
Deprecated Term: ISDs SHOULD NOT use this term. It is not listed Deprecated Term: ISDs SHOULD NOT use this term. It is not listed
in most dictionaries, and it is likely that other cultures have in most English dictionaries, and other cultures are likely to use
different metaphors for this concept. (The Smurfs are a fictional different metaphors for this concept.
race of many small blue creatures that were created by a
cartoonist. Perhaps the inventor of this attack thought that a Derivation: The Smurfs are a fictional race of many small, blue
swarm of ping packets resembled a group of smurfs.) (See: creatures that were created by a cartoonist. Perhaps the inventor
(Deprecated Usage under) Green Book.) of this attack thought that a swarm of ping packets resembled a
gang of smurfs. (See: Deprecated Usage under "Green Book".)
Tutorial: The attacker sends ICMP echo request ("ping") packets Tutorial: The attacker sends ICMP echo request ("ping") packets
that appear to originate not from the attacker's own IP address, that appear to originate not from the attacker's own IP address,
but from the address of the host or router that is target of the but from the address of the host or router that is the target of
attack. Each packet is addressed to an IP broadcast address, e.g., the attack. Each packet is addressed to an IP broadcast address,
to all IP addresses in a given network. Thus, each echo request e.g., to all IP addresses in a given network. Thus, each echo
that is sent by the attacker results in many echo responses being request that is sent by the attacker results in many echo
sent to the target address. This attack can disrupt service at a responses being sent to the target address. This attack can
particular host, at the hosts that depend on a particular router, disrupt service at a particular host, at the hosts that depend on
or in an entire network. a particular router, or in an entire network.
$ sneaker net $ sneaker net
(D) A process that transfers data between systems only manually, (D) /slang/ A process that transfers data between systems only
under human control; i.e., a data transfer process that involves manually, under human control; i.e., a data transfer process that
an air gap. involves an air gap.
Deprecated Term: ISDs SHOULD NOT use this term. It is not listed Deprecated Term: ISDs SHOULD NOT use this term. It is not listed
in most dictionaries, and it is likely that other cultures have in most English dictionaries, and other cultures are likely to use
different metaphors for this concept. different metaphors for this concept.
$ Snefru $ Snefru
(N) A public-domain, cryptographic hash function (also called "The (N) A public-domain, cryptographic hash function (also called "The
Xerox Secure Hash Function") designed by Ralph C. Merkle at Xerox Xerox Secure Hash Function") designed by Ralph C. Merkle at Xerox
Corporation. Snefru can produce either a 128-bit or 256-bit output Corporation. Snefru can produce either a 128-bit or 256-bit output
(i.e., hash result). [Schn] (See: Khafre, Khufu.) (i.e., hash result). [Schn] (See: Khafre, Khufu.)
$ sniffing $ sniffing
(D) Synonym for "passive wiretapping". (See: password sniffing.) (D) /slang/ Synonym for "passive wiretapping". (See: password
sniffing.)
Deprecated Term: ISDs SHOULD NOT use this term; it unnecessarily Deprecated Term: ISDs SHOULD NOT use this term; it unnecessarily
duplicates the meaning of a term that is better established. (See: duplicates the meaning of a term that is better established. (See:
(Deprecated Usage under) Green Book. Deprecated Usage under "Green Book".
$ SNMP $ SNMP
(I) See: Simple Network Management Protocol. (I) See: Simple Network Management Protocol.
$ social engineering $ social engineering
(D) A euphemism for non-technical or low-technology methods used (D) A euphemism for non-technical or low-technology methods, often
to attack information systems. involving trickery or fraud, that are used to attack information
systems.
Deprecated Term: ISDs SHOULD NOT use this term; it is too vague. Deprecated Term: ISDs SHOULD NOT use this term; it is too vague.
Instead, use a term that is specific with regard to the means of Instead, use a term that is specific with regard to the means of
attack, e.g., lies, impersonation, tricks, bribes, blackmail, and attack, e.g., blackmail, bribery, coercion, impersonation,
threats. intimidation, lying, or theft.
$ SOCKS $ SOCKS
(I) An Internet protocol [R1928] that provides a generalized proxy (I) An Internet protocol [R1928] that provides a generalized proxy
server that enables client-server applications -- such as TELNET, server that enables client-server applications (e.g., TELNET, FTP,
FTP, and HTTP; running over either TCP or UDP -- to use the or HTTP; running over either TCP or UDP) to use the services of a
services of a firewall. firewall.
Tutorial: SOCKS is layered under the IPS application layer and Tutorial: SOCKS is layered under the IPS Application Layer and
above the transport layer. When a client inside a firewall wishes above the Transport Layer. When a client inside a firewall wishes
to establish a connection to an object that is reachable only to establish a connection to an object that is reachable only
through the firewall, it uses TCP to connect to the SOCKS server, through the firewall, it uses TCP to connect to the SOCKS server,
negotiates with the server for the authentication method to be negotiates with the server for the authentication method to be
used, authenticates with the chosen method, and then sends a relay used, authenticates with the chosen method, and then sends a relay
request. The SOCKS server evaluates the request, typically based request. The SOCKS server evaluates the request, typically based
on source and destination addresses, and either establishes the on source and destination addresses, and either establishes the
appropriate connection or denies it. appropriate connection or denies it.
$ soft TEMPEST $ soft TEMPEST
(O) The use of software techniques to reduce the radio frequency (O) The use of software techniques to reduce the radio frequency
information leakage from computer displays and keyboards. [Kuhn] information leakage from computer displays and keyboards. [Kuhn]
(See: TEMPEST.) (See: TEMPEST.)
$ software $ software
(I) Computer programs (which are stored in and executed by (I) Computer programs (which are stored in and executed by
computer hardware) and associated data (which also is stored in computer hardware) and associated data (which also is stored in
the hardware) that may be dynamically written or modified during the hardware) that may be dynamically written or modified during
execution. (See: firmware, hardware.) execution. (Compare: firmware.)
$ SORA $ SORA
(O) See: SSO-PIN ORA. (O) See: SSO-PIN ORA.
$ source authentication $ source authentication
(D) Deprecated Term: ISDs SHOULD NOT use this term; it is (D) Synonym for "data origin authentication" or "peer entity
ambiguous. If the intent is to authenticate the original creator authentication". (See: data origin authentication, peer entity
or packager of data received, then say "data origin authentication).
authentication". If the intent is to authenticate the identity of
the sender of data, then say "peer entity authentication". (See: Deprecated Term: ISDs SHOULD NOT use this term because it is
data origin authentication, peer entity authentication). ambiguous and, in either meaning, duplicates the meaning of
internationally standardized terms. If the intent is to
authenticate the original creator or packager of data received,
then use "data origin authentication". If the intent is to
authenticate the identity of the sender of data in the current
instance, then use "peer entity authentication".
$ source integrity $ source integrity
(I) The degree of confidence that can be placed in information (I) The property that data is trustworthy (i.e., worthy of
based on the trustworthiness of its sources. (See: integrity.) reliance or trust), based on the trustworthiness of its sources
and the trustworthiness of any procedures used for handling data
in the system. Usage: a.k.a. Biba integrity. (See: integrity.
Compare: correctness integrity, data integrity.)
Tutorial: For this kind of integrity, there are formal models of
unauthorized modification (see: Biba model) that logically
complement the more familiar models of unauthorized disclosure
(see: Bell-LaPadula model). In these models, objects are labeled
to indicate the credibility of the data they contain, and there
are rules for access control that depend on the labels.
$ SP3 $ SP3
(O) See: Security Protocol 3. (O) See: Security Protocol 3.
$ SP4 $ SP4
(O) See: Security Protocol 4. (O) See: Security Protocol 4.
$ spam, SPAM(trademark) $ spam
1a. (I) /verb/ To indiscriminately send unsolicited, unwanted, 1a. (I) /slang verb/ To indiscriminately send unsolicited,
irrelevant, or inappropriate messages, especially commercial unwanted, irrelevant, or inappropriate messages, especially
advertising in mass quantities. commercial advertising in mass quantities.
1b. (I) /noun/ Electronic "junk mail". [R2635] 1b. (I) /slang noun/ Electronic "junk mail". [R2635]
Deprecated Usage: ISDs SHOULD NOT use this term in upper-case Deprecated Usage: ISDs SHOULD NOT use this term in upper-case
letters, because SPAM(trademark) is a trademark of Hormel Foods letters, because SPAM(trademark) is a trademark of Hormel Foods
Corporation. Hormel says, "We do not object to use of this slang Corporation. Hormel says, "We do not object to use of this slang
term [spam] to describe [unsolicited advertising email], although term [spam] to describe [unsolicited advertising email], although
we do object to the use of our product image in association with we do object to the use of our product image in association with
that term. Also, if the term is to be used, it should be used in that term. Also, if the term is to be used, it SHOULD be used in
all lower-case letters to distinguish it from our trademark SPAM, all lower-case letters to distinguish it from our trademark SPAM,
which should be used with all uppercase letters." (See: metadata.) which SHOULD be used with all uppercase letters." (See: metadata.)
Tutorial: In sufficient volume, spam can cause denial of service. Tutorial: In sufficient volume, spam can cause denial of service.
(See: flooding.) According to Hormel, the term was adopted as a (See: flooding.) According to Hormel, the term was adopted as a
result of a Monty Python skit in which a group of Vikings sang a result of a Monty Python skit in which a group of Vikings sang a
chorus of 'SPAM, SPAM, SPAM ...' in an increasing crescendo, chorus of 'SPAM, SPAM, SPAM ...' in an increasing crescendo,
drowning out other conversation. This lyric became a metaphor for drowning out other conversation. This lyric became a metaphor for
the unsolicited advertising messages that threaten to overwhelm the unsolicited advertising messages that threaten to overwhelm
other discourse on the Internet. other discourse on the Internet.
$ SPD $ SPD
(I) See: Security Policy Database. (I) See: Security Policy Database.
$ special access program (SAP) $ special access program (SAP)
(O) /U.S. Government/ "[A kind of p]rogram [that is] established (O) /U.S. Government/ "[A kind of p]rogram [that is] established
for a specific class of classified information [and] that imposes for a specific class of classified information [and] that imposes
safeguarding and access requirements that exceed those normally safeguarding and access requirements that exceed those normally
required for information at the same classified level." [C4009] required for information at the same classified level." [C4009]
(See: formal access approval, SCI.)
$ SPI $ SPI
(I) See: Security Parameters Index. (I) See: Security Parameters Index.
$ SPKI $ SPKI
(I) See: Simple Public Key Infrastructure. (I) See: Simple Public Key Infrastructure.
$ split key $ split key
(I) A cryptographic key that is divided into two or more separate (I) A cryptographic key that is generated and distributed as two
data items that individually convey no knowledge of the whole key or more separate data items that individually convey no knowledge
that results from combining the items. (See: dual control, split of the whole key that results from combining the items. (See: dual
knowledge.) control, split knowledge.)
$ split knowledge $ split knowledge
1. (I) A security technique in which two or more entities 1. (I) A security technique in which two or more entities
separately hold data items that individually convey no knowledge separately hold data items that individually do not convey
of the information that results from combining the items. (See: knowledge of the information that results from combining the
dual control, split key.) items. (See: dual control, split key.)
2. (O) "A condition under which two or more entities separately 2. (O) "A condition under which two or more entities separately
have key components which individually convey no knowledge of the have key components which individually convey no knowledge of the
plaintext key which will be produced when the key components are plaintext key which will be produced when the key components are
combined in the cryptographic module." [FP140] combined in the cryptographic module." [FP140]
$ spoofing attack $ spoofing attack
(I) Synonym for "masquerade attack". (I) Synonym for "masquerade attack".
$ spread spectrum $ spread spectrum
1. (N) A TRANSEC technique that transmits a signal in a bandwidth (N) A TRANSEC technique that transmits a signal in a bandwidth
much greater than the transmitted information needs. [F1037] much greater than the transmitted information needs. [F1037]
Example: frequency hopping. Example: frequency hopping.
Tutorial: Usually uses a sequential noise-like signal structure to Tutorial: Usually uses a sequential, noise-like signal structure
spread the normally narrowband information signal over a to spread the normally narrowband information signal over a
relatively wide band of frequencies. The receiver correlates the relatively wide band of frequencies. The receiver correlates the
signals to retrieve the original information signal. This signals to retrieve the original information signal. This
technique decreases potential interference to other receivers, technique decreases potential interference to other receivers,
while achieving data confidentiality and increasing immunity of while achieving data confidentiality and increasing immunity of
spread spectrum receivers to noise and interference. spread spectrum receivers to noise and interference.
$ spyware $ spyware
(I) Software that an intruder has installed surreptitiously on a (D) /slang/ Software that an intruder has installed
networked computer to gather data from that computer and send it surreptitiously on a networked computer to gather data from that
through the network to the intruder or some other interested computer and send it through the network to the intruder or some
party. (See: malicious logic, Trojan horse.) other interested party. (See: malicious logic, Trojan horse.)
Deprecated Usage: The term is used in many ways and could easily Deprecated Usage: ISDs that use this term SHOULD state a
be misunderstood; therefore, ISDs that use this term SHOULD state definition for it because the term is used in many ways and could
a definition for it. easily be misunderstood.
Tutorial: Some examples of the types of data that might be Tutorial: Some examples of the types of data that might be
gathered by spyware are application files, passwords, email gathered by spyware are application files, passwords, email
addresses, usage histories, and keystrokes. Some examples of addresses, usage histories, and keystrokes. Some examples of
motivations for gathering the data are blackmail, financial fraud, motivations for gathering the data are blackmail, financial fraud,
identity theft, industrial espionage, market research, and identity theft, industrial espionage, market research, and
voyeurism. voyeurism.
$ SSH(trademark) $ SSH(trademark)
(N) See: Secure Shell(trademark). (N) See: Secure Shell(trademark).
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including security management, (b) Secure Data Exchange protocol, including security management, (b) Secure Data Exchange protocol,
(c) Key Management, (d) [has been incorporated in (a)], (e) SDE (c) Key Management, (d) [has been incorporated in (a)], (e) SDE
Over Ethernet 2.0, (f) SDE Sublayer Management, (g) SDE Security Over Ethernet 2.0, (f) SDE Sublayer Management, (g) SDE Security
Labels, and (h) SDE PICS Conformance. Parts b, e, f, g, and h are Labels, and (h) SDE PICS Conformance. Parts b, e, f, g, and h are
incorporated in IEEE Standard 802.10-1998. incorporated in IEEE Standard 802.10-1998.
$ star property $ star property
(N) See: *-property. (N) See: *-property.
$ Star Trek attack $ Star Trek attack
(D) An attack that penetrates your system where no attack has ever (D) /slang/ An attack that penetrates your system where no attack
gone before. has ever gone before.
Deprecated Usage: This is a joke for Trekkies. (See: (Deprecated Deprecated Usage: This is a joke for Trekkies. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ static $ static
(I) /adjective/ Refers to a cryptographic key or other parameter (I) /adjective/ Refers to a cryptographic key or other parameter
that is relatively long-lived. (Compare: ephemeral.) that is relatively long-lived. (Compare: ephemeral.)
$ steganography $ steganography
(I) Methods of hiding the existence of a message or other data. (I) Methods of hiding the existence of a message or other data.
This is different than cryptography, which hides the meaning in a This is different than cryptography, which hides the meaning of a
message but does not hide the message itself. Example: "Invisible" message but does not hide the message itself. Examples: For
ink. (See: cryptology. Compare: digital watermarking.) classic, physical methods, see [Kahn]; for modern, digital
methods, see [John]. (See: cryptology. Compare: digital
watermarking.)
$ storage channel $ storage channel
See: covert storage channel. (I) See: covert storage channel.
$ storage key
(I) A cryptographic key used by a device for protecting
information that is being maintained in the device, as opposed to
protecting information that is being transmitted between devices.
(See: cryptographic token, token copy. Compare: traffic key.)
$ stream cipher $ stream cipher
(I) An encryption algorithm that breaks plain text into a stream (I) An encryption algorithm that breaks plain text into a stream
of successive elements (usually, bits) and encrypts the n-th of successive elements (usually, bits) and encrypts the n-th
plaintext element with the n-th element of a parallel key stream, plaintext element with the n-th element of a parallel key stream,
thus converting the plaintext stream into a ciphertext stream. thus converting the plaintext stream into a ciphertext stream.
[Schn] (See: block cipher.) [Schn] (See: block cipher.)
$ stream integrity service
(I) A data integrity service that preserves integrity for a
sequence of data packets, including both (a) bit-by-bit datagram
integrity of each individual packet in the set and (b) packet-by-
packet sequential integrity of the set as a whole. (See: data
integrity. Compare: datagram integrity service.)
Tutorial: Some internet applications need only datagram integrity,
but others require that an entire stream of packets be protected
against insertion, reordering, deletion, and delay:
- "Insertion": The destination receives an additional packet that
was not sent by the source.
- "Reordering": The destination receives packets in a different
order than that in which they were sent by the source.
- "Deletion": A packet sent by the source is not ever delivered
to the intended destination.
- "Delay": A packet is detained for some period of time at a
relay, thus hampering and postponing the packet's normal timely
delivery from source to destination.
$ strength $ strength
(I) /COMPUSEC/ A rating of effectiveness of a security mechanism, 1. (I) /cryptography/ A cryptographic mechanism's level of
stated in terms of the minimum effort believed to be needed to resistance to attacks [R3776].
defeat the mechanism. (See: entropy, strong, work factor.)
$ strength of function 2. (N) /Common Criteria/ "Strength of function" is a
(N) /Common Criteria/ "A qualification of a TOE security function "qualification of a TOE security function expressing the minimum
expressing the minimum efforts assumed necessary to defeat its efforts assumed necessary to defeat its expected security behavior
expected security behavior by directly attacking its underlying by directly attacking its underlying security mechanisms": (See:
security mechanisms": (See: strength, strong.) strong.)
- Basic: "A level of the TOE strength of function where analysis - Basic: "A level of the TOE strength of function where analysis
shows that the function provides adequate protection against shows that the function provides adequate protection against
casual breach of TOE security by attackers possessing a low casual breach of TOE security by attackers possessing a low
attack potential." attack potential."
- Medium: "... against straightforward or intentional breach ... - Medium: "... against straightforward or intentional breach ...
by attackers possessing a moderate attack potential. by attackers possessing a moderate attack potential.
- High: "... against deliberately planned or organized breach ... - High: "... against deliberately planned or organized breach ...
by attackers possessing a high attack potential." by attackers possessing a high attack potential."
$ strong $ strong
1. (I) /COMPUSEC/ Used to describe a security mechanism that would 1. (I) /cryptography/ Used to describe a cryptographic algorithm
be difficult to defeat. (See: strength.)
2. (I) /cryptography/ Used to describe a cryptographic algorithm
that would require a large amount of computational power to defeat that would require a large amount of computational power to defeat
it. (See: work factor.) it. (See: work factor, strength.)
2. (I) /COMPUSEC/ Used to describe a security mechanism that would
be difficult to defeat. (See: strength.)
$ strong authentication $ strong authentication
1. (I) An authentication process that uses a cryptographic 1. (I) An authentication process that uses a cryptographic
security mechanism -- particularly public-key certificates -- to security mechanism -- particularly public-key certificates -- to
verify the identity claimed for an entity. (Compare: simple verify the identity claimed for an entity. (Compare: simple
authentication.) authentication.)
2. (O) "Authentication by means of cryptographically derived 2. (O) "Authentication by means of cryptographically derived
credentials." [X509] credentials." [X509]
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OU=Treasurer, CN=DukePinchpenny> is subordinate to the DN OU=Treasurer, CN=DukePinchpenny> is subordinate to the DN
<C=FooLand, O=Gov, CN=KingFooCA>. <C=FooLand, O=Gov, CN=KingFooCA>.
$ subscriber $ subscriber
(I) /PKI/ A user that is registered in a PKI and, therefore, can (I) /PKI/ A user that is registered in a PKI and, therefore, can
be named in the "subject" field of a certificate issued by a CA in be named in the "subject" field of a certificate issued by a CA in
that PKI. (See: registration, user.) that PKI. (See: registration, user.)
Usage: This term is needed to distinguish registered users from Usage: This term is needed to distinguish registered users from
two other kinds of PKI users: two other kinds of PKI users:
- Users that access the PKI but are not identified to it. For - Users that access the PKI but are not identified to it: For
example a relying party may access a PKI repository to obtain example a relying party may access a PKI repository to obtain
the certificate of some other party. (See: access) the certificate of some other party. (See: access.)
- Users that does not access the PKI. For example, a relying - Users that do not access the PKI: For example, a relying party
party (see: certificate user) may use a digital certificate (see: certificate user) may use a digital certificate that was
that was obtained from a database that is not part of the PKI obtained from a database that is not part of the PKI that
that issued the certificate. issued the certificate.
$ substitution $ substitution
(I) /cryptography/ A method of encryption in which elements of the (I) /cryptography/ A method of encryption in which elements of the
plain text retain their original sequence but are replaced by plain text retain their original sequence but are replaced by
other elements. (Compare: transposition.) other elements. (Compare: transposition.)
$ subsystem $ subsystem
(I) A collection of related system components that together (I) A collection of related system components that together
perform a system function or deliver a system service. perform a system function or deliver a system service.
$ superuser
(I) /UNIX/ Synonym for "root".
$ superencryption $ superencryption
(I) An encryption operation for which the plaintext input to be (I) An encryption operation for which the plaintext input to be
transformed is the ciphertext output of a previous encryption transformed is the ciphertext output of a previous encryption
operation. (Compare: hybrid encryption.) operation. (Compare: hybrid encryption.)
$ survivability $ survivability
(I) The ability of a system to remain in operation or existence (I) The ability of a system to remain in operation or existence
despite adverse conditions, including both natural occurrences, despite adverse conditions, including natural occurrences,
accidental actions, and attacks on the system. (Compare: accidental actions, and attacks. (Compare: availability,
availability, reliability.) reliability.)
$ swIPe $ swIPe
(I) An encryption protocol for IP that provides confidentiality, (I) An encryption protocol for IP that provides confidentiality,
integrity, and authentication and can be used for both end-to-end integrity, and authentication and can be used for both end-to-end
and intermediate-hop security. [Ioan] (Compare: IPsec.) and intermediate-hop security. [Ioan] (Compare: IPsec.)
Tutorial: The swIPe protocol is an IP predecessor that is Tutorial: The swIPe protocol is an IP predecessor that is
concerned only with encryption mechanisms; policy and key concerned only with encryption mechanisms; policy and key
management are handled outside the protocol. management are handled outside the protocol.
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Tutorial: Symmetric cryptography has been used for thousands of Tutorial: Symmetric cryptography has been used for thousands of
years [Kahn]. A modern example is AES. years [Kahn]. A modern example is AES.
Symmetric cryptography has a disadvantage compared to asymmetric Symmetric cryptography has a disadvantage compared to asymmetric
cryptography with regard to key distribution. For example, when cryptography with regard to key distribution. For example, when
Alice wants to ensure confidentiality for data she sends to Bob, Alice wants to ensure confidentiality for data she sends to Bob,
she encrypts the data with a key, and Bob uses the same key to she encrypts the data with a key, and Bob uses the same key to
decrypt. However, keeping the shared key secret entails both cost decrypt. However, keeping the shared key secret entails both cost
and risk when the key is distributed to both Alice and Bob. (See: and risk when the key is distributed to both Alice and Bob. (See:
key management system.) key distribution, key management.)
$ symmetric key $ symmetric key
(I) A cryptographic key that is used in a symmetric cryptographic (I) A cryptographic key that is used in a symmetric cryptographic
algorithm. (See: symmetric cryptography.) algorithm. (See: symmetric cryptography.)
$ SYN flood $ SYN flood
(I) A denial-of-service attack that sends a large number of TCP (I) A denial-of-service attack that sends a large number of TCP
SYN (synchronize) packets to a host with the intent of disrupting SYN (synchronize) packets to a host with the intent of disrupting
the operation of that host. (See: flooding.) the operation of that host. (See: flooding.)
Tutorial: This attack seeks to exploit a vulnerability in the TCP Tutorial: This attack seeks to exploit a vulnerability in the TCP
specification or in a TCP implementation. Normally, two hosts use specification or in a TCP implementation. Normally, two hosts use
a three-way exchange of packets to establish a TCP connection: (a) a three-way exchange of packets to establish a TCP connection: (a)
host 1 requests a connection by sending a SYN packet to host 2; host 1 requests a connection by sending a SYN packet to host 2;
(b) host 2 replies by sending a SYN-ACK (acknowledgement) packet (b) host 2 replies by sending a SYN-ACK (acknowledgement) packet
to host 1; and (c) host 1 completes the connection by sending an to host 1; and (c) host 1 completes the connection by sending an
ACK packet to host 2. To attack host 2, host 1 can send a series ACK packet to host 2. To attack host 2, host 1 can send a series
of TCP SYNs, each with a different phony source address. ([R2267] of TCP SYNs, each with a different phony source address. ([R2827]
discusses how to use packet filtering to prevent such attacks from discusses how to use packet filtering to prevent such attacks from
being launched from behind an Internet service provider's being launched from behind an Internet service provider's
aggregation point.) Host 2 treats each SYN as a request from a aggregation point.) Host 2 treats each SYN as a request from a
separate host, replies to each with a SYN-ACK, and waits to separate host, replies to each with a SYN-ACK, and waits to
receive the matching ACKs. (The attacker can use random or receive the matching ACKs. (The attacker can use random or
unreachable sources addresses in the SYN packets, or can use unreachable sources addresses in the SYN packets, or can use
source addresses that belong to third parties, that then become source addresses that belong to third parties, that then become
secondary victims.) secondary victims.)
For each SYN-ACK that is sent, the TCP process in host 2 needs For each SYN-ACK that is sent, the TCP process in host 2 needs
some memory space to store state information while waiting for the some memory space to store state information while waiting for the
matching ACK to be returned. If the matching ACK never arrives at matching ACK to be returned. If the matching ACK never arrives at
host 2, a timer associated with the pending SYN-ACK will host 2, a timer associated with the pending SYN-ACK will
eventually expire and release the space. But if host 1 (or a eventually expire and release the space. But if host 1 (or a
cooperating group of hosts) can rapidly send many SYNs to host 2, cooperating group of hosts) can rapidly send many SYNs to host 2,
host 2 will need to store state information for many pending SYN- host 2 will need to store state information for many pending SYN-
ACKs and may run out of space. This can prevent host 2 from ACKs and may run out of space. This can prevent host 2 from
responding to legitimate connection requests from other hosts or responding to legitimate connection requests from other hosts or
even, if there are flaws in host 2's TCP implementation, crash even, if there are flaws in host 2's TCP implementation, crash
when the space is exhausted. when the available space is exhausted.
$ synchronization $ synchronization
(I) Any technique by which a receiving (decrypting) cryptographic (I) Any technique by which a receiving (decrypting) cryptographic
process attains an internal state that matches the transmitting process attains an internal state that matches the transmitting
(encrypting) process, i.e., has the appropriate keying material to (encrypting) process, i.e., has the appropriate keying material to
process the cipher text and is correctly initialized to do so. process the cipher text and is correctly initialized to do so.
$ system $ system
Usage: In this Glossary, the term is mainly used as an Usage: In this Glossary, the term is mainly used as an
abbreviation for "information system". (See: subsystem.) abbreviation of "information system". (See: subsystem.)
$ system architecture $ system architecture
(N) The structure of system components, their relationships, and (N) The structure of system components, their relationships, and
the principles and guidelines governing their design and evolution the principles and guidelines governing their design and evolution
over time. [DoDAF1] (Compare: security architecture.) over time. [DoDAF1] (Compare: security architecture.)
$ system component $ system component
1. (I) A collection of system resources that (a) forms a physical 1. (I) A collection of system resources that (a) forms a physical
or logical part of the system, (b) has specified functions and or logical part of the system, (b) has specified functions and
interfaces, and (c) is treated (e.g., by policies or requirement interfaces, and (c) is treated (e.g., by policies or
statements) as existing independently of other parts of the specifications) as existing independently of other parts of the
system. (See: subsystem.) system. (See: subsystem.)
2. (O) /ITSEC/ An identifiable and self-contained part of a TOE. 2. (O) /ITSEC/ An identifiable and self-contained part of a TOE.
Usage: Component is a relative term because components may be Usage: Component is a relative term because components may be
nested; i.e., one component of system may be a part of another nested; i.e., one component of system may be a part of another
component of that system. component of that system.
Tutorial: Components can be characterized as follows: Tutorial: Components can be characterized as follows:
- A "physical component" has mass and takes up space. - A "physical component" has mass and takes up space.
- A "logical component" is an abstraction used to manage and - A "logical component" is an abstraction used to manage and
coordinate aspects of the physical environment, and typically coordinate aspects of the physical environment, and typically
represents a set of states or capabilities of the system. represents a set of states or capabilities of the system.
$ system entity $ system entity
(I) An active component of a system -- e.g., an automated process (I) An active component of a system -- e.g., an automated process
or set of processes (see: subsystem), or a person or set of or set of processes (see: subsystem), or a person or set of
persons (e.g., an organization) -- that incorporates a specific persons (e.g., an organization) -- that incorporates a specific
set of capabilities. (Compare: subject, user.) set of capabilities. (Compare: subject, user.)
$ system high $ system high
(I) The highest security level at which a system operates, or is (I) The highest security level at which a system operates, or is
capable of operating, at a particular time or in a particular capable of operating, at a particular time or in a particular
environment. (See: system high security mode.) environment. (See: system-high security mode.)
$ system high security mode $ system-high security mode
(I) A mode of operation of an information system, wherein all (I) A mode of system operation wherein all users having access to
users having access to the system possess a security clearance or the system possess all necessary authorizations (both security
authorization, but not necessarily a need-to-know, for all data clearance and formal access approval) for all data handled by the
handled by the system. (See: (system operation) mode.) system, but some users might not have need-to-know for all the
data. (See: /system operation/ under "mode", formal access
approval, protection level, security clearance.)
Usage: This mode was defined formally in U.S. DoD policy that Usage: Usually abbreviated as "system-high mode". This mode was
applied to system accreditation [DoD2], but the term is widely defined in U.S. DoD policy that applied to system accreditation,
used outside the Defense Department and outside the Government. but the term is widely used outside the Government.
$ system integrity $ system integrity
(I) "The quality that a system has when it can perform its (I) "The quality that a system has when it can perform its
intended function in a unimpaired manner, free from deliberate or intended function in a unimpaired manner, free from deliberate or
inadvertent unauthorized manipulation." [NCS04] (See: recovery, inadvertent unauthorized manipulation." [NCS04] (See: recovery,
system integrity service.) system integrity service.)
$ system integrity service $ system integrity service
(I) A security service that protects system resources in a (I) A security service that protects system resources in a
verifiable manner against unauthorized or accidental change, loss, verifiable manner against unauthorized or accidental change, loss,
or destruction. (See: system integrity.) or destruction. (See: system integrity.)
$ system low $ system low
(I) The lowest security level supported by a system at a (I) The lowest security level supported by a system at a
particular time or in a particular environment. (See: system particular time or in a particular environment. (Compare: system
high.) high.)
$ system resource $ system resource
(I) Data contained in an information system; or a service provided (I) Data contained in an information system; or a service provided
by a system; or a system capability, such as processing power or by a system; or a system capacity, such as processing power or
communication bandwidth; or an item of system equipment (i.e., communication bandwidth; or an item of system equipment (i.e.,
hardware, firmware, software, or documentation); or a facility hardware, firmware, software, or documentation); or a facility
that houses system operations and equipment. (See: system that houses system operations and equipment. (See: system
component.) component.)
$ system security officer (SSO) $ system security officer (SSO)
(I) A person responsible for enforcement or administration of the (I) A person responsible for enforcement or administration of the
security policy that applies to the system. security policy that applies to a system.
$ TACACS $ TACACS
(I) See: Terminal Access Controller (TAC) Access Control System. (I) See: Terminal Access Controller (TAC) Access Control System.
$ TACACS+ $ TACACS+
(I) A TCP-based protocol that improves on TACACS and XTACACS by (I) A TCP-based protocol that improves on TACACS and XTACACS by
separating the functions of authentication, authorization, and separating the functions of authentication, authorization, and
accounting and by encrypting all traffic between the network accounting and by encrypting all traffic between the network
access server and authentication server. TACACS+ is extensible to access server and authentication server. TACACS+ is extensible to
allow any authentication mechanism to be used with TACACS+ allow any authentication mechanism to be used with TACACS+
clients. (See: TACACS, XTACACS.) clients. (See: TACACS, XTACACS.)
$ tamper $ tamper
(I) Make an unauthorized modification in a system that alters the (I) Make an unauthorized modification in a system that alters the
system's functioning in a way that degrades the security services system's functioning in a way that degrades the security services
that the system was intended to provide. (See: QUADRANT. Compare: that the system was intended to provide. (See: QUADRANT. Compare:
(secondary definitions under) "corruption" and "misuse".) secondary definitions under "corruption" and "misuse".)
$ tamper-evident $ tamper-evident
(I) A characteristic of a system component that provides evidence (I) A characteristic of a system component that provides evidence
that an attack has been attempted on that component or system. that an attack has been attempted on that component or system.
Usage: Normally refers to physical evidence. (See: tamper.) Usage: Usually involves physical evidence. (See: tamper.)
$ tamper-resistant $ tamper-resistant
(I) A characteristic of a system component that provides passive (I) A characteristic of a system component that provides passive
protection against an attack. (See: tamper.) protection against an attack. (See: tamper.)
Usage: Normally refers to physical means of protection. Usage: Usually involves physical means of protection.
$ target of evaluation (TOE) $ target of evaluation (TOE)
(N) /Common Criteria/ An information technology product or system (N) /Common Criteria/ An information technology product or system
that is the subject of a security evaluation, together with the that is the subject of a security evaluation, together with the
product's associated administrator and user documentation. product's associated administrator and user documentation.
(Compare: protection profile.)
Tutorial: The security characteristics of the target of evaluation Tutorial: The security characteristics of the target of evaluation
(TOE) are described in specific terms by a corresponding security (TOE) are described in specific terms by a corresponding security
target, or in more general terms by a protection profile. In target, or in more general terms by a protection profile. In
Common Criteria philosophy, it is important that a TOE be Common Criteria philosophy, it is important that a TOE be
evaluated against the specific set of criteria expressed in the evaluated against the specific set of criteria expressed in the
security target (ST). This evaluation consists of rigorous target. This evaluation consists of rigorous analysis and testing
analysis and testing performed by an accredited, independent performed by an accredited, independent laboratory. The scope of a
laboratory. The scope of a TOE evaluation is set by the EAL and TOE evaluation is set by the EAL and other requirements specified
other requirements specified in the ST. Part of this process is an in the target. Part of this process is an evaluation of the target
evaluation of the ST itself, to ensure that it is correct, itself, to ensure that it is correct, complete, and internally
complete, and internally consistent and can be used as the consistent and can be used as the baseline for the TOE evaluation.
baseline for the TOE evaluation.
$ TCB $ TCB
(N) See: trusted computing base. (N) See: trusted computing base.
$ TCC field $ TCC field
(I) See: Transmission Control Code field. (I) See: Transmission Control Code field.
$ TCP $ TCP
(I) See: Transmission Control Protocol. (I) See: Transmission Control Protocol.
$ TCP/IP $ TCP/IP
(I) Synonym for "Internet Protocol Suite", in which the (I) Synonym for "Internet Protocol Suite".
Transmission Control Protocol (TCP) and the Internet Protocol (IP)
are important parts.
$ TCSEC $ TCSEC
(N) See: Trusted Computer System Evaluation Criteria. (Compare: (N) See: Trusted Computer System Evaluation Criteria. (Compare:
TSEC.) TSEC.)
$ TDEA $ TDEA
(I) See: Triple Data Encryption Algorithm. (I) See: Triple Data Encryption Algorithm.
$ teardrop attack $ teardrop attack
(D) An denial-of-service attack that sends improperly formed IP (D) /slang/ An denial-of-service attack that sends improperly
packet fragments with the intent of causing the destination system formed IP packet fragments with the intent of causing the
to fail. destination system to fail.
Deprecated Term: The term is often used imprecisely and could Deprecated Term: ISDs that use this term SHOULD state a definition
easily be misunderstood; therefore, ISDs that use this term SHOULD for it because the term is often used imprecisely and could easily
state a definition for it. (See: (Deprecated Usage under) Green be misunderstood. (See: Deprecated Usage under "Green Book".)
Book.)
$ technical non-repudiation $ technical non-repudiation
(I) See: (secondary definition under) non-repudiation. (I) See: (secondary definition under) non-repudiation.
$ technical security $ technical security
(I) Security mechanisms and procedures that are implemented in and (I) Security mechanisms and procedures that are implemented in and
executed by hardware, software, or firmware (rather than by executed by computer hardware, firmware, or software to provide
people) to provide automated protection for a system. (See: automated protection for a system. (See: security architecture.
security architecture. Compare: administrative security.) Compare: administrative security.)
$ Telecommunications Security Nomenclature System (TSEC) $ Telecommunications Security Word System (TSEC)
(O) An NSA designation system for telecommunication security (O) /U.S. Government/ A terminology for designating
equipment. (Compare: TCSEC.) telecommunication security equipment. (Compare: TCSEC.)
Tutorial: A TSEC designator has the following parts: Tutorial: A TSEC designator has the following parts:
- Prefix "TSEC/" for items and systems, or suffix "/TSEC" for - Prefix "TSEC/" for items and systems, or suffix "/TSEC" for
assemblies. (Often omitted when the context is clear.) assemblies. (Often omitted when the context is clear.)
- First letter, for function: "C" COMSEC equipment system, "G" - First letter, for function: "C" COMSEC equipment system, "G"
general purpose, "K" cryptographic, "H" crypto-ancillary, "M" general purpose, "K" cryptographic, "H" crypto-ancillary, "M"
manufacturing, "N" noncryptographic, "S" special purpose. manufacturing, "N" noncryptographic, "S" special purpose.
- Second letter, for type or purpose: "G" key generation, "I" - Second letter, for type or purpose: "G" key generation, "I"
data transmission, "L" literal conversion, "N" signal data transmission, "L" literal conversion, "N" signal
conversion, "O" multipurpose, "P" materials production, "S" conversion, "O" multipurpose, "P" materials production, "S"
special purpose, "T" testing or checking, "U" television, "W" special purpose, "T" testing or checking, "U" television, "W"
teletypewriter, "X" facsimile, "Y" speech. teletypewriter, "X" facsimile, "Y" speech.
- Optional third letter, used only in designations of assemblies, - Optional third letter, used only in designations of assemblies,
for type or purpose: "A" advancing, "B" base or cabinet, "C" for type or purpose: "A" advancing, "B" base or cabinet, "C"
combining, "D" drawer or panel, "E" strip or chassis, "F" frame combining, "D" drawer or panel, "E" strip or chassis, "F" frame
or rack, "G" key generator, "H" keyboard, "I" translator or or rack, "G" key generator, "H" keyboard, "I" translator or
reader, "J" speech processing, "K" keying or permuting, "L" reader, "J" speech processing, "K" keying or permuting, "L"
repeater, "M" memory or storage, "O" observation, "P" power repeater, "M" memory or storage, "O" observation, "P" power
supply or converter, "R" receiver, "S" synchronizing, "T" supply or converter, "R" receiver, "S" synchronizing, "T"
transmitter, "U" printer, "V" removable COMSEC component, "W" transmitter, "U" printer, "V" removable COMSEC component, "W"
logic programmer/programming, "X" special purpose. logic programmer/programming, "X" special purpose.
- Model number, usually two or 3 digits, assigned sequentially - Model number, usually two or 3 digits, assigned sequentially
within each letter combination (e.g., KG-34, KG-84). within each letter combination (e.g., KG-34, KG-84).
- Optional suffix letter, used to designate a version. First - Optional suffix letter, used to designate a version. First
version has no letter, next version has "A" (e.g., KG-84, KG- version has no letter, next version has "A" (e.g., KG-84, KG-
84A), etc. 84A), etc.
$ TELNET $ TELNET
(I) A TCP-based, application-level, Internet Standard protocol (I) A TCP-based, Application-Layer, Internet Standard protocol
(RFC 854) for remote login from one host to another. (RFC 854) for remote login from one host to another.
$ TEMPEST $ TEMPEST
(N) Short name for technology and methods for protecting against (N) Short name for technology and methods for protecting against
data compromise due to electromagnetic emanations from electrical data compromise due to electromagnetic emanations from electrical
and electronic equipment. [Russ] (See: inspectable space, soft and electronic equipment. [Russ] (See: inspectable space, soft
TEMPEST, TEMPEST zone. Compare: QUADRANT) TEMPEST, TEMPEST zone. Compare: QUADRANT)
(O) /U.S. Government/ "Short name referring to investigation, (O) /U.S. Government/ "Short name referring to investigation,
study, and control of compromising emanations from IS equipment." study, and control of compromising emanations from IS equipment."
[N4009] [N4009]
Deprecated Usage: ISDs SHOULD NOT use this term as a synonym for Deprecated Usage: ISDs SHOULD NOT use this term as a synonym for
"electromagnetic emanations security"; instead, use EMSEC. Also, "electromagnetic emanations security"; instead, use EMSEC. Also,
the term is NOT an acronym for Transient Electromagnetic Pulse the term is NOT an acronym for Transient Electromagnetic Pulse
Surveillance Technology. Surveillance Technology.
Tutorial: U.S. Government security policy states (a) Tutorial: The U.S. Federal Government issues security policies
specifications and standards for techniques to reduce the that (a) state specifications and standards for techniques to
strength of emanations from systems and reduce the ability of reduce the strength of emanations from systems and reduce the
unauthorized parties to receive and make use of emanations, and ability of unauthorized parties to receive and make use of
(b) rules for applying those techniques. Other nations presumably emanations and (b) state rules for applying those techniques.
do the same. Other nations presumably do the same.
$ TEMPEST zone $ TEMPEST zone
(O) "Designated area [i.e., a physical volume] within a facility (O) "Designated area [i.e., a physical volume] within a facility
where equipment that has appropriate TEMPEST characteristics ... where equipment that has appropriate TEMPEST characteristics ...
may be operated." [C4009] (See: emanation security, TEMPEST. may be operated." [C4009] (See: emanation security, TEMPEST.
Compare: inspectable space.) Compare: inspectable space.)
Tutorial: The strength of an electromagnetic signal decreases in Tutorial: The strength of an electromagnetic signal decreases in
proportion to the square of the distance between the source and proportion to the square of the distance between the source and
the receiver. Therefore, EMSEC for electromagnetic signals can be the receiver. Therefore, EMSEC for electromagnetic signals can be
achieved by a combination of (a) reducing the strength of achieved by a combination of (a) reducing the strength of
emanations to a defined level and (b) establishing around that emanations to a defined level and (b) establishing around that
equipment an appropriately sized physical buffer zone from which equipment an appropriately sized physical buffer zone from which
unauthorized entities are excluded. By making the zone large unauthorized entities are excluded. By making the zone large
enough, it is possible to limit the signal strength available to enough, it is possible to limit the signal strength available to
skipping to change at page 246, line 51 skipping to change at page 264, line 4
1a. (I) A potential for violation of security, which exists when 1a. (I) A potential for violation of security, which exists when
there is an entity, circumstance, capability, action, or event there is an entity, circumstance, capability, action, or event
that could cause harm. (See: dangling threat, INFOCON level, that could cause harm. (See: dangling threat, INFOCON level,
threat action, threat agent, threat consequence. Compare: attack, threat action, threat agent, threat consequence. Compare: attack,
vulnerability.) vulnerability.)
1b. (N) Any circumstance or event with the potential to adversely 1b. (N) Any circumstance or event with the potential to adversely
affect a system through unauthorized access, destruction, affect a system through unauthorized access, destruction,
disclosure, or modification of data, or denial of service. [C4009] disclosure, or modification of data, or denial of service. [C4009]
(See: sensitive information.) (See: sensitive information.)
Usage: (a) Frequently misused with the meaning of either "threat Usage: (a) Frequently misused with the meaning of either "threat
action" or "vulnerability". (b) In some contexts, "threat" is used action" or "vulnerability". (b) In some contexts, "threat" is used
more narrowly to refer only to intelligent threats; for example, more narrowly to refer only to intelligent threats; for example,
see definition 2 below. (c) In some contexts, "threat" is used see definition 2 below. (c) In some contexts, "threat" is used
more broadly to cover both definition 1 and other concepts, such more broadly to cover both definition 1 and other concepts, such
as in definition 3 below. as in definition 3 below.
Tutorial: A threat is a possible danger that might exploit a Tutorial: A threat is a possible danger that might exploit a
vulnerability. vulnerability. Thus, a threat may be intentional or not:
- "Intentional threat": A possibility of an attack by an - "Intentional threat": A possibility of an attack by an
intelligent entity (e.g., an individual cracker or a criminal intelligent entity (e.g., an individual cracker or a criminal
organization). organization).
- "Accidental threat": A possibility of human error or omission, - "Accidental threat": A possibility of human error or omission,
unintended equipment malfunction, or natural disaster (e.g., unintended equipment malfunction, or natural disaster (e.g.,
fire, flood, earthquake, or windstorm). (See list in [FP031].) fire, flood, earthquake, windstorm, and other causes listed in
[FP031]).
The Common Criteria characterizes a threat in terms of (a) a The Common Criteria characterizes a threat in terms of (a) a
threat agent, (b) a presumed method of attack, (c) any threat agent, (b) a presumed method of attack, (c) any
vulnerabilities that are the foundation for the attack, and (d) vulnerabilities that are the foundation for the attack, and (d)
the system resource that is attacked. the system resource that is attacked. That characterization agrees
with the definitions in this Glossary (see: diagram under
"attack").
2. (O) The technical and operational capability of a hostile 2. (O) The technical and operational ability of a hostile entity
entity to detect, exploit, or subvert a friendly system and the to detect, exploit, or subvert a friendly system and the
demonstrated, presumed, or inferred intent of that entity to demonstrated, presumed, or inferred intent of that entity to
conduct such activity. conduct such activity.
Tutorial: To be likely to launch an attack, an adversary must have Tutorial: To be likely to launch an attack, an adversary must have
(a) a motive to attack, (b) a method or technical capability to (a) a motive to attack, (b) a method or technical ability to make
make the attack, and (c) an opportunity to appropriately access the attack, and (c) an opportunity to appropriately access the
the targeted system. targeted system.
3. (O) "An indication of an impending undesirable event." [Park] 3. (O) "An indication of an impending undesirable event." [Park]
Tutorial: Definition 3 was intended to include these meanings: Tutorial: Definition 3 was intended to include these meanings:
- "Potential threat": A possible security violation; i.e., the - "Potential threat": A possible security violation; i.e., the
same as definition 1. same as definition 1.
- "Active threat": An expression of intent to violate security. - "Active threat": An expression of intent to violate security.
(Context usually distinguishes this meaning from the previous (Context usually distinguishes this meaning from the previous
one.) one.)
- "Accomplished threat" or "actualized threat": That is, an - "Accomplished threat" or "actualized threat": That is, a threat
attack. Deprecated Usage: ISDs SHOULD NOT use the term "threat" action. Deprecated Usage: ISDs SHOULD NOT use the term "threat"
with this meaning; instead, use "threat action". with this meaning; instead, use "threat action".
$ threat action $ threat action
(I) A realization of a threat, i.e., an occurrence in which system (I) A realization of a threat, i.e., an occurrence in which system
security is assaulted as the result of either an accidental event security is assaulted as the result of either an accidental event
or an intentional act. (See: attack, threat, threat consequence.) or an intentional act. (See: attack, threat, threat consequence.)
Tutorial: A complete security architecture deals with both Tutorial: A complete security architecture deals with both
intentional acts (i.e. attacks) and accidental events [FIPS31]. intentional acts (i.e. attacks) and accidental events [FIPS31].
(See: (various kinds of threat actions defined as subentries (See: various kinds of threat actions defined under the four kinds
under) threat consequence.) of "threat consequence".)
$ threat agent $ threat agent
(I) A system entity that performs a threat action, or an event (I) A system entity that performs a threat action, or an event
that results in a threat action. that results in a threat action.
$ threat analysis $ threat analysis
(I) An analysis of the probability of occurrences and consequences (I) An analysis of the threat actions that might affect a system,
of damaging actions to a system. primarily emphasizing their probability of occurrence but also
considering their resulting threat consequences. (Compare: risk
analysis.)
$ threat consequence $ threat consequence
(I) A security violation that results from a threat action. (I) A security violation that results from a threat action.
Tutorial: The four basic types of threat consequence are Tutorial: The four basic types of threat consequence are
"unauthorized disclosure", "deception", "disruption", and "unauthorized disclosure", "deception", "disruption", and
"usurpation" (see definitions of these four terms for discussion "usurpation". (See main Glossary entries of each of these four
of the types of threat actions that can these consequences). terms for lists of the types of threat actions that can result in
these consequences.)
$ thumbprint $ thumbprint
(I) A pattern of curves formed by the ridges on the tip of a 1. (I) A pattern of curves formed by the ridges on the tip of a
thumb. (See: biometric authentication, fingerprint.) thumb. (See: biometric authentication, fingerprint.)
2. (D) Synonym for some type of "hash result". (See: biometric
authentication. Compare: fingerprint.)
Deprecated Usage: ISDs SHOULD NOT use this term as a synonym for Deprecated Usage: ISDs SHOULD NOT use this term as a synonym for
"hash result" because that meaning mixes concepts in a potentially "hash result" because that meaning mixes concepts in a potentially
misleading way. misleading way.
$ ticket $ ticket
(I) Synonym for "capability". (I) Synonym for "capability token".
Tutorial: A ticket is usually granted by a centralized access Tutorial: A ticket is usually granted by a centralized access
control server (ticket-granting agent) to authorize access to a control server (ticket-granting agent) to authorize access to a
system resource for a limited time. Tickets can be implemented system resource for a limited time. Tickets can be implemented
with either symmetric cryptography (see: Kerberos) or asymmetric with either symmetric cryptography (see: Kerberos) or asymmetric
cryptography (see: attribute certificate). cryptography (see: attribute certificate).
$ tiger team $ tiger team
(I) A group of evaluators employed by a system's managers to (I) A group of evaluators employed by a system's managers to
perform penetration tests on the system. perform penetration tests on the system.
Deprecated Term: It is likely that other cultures have different Deprecated Term: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ time stamp $ time stamp
(I) /noun/ With respect to a data object, a label or marking in (I) /noun/ With respect to a data object, a label or marking in
which is recorded the time (time of day or other instant of which is recorded the time (time of day or other instant of
elapsed time) at which the label or marking was affixed to the elapsed time) at which the label or marking was affixed to the
data object. (See: Time-Stamp Protocol.) data object. (See: Time-Stamp Protocol.)
(O) /noun/ "With respect to a recorded network event, a data field (O) /noun/ "With respect to a recorded network event, a data field
in which is recorded the time (time of day or other instant of in which is recorded the time (time of day or other instant of
elapsed time) at which the event took place." [A1523] elapsed time) at which the event took place." [A1523]
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containing a time stamp. The authority creates the stamp by containing a time stamp. The authority creates the stamp by
concatenating (a) a hash value of the input data object with (b) a concatenating (a) a hash value of the input data object with (b) a
UTC time value and other parameters (policy OID, serial number, UTC time value and other parameters (policy OID, serial number,
indication of time accuracy, nonce, DN of the authority, and indication of time accuracy, nonce, DN of the authority, and
various extensions), and then signing that dataset with the various extensions), and then signing that dataset with the
authority's private key as specified in CMS. Such an authority authority's private key as specified in CMS. Such an authority
typically would operate as a trusted third-party service, but typically would operate as a trusted third-party service, but
other operational models might be used. other operational models might be used.
$ timing channel $ timing channel
See: covert timing channel. (I) See: covert timing channel.
$ TLS $ TLS
(I) See: Transport Layer Security. (I) See: Transport Layer Security.
$ TLSP $ TLSP
(N) See: Transport Layer Security Protocol. (N) See: Transport Layer Security Protocol.
$ TOE $ TOE
(N) See: target of evaluation (N) See: target of evaluation
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(I) See: Transport Layer Security. (I) See: Transport Layer Security.
$ TLSP $ TLSP
(N) See: Transport Layer Security Protocol. (N) See: Transport Layer Security Protocol.
$ TOE $ TOE
(N) See: target of evaluation (N) See: target of evaluation
$ token $ token
1. (I) /cryptography/ See: cryptographic token. (Compare: dongle.) 1. (I) /cryptography/ See: cryptographic token. (Compare: dongle.)
2. (I) /access control/ An object that is used to control access 2. (I) /access control/ An object that is used to control access
and is passed between cooperating entities in a protocol that and is passed between cooperating entities in a protocol that
synchronizes use of a shared resource. Usually, the entity that synchronizes use of a shared resource. Usually, the entity that
currently holds the token has exclusive access to the resource. currently holds the token has exclusive access to the resource.
(See: capability token.)
Usage: This term is heavily overloaded in the computing Usage: This term is heavily overloaded in the computing
literature; therefore, ISDs SHOULD NOT use this term with any literature; therefore, ISDs SHOULD NOT use this term with any
definition other than 1 or 2. definition other than 1 or 2.
3a. (D) /authentication/ A data object or a physical device used 3a. (D) /authentication/ A data object or a physical device used
to verify an identity in an authentication process. to verify an identity in an authentication process.
3b. (D) /U.S. Government/ Something that the claimant in an 3b. (D) /U.S. Government/ Something that the claimant in an
authentication process (i.e., the entity that claims an identity) authentication process (i.e., the entity that claims an identity)
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verification step of the process. [SP63] verification step of the process. [SP63]
Usage: Deprecated usage: ISDs SHOULD NOT use this term with Usage: Deprecated usage: ISDs SHOULD NOT use this term with
definitions 3a and 3b; instead, use more specifically descriptive definitions 3a and 3b; instead, use more specifically descriptive
and informative terms such as "authentication information" or and informative terms such as "authentication information" or
"cryptographic token", depending on what is meant. "cryptographic token", depending on what is meant.
NIST defines four types of claimant tokens for electronic NIST defines four types of claimant tokens for electronic
authentication in an information system [SP63]. ISDs SHOULD NOT authentication in an information system [SP63]. ISDs SHOULD NOT
use these four NIST terms; they mix concepts in potentially use these four NIST terms; they mix concepts in potentially
confusing ways. These terms can be avoided by using more confusing ways and duplicate the meaning of better-established
specifically descriptive terms as follows: terms. These four terms can be avoided by using more specifically
- NIST "hard token": A hardware device that contains a protected descriptive terms as follows:
- NIST "hard token": A hardware device that contains a protected
cryptographic key. (This is a type of "cryptographic token", cryptographic key. (This is a type of "cryptographic token",
and the key is a type of "authentication information".) and the key is a type of "authentication information".)
- NIST "one-time password device token": A personal hardware - NIST "one-time password device token": A personal hardware
device that generates one-time passwords. (One-time passwords device that generates one-time passwords. (One-time passwords
are typically generated cryptographically. Therefore, this is a are typically generated cryptographically. Therefore, this is a
type of "cryptographic token", and the key is a type of type of "cryptographic token", and the key is a type of
"authentication information".) "authentication information".)
- NIST "soft token": A cryptographic key that typically is stored - NIST "soft token": A cryptographic key that typically is stored
on disk or some other magnetic media. (The key is a type of on disk or some other magnetic media. (The key is a type of
"authentication information"; "authentication key" would be a "authentication information"; "authentication key" would be a
better description.) better description.)
- NIST "password token": A secret data value that the claimant - NIST "password token": A secret data value that the claimant
memorizes. (This is a "password" that is being used as memorizes. (This is a "password" that is being used as
"authentication information".) "authentication information".)
$ token backup $ token backup
(I) A token management operation that stores sufficient (I) A token management operation that stores sufficient
information in a database (e.g., in a CAW) to recreate or restore information in a database (e.g., in a CAW) to recreate or restore
a security token (e.g., a smart card) if it is lost or damaged. a security token (e.g., a smart card) if it is lost or damaged.
$ token copy $ token copy
(I) A token management operation that copies all the personality (I) A token management operation that copies all the personality
information from one security token to another. However, unlike in information from one security token to another. However, unlike in
a token restore operation, the second token is initialized with a token restore operation, the second token is initialized with
its own, different local security values such as PINs and storage its own, different local security values such as PINs and storage
keys. keys.
$ token management $ token management
(I) The process of initializing security tokens (e.g., see: smart (I) The process that includes initializing security tokens (e.g.,
card), loading data into the tokens, and controlling the tokens see: smart card), loading data into the tokens, and controlling
during their life cycle. May include performing key management and the tokens during their life cycle. May include performing key
certificate management functions; generating and installing PINs; management and certificate management functions; generating and
loading user personality data; performing card backup, card copy, installing PINs; loading user personality data; performing card
and card restore operations; and updating firmware. backup, card copy, and card restore operations; and updating
firmware.
$ token restore $ token restore
(I) A token management operation that loads a security token with (I) A token management operation that loads a security token with
data for the purpose of recreating (duplicating) the contents data for the purpose of recreating (duplicating) the contents
previously held by that or another token. (See: recovery.) previously held by that or another token. (See: recovery.)
$ token storage key $ token storage key
(I) A cryptographic key used to protect data that is stored on a (I) A cryptographic key used to protect data that is stored on a
security token. security token.
$ top CA $ top CA
(I) A synonym for "root" in a certification hierarchy. (I) A synonym for "root" in a certification hierarchy. (See: apex
trust anchor.)
$ top-level specification $ top-level specification
(I) "A non-procedural description of system behavior at the most (I) "A non-procedural description of system behavior at the most
abstract level; typically a functional specification that omits abstract level; typically a functional specification that omits
all implementation details." [NCS04] (See: (discussion under) all implementation details." [NCS04] (See: Tutorial under
security policy.) "security policy".)
Tutorial: A top-level specification may be descriptive or formal: Tutorial: A top-level specification is at a level of abstraction
- "Descriptive top-level specification": One that is written in a below "security model" and above "security architecture" (see:
Tutorial under "security policy").
A top-level specification may be descriptive or formal:
- "Descriptive top-level specification": One that is written in a
natural language like English or an informal design notation. natural language like English or an informal design notation.
- "Formal top-level specification": One that is written in a - "Formal top-level specification": One that is written in a
formal mathematical language to enable theorems to be proven formal mathematical language to enable theorems to be proven
that show that the specification correctly implements a set of that show that the specification correctly implements a set of
formal requirements or a formal security model. (See: formal requirements or a formal security model. (See:
correctness proof.) correctness proof.)
$ traceback $ traceback
(I) Identification of the source of a data packet. (See: network (I) Identification of the source of a data packet. (See:
weaving.) masquerade, network weaving.)
$ tracker $ tracker
(N) An attack technique for achieving unauthorized disclosure from (N) An attack technique for achieving unauthorized disclosure from
a statistical database. [Denns] (See: (Tutorial under) inference a statistical database. [Denns] (See: Tutorial under "inference
control.) control".)
$ traffic analysis $ traffic analysis
1. (I) Gaining knowledge of information by inference from 1. (I) Gaining knowledge of information by inference from
observable characteristics of data flow(s), even when the observable characteristics of a data flow, even if the information
information is encrypted or otherwise not directly available. Such is not directly available (e.g., when the data is encrypted).
characteristics include the identities and locations of the These characteristics include the identities and locations of the
source(s) and destination(s), and the presence, amount, frequency, source(s) and destination(s) of the flow, and the flow's presence,
and duration of occurrence. (See: inference, traffic-flow amount, frequency, and duration of occurrence. The object of the
confidentiality, wiretapping. Compare: signal analysis.) analysis might be information in SDUs, information in the PCI, or
both. (See: inference, traffic-flow confidentiality, wiretapping.
Compare: signal analysis.)
2. (O) "The inference of information from observation of traffic 2. (O) "The inference of information from observation of traffic
flows (presence, absence, amount, direction, and frequency)." flows (presence, absence, amount, direction, and frequency)."
[I7498 Part 2] [I7498 Part 2]
$ traffic-flow analysis $ traffic-flow analysis
(I) Synonym for "traffic analysis". (I) Synonym for "traffic analysis".
$ traffic-flow confidentiality $ traffic-flow confidentiality (TFC)
1. (I) A data confidentiality service to protect against traffic 1. (I) A data confidentiality service to protect against traffic
analysis. (See: communications cover.) analysis. (See: communications cover.)
2. (O) "A confidentiality service to protect against traffic 2. (O) "A confidentiality service to protect against traffic
analysis." [I7498 Part 2] analysis." [I7498 Part 2]
Tutorial: Confidentiality concerns involve both direct and
indirect disclosure of data, and the latter includes traffic
analysis. However, operational considerations can make TFC
difficult to achieve. For example, if Alice sends a product idea
to Bob in an email message, she wants data confidentiality for the
message's content, and she might also want to conceal the
destination of the message in order to hide Bob's identity from
her competitors. However, the identity of the intended recipient,
or at least a network address for that recipient, needs to be made
available to the mail system. Thus, complex forwarding schemes may
be needed to conceal the ultimate destination as the message
travels through the open Internet (see: onion routing).
Later, if Alice uses an ATM during a clandestine visit to
negotiate with Bob, she might prefer that her bank conceal the
origin of her transaction, because knowledge of the ATM's location
might allow a competitor to infer Bob's identity. The bank, on the
other hand, might prefer to protect only Alice's PIN (see:
selective-field confidentiality).
A TFC service can be either full or partial:
- "Full TFC": This type of service conceals all traffic
characteristics.
- "Partial TFC": This type of service either (a) conceals some
but not all of the characteristics or (b) does not completely
conceal some characteristic.
On point-to-point data links, full TFC can be provided by
enciphering all PDUs and also generating a continuous, random data
stream to seamlessly fill all gaps between PDUs. To a wiretapper,
the link then appears to be carrying an unbroken stream of
enciphered data. In other cases -- including on a shared or
broadcast medium, or end-to-end in a network -- only partial TFC
is possible, and that may require a combination of techniques. For
example, a LAN that uses "carrier sense multiple access with
collision detection" (CSMA/CD; a.k.a. "listen while talk") to
control access to the medium, relies on detecting intervals of
silence, which prevents using full TFC. Partial TFC can be
provided on that LAN by measures such as adding spurious PDUs,
padding PDUs to a constant size, or enciphering addresses just
above the Physical Layer; but these measures reduce the efficiency
with which the LAN can carry traffic. At higher protocol layers,
SDUs can be protected, but addresses and other items of PCI must
be visible at the layers below.
$ traffic key
(I) A cryptographic key used by a device for protecting
information that is being transmitted between devices, as opposed
to protecting information that being is maintained in the device.
(Compare: storage key.)
$ traffic padding $ traffic padding
(I) "The generation of spurious instances of communication, (I) "The generation of spurious instances of communication,
spurious data units, and/or spurious data within data units." spurious data units, and/or spurious data within data units."
[I7498 Part 2] [I7498 Part 2]
$ tranquillity property $ tranquillity property
(N) /formal model/ Property of a system whereby the security level (N) /formal model/ Property of a system whereby the security level
of an object cannot change while the object is being processed by of an object cannot change while the object is being processed by
the system. (See: Bell-LaPadula model.) the system. (See: Bell-LaPadula model.)
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1. (I) A unit of interaction between an external entity and a 1. (I) A unit of interaction between an external entity and a
system, or between components within a system, that involves a system, or between components within a system, that involves a
series of system actions or events. series of system actions or events.
2. (O) "A discrete event between user and systems that supports a 2. (O) "A discrete event between user and systems that supports a
business or programmatic purpose." [M0404] business or programmatic purpose." [M0404]
Tutorial: To maintain secure state, transactions need to be Tutorial: To maintain secure state, transactions need to be
processed coherently and reliably. Usually, they need to be processed coherently and reliably. Usually, they need to be
designed to be atomic, consistent, isolated, and durable [Gray]: designed to be atomic, consistent, isolated, and durable [Gray]:
- "Atomic": All actions and events that comprise the transaction - "Atomic": All actions and events that comprise the transaction
are guaranteed to be completed successfully, or else the result are guaranteed to be completed successfully, or else the result
is as if none at all were executed. is as if none at all were executed.
- "Consistent": The transaction satisfies correctness constraints - "Consistent": The transaction satisfies correctness constraints
defined for the data that is being processed. defined for the data that is being processed.
- "Isolated": If two transactions are performed concurrently, - "Isolated": If two transactions are performed concurrently,
they do not interfere with each other, and it appears as though they do not interfere with each other, and it appears as though
the system performs one at a time. the system performs one at a time.
- "Durable": System state and transaction semantics survive - "Durable": System state and transaction semantics survive
system failures. system failures.
$ TRANSEC $ TRANSEC
(I) See: transmission security. (I) See: transmission security.
$ Transmission Control Code field (TCC field) $ Transmission Control Code field (TCC field)
(I) A data field that provides a means to segregate traffic and (I) A data field that provides a means to segregate traffic and
define controlled communities of interest in the security option define controlled communities of interest in the security option
(option type = 130) of IP's datagram header format. The TCC values (option type = 130) of IPv4's datagram header format. The TCC
are alphanumeric trigraphs assigned by the U.S. Government as values are alphanumeric trigraphs assigned by the U.S. Government
specified in RFC 791. as specified in RFC 791.
$ Transmission Control Protocol (TCP) $ Transmission Control Protocol (TCP)
(I) An Internet Standard, transport-layer protocol (RFC 793) that (I) An Internet Standard, Transport-Layer protocol (RFC 793) that
reliably delivers a sequence of datagrams from one computer to reliably delivers a sequence of datagrams from one computer to
another in a computer network. (See: TCP/IP.) another in a computer network. (See: TCP/IP.)
Tutorial: TCP is designed to fit into a layered suite of protocols Tutorial: TCP is designed to fit into a layered suite of protocols
that support internetwork applications. TCP assumes it can obtain that support internetwork applications. TCP assumes it can obtain
a simple but potentially unreliable end-to-end datagram service a simple but potentially unreliable end-to-end datagram service
(such as IP) from the lower level protocols. (such as IP) from the lower layer protocols.
$ transmission security (TRANSEC) $ transmission security (TRANSEC)
(I) Measures that protect communications from interception and (I) Measures that protect communications from interception and
exploitation by means other than cryptanalysis. Usually understood exploitation by means other than cryptanalysis. Usually understood
to be a part of COMSEC. (Compare: traffic flow confidentiality.) to be a part of COMSEC. (Compare: traffic flow confidentiality.)
$ Transport Layer
See: Internet Protocol Suite, OSIRM.
$ Transport Layer Security (TLS) $ Transport Layer Security (TLS)
(I) TLS Version 1.0 is an Internet protocol [R2246] that is based (I) TLS Version 1.0 is an Internet protocol [R2246] that is based
on, and very similar to, SSL Version 3.0. (Compare: TLSP.) on, and very similar to, SSL Version 3.0. (Compare: TLSP.)
Usage: The TLS protocol is misnamed, because it operates well Deprecated Usage: The TLS protocol is misnamed. The name
above the IPS transport layer. misleadingly suggests that TLS is situated in the IPS Transport
Layer, but TLS is always layered above a reliable Transport-Layer
protocol (usually TCP) and either layered immediately below or
integrated with an Application-Layer protocol (often HTTP).
$ Transport Layer Security Protocol (TLSP) $ Transport Layer Security Protocol (TLSP)
(N) An end-to-end encryption protocol (ISO 10736) that provides (N) An end-to-end encryption protocol (ISO 10736) that provides
security services at the bottom of OSIRM layer 4, i.e., directly security services at the bottom of OSIRM Layer 4, i.e., directly
above layer 3. (Compare: TLS.) above Layer 3. (Compare: TLS.)
Tutorial: TLSP evolved directly from SP4. Tutorial: TLSP evolved directly from SP4.
$ transport mode $ transport mode
(I) One of two ways to apply AH or ESP to protect data packets; in (I) One of two ways to apply AH or ESP to protect data packets; in
this mode, the IPsec protocol encapsulates (i.e., the protection this mode, the IPsec protocol encapsulates (i.e., the protection
applies to) the packets of an IPS transport protocol (e.g., TCP, applies to) the packets of an IPS Transport-Layer protocol (e.g.,
UDP), which is normally carried directly above IP in an IPS TCP, UDP), which is normally carried directly above IP in an IPS
protocol stack. (Compare: tunnel mode.) protocol stack. (Compare: tunnel mode.)
Tutorial: An IPsec transport-mode security association is always Tutorial: An IPsec transport-mode security association is always
between two hosts; neither end has the role of a security gateway. between two hosts; neither end has the role of a security gateway.
Whenever either end of an IPsec security association is a security Whenever either end of an IPsec security association is a security
gateway, the association is required to be in tunnel mode. gateway, the association is required to be in tunnel mode.
$ transposition $ transposition
(I) /cryptography/ A method of encryption in which elements of the (I) /cryptography/ A method of encryption in which elements of the
plain text retain their original form but undergo some change in plain text retain their original form but undergo some change in
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their relative position. (Compare: substitution.) their relative position. (Compare: substitution.)
$ trap door $ trap door
(I) Synonym for "back door". (I) Synonym for "back door".
$ Triple Data Encryption Algorithm $ Triple Data Encryption Algorithm
(I) An block cipher that transforms each 64-bit plaintext block by (I) An block cipher that transforms each 64-bit plaintext block by
applying the DEA three successive times, using either two or three applying the DEA three successive times, using either two or three
different keys for an effective key length of 112 or 168 bits. different keys for an effective key length of 112 or 168 bits.
[A9052, SP67] [A9052, SP67]
Example: A variation proposed for IPsec's ESP uses a 168-bit key, Example: A variation proposed for IPsec's ESP uses a 168-bit key,
consisting of three independent 56-bit values used by the DEA, and consisting of three independent 56-bit values used by the DEA, and
a 64-bit initialization vector. Each datagram contains an IV to a 64-bit initialization vector. Each datagram contains an IV to
ensure that each received datagram can be decrypted even when ensure that each received datagram can be decrypted even when
other datagrams are dropped or a sequence of datagrams is other datagrams are dropped or a sequence of datagrams is
reordered in transit. [R1851] reordered in transit. [R1851]
$ triple-wrapped $ triple-wrapped
(I) /S-MIME/ Data that has been signed with a digital signature, (I) /S-MIME/ Data that has been signed with a digital signature,
and then encrypted, and then signed again. [R2634] then encrypted, and then signed again. [R2634]
$ Trojan horse $ Trojan horse
(I) A computer program that appears to have a useful function, but (I) A computer program that appears to have a useful function, but
also has a hidden and potentially malicious function that evades also has a hidden and potentially malicious function that evades
security mechanisms, sometimes by exploiting legitimate security mechanisms, sometimes by exploiting legitimate
authorizations of a system entity that invokes the program. (See: authorizations of a system entity that invokes the program. (See:
malware, spyware. Compare: logic bomb, virus, worm.) malware, spyware. Compare: logic bomb, virus, worm.)
$ trust $ trust
1. (I) /information system/ The extent to which someone who relies 1. (I) /information system/ A feeling of certainty (sometimes
on a system can have confidence that the system meets its based on inconclusive evidence) either (a) that the system will
specifications, i.e., that the system does what it claims to do not fail or (b) that the system meets its specifications (i.e.,
and does not perform unwanted functions. (See: trust level, the system does what it claims to do and does not perform unwanted
trusted system, trustworthy system. Compare: assurance.) functions). (See: trust level, trusted system, trustworthy system.
Compare: assurance.)
2. (I) /PKI/ A relationship between a certificate user and a CA in 2. (I) /PKI/ A relationship between a certificate user and a CA in
which the user acts according to the assumption that the CA which the user acts according to the assumption that the CA
creates only valid digital certificates. creates only valid digital certificates.
Tutorial: "Generally, an entity is said to 'trust' a second entity Tutorial: "Generally, an entity is said to 'trust' a second entity
when the first entity makes the assumption that the second entity when the first entity makes the assumption that the second entity
will behave exactly as the first entity expects. This trust may will behave exactly as the first entity expects. This trust may
apply only for some specific function. The key role of trust in apply only for some specific function. The key role of trust in
[X.509] is to describe the relationship between an entity and a [X.509] is to describe the relationship between an entity [i.e., a
[CA]; an entity shall be certain that it can trust the CA to certificate user] and a [CA]; an entity shall be certain that it
create only valid and reliable certificates." [X509] can trust the CA to create only valid and reliable certificates."
[X509]
Components can be grouped into three categories of trust [Gass]: Components of a system can be grouped into three classes of trust
- "Trusted": The component is responsible for enforcing security [Gass]:
- "Trusted": The component is responsible for enforcing security
policy on other components; the system's security depends on policy on other components; the system's security depends on
flawless operation of the component. (See: trusted process.) flawless operation of the component. (See: trusted process.)
- "Benign": The component is not responsible for enforcing - "Benign": The component is not responsible for enforcing
security policy, but it has sensitive authorizations. It must security policy, but it has sensitive authorizations. It must
be trusted not to intentionally violate security policy, but be trusted not to intentionally violate security policy, but
security violations are assumed to be accidental and not likely security violations are assumed to be accidental and not likely
to affect overall system security. to affect overall system security.
- "Untrusted": The component is of unknown or suspicious - "Untrusted": The component is of unknown or suspicious
provenance and must be treated as deliberately malicious. (See: provenance and must be treated as deliberately malicious. (See:
malicious logic.) malicious logic.)
$ trust anchor $ trust anchor
(D) /PKI/ Synonym for "trusted certificate", "root", "root (I) /PKI/ An established point of trust (usually based on the
certificate", or "root key". (See: trust chain.) authority of some person, office, or organization) from which a
certificate user begins the validation of a certification path.
(See: path validation, trust anchor CA, trust anchor certificate,
trust anchor key.)
Deprecated Term: ISDs SHOULD NOT use this term; it unnecessarily Usage: ISDs that use this term SHOULD state a definition for it
duplicates the meaning of other terms and mixes concepts in a because it is used in various ways in existing ISDs and other PKI
potentially misleading way. (See: (Deprecated Term under) trust literature. The literature almost always uses this term in a sense
chain.) that is equivalent to this definition, but usage often differs
with regard to what constitutes the point of trust.
Tutorial: A trust anchor may be defined as being based on a public
key, a CA, a public-key certificate, or some combination or
variation of those:
- A public key as a point of trust: Although a certification path
is defined as beginning with a "sequence of public-key
certificates", an implementation of a path validation process
might not explicitly handle a root certificate as part of the
path, but instead begin the process by using a trusted root key
to verify the signature on a certificate that was issued by the
root.
Therefore, "trust anchor" is sometimes defined as just a public
key. (See: root key, trust anchor key, trusted key.)
- A CA as a point of trust: A trusted public key is just one of
the data elements needed for path validation; the IPS path
validation algorithm [R3280] also needs the name of the CA to
which that key belongs, i.e., the DN of the issuer of the first
X.509 certificate to be validated on the path. (See: issue.)
Therefore, "trust anchor" is sometimes defined as either just a
CA (where some public key is implied) or as a CA together with
a specified public key belonging to that CA. (See: root, trust
anchor CA, trusted CA.)
Example: "A public key and the name of a [CA] that is used to
validate the first certificate in a sequence of certificates.
The trust anchor public key is used to verify the signature on
a certificate issued by a trust anchor [CA]." [SP57]
- A public-key certificate as a point of trust: In addition to
the trusted CA's public key and name, the path validation
algorithm needs to know the digital signature algorithm and any
associated parameters with which the public key is used, and
also any constraints that have been placed on the set of paths
that may be validated using the key. All of this information is
available from a CA's public-key certificate.
Therefore, "trust anchor" is sometimes defined as a public-key
certificate of a CA. (See: root certificate, trust anchor
certificate, trusted certificate.)
- Combinations: Combinations and variations of the first three
definitions are also used in the PKI literature.
Example: "trust anchor information". The IPS standard for path
validation [R3280] specifies the information that describes "a
CA that serves as a trust anchor for the certification path.
The trust anchor information includes: (1) the trusted issuer
name, (2) the trusted public key algorithm, (3) the trusted
public key, and (4) optionally, the trusted public key
parameters associated with the public key. The trust anchor
information may be provided to the path processing procedure in
the form of a self-signed certificate. The trusted anchor
information is trusted because it was delivered to the path
processing procedure by some trustworthy out-of-band procedure.
If the trusted public key algorithm requires parameters, then
the parameters are provided along with the trusted public key."
$ trust anchor CA
(I) A CA that is the subject of a trust anchor certificate or
otherwise establishes a trust anchor key. (See: root, trusted CA.)
Tutorial; The selection of a CA to be a trust anchor is a matter
of policy. Some of the possible choices include (a) the top CA in
a hierarchical PKI, (b) the CA that issued the verifier's own
certificate, or (c) any other CA in a network PKI. Different
applications may rely on different trust anchors, or may accept
paths that begin with any of a set of trust anchors. The IPS path
validation algorithm is the same regardless of the choice.
$ trust anchor certificate
(I) A public-key certificate that is used to provide the first
public key in a certification path. (See: root certificate, trust
anchor, trusted certificate.)
$ trust anchor key
(I) A public key that is used as the first public key in a
certification path. (See: root key, trust anchor, trusted public
key.)
$ trust anchor information
(I) See: secondary definition under "trust anchor".
$ trust chain $ trust chain
(D) Synonym for "certification path". (See: trust anchor, trusted (D) Synonym for "certification path". (See: trust anchor, trusted
certificate.) certificate.)
Deprecated Term: ISDs SHOULD NOT use this term, because it Deprecated Term: ISDs SHOULD NOT use this term, because it
unnecessarily duplicates the meaning of the internationally unnecessarily duplicates the meaning of the internationally
standardized term. standardized term.
This term also mixes concepts in a potentially misleading way. Also, the term mixes concepts in a potentially misleading way.
Having "trust" involves factors unrelated to verifying signatures Having "trust" involves factors unrelated to simply verifying
and performing other tests as specified by a standard for path signatures and performing other tests as specified by a standard
validation (e.g., RFC 3280). Thus, even if a user is able to algorithm for path validation (e.g., RFC 3280). Thus, even if a
validate a certification path, the user still might distrust one user is able to validate a certification path algorithmically, the
of the CAs that issued certificates in that path or distrust some user still might distrust one of the CAs that issued certificates
other aspects of the PKI. in that path or distrust some other aspects of the PKI.
$ trust-file PKI $ trust-file PKI
(I) A non-hierarchical PKI in which each certificate user has a (I) A non-hierarchical PKI in which each certificate user has a
local file (which is used by application software) of public-key local file (which is used by application software) of public-key
certificates that the user trusts as starting points (i.e., roots) certificates that the user trusts as starting points (i.e., trust
for certification paths. (Compare: hierarchical PKI, mesh PKI, anchors) for certification paths. (Compare: hierarchical PKI, mesh
trusted certificate, web of trust.) PKI, trusted certificate, web of trust.)
Example: Popular browsers are distributed with an initial file of Example: Popular browsers are distributed with an initial file of
root certificates, which often are self-signed certificates. Users trust anchor certificates, which often are self-signed
can add certificates to the file or delete from it. The file may certificates. Users can add certificates to the file or delete
be directly managed by the user, or the user's organization may from it. The file may be directly managed by the user, or the
manage it from a centralized server. user's organization may manage it from a centralized server.
$ trust hierarchy $ trust hierarchy
(D) Synonym for "certification hierarchy". (D) Synonym for "certification hierarchy".
Deprecated Usage: ISDs SHOULD NOT use this term because it mixes Deprecated Usage: ISDs SHOULD NOT use this term because it mixes
concepts in a potentially misleading way. (See: trust, trust concepts in a potentially misleading way. (See: trust, trust
chain, web of trust.) chain, web of trust.)
$ trust level $ trust level
(I) A characterization of a standard of security protection to be (N) A characterization of a standard of security protection to be
met by an information system. (See: Common Criteria, TCSEC.) met by an information system. (See: Common Criteria, TCSEC.)
Tutorial: A trust level is based not only on (a) the presence of Tutorial: A trust level is based not only on (a) the presence of
security mechanisms, but also on the use of (b) systems security mechanisms, but also on the use of (b) systems
engineering discipline to properly structure the system and (c) engineering discipline to properly structure the system and (c)
implementation analysis to ensure that the system provides an implementation analysis to ensure that the system provides an
appropriate degree of trust. appropriate degree of trust.
$ trusted CA
(I) A CA upon which a certificate user relies as issuing valid
certificates; especially a CA that is used as a trust anchor CA.
(See: certification path, root, trust anchor CA, validation.)
Tutorial. This trust is transitive to the extent that the X.509
certificate extensions permit; that is, if a trusted CA issues a
certificate to another CA, a user that trusts the first CA also
trusts the second CA if the user succeeds in validating the
certificate path (see: path validation).
$ trusted certificate $ trusted certificate
(I) A certificate upon which a certificate user relies as being 1. (I) A digital certificate that a certificate user accepts as
valid without the need for validation testing; especially a being valid "a priori", i.e., without testing the certificate to
public-key certificate that is used to provide the first public validate it as the final certificate on a certification path;
key in a certification path. (See: certification path, root especially a certificate that is used as a trust anchor
certificate, validation.) certificate. (See: certification path, root certificate, trust
anchor certificate, trust-file PKI, validation.)
Tutorial: A trusted public-key certificate might be (a) the root Tutorial: The acceptance of a certificate as trusted is a matter
certificate in a hierarchical PKI, (b) the certificate of the CA of policy and choice. Usually, a certificate is accepted as
that issued the user's own certificate in a mesh PKI, or (c) a trusted because the user obtained it by reliable, out-of-band
certificate accepted by the user in a trust-file PKI. means that cause the user to believe the certificate accurately
binds its subject's name to the subject's public key or other
attribute values. Many choices are possible; e.g., a trusted
public-key certificate might be (a) the root certificate in a
hierarchical PKI, (b) the certificate of the CA that issued the
user's own certificate in a mesh PKI, or (c) a certificate
provided with an application that uses a trust-file PKI.
$ Trusted Computer System Evaluation Criteria (TCSEC) $ Trusted Computer System Evaluation Criteria (TCSEC)
(N) A standard for evaluating the security provided by operating (N) A standard for evaluating the security provided by operating
systems [CSC001, DoD1]. Known as the "Orange Book" because of the systems [CSC001, DoD1]. Known as the "Orange Book" because of the
color of its cover; first document in the Rainbow Series. (See: color of its cover; first document in the Rainbow Series. (See:
Common Criteria, (Deprecated Usage under) Green Book, Orange Book, Common Criteria, Deprecated Usage under "Green Book", Orange Book,
trust level, trusted computer system. Compare: TSEC.) trust level, trusted computer system. Compare: TSEC.)
Tutorial: The TCSEC defines classes of hierarchically ordered Tutorial: The TCSEC defines classes of hierarchically ordered
assurance levels for rating computer systems. From highest to assurance levels for rating computer systems. From highest to
lowest, the classes are as follows: lowest, the classes are as follows:
- Division A: Verified protection.
- Division A. Verified protection. Beyond A1 Beyond current technology. (See: beyond A1.)
Beyond A1. Beyond current technology. (See: beyond A1.) Class A1 Verified design. (See: SCOMP.)
Class A1. Verified design. (See: SCOMP.) - Division B: Mandatory protection.
- Division B: Mandatory protection. Class B3 Security domains.
Class B3. Security domains. Class B2 Structured protection. (See: Multics.)
Class B2. Structured protection. (See: Multics.) Class B1 Labeled security protection.
Class B1. Labeled security protection. - Division C: Discretionary protection.
- Division C: Discretionary protection. Class C2 Controlled access protection.
Class C2. Controlled access protection. Class C1 Discretionary security protection.
Class C1. Discretionary security protection. - Division D: Minimal protection, i.e., has been evaluated but
- Division D: Minimal protection; i.e., has been evaluated but does not meet the requirements for a higher evaluation class.
does not meet the requirements for a higher evaluation class.
$ trusted computing base (TCB) $ trusted computing base (TCB)
(N) "The totality of protection mechanisms within a computer (N) "The totality of protection mechanisms within a computer
system, including hardware, firmware, and software, the system, including hardware, firmware, and software, the
combination of which is responsible for enforcing a security combination of which is responsible for enforcing a security
policy." [NCS04] (See: (discussion of "trusted" under) trust.) policy." [NCS04] (See: "trusted" under "trust".)
$ trusted distribution $ trusted distribution
(I) /computer security/ "A trusted method for distributing the TCB (I) /computer security/ "A trusted method for distributing the TCB
hardware, software, and firmware components, both originals and hardware, software, and firmware components, both originals and
updates, that provides methods for protecting the TCB from updates, that provides methods for protecting the TCB from
modification during distribution and for detection of any changes modification during distribution and for detection of any changes
to the TCB that may occur." [NCS04] (See: code signing, to the TCB that may occur." [NCS04] (See: code signing,
configuration control.) configuration control.)
$ trusted key $ trusted key
(I) A public key upon which a user relies; especially a public key (D) Abbreviation for "trusted public key" and also for other types
that can be used as the first public key in a certification path. of keys. (See: root key, trust anchor key.)
(See: certification path, root key, validation.)
Tutorial: A trusted public key might be (a) the root key in a Deprecated Usage: ISDs SHOULD either (a) state a definition for
hierarchical PKI, (b) the key of the CA that issued the user's own this term or (b) use a different, less ambiguous term. This term
certificate in a mesh PKI, or (c) any key accepted by the user in is ambiguous when it stands alone; e.g., it could refer to a
a trust-file PKI. trusted public key or to a private key or symmetric key that is
believed to be secure (i.e., not compromised).
$ trusted path $ trusted path
1a. (I) /COMPUSEC/ A mechanism by which a computer system user can 1a. (I) /COMPUSEC/ A mechanism by which a computer system user can
communicate directly and reliably with the TCB and that can only communicate directly and reliably with the TCB and that can only
be activated by the user or the TCB and cannot be imitated by be activated by the user or the TCB and cannot be imitated by
untrusted software within the computer. [NCS04] untrusted software within the computer. [NCS04]
1b. (I) /COMSEC/ A mechanism by which a person or process can 1b. (I) /COMSEC/ A mechanism by which a person or process can
communicate directly with a cryptographic module and that can only communicate directly with a cryptographic module and that can only
be activated by the person, process, or module, and cannot be be activated by the person, process, or module, and cannot be
imitated by untrusted software within the module. [FP140] imitated by untrusted software within the module. [FP140]
$ trusted process $ trusted process
1. (I) A system component that has privileges that enable it to 1. (I) A system component that has privileges that enable it to
affect the state of system security and that can, therefore, affect the state of system security and that can, therefore,
through incorrect or malicious execution, violate the system's through incorrect or malicious execution, violate the system's
security policy. (See: privileged process, trusted system.) security policy. (See: privileged process, trusted system.)
$ trusted public key
(I) A public key upon which a user relies; especially a public key
that is used as a trust anchor key. (See: certification path, root
key, trust anchor key, validation.)
Tutorial: A trusted public key could be (a) the root key in a
hierarchical PKI, (b) the key of the CA that issued the user's own
certificate in a mesh PKI, or (c) any key accepted by the user in
a trust-file PKI.
$ trusted recovery $ trusted recovery
(I) A process that, after a system has experienced a failure or an (I) A process that, after a system has experienced a failure or an
attack, restores the system to normal operation (or to a secure attack, restores the system to normal operation (or to a secure
state) without causing a security compromise. (See: recovery.) state) without causing a security compromise. (See: recovery.)
$ trusted subnetwork $ trusted subnetwork
(I) A subnetwork containing hosts and routers that trust each (I) A subnetwork containing hosts and routers that trust each
other not to engage in active or passive attacks. (There also is other not to engage in active or passive attacks. (There also is
an assumption that the underlying communication channels -- e.g., an assumption that the underlying communication channels -- e.g.,
telephone lines, or a LAN -- are protected from attack.) telephone lines, or a LAN -- are protected from attack.)
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(Compare: TCSEC.) (Compare: TCSEC.)
$ TSIG $ TSIG
(N) See: Trusted System Interoperability Group. (N) See: Trusted System Interoperability Group.
$ tunnel $ tunnel
1. (I) A communication channel created in a computer network by 1. (I) A communication channel created in a computer network by
encapsulating (i.e., layering) a communication protocol's data encapsulating (i.e., layering) a communication protocol's data
packets in (i.e., above) a second protocol that normally would be packets in (i.e., above) a second protocol that normally would be
carried above, or at the same layer as, the first one. (See: L2TP, carried above, or at the same layer as, the first one. (See: L2TP,
VPN.) VPN.) (Compare: covert channel.)
Tutorial: Tunneling can involve almost any OSIRM or TCP/IP Tutorial: Tunneling can involve almost any two IPS protocol
protocol layers; for example, a TCP connection between two hosts layers. For example, a TCP connection between two hosts could
could conceivably be tunneled through email messages across the conceivably be carried above SMTP (i.e., in SMTP messages) as a
Internet. However, a tunnel usually is a logical point-to-point covert channel to evade access controls that a security gateway
link -- i.e., an OSIRM layer 2 connection -- created by applies to the normal TCP layer that is below SMTP.
encapsulating the layer 2 protocol in an IPS transport layer
protocol (such as TCP), in an IPS network or internetwork layer Usually, however, a tunnel is a logical point-to-point link --
protocol (such as IP), or in another layer 2 protocol. In many i.e., an OSIRM Layer 2 connection -- created by encapsulating the
cases, the encapsulation is accomplished with an extra, Layer 2 protocol in one of the following three types of IPS
intermediate protocol, i.e., a tunneling protocol (such as L2TP) protocols: (a) an IPS Transport-Layer protocol (such as TCP), (b)
that is layered between the tunneled layer 2 protocol and the an IPS Network-Layer or Internet-Layer protocol (such as IP), or
encapsulating protocol. (c) another Layer 2 protocol. In many cases, the encapsulation is
accomplished with an extra, intermediate protocol (i.e., a
"tunneling protocol"; e.g., L2TP) that is layered below the
tunneled Layer 2 protocol and above the encapsulating protocol.
Tunneling can be used to move data between computers that use a Tunneling can be used to move data between computers that use a
protocol not supported by the network connecting them. Tunneling protocol not supported by the network connecting them. Tunneling
also can enable a computer network to use the services of a second also can enable a computer network to use the services of a second
network as though the second network were a set of point-to-point network as though the second network were a set of point-to-point
links between the first network's nodes. (See: virtual private links between the first network's nodes. (See: virtual private
network.) network.)
2. (O) /SET/ The name of a SET private extension that indicates 2. (O) /SET/ The name of a SET private extension that indicates
whether the CA or the payment gateway supports passing encrypted whether the CA or the payment gateway supports passing encrypted
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is required to be in tunnel mode. is required to be in tunnel mode.
$ two-person control $ two-person control
(I) The close surveillance and control of a system, a process, or (I) The close surveillance and control of a system, a process, or
materials (especially with regard to cryptography) at all times by materials (especially with regard to cryptography) at all times by
a minimum of two appropriately authorized persons, each capable of a minimum of two appropriately authorized persons, each capable of
detecting incorrect and unauthorized procedures with respect to detecting incorrect and unauthorized procedures with respect to
the tasks to be performed and each familiar with established the tasks to be performed and each familiar with established
security requirements. (See: dual control, no-lone zone.) security requirements. (See: dual control, no-lone zone.)
$ Twofish
(O) A symmetric, 128-bit block cipher with variable key length
(128, 192, or 256 bits), developed by Counterpane Labs as a
candidate for the AES. (See: Blowfish.)
$ type 0 product $ type 0 product
(O) /cryptography, U.S. Government/ Classified cryptographic (O) /cryptography, U.S. Government/ Classified cryptographic
equipment endorsed by NSA specifically for use (when appropriately equipment endorsed by NSA specifically for use (when appropriately
keyed) in electronically distributing bulk keying material. keyed) in electronically distributing bulk keying material.
$ type 1 product $ type 1 product
(O) /cryptography, U.S. Government/ "Classified or controlled (O) /cryptography, U.S. Government/ "Classified or controlled
cryptographic item endorsed by the NSA for securing classified and cryptographic item endorsed by the NSA for securing classified and
sensitive U.S. Government information, when appropriately keyed. sensitive U.S. Government information, when appropriately keyed.
The term refers only to products, and not to information, key, The term refers only to products, and not to information, key,
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$ type 4 algorithm $ type 4 algorithm
(O) /cryptography, U.S. Government/ "Unclassified cryptographic (O) /cryptography, U.S. Government/ "Unclassified cryptographic
algorithm that has been registered by [NIST] but not published as algorithm that has been registered by [NIST] but not published as
a [FIPS]." [C4009] a [FIPS]." [C4009]
$ UDP $ UDP
(I) See: User Datagram Protocol. (I) See: User Datagram Protocol.
$ UDP flood $ UDP flood
(I) A denial-of-service attack that connects one system's UDP test (I) A denial-of-service attack that takes advantage of (a) one
function that generates a series of characters for each packet it system's UDP test function that generates a series of characters
receives, to another system's UPD test function that echoes any for each packet it receives and (b) another system's UPD test
character it receives, resulting in a nonstop flood of data function that echoes any character it receives; the attack
between the two systems. connects (a) to (b) to cause a nonstop flood of data between the
two systems.
$ unauthorized disclosure $ unauthorized disclosure
(I) A circumstance or event whereby an entity gains access to (I) A circumstance or event whereby an entity gains access to
information for which the entity is not authorized. information for which the entity is not authorized.
Tutorial: This type of threat consequence can be caused by the Tutorial: This type of threat consequence can be caused by the
following types of threat actions: exposure, interception, following types of threat actions: exposure, interception,
inference, intrusion. Some methods of protecting against this inference, intrusion. Some methods of protecting against this
consequence include access control, flow control, and inference consequence include access control, flow control, and inference
control. (See: data confidentiality.) control. (See: data confidentiality.)
$ unauthorized user $ unauthorized user
(I) /access control/ A system entity that accesses a system (I) /access control/ A system entity that accesses a system
resource for which the entity has not received an authorization. resource for which the entity has not received an authorization.
(See: user. Compare: authorized user, insider, outsider.) (See: user. Compare: authorized user, insider, outsider.)
Usage: The term is used in many ways and could easily be Usage: ISDs that use this term SHOULD state a definition for it
misunderstood; therefore, ISDs that use this term SHOULD state a because the term is used in many ways and could easily be
definition for it. misunderstood.
$ uncertainty $ uncertainty
(I) An information-theoretic measure (usually stated as a number (N) An information-theoretic measure (usually stated as a number
of bits) of the minimum amount of plaintext information that needs of bits) of the minimum amount of plaintext information that needs
to be recovered from cipher text in order to learn the entire to be recovered from cipher text in order to learn the entire
plain text that was encrypted. [SP63] (See: entropy.) plain text that was encrypted. [SP63] (See: entropy.)
$ unclassified $ unclassified
(I) Not classified. (I) Not classified.
$ unencrypted $ unencrypted
(I) Not encrypted. (I) Not encrypted.
$ unforgeable $ unforgeable
(I) /cryptography/ The property of a cryptographic data structure (I) /cryptography/ The property of a cryptographic data structure
(i.e., a data structure that is defined using one or more (i.e., a data structure that is defined using one or more
cryptographic functions; e.g., see digital certificate) that makes cryptographic functions, e.g., see digital certificate) that makes
it computationally infeasible to construct (i.e., compute) an it computationally infeasible to construct (i.e., compute) an
unauthorized but correct value of the structure without having unauthorized but correct value of the structure without having
knowledge of one of more keys. knowledge of one of more keys.
Tutorial: This definition is narrower than general English usage, Tutorial: This definition is narrower than general English usage,
where "unforgeable" means unable to be fraudulently created or where "unforgeable" means unable to be fraudulently created or
duplicated. In that broader sense, anyone can forge a digital duplicated. In that broader sense, anyone can forge a digital
certificate containing any set of data items whatsoever by certificate containing any set of data items whatsoever by
generating the to-be-signed certificate and signing it with any generating the to-be-signed certificate and signing it with any
private key whatsoever. But for PKI purposes, the forged data private key whatsoever. But for PKI purposes, the forged data
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2. (I) A system component that (a) has not been evaluated or 2. (I) A system component that (a) has not been evaluated or
examined for adherence to a specified security policy and, examined for adherence to a specified security policy and,
therefore, (b) must be assumed to contain logic that might attempt therefore, (b) must be assumed to contain logic that might attempt
to circumvent system security. to circumvent system security.
$ UORA $ UORA
(O) See: user-PIN ORA. (O) See: user-PIN ORA.
$ update $ update
See: certificate update and key update. See: "certificate update" and "key update".
$ upgrade $ upgrade
(I) /data security/ Increase the classification level of data (I) /data security/ Increase the classification level of data
without changing the information content of the data. (Compare: without changing the information content of the data. (See:
downgrade. See: regrade.) classify, downgrade, regrade.)
$ URI $ URI
(I) See: uniform resource identifier. (I) See: uniform resource identifier.
$ URL $ URL
(I) See: uniform resource locator. (I) See: uniform resource locator.
$ URN $ URN
(I) See: uniform resource name. (I) See: uniform resource name.
$ user $ user
(I) An active system entity that uses a product or service (I) An active system entity that uses a product or service
provided by the system, or that accesses system resources to provided by the system, or that accesses system resources to
produce a product or service of the system. (See: access, [R2504]. produce a product or service of the system. (See: access, [R2504].
Compare: authorized user, manager, operator, principal, subject, Compare: authorized user, manager, operator, principal, privileged
subscriber, unauthorized user.) user, subject, subscriber, unauthorized user.)
Usage: The term is used in many ways and could easily be
misunderstood; therefore, ISDs that use this term SHOULD state a
definition for it.
- This term usually refers to an entity that has been authorized Usage: ISDs that use this term SHOULD state a definition for it
because the term is used in many ways and could easily be
misunderstood:
- This term usually refers to an entity that has been authorized
to access the system, but the term sometimes is used without to access the system, but the term sometimes is used without
regard for whether access is authorized. regard for whether access is authorized.
- This term usually refers to a living human being acting either - This term usually refers to a living human being acting either
personally or in an organizational role, but the term may refer personally or in an organizational role, but the term also may
to an automated process in the form of either hardware or refer to an automated process in the form of hardware,
software or both, or to a set of persons, or to a set of softwarr, or firmware; to a set of persons; or to a set of
processes processes.
- ISDs SHOULD exclude the case of a mixed set containing both - ISDs SHOULD exclude the case of a mixed set containing both
persons and processes. The exclusion is intended to prevent persons and processes. The exclusion is intended to prevent
situations that might require a security policy to be situations that might require a security policy to be
interpreted in two different and conflicting ways. interpreted in two different and conflicting ways.
A user can be characterized as direct or indirect:
- "Passive user": A system entity that is (a) outside the
system's security perimeter *and* (b) can receive output from
the system but cannot provide input or otherwise interact with
the system.
- "Active user": A system entity that is (a) inside the system's
security perimeter *or* (b) can provide input or otherwise
interact with the system.
$ user authentication service $ user authentication service
(I) A security service that verifies that the identity claimed by (I) A security service that verifies the identity claimed by an
an entity that attempts to access the system. (See: entity that attempts to access the system. (See: authentication,
authentication, user.) user.)
$ User Datagram Protocol (UDP) $ User Datagram Protocol (UDP)
(I) An Internet Standard, transport-layer protocol (RFC 768) that (I) An Internet Standard, Transport-Layer protocol (RFC 768) that
delivers a sequence of datagrams from one computer to another in a delivers a sequence of datagrams from one computer to another in a
computer network. (See: UPD flood.) computer network. (See: UPD flood.)
Tutorial: UDP assumes that IP is the underlying protocol. UDP Tutorial: UDP assumes that IP is the underlying protocol. UDP
enables application programs to send transaction-oriented data to enables application programs to send transaction-oriented data to
other programs with minimal protocol mechanism. UDP does not other programs with minimal protocol mechanism. UDP does not
provide reliable delivery, flow control, sequencing, or other end- provide reliable delivery, flow control, sequencing, or other end-
to-end service guarantees that TCP does. to-end service guarantees that TCP does.
$ user identity $ user identity
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$ UTCTime $ UTCTime
(N) The ASN.1 data type "UTCTime" contains a calendar date (N) The ASN.1 data type "UTCTime" contains a calendar date
(YYMMDD) and a time to a precision of either one minute (HHMM) or (YYMMDD) and a time to a precision of either one minute (HHMM) or
one second (HHMMSS), where the time is either (a) Coordinated one second (HHMMSS), where the time is either (a) Coordinated
Universal Time or (b) the local time followed by an offset that Universal Time or (b) the local time followed by an offset that
enables Coordinated Universal Time to be calculated. Note: UTCTime enables Coordinated Universal Time to be calculated. Note: UTCTime
has the Year 2000 problem. (See: Coordinated Universal Time, has the Year 2000 problem. (See: Coordinated Universal Time,
GeneralizedTime.) GeneralizedTime.)
$ v1 certificate $ v1 certificate
(I) An abbreviation that ambiguously refers to either an "X.509 (N) An abbreviation that ambiguously refers to either an "X.509
public-key certificate in version 1 format" or an "X.509 attribute public-key certificate in version 1 format" or an "X.509 attribute
certificate in version 1 format". certificate in version 1 format".
Deprecated Usage: ISDs MAY use this term as an abbreviation for Deprecated Usage: ISDs MAY use this term as an abbreviation of
"version 1 X.509 public-key certificate", but only after using the "version 1 X.509 public-key certificate", but only after using the
full term at the first instance. Otherwise, the term is ambiguous, full term at the first instance. Otherwise, the term is ambiguous,
because X.509 specifies both v1 public-key certificates and v1 because X.509 specifies both v1 public-key certificates and v1
attribute certificates. (See: X.509 attribute certificate, X.509 attribute certificates. (See: X.509 attribute certificate, X.509
public-key certificate.) public-key certificate.)
$ v1 CRL $ v1 CRL
(I) An abbreviation for "X.509 CRL in version 1 format". (N) Abbreviation of "X.509 CRL in version 1 format".
Usage: ISDs MAY use this abbreviation, but SHOULD use the full Usage: ISDs MAY use this abbreviation, but SHOULD use the full
term at its first occurrence and define the abbreviation there. term at its first occurrence and define the abbreviation there.
$ v2 certificate $ v2 certificate
(I) An abbreviation for "X.509 public-key certificate in version 2 (N) Abbreviation of "X.509 public-key certificate in version 2
format". format".
Usage: ISDs MAY use this abbreviation, but SHOULD use the full Usage: ISDs MAY use this abbreviation, but SHOULD use the full
term at its first occurrence and define the abbreviation there. term at its first occurrence and define the abbreviation there.
$ v2 CRL $ v2 CRL
(I) An abbreviation for "X.509 CRL in version 2 format". (N) Abbreviation of "X.509 CRL in version 2 format".
Usage: ISDs MAY use this abbreviation, but SHOULD use the full Usage: ISDs MAY use this abbreviation, but SHOULD use the full
term at its first occurrence and define the abbreviation there. term at its first occurrence and define the abbreviation there.
$ v3 certificate $ v3 certificate
(I) An abbreviation for "X.509 public-key certificate in version 3 (N) Abbreviation of "X.509 public-key certificate in version 3
format". format".
Usage: ISDs MAY use this abbreviation, but SHOULD use the full Usage: ISDs MAY use this abbreviation, but SHOULD use the full
term at its first occurrence and define the abbreviation there. term at its first occurrence and define the abbreviation there.
$ valid certificate $ valid certificate
1. (I) A digital certificate that can be validated successfully. 1. (I) A digital certificate that can be validated successfully.
(See: validate, verify.) (See: validate, verify.)
2. (I) A digital certificate for which the binding of the data 2. (I) A digital certificate for which the binding of the data
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2. (I) A digital certificate for which the binding of the data 2. (I) A digital certificate for which the binding of the data
items can be trusted. items can be trusted.
$ valid signature $ valid signature
(D) Synonym for "authentic signature". (D) Synonym for "authentic signature".
Deprecated Term: ISDs SHOULD NOT use this term; instead, say Deprecated Term: ISDs SHOULD NOT use this term; instead, say
"authentic signature". This Glossary recommends saying "validate "authentic signature". This Glossary recommends saying "validate
the certificate" and "verify the signature"; therefore, it would the certificate" and "verify the signature"; therefore, it would
be inconsistent to say that a signature is "valid". (See: be inconsistent to say that a signature is "valid". (See:
validate, verify.) validate, verify.)
$ validate $ validate
1. (I) Establish the soundness or correctness of a construct. 1. (I) Establish the soundness or correctness of a construct.
Example: certificate validation. (See: validate vs. verify.) Example: certificate validation. (See: validate vs. verify.)
2. (I) To officially approve something, sometimes in relation to a 2. (I) To officially approve something, sometimes in relation to a
standard. Example: NIST validates cryptographic modules for standard. Example: NIST validates cryptographic modules for
conformance with FIPS PUB 140 [FP140]. conformance with FIPS PUB 140 [FP140].
$ validate vs. verify $ validate vs. verify
Usage: To ensure consistency and align with ordinary English Usage: To ensure consistency and align with ordinary English
usage, ISDs SHOULD comply with the following two rules: usage, ISDs SHOULD comply with the following two rules:
- Rule 1: Use "validate" when referring to a process intended to - Rule 1: Use "validate" when referring to a process intended to
establish the soundness or correctness of a construct (e.g., establish the soundness or correctness of a construct (e.g.,
see: certificate validation). (See: validate.) see: certificate validation). (See: validate.)
- Rule 2: Use "verify" when referring to a process intended to - Rule 2: Use "verify" when referring to a process intended to
test or prove the truth or accuracy of a fact or value (e.g., test or prove the truth or accuracy of a fact or value (e.g.,
see: authenticate). (See: verify.) see: authenticate). (See: verify.)
Tutorial: The Internet security community sometimes uses these two Tutorial: The Internet security community sometimes uses these two
terms inconsistently, especially in a PKI context. Most often, terms inconsistently, especially in a PKI context. Most often,
however, we say "verify the signature" but say "validate the however, we say "verify the signature" but say "validate the
certificate". That is, we "verify" atomic truths but "validate" certificate". That is, we "verify" atomic truths but "validate"
data structures, relationships, and systems that are composed of data structures, relationships, and systems that are composed of
or depend on verified items. This usage has a basis in Latin: or depend on verified items. This usage has a basis in Latin:
skipping to change at page 265, line 50 skipping to change at page 287, line 6
certificate, a certificate user verifies the digital signature on certificate, a certificate user verifies the digital signature on
the certificate by performing calculations, verifies that the the certificate by performing calculations, verifies that the
current time is within the certificate's validity period, and may current time is within the certificate's validity period, and may
need to validate a certification path involving additional need to validate a certification path involving additional
certificates. certificates.
$ validation $ validation
(I) See: validate vs. verify. (I) See: validate vs. verify.
$ validity period $ validity period
(I) A data item in a digital certificate that specifies the time (I) /PKI/ A data item in a digital certificate that specifies the
period for which the binding between data items (especially time period for which the binding between data items (especially
between the subject name and the public key value in a public-key between the subject name and the public key value in a public-key
certificate) is valid, except if the certificate appears on a CRL certificate) is valid, except if the certificate appears on a CRL
or the key appears on a CKL. or the key appears on a CKL. (See: cryptoperiod, key lifetime.)
$ value-added network (VAN) $ value-added network (VAN)
(I) A computer network or subnetwork (usually a commercial (I) A computer network or subnetwork (usually a commercial
enterprise) that transmits, receives, and stores EDI transactions enterprise) that transmits, receives, and stores EDI transactions
on behalf of its users. on behalf of its users.
Tutorial: A VAN may also provide additional services, ranging from Tutorial: A VAN may also provide additional services, ranging from
EDI format translation, to EDI-to-FAX conversion, to integrated EDI format translation, to EDI-to-FAX conversion, to integrated
business systems. business systems.
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is employed by a wide range of users, then it is likely that there is employed by a wide range of users, then it is likely that there
will be enough motivation for someone to launch an attack. will be enough motivation for someone to launch an attack.
$ W3 $ W3
(D) Synonym for WWW. (D) Synonym for WWW.
Deprecated Abbreviation: This abbreviation could be confused with Deprecated Abbreviation: This abbreviation could be confused with
W3C; use "WWW" instead. W3C; use "WWW" instead.
$ W3C $ W3C
See: World Wide Web Consortium. (N) See: World Wide Web Consortium.
$ war dialer $ war dialer
(I) A computer program that automatically dials a series of (I) /slang/ A computer program that automatically dials a series
telephone numbers to find lines connected to computer systems, and of telephone numbers to find lines connected to computer systems,
catalogs those numbers so that a cracker can try to break the and catalogs those numbers so that a cracker can try to break the
systems. systems.
Deprecated Usage: This term could confuse international readers; Deprecated Usage: ISDs that use this term SHOULD state a
therefore, ISDs that use it SHOULD state a definition for it. definition for it because the term could confuse international
readers.
$ Wassenaar Arrangement $ Wassenaar Arrangement
(N) The Wassenaar Arrangement on Export Controls for Conventional (N) The Wassenaar Arrangement on Export Controls for Conventional
Arms and Dual-Use Goods and Technologies is a global, multilateral Arms and Dual-Use Goods and Technologies is a global, multilateral
agreement approved by 33 countries in July 1996 to contribute to agreement approved by 33 countries in July 1996 to contribute to
regional and international security and stability, by promoting regional and international security and stability, by promoting
information exchange concerning, and greater responsibility in, information exchange concerning, and greater responsibility in,
transfers of arms and dual-use items, thus preventing transfers of arms and dual-use items, thus preventing
destabilizing accumulations. (See: International Traffic in Arms destabilizing accumulations. (See: International Traffic in Arms
Regulations.) Regulations.)
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$ watermarking $ watermarking
See: digital watermarking. See: digital watermarking.
$ weak key $ weak key
(I) In the context of a particular cryptographic algorithm, a key (I) In the context of a particular cryptographic algorithm, a key
value that provides poor security. value that provides poor security.
Example: The DEA has four "weak keys" [Schn] for which encryption Example: The DEA has four "weak keys" [Schn] for which encryption
produces the same result as decryption. It also has ten pairs of produces the same result as decryption. It also has ten pairs of
"semi-weak keys" [Schn] (also known as "dual keys" [FP074]) for "semi-weak keys" [Schn] (a.k.a. "dual keys" [FP074]) for which
which encryption with one key in the pair produces the same result encryption with one key in the pair produces the same result as
as decryption with the other key. decryption with the other key.
$ web, Web $ web, Web
1. (C) /not capitalized/ ISD SHOULD NOT capitalize "web" when 1. (I) /not capitalized/ ISDs SHOULD NOT capitalize "web" when
using the term (usually as an adjective) to refer generically to using the term (usually as an adjective) to refer generically to
technology -- such as web browsers, web servers, HTTP, and HTML -- technology -- such as web browsers, web servers, HTTP, and HTML --
that is used in the Web or similar networks. that is used in the Web or similar networks.
2. (I) /capitalized/ ISDs SHOULD capitalize "Web" when using the 2. (I) /capitalized/ ISDs SHOULD capitalize "Web" when using the
term (as either a noun or an adjective) to refer specifically to term (as either a noun or an adjective) to refer specifically to
the World Wide Web. (Similarly, see: internet.) the World Wide Web. (Similarly, see: internet.)
Usage: IETF documents SHOULD spell out "World Wide Web" fully at Usage: ISDs SHOULD NOT use "web" or "Web" in a way that might
the first instance of usage and MUST use "Web" and "web" confuse these definitions with the PGP "web of trust". When using
especially carefully where confusion with the PGP web of trust is Web as an abbreviation for "World Wide Web", ISDs SHOULD fully
possible. spell out the term at the first instance of usage.
$ web of trust $ web of trust
(D) /PGP/ A trust-file PKI technique used for building a file of (D) /PGP/ A trust-file PKI technique used for building a file of
trusted public keys by making personal judgments about being able trusted public keys by making personal judgments about being able
to trust certain people to be holding properly certified keys of to trust certain people to be holding properly certified keys of
other people. (See: certification hierarchy, mesh PKI.) other people. (See: certification hierarchy, mesh PKI, trust
anchor, web, Web.)
Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts Deprecated Term: ISDs SHOULD NOT use this term; it mixes concepts
in a potentially misleading way. This PKI technique does not in a potentially misleading way. This PKI technique does not
depend on World Wide Web technology. depend on World Wide Web technology.
$ web server $ web server
(I) A software process that runs on a host computer connected to a (I) A software process that runs on a host computer connected to a
network and responds to HTTP requests made by client web browsers. network and responds to HTTP requests made by client web browsers.
$ WEP $ WEP
(N) See: Wired Equivalency Protocol. (N) See: Wired Equivalency Protocol.
$ Wired Equivalent Privacy (WEP) $ Wired Equivalent Privacy (WEP)
(N) A cryptographic protocol defined in the IEEE 802.11 standard (N) A cryptographic protocol that is defined in the IEEE 802.11
encapsulate the packets on wireless LANs. (Frequently referred to standard and encapsulates the packets on wireless LANs. Usage:
as "Wired Equivalency Protocol".) a.k.a. "Wired Equivalency Protocol".
Tutorial: The WEP design, which uses RC4 to encrypt the plaintext Tutorial: The WEP design, which uses RC4 to encrypt both the plain
and a CRC, has been shown to be flawed in multiple ways; and it text and a CRC, has been shown to be flawed in multiple ways; and
also has often been flawed in implementation and management. it also has often suffered from flawed implementation and
management.
$ wiretapping $ wiretapping
(I) An attack that intercepts and accesses information contained (I) An attack that intercepts and accesses information contained
in a data flow in a communication system. (See: active in a data flow in a communication system. (See: active
wiretapping, end-to-end encryption, passive wiretapping.) wiretapping, end-to-end encryption, passive wiretapping.)
Usage: Although the term originally referred to making a Usage: Although the term originally referred to making a
mechanical connection to an electrical conductor that links two mechanical connection to an electrical conductor that links two
nodes, it is now used to refer to accessing information from any nodes, it is now used to refer to accessing information from any
sort of medium used for a link or even from a node, such as a sort of medium used for a link or even from a node, such as a
gateway or subnetwork switch. gateway or subnetwork switch.
Tutorial: Wiretapping can be characterized according to intent: Tutorial: Wiretapping can be characterized according to intent:
- "Active wiretapping" attempts to alter the data or otherwise - "Active wiretapping" attempts to alter the data or otherwise
affect the flow. affect the flow.
- "Passive wiretapping" only attempts to observe the data flow - "Passive wiretapping" only attempts to observe the data flow
and gain knowledge of information contained in it. and gain knowledge of information contained in it.
$ work factor $ work factor
1. (I) /COMPUSEC/ The estimated amount of effort or time that can 1. (I) /COMPUSEC/ The estimated amount of effort or time that can
be expected to be expended by a potential intruder to penetrate a be expected to be expended by a potential intruder to penetrate a
system, or defeat a particular countermeasure, when using system, or defeat a particular countermeasure, when using
specified amounts of expertise and resources. (See: strength.) specified amounts of expertise and resources. (See: strength.)
2. (I) /cryptography/ The estimated amount of computing power and 2. (I) /cryptography/ The estimated amount of computing power and
time needed to break a cryptographic system. time needed to break a cryptographic system.
$ World Wide Web ("the Web", WWW) $ World Wide Web ("the Web", WWW)
(N) The global, hypermedia-based collection of information and (N) The global, hypermedia-based collection of information and
services that is available on Internet servers and is accessed by services that is available on Internet servers and is accessed by
browsers using Hypertext Transfer Protocol and other information browsers using Hypertext Transfer Protocol and other information
retrieval mechanisms. (See: web vs. Web, [R2084].) retrieval mechanisms. (See: web vs. Web, [R2084].)
$ World Wide Web Consortium (W3C) $ World Wide Web Consortium (W3C)
(N) Created in October 1994 to develop and standardize protocols (N) Created in October 1994 to develop and standardize protocols
to promote the evolution and interoperability of the Web, and now to promote the evolution and interoperability of the Web, and now
consisting of over 300 member organizations (commercial firms, consisting of hundreds of member organizations (commercial firms,
government agencies, schools, and other organizations). government agencies, schools, and others).
Tutorial: W3C Recommendations are developed through a process Tutorial: W3C Recommendations are developed through a process
similar to that of the standards published by other organizations, similar to that of the standards published by other organizations,
such as the IETF. The W3 Recommendation Track (i.e., standards such as the IETF. The W3 Recommendation Track (i.e., standards
track) has four levels of increasing maturity: Working, Candidate track) has four levels of increasing maturity: Working, Candidate
Recommendation, Proposed Recommendation, and W3C Recommendation Recommendation, Proposed Recommendation, and W3C Recommendation
W3C Recommendations are similar to the standards published by W3C Recommendations are similar to the standards published by
other organizations. (Compare: Internet Standard, ISO.) others organizations. (Compare: Internet Standard, ISO.)
$ worm $ worm
(I) A computer program that can run independently, can propagate a (I) A computer program that can run independently, can propagate a
complete working version of itself onto other hosts on a network, complete working version of itself onto other hosts on a network,
and may consume system resources destructively. (See: Morris Worm, and may consume system resources destructively. (See: mobile code,
virus.) Morris Worm, virus.)
$ wrap $ wrap
(D) To use cryptography to provide data confidentiality service (D) To use cryptography to provide data confidentiality service
for keying material. (See: encrypt. Compare: seal.) for keying material. (See: encrypt. Compare: seal.)
Deprecated Term: ISDs SHOULD NOT use this term as defined here; Deprecated Term: ISDs SHOULD NOT use this term as defined here;
the definition duplicates the meaning of other, standard terms. the definition duplicates the meaning of other, standard terms.
Instead, use "encrypt" or another term that is specific with Instead, use "encrypt" or another term that is specific with
regard to the mechanism being used. regard to the mechanism being used.
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attribute certificates associated with each of its public-key attribute certificates associated with each of its public-key
certificates, and an attribute certificate may be issued by a certificates, and an attribute certificate may be issued by a
different CA than the one that issued the associated public-key different CA than the one that issued the associated public-key
certificate. certificate.
An X.509 attribute certificate contains a sequence of data items An X.509 attribute certificate contains a sequence of data items
and has a digital signature that is computed from that sequence. and has a digital signature that is computed from that sequence.
In addition to the signature, an attribute certificate contains In addition to the signature, an attribute certificate contains
items 1 through 9 listed below: items 1 through 9 listed below:
1. version Identifies v1. 1. version Identifies v1.
2. subject Is one of the following: 2. subject Is one of the following:
2a. baseCertificateID Issuer and serial number of an 2a. baseCertificateID Issuer and serial number of an
X.509 public-key certificate. X.509 public-key certificate.
2b. subjectName DN of the subject. 2b. subjectName DN of the subject.
3. issuer DN of the issuer (the CA who signed). 3. issuer DN of the issuer (the CA who signed).
4. signature OID of algorithm that signed the cert. 4. signature OID of algorithm that signed the cert.
5. serialNumber Certificate serial number; 5. serialNumber Certificate serial number;
an integer assigned by the issuer. an integer assigned by the issuer.
6. attCertValidityPeriod Validity period; a pair of UTCTime 6. attCertValidityPeriod Validity period; a pair of UTCTime
values: "not before" and "not after". values: "not before" and "not after".
7. attributes Sequence of attributes describing the 7. attributes Sequence of attributes describing the
subject. subject.
8. issuerUniqueId Optional, when a DN is not sufficient. 8. issuerUniqueId Optional, when a DN is not sufficient.
9. extensions Optional. 9. extensions Optional.
$ X.509 authority revocation list
(N) An ARL in one of the formats defined by X.509 -- version 1
(v1) or version 2 (v2). A specialized kind of certificate
revocation list.
$ X.509 certificate $ X.509 certificate
(N) Synonym for "X.509 public-key certificate". (N) Synonym for "X.509 public-key certificate".
Usage: ISDs MAY use this term as an abbreviation for "X.509 Usage: ISDs MAY use this term as an abbreviation of "X.509 public-
public-key certificate", but only after using the full term at the key certificate", but only after using the full term at the first
first instance. Otherwise, the term is ambiguous, because X.509 instance. Otherwise, the term is ambiguous, because X.509
specifies both public-key certificates and attribute certificates. specifies both public-key certificates and attribute certificates.
(See: X.509 attribute certificate, X.509 public-key certificate.) (See: X.509 attribute certificate, X.509 public-key certificate.)
Deprecated Usage: ISDs SHOULD NOT use this term as an abbreviation Deprecated Usage: ISDs SHOULD NOT use this term as an abbreviation
for "X.509 attribute certificate", because the term is likely to of "X.509 attribute certificate", because the term is much more
be misunderstood to mean "X.509 public-key certificate". commonly used to mean "X.509 public-key certificate" and,
therefore, is likely to be misunderstood.
$ X.509 certificate revocation list (CRL) $ X.509 certificate revocation list (CRL)
(N) A CRL in one of the formats defined by X.509 -- version 1 (v1) (N) A CRL in one of the formats defined by X.509 -- version 1 (v1)
or version 2 (v2). (The v1 and v2 designations for an X.509 CRL or version 2 (v2). (The v1 and v2 designations for an X.509 CRL
are disjoint from the v1 and v2 designations for an X.509 public- are disjoint from the v1 and v2 designations for an X.509 public-
key certificate, and from the v1 designation for an X.509 key certificate, and from the v1 designation for an X.509
attribute certificate.) (See: certificate revocation.) attribute certificate.) (See: certificate revocation.)
Usage: ISDs SHOULD NOT refer to an X.509 CRL as a digital Usage: ISDs SHOULD NOT refer to an X.509 CRL as a digital
certificate; however, note that an X.509 CRL does meet this certificate; however, note that an X.509 CRL does meet this
Glossary's definition of "digital certificate". Like a digital Glossary's definition of "digital certificate". That is, like a
certificate, an X.509 CRL makes an assertion and is signed by a digital certificate, an X.509 CRL makes an assertion and is signed
CA. But instead of binding a key or other attributes to a subject, by a CA. But instead of binding a key or other attributes to a
an X.509 CRL asserts that certain previously-issued X.509 subject, an X.509 CRL asserts that certain previously issued,
certificates have been revoked. X.509 certificates have been revoked.
Tutorial: An X.509 CRL contains a sequence of data items and has a Tutorial: An X.509 CRL contains a sequence of data items and has a
digital signature computed on that sequence. In addition to the digital signature computed on that sequence. In addition to the
signature, both v1 and v2 contain items 2 through 6b listed below. signature, both v1 and v2 contain items 2 through 6b listed below.
Version 2 contains item 1 and may optionally contain 6c and 7. Version 2 contains item 1 and may optionally contain 6c and 7.
1. version Optional. If present, identifies v2. 1. version Optional. If present, identifies v2.
2. signature OID of the algorithm that signed CRL. 2. signature OID of the algorithm that signed CRL.
3. issuer DN of the issuer (the CA who signed). 3. issuer DN of the issuer (the CA who signed).
4. thisUpdate A UTCTime value. 4. thisUpdate A UTCTime value.
5. nextUpdate A UTCTime value. 5. nextUpdate A UTCTime value.
6. revokedCertificates 3-tuples of 6a, 6b, and (optional) 6c: 6. revokedCertificates 3-tuples of 6a, 6b, and (optional) 6c:
6a. userCertificate A certificate's serial number. 6a. userCertificate A certificate's serial number.
6b. revocationDate UTCTime value for the revocation date. 6b. revocationDate UTCTime value for the revocation date.
6c. crlEntryExtensions Optional. 6c. crlEntryExtensions Optional.
7. crlExtensions Optional. 7. crlExtensions Optional.
$ X.509 public-key certificate $ X.509 public-key certificate
(N) A public-key certificate in one of the formats defined by (N) A public-key certificate in one of the formats defined by
X.509 -- version 1 (v1), version 2 (v2), or version 3 (v3). (The X.509 -- version 1 (v1), version 2 (v2), or version 3 (v3). (The
v1 and v2 designations for an X.509 public-key certificate are v1 and v2 designations for an X.509 public-key certificate are
disjoint from the v1 and v2 designations for an X.509 CRL, and disjoint from the v1 and v2 designations for an X.509 CRL, and
from the v1 designation for an X.509 attribute certificate.) from the v1 designation for an X.509 attribute certificate.)
Tutorial: An X.509 public-key certificate contains a sequence of Tutorial: An X.509 public-key certificate contains a sequence of
data items and has a digital signature computed on that sequence. data items and has a digital signature computed on that sequence.
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Tutorial: An X.509 public-key certificate contains a sequence of Tutorial: An X.509 public-key certificate contains a sequence of
data items and has a digital signature computed on that sequence. data items and has a digital signature computed on that sequence.
In addition to the signature, all three versions contain items 1 In addition to the signature, all three versions contain items 1
through 7 listed below. Only v2 and v3 certificates may also through 7 listed below. Only v2 and v3 certificates may also
contain items 8 and 9, and only v3 may contain item 10. contain items 8 and 9, and only v3 may contain item 10.
1. version Identifies v1, v2, or v3. 1. version Identifies v1, v2, or v3.
2. serialNumber Certificate serial number; 2. serialNumber Certificate serial number;
an integer assigned by the issuer. an integer assigned by the issuer.
3. signature OID of algorithm that was used to 3. signature OID of algorithm that was used to
sign the certificate. sign the certificate.
4. issuer DN of the issuer (the CA who signed). 4. issuer DN of the issuer (the CA who signed).
5. validity Validity period; a pair of UTCTime 5. validity Validity period; a pair of UTCTime
values: "not before" and "not after". values: "not before" and "not after".
6. subject DN of entity who owns the public key. 6. subject DN of entity who owns the public key.
7. subjectPublicKeyInfo Public key value and algorithm OID. 7. subjectPublicKeyInfo Public key value and algorithm OID.
8. issuerUniqueIdentifier Defined for v2, v3; optional. 8. issuerUniqueIdentifier Defined for v2, v3; optional.
9. subjectUniqueIdentifier Defined for v2, v2; optional. 9. subjectUniqueIdentifier Defined for v2, v2; optional.
10. extensions Defined only for v3; optional. 10. extensions Defined only for v3; optional.
$ X9 $ X9
See: (Accredited Standards Committee X9 under) ANSI. See: "Accredited Standards Committee X9" under "ANSI".
$ XML $ XML
(N) See: Extensible Markup Language. (N) See: Extensible Markup Language.
$ XML-Signature. $ XML-Signature.
(N) A W3C Recommendation (i.e. approved standard) that specifies (N) A W3C Recommendation (i.e. approved standard) that specifies
XML syntax and processing rules for creating and representing XML syntax and processing rules for creating and representing
digital signatures (based on asymmetric cryptography) that can be digital signatures (based on asymmetric cryptography) that can be
applied to any digital content (i.e., any data object) including applied to any digital content (i.e., any data object) including
other XML material. other XML material.
$ XTACACS $ XTACACS
(I) Cisco Corporation's implementation of the Terminal Access (I) Cisco Corporation's implementation of the Terminal Access
Controller (TAC) Access Control System. This implementation Controller (TAC) Access Control System. This implementation
enhances and extends the original TACACS. (See: TACACS, TACACS+.) enhances and extends the original TACACS. (See: TACACS, TACACS+.)
$ Yellow Book $ Yellow Book
(D) Synonym for "Computer Security Requirements: Guidance for (D) /slang/ Synonym for "Computer Security Requirements: Guidance
Applying the [U.S.] Department of Defense Trusted Computer System for Applying the [U.S.] Department of Defense Trusted Computer
Evaluation Criteria in Specific Environments" [CSC3] (See: (first System Evaluation Criteria in Specific Environments" [CSC3] (See:
law under) Courtney's laws). "first law" under "Courtney's laws".)
Deprecated Term: ISDs SHOULD NOT use this term as a synonym for Deprecated Term: ISDs SHOULD NOT use this term as a synonym for
that or any other document. Instead, use the full proper name of that or any other document. Instead, use the full proper name of
the document or, in subsequent references, a conventional the document or, in subsequent references, a conventional
abbreviation. (See: (Deprecated Usage under) Green Book, Rainbow abbreviation. (See: Deprecated Usage under "Green Book", Rainbow
Series.) Series.)
$ zero-knowledge proof $ zero-knowledge proof
(I) /cryptography/ A proof-of-possession protocol whereby a system (I) /cryptography/ A proof-of-possession protocol whereby a system
entity can prove possession of some information to another entity, entity can prove possession of some information to another entity,
without revealing any of that information. (See: proof-of- without revealing any of that information. (See: proof-of-
possession protocol.) possession protocol.)
$ zeroize $ zeroize
1. (I) Synonym for "purge". Usage: Particularly with regard to 1. (I) Synonym for "purge". Usage: Particularly with regard to
erasing keys that are stored in a cryptographic module. erasing keys that are stored in a cryptographic module.
2. (O) Erase electronically stored data by altering the contents 2. (O) Erase electronically stored data by altering the contents
of the data storage so as to prevent the recovery of the data. of the data storage so as to prevent the recovery of the data.
[FP140] [FP140]
$ zombie $ zombie
(I) An Internet host computer that has been surreptitiously (I) /slang/ An Internet host computer that has been
penetrated by an intruder that installed malicious daemon software surreptitiously penetrated by an intruder that installed malicious
to cause the host to operate as an accomplice in attacking other daemon software to cause the host to operate as an accomplice in
hosts, particularly in distributed attacks that attempt denial of attacking other hosts, particularly in distributed attacks that
service through flooding. attempt denial of service through flooding.
Deprecated Term: It is likely that other cultures have different Deprecated Term: It is likely that other cultures use different
metaphors for this concept. Therefore, to ensure international metaphors for this concept. Therefore, to avoid international
understanding, ISDs SHOULD NOT use this term. (See: (Deprecated misunderstanding, ISDs SHOULD NOT use this term. (See: Deprecated
Usage under) Green Book.) Usage under "Green Book".)
$ zone of control $ zone of control
(O) /EMSEC/ Synonym for "inspectable space". [C4009] (See: (O) /EMSEC/ Synonym for "inspectable space". [C4009] (See:
TEMPEST.) TEMPEST.)
5. References 5. Informative References
This Glossary focuses on the Internet Standards Process. Therefore, This Glossary focuses on the Internet Standards Process. Therefore,
this set of references emphasizes international, governmental, and this set of references emphasizes international, governmental, and
industry standards documents. industry standards documents. RFCs referenced in Glossary entries are
listed here if they are specifically security-relevant; other
referenced RFCs are only mentioned by number (e.g., see "RFC 959" in
the entry for "File Transport Protocol").
[A1523] American National Standards Institute, "American National [A1523] American National Standards Institute, "American National
Standard Telecomm Glossary", ANSI T1.523-2001. Standard Telecomm Glossary", ANSI T1.523-2001.
[A3092] ---, "American National Standard Data Encryption Algorithm", [A3092] ---, "American National Standard Data Encryption Algorithm",
ANSI X3.92-1981, 30 Dec 1980. ANSI X3.92-1981, 30 December 1980.
[A9009] ---, "Financial Institution Message Authentication [A9009] ---, "Financial Institution Message Authentication
(Wholesale)", ANSI X9.9-1986, 15 Aug 1986. (Wholesale)", ANSI X9.9-1986, 15 August 1986.
[A9017] ---, "Financial Institution Key Management (Wholesale)", [A9017] ---, "Financial Institution Key Management (Wholesale)",
X9.17, 4 Apr 1985. [Defines procedures for the manual and X9.17, 4 April 1985. (Defines procedures for manual and
automated management of keying material and uses DES to automated management of keying material and uses DES to
provide key management for a variety of operational provide key management for a variety of operational
environments.] environments.)
[A9042] ---, "Public key Cryptography for the Financial Service [A9042] ---, "Public key Cryptography for the Financial Service
Industry: Agreement of Symmetric Keys Using Diffie-Hellman Industry: Agreement of Symmetric Keys Using Diffie-Hellman
and MQV Algorithms", X9.42, 29 Jan 1999. and MQV Algorithms", X9.42, 29 January 1999.
[A9052] ---, "Triple Data Encryption Algorithm Modes of Operation", [A9052] ---, "Triple Data Encryption Algorithm Modes of Operation",
X9.52-1998, ANSI approval 9 Nov 1998. X9.52-1998, ANSI approval 9 November 1998.
[A9062] ---, "Public Key Cryptography for the Financial Services [A9062] ---, "Public Key Cryptography for the Financial Services
Industry: The Elliptic Curve Digital Signature Algorithm Industry: The Elliptic Curve Digital Signature Algorithm
(ECDSA)", X9.62-1998, ANSI approval 7 Jan 1999. (ECDSA)", X9.62-1998, ANSI approval 7 January 1999.
[A9063] ---, "---: Key Agreement and Key Transport Using Elliptic [A9063] ---, "---: Key Agreement and Key Transport Using Elliptic
Curve Cryptography", X9.63-2001. Curve Cryptography", X9.63-2001.
[ABA] American Bar Association, "Digital Signature Guidelines: [ABA] American Bar Association, "Digital Signature Guidelines:
Legal Infrastructure for Certification Authorities and Legal Infrastructure for Certification Authorities and
Secure Electronic Commerce", Chicago, IL, 1 Aug 1996. Secure Electronic Commerce", Chicago, IL, 1 August 1996.
[ACM] Association for Computing Machinery, "Communications of the [ACM] Association for Computing Machinery, "Communications of the
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Computing in the Information Age", National Academy Press, Computing in the Information Age", National Academy Press,
1991. 1991.
[NRC98] F. Schneider, ed., "Trust in Cyberspace", National Research [NRC98] Schneider, F., ed., "Trust in Cyberspace", National Research
Council, National Academy of Sciences, 1998. Council, National Academy of Sciences, 1998.
[Park] D. Parker, "Computer Security Management", ISBN 0-8359-0905- [Padl] Padlipsky, M., "The Elements of Networking Style", 1985,
0, 1981 ISBN 0-13-268111-0.
[Perr] T. Perrine et al, "An Overview of the Kernelized Secure [Park] Parker, D., "Computer Security Management", ISBN 0-8359-
Operating System (KSOS)" in "Proceedings of the 7th DoD/NBS 0905-0, 1981
Computer Security Conference", 24-26 Sep 1984.
[PGP] S. Garfinkel, "PGP: Pretty Good Privacy", O'Reilly & [Perr] Perrine, T. et al, "An Overview of the Kernelized Secure
Operating System (KSOS)", in "Proceedings of the 7th DoD/NBS
Computer Security Conference", 24-26 September 1984.
[PGP] Garfinkel, S.. "PGP: Pretty Good Privacy", O'Reilly &
Associates, Inc., Sebastopol, CA, 1995. Associates, Inc., Sebastopol, CA, 1995.
[PKCS] B. Kaliski, Jr., "An Overview of the PKCS Standards", RSA [PKCS] Kaliski Jr., B., "An Overview of the PKCS Standards", RSA
Data Security, Inc., 3 Jun 1991. Data Security, Inc., 3 June 1991.
[PKC05] RSA Laboratories, "PKCS #5: Password-Based Encryption [PKC05] RSA Laboratories, "PKCS #5: Password-Based Encryption
Standard ", ver. 1.5, RSA Laboratories Technical Note, 1 Nov Standard ", version 1.5, RSA Laboratories Technical Note, 1
1993. November 1993. (See: [R2898].)
[PKC07] ---, "PKCS #7: Cryptographic Message Syntax Standard", ver. [PKC07] ---, "PKCS #7: Cryptographic Message Syntax Standard",
1.5, RSA Laboratories Technical Note, 1 Nov 1993. version 1.5, RSA Laboratories Technical Note, 1 November
1993.
[PKC10] ---, "PKCS #10: Certification Request Syntax Standard", ver. [PKC10] ---, "PKCS #10: Certification Request Syntax Standard",
1.0, RSA Laboratories Technical Note, 1 Nov 1993. version 1.0, RSA Laboratories Technical Note, 1 November
1993.
[PKC11] ---, "PKCS #11: Cryptographic Token Interface Standard", [PKC11] ---, "PKCS #11: Cryptographic Token Interface Standard",
ver. 1.0, 28 Apr 1995. version 1.0, 28 April 1995.
[R1108] S. Kent, "U.S. Department of Defense Security Options for [R1108] Kent, S., "U.S. Department of Defense Security Options for
the Internet Protocol", RFC 1108, Nov 1991. the Internet Protocol", RFC 1108, November 1991.
[R1135] J. Reynolds, "The Helminthiasis of the Internet", RFC 1135, [R1135] Reynolds, J., "The Helminthiasis of the Internet", RFC 1135,
Dec 1989 December 1989
[R1157] J. Case et al, "A Simple Network Management Protocol (SNMP)" [R1208] Jacobsen, O. and D. Lynch, "A Glossary of Networking Terms",
[version 1], STD 15, RFC 1157, May 1990. RFC 1208, March 1991.
[R1208] O. Jacobsen et al, "A Glossary of Networking Terms", RFC [R1281] Pethia, R., Crocker, S., and B. Fraser, "Guidelines for
1208, Mar 1991. Secure Operation of the Internet", RFC 1281, November 1991.
[R1281] R. Pethia et al, "Guidelines for Secure Operation of the [R1319] Kaliski, B., "The MD2 Message-Digest Algorithm", RFC 1319,
Internet", RFC 1281, Nov 1991. April 1992.
[R1319] B. Kaliski, "The MD2 Message-Digest Algorithm", RFC 1319, [R1320] Rivest, R., "The MD4 Message-Digest Algorithm", RFC 1320,
Apr 1992. April 1992.
[R1320] R. Rivest, "The MD4 Message-Digest Algorithm", RFC 1320, Apr [R1321] ---, "The MD5 Message-Digest Algorithm", RFC 1321, April
1992. 1992.
[R1321] ---, "The MD5 Message-Digest Algorithm", RFC 1321, Apr 1992. [R1334] Lloyd, B. and W. Simpson, "PPP Authentication Protocols",
RFC 1334, October 1992.
[R1334] B. Lloyd et al, "PPP Authentication Protocols", RFC 1334,
Oct 1992.
[R1413] M. St. Johns, "Identification Protocol", RFC 1413, Feb 1993. [R1413] St. Johns, M., "Identification Protocol", RFC 1413, February
1993.
[R1421] J. Linn, "Privacy Enhancement for Internet Electronic Mail, [R1421] Linn, J., "Privacy Enhancement for Internet Electronic Mail,
Part I: Message Encryption and Authentication Procedures", Part I: Message Encryption and Authentication Procedures",
RFC 1421, Feb 1993. RFC 1421, February 1993.
[R1422] S. Kent, "Privacy Enhancement for Internet Electronic Mail, [R1422] Kent, S., "Privacy Enhancement for Internet Electronic Mail,
Part II: Certificate-Based Key Management", RFC 1422, Feb Part II: Certificate-Based Key Management", RFC 1422,
1993. February 1993.
[R1455] D. Eastlake, III, "Physical Link Security Type of Service", [R1455] Eastlake 3rd, D., "Physical Link Security Type of Service",
RFC 1455, May 1993. RFC 1455, May 1993.
[R1457] R. Housley, "Security Label Framework for the Internet", RFC [R1457] Housley, R., "Security Label Framework for the Internet",
1457, May 1993. RFC 1457, May 1993.
[R1492] C. Finseth, "An Access Control Protocol, Sometimes Called [R1492] Finseth, C., "An Access Control Protocol, Sometimes Called
TACACS", RFC 1492, Jul 1993. TACACS", RFC 1492, July 1993.
[R1507] C. Kaufman, "DASS: Distributed Authentication Security [R1507] Kaufman, C., "DASS: Distributed Authentication Security
Service", RFC 1507, Sep 1993. Service", RFC 1507, September 1993.
[R1510] J. Kohl et al, "The Kerberos Network Authentication Service [R1510] Kohl, J. and C. Neuman, "The Kerberos Network Authentication
(V5)", RFC 1510, Sep 1993 Service (V5)", RFC 1510, September 1993
[R1731] J. Myers, "IMAP4 Authentication Mechanisms", RFC 1731, Dec [R1731] Myers, J., "IMAP4 Authentication Mechanisms", RFC 1731,
1994. December 1994.
[R1734] ---, "POP3 AUTHentication Command", RFC 1734, Dec, 1994. [R1734] ---, "POP3 AUTHentication Command", RFC 1734, Dec, 1994.
[R1750] D. Eastlake, 3rd, et al, "Randomness Recommendations for [R1750] Eastlake 3rd, D., Crocker, S., and J. Schiller, "Randomness
Security", Dec 1994. Recommendations for Security", RFC 1750, December 1994.
[R1824] H. Danisch, "The Exponential Security System TESS: An [R1760] Haller, N., "The S/KEY One-Time Password System", RFC 1760,
February 1995.
[R1824] Danisch, H., "The Exponential Security System TESS: An
Identity-Based Cryptographic Protocol for Authenticated Key- Identity-Based Cryptographic Protocol for Authenticated Key-
Exchange (E.I.S.S.-Report 1995/4)", RFC 1824, Aug 1995. Exchange (E.I.S.S.-Report 1995/4)", RFC 1824, August 1995.
[R1828] P. Metzger et al, "IP Authentication using Keyed MD5", RFC [R1828] Metzger, P. and W. Simpson, "IP Authentication using Keyed
1828, Aug 1995. MD5", RFC 1828, August 1995.
[R1829] P. Karn et al, "The ESP DES-CBC Transform", RFC 1829, Aug [R1829] Karn, P., Metzger, P., and W. Simpson, "The ESP DES-CBC
1995. Transform", RFC 1829, August 1995.
[R1848] S. Crocker et al, "MIME Object Security Services", RFC 1848, [R1848] Crocker, S., Freed, N., Galvin, J., and S. Murphy, "MIME
Oct 1995. Object Security Services", RFC 1848, October 1995.
[R1851] P. Karn et al, "The ESP Triple DES Transform", RFC 1851, Sep [R1851] Karn, P., Metzger, P., and W. Simpson, "The ESP Triple DES
1995. Transform", RFC 1851, September 1995.
[R1885] A. Conta et al, "Internet Control Message Protocol (ICMPv6) [R1928] Leech, M., Ganis, M., Lee, Y., Kuris, R., Koblas, D., and L.
for the Internet Protocol Version 6 (IPv6) Specification", Jones, "SOCKS Protocol Version 5", RFC 1928, March 1996.
RFC 1885, Dec 1995.
[R1928] M. Leech et al, "SOCKS Protocol Version 5", RFC 1928, Mar [R1938] Haller, N. and C. Metz, "A One-Time Password System", RFC
1996. 1938, May 1996.
[R1938] N. Haller et al, "A One-Time Password System", RFC 1938, May [R1958] Carpenter, B., ed., "Architectural Principles of the
1996. Internet", RFC 1958, June 1996.
[R1983] G. Malkin, ed., "Internet Users' Glossary", FYI 18, RFC [R1983] Malkin, G., ed., "Internet Users' Glossary", FYI 18, RFC
1983, Aug 1996. 1983, August 1996.
[R1994] W. Simpson, "PPP Challenge Handshake Authentication Protocol [R1994] Simpson, W., "PPP Challenge Handshake Authentication
(CHAP)", RFC 1994, Aug 1996. Protocol (CHAP)", RFC 1994, August 1996.
[R2026] S. Bradner, "The Internet Standards Process--Revision 3", [R2078] Linn, J., "Generic Security Service Application Program
BCP009, RFC 2026, Mar 1994. Interface, Version 2", RFC 2078, January 1997.
[R2065] D. Eastlake, 3rd, "Domain Name System Security Extensions", [R2084] Bossert, G., Cooper, S., and W. Drummond, "Considerations
RFC 2065, Jan 1997. for Web Transaction Security", RFC 2084, January 1997.
[R2078] J. Linn, "Generic Security Service Application Program [R2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Interface, Version 2", RFC 2078, Jan 1997. Hashing for Message Authentication", RFC 2104, February
1997.
[R2084] G. Bossert et al, "Considerations for Web Transaction [R2144] Adams, C., "The CAST-128 Encryption Algorithm", RFC 2144,
Security", RFC 2084, Jan 1997. May 1997.
[R2104] H. Krawczyk et al, "HMAC: Keyed-Hashing for Message [R2179] Gwinn, A., "Network Security For Trade Shows", RFC 2179,
Authentication", RFC 2104, Feb 1997. July 1997.
[R2137] D. Eastlake, 3rd, "Secure Domain Name System Dynamic [R2195] Klensin, J., Catoe, R., and P. Krumviede, "IMAP/POP
Update", RFC 2137, Apr 1997. AUTHorize Extension for Simple Challenge/Response", RFC
2195, September 1997.
[R2138] C. Rigney et al, "Remote Authentication Dial In User Service [R2196] Fraser, B., "Site Security Handbook", FYI 8, RFC 2196,
(RADIUS)", RFC 2138, Apr 1997. September 1997.
[R2179] A. Gwinn, "Network Security For Trade Shows", RFC 2179, Jul [R2202] Cheng, P. and R. Glenn, "Test Cases for HMAC-MD5 and HMAC-
1997. SHA-1", RFC 2202, Sep. 1997.
[R2195] J. Klensin et al, "IMAP/POP AUTHorize Extension for Simple [R2222] Myers, J., "Simple Authentication and Security Layer
Challenge/Response", RFC 2195, Sep 1997. (SASL)", RFC 2222, October 1997.
[R2196] B. Fraser, "Site Security Handbook", FYI 8, RFC 2196, Sep [R2246] Dierks, T. and C. Allen, "The TLS Protocol, Version 1.0",
1997. RFC 2246, January 1999.
[R2202] P. Cheng et al, "Test Cases for HMAC-MD5 and HMAC- [R2315] Kaliski, B., "PKCS #7: Cryptographic Message Syntax, Version
SHA-1", RFC 2202, Sep. 1997. 1.5", RFC 2315, March 1998.
[R2222] J. Myers, "Simple Authentication and Security Layer (SASL)", [R2323] Ramos, A., "IETF Identification and Security Guidelines",
RFC 2222, Oct 1997. RFC 2323, 1 April 1998. (Intended for humorous entertainment
-- "please laugh loud and hard" -- and does not contain
serious security information.)
[R2223] J. Postel, "Instructions to RFC Authors", RFC 2223, Oct [R2350] Brownlee, N. and E. Guttman, "Expectations for Computer
1997. Security Incident Response", RFC 2350, June 1998.
[R2246] T. Dierks et al, "The TLS Protocol, Version 1.0", RFC 2246, [R2356] Montenegro, G. and V. Gupta, "Sun's SKIP Firewall Traversal
Jan 1999. for Mobile IP", RFC 2356, June 1998.
[R2267] P. Ferguson et al, "Network Ingress Filtering: Defeating [R2401] Kent, S. and R. Atkinson, "Security Architecture for the
Denial of Service Attacks Which Employ IP Source Address Internet Protocol", RFC 2401, November 1998.
Spoofing", RFC 2267, Jan 1998
[R2315] B. Kaliski, "PKCS #7: Cryptographic Message Syntax, Version [R2402] ---, "IP Authentication Header", RFC 2402, November 1998.
1.5", RFC 2315, Mar 1998.
[R2323] A. Ramos, "IETF Identification and Security Guidelines", RFC [R2403] Madson, C. and R. Glenn, "The Use of HMAC-MD5-96 within ESP
2323, 1 Apr 1998. [Intended for humorous entertainment and AH", RFC 2403, November 1998.
("please laugh loud and hard"); does not contain serious
security information.]
[R2350] N. Brownlee et al, "Expectations for Computer Security [R2404] ---, "The Use of HMAC-SHA-1-96 within ESP and AH", RFC 2404,
Incident Response", RFC 2350, Jun 1998. November 1998.
[R2356] G. Montenegro et al, "Sun's SKIP Firewall Traversal for [R2405] Madson, C. and N. Doraswamy, "The ESP DES-CBC Cipher
Mobile IP", RFC 2356, Jun 1998. Algorithm With Explicit IV", RFC 2405, November 1998.
[R2401] S. Kent et al, "Security Architecture for the Internet [R2406] Kent, S. and R. Atkinson, "IP Encapsulating Security Payload
Protocol", RFC 2401, Nov 1998. (ESP)", RFC 2406, November 1998.
[R2402] S. Kent et al, "IP Authentication Header", RFC 2402, Nov [R2407] Piper, D. "The Internet IP Security Domain of Interpretation
1998. for ISAKMP", RFC 2407, November 1998.
[R2403] C. Madson et al, "The Use of HMAC-MD5-96 within ESP and AH", [R2408] Maughan, D., Schertler, M., Schneider, M., and J. Turner,
RFC 2403, Nov 1998. "Internet Security Association and Key Management Protocol
(ISAKMP)", RFC 2408, November 1998.
[R2404] C. Madson et al, "The Use of HMAC-SHA-1-96 within ESP and [R2409] Harkins, D. and D. Carrel, "The Internet Key Exchange
AH", RFC 2404, Nov 1998. (IKE)", RFC 2409, November 1998.
[R2405] C. Madson et al, "The ESP DES-CBC Cipher Algorithm With [R2410] Glenn, R. and S. Kent, "The NULL Encryption Algorithm and
Explicit IV", RFC 2405, Nov 1998. Its Use With IPsec", RFC 2410, November 1998.
[R2406] S. Kent et al, "IP Encapsulating Security Payload (ESP)", [R2412] Orman, H., "The OAKLEY Key Determination Protocol", RFC
RFC 2406, Nov 1998. 2412, November 1998.
[R2407] D. Piper, "The Internet IP Security Domain of Interpretation [R2451] Pereira, R. and R. Adams, "The ESP CBC-Mode Cipher
for ISAKMP", RFC 2407, Nov 1998. Algorithms", RFC 2451, November 1998.
[R2408] D. Maughan et al, "Internet Security Association and Key [R2504] Guttman, E., Leong, L., and G. Malkin, "Users' Security
Management Protocol (ISAKMP)", RFC 2408, Nov 1998. Handbook", RFC 2504, February 1999.
[R2409] D. Harkins and D. Carrel, "The Internet Key Exchange (IKE)", [R2510] Adams, C. and S. Farrell, "Internet X.509 Public Key
RFC 2409, Nov 1998. Infrastructure Certificate Management Protocols", RFC 2510,
March 1999.
[R2410] R. Glenn et al, "The NULL Encryption Algorithm and Its Use [R2535] Eastlake 3rd, D., Domain Name System Security Extensions,
With IPsec", RFC 2410, Nov 1998. RFC 2535, March 1999.
[R2412] H. Orman, "The OAKLEY Key Determination Protocol", RFC 2412, [R2536] Eastlake 3rd, D., "DSA KEYs and SIGs in the Domain Name
Nov 1998. System (DNS)", RFC 2536, March 1999.
[R2451] R. Pereira et al, "The ESP CBC-Mode Cipher Algorithms", RFC [R2560] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C.
2451, Nov 1998. Adams, "X.509 Internet Public Key Infrastructure Online
Certificate Status Protocol", RFC 2560, June 1999.
[R2459] R. Housley et al, " Internet X.509 Public Key Infrastructure [R2612] Adams, C. and J. Gilchrist, "The CAST-256 Encryption
Certificate and CRL Profile", RFC 2459, Jan 1999. Algorithm", RFC 2612, June 1999.
[R2504] E. Guttman et al, "Users' Security Handbook", RFC 2504, Feb [R2628] Smyslov, V., "Simple Cryptographic Program Interface", RFC
2628, June 1999.
[R2631] Rescorla, E., "Diffie-Hellman Key Agreement Method", RFC
2631, June 1999.
[R2634] Hoffman, P., ed., "Enhanced Security Services for S/MIME",
RFC 2634, June 1999.
[R2635] Hambridge, S. and A. Lunde, "Don't Spew: A Set of Guidelines
for Mass Unsolicited Mailings and Postings", RFC 2635, June
1999. 1999.
[R2510] C. Adams et al, "Internet X.509 Public Key Infrastructure [R2660] Rescorla, E. and A. Schiffman, "The Secure HyperText
Certificate Management Protocols", RFC 2510, Mar 1999. Transfer Protocol", RFC 2660, August 1999.
[R2527] S. Chokhani et al, "Internet X.509 Public Key [R2773] Housley, R., Yee, P., and W. Nace, "Encryption using KEA and
Infrastructure, Certificate Policy and Certification SKIPJACK", RFC 2773, February 2000.
Practices Framework", RFC 2527, Mar 1999.
[R2536] D. Eastlake, "DSA KEYs and SIGs in the Domain Name System [R2801] Burdett, D., "Internet Open Trading Protocol - IOTP, Version
(DNS)", RFC 2536, Mar 1999. 1.0", RFC 2801, April 2000.
[R2560] M. Myers et al, "X.509 Internet Public Key Infrastructure [R2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Online Certificate Status Protocol", RFC 2560, Jun 1999. Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, May 2000.
[R2570] J. Case et al, "Introduction to Version 3 of the Internet- [R2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote
Standard Network Management Framework", RFC 2570, Apr 1999. Authentication Dial In User Service (RADIUS)", RFC 2865,
June 2000.
[R2574] U. Blumenthal et al, "User-based Security Model (USM) for [R2898] Kaliski, B., "PKCS #5: Password-Based Cryptography
Version 3 of the Simple Network Management Protocol Specification, Version 2.0", RFC 2898, September 2000. (See:
(SNMPv3)", RFC 2574, Apr 1999. [PKC05].)
[R2612] C. Adams et al, "The CAST-256 Encryption Algorithm", RFC [R3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic
2612, Jun 1999. Update", RFC 3007, November 2000.
[R2628] V. Smyslov, "Simple Cryptographic Program Interface", RFC [R3060] Moore, B., Ellesson, E., Strassner, J., and A. Westerinen,
2628, Jun 1999. "Policy Core Information Model -- Version 1 Specification",
RFC 3060, February 2001.
[R2631] E. Rescorla, "Diffie-Hellman Key Agreement Method", RFC [R3198] Westerinen, A., Schnizlein, J., Strassner, J., Scherling,
2631, Jun 1999. M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry,
J., and S. Waldbusser, "Terminology for Policy-Based
Management", RFC 3198, November 2001.
[R2634] P. Hoffman, ed., "Enhanced Security Services for S/MIME", [R3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
RFC 2634, Jun 1999. X.509 Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile", RFC 3280, April 2002.
[R2635] S. Hambridge et al, "Don't Spew: A Set of Guidelines for [R3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
Mass Unsolicited Mailings and Postings", RFC 2635, Jun 1999. "Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
[R2773] R. Housley et al, "Encryption using KEA and SKIPJACK", RFC [R3414] Blumenthal, U. and B. Wijnen, "User-based Security Model
2773, Feb 2000. (USM) for version 3 of the Simple Network Management
Protocol (SNMPv3)", STD 62, RFC 3414, December 2002.
[R2898] B. Kaliski, PKCS #5: Password-Based Cryptography [R3547] Baugher, M., Weis, B., Hardjono, T., and H. Harney, "Group
Specification, Version 2.0", RFC 2898, Sep 2000. Domain of Interpretation", RFC 3547, July 2003.
[R3198] A. Westerinen et al, "Terminology for Policy-Based [R3647] Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S. Wu,
Management", RFC 3198, Nov 2001. "Internet X.509 Public Key Infrastructure Certificate Policy
and Certification Practices Framework", RFC 3647, November
2003.
[R3547] M. Baugher et al, "Group Domain of Interpretation", RFC [R3739] Santesson, S., Nystrom, M., and T. Polk, "Internet X.509
3547, Jul 2003. Public Key Infrastructure: Qualified Certificates Profile",
RFC 3739, March 2004.
[R3739] S. Santesson et al, "Internet X.509 Public Key [R3740] Hardjono, T. and B. Weis, "The Multicast Group Security
Infrastructure: Qualified Certificates Profile", RFC 3739, Architecture", RFC 3740, March 2004.
Mar 2004.
[R3740] T. Hardjono et al, "The Multicast Group Security [R3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Architecture", RFC 3740, Mar 2004. Levkowetz, "Extensible Authentication Protocol (EAP)", RFC
3748, June 2004.
[R3748] B. Aboda, et al, "Extensible Authentication Protocol (EAP)", [R3766] Orman, H. and P. Hoffman, "Determining Strengths For Public
RFC 3748, Jun 2004. Keys Used For Exchanging Symmetric Keys", BCP 86, RFC 3766,
April 2004.
[R3753] J. Manner et al, ed's., "Mobility Related Terminology", RFC [R3820] Tuecke, S., Welch, V., Engert, D., Pearlman, L., and M.
3573, Jun 2004. Thompson, "Internet X.509 Public Key Infrastructure (PKI)
Proxy Certificate Profile", RFC 3820, June 2004.
[R3820] S. Tuecke et al, "Internet X.509 Public Key Infrastructure [R3851] Ramsdell, B., ed., "Secure/Multipurpose Internet Mail
(PKI) Proxy Certificate Profile", RFC 3280, Jun 2004. Extensions (S/MIME) Version 3.1 Message Specification", RFC
3851, July 2004.
[Raym] E. Raymond, ed., "The On-Line Hacker Jargon File", ver. [R3871] Jones, G., ed., "Operational Security Requirements for Large
4.0.0, 24 Jul 1996. (Also available as "The New Hacker's Internet Service Provider (ISP) IP Network Infrastructure",
Dictionary", 2nd edition, MIT Press, Sep 1993, ISBN 0-262- RFC 3871, September 2004.
18154-1. See: http://www.tuxedo.org/jargon/ for the latest
version.)
[Roge] H. Rogers, "An Overview of the Caneware Program", in [Raym] Raymond, E., ed., "The On-Line Hacker Jargon File", version
4.0.0, 24 July 1996. (See: http://www.tuxedo.org/jargon/ for
the latest version. Also, "The New Hacker's Dictionary", 2nd
edition, MIT Press, September 1993, ISBN 0-262-18154-1.)
[Roge] Rogers, H., "An Overview of the Caneware Program", in
"Proceedings of the 10th National Computer Security "Proceedings of the 10th National Computer Security
Conference", NIST and NCSC, Sep 1987. Conference", NIST and NCSC, September 1987.
[Russ] D. Russell et al, Chapter 10 ("TEMPEST") in "Computer [RSCG] NSA, "Router Security Configuration Guide: Principles and
Guidance for Secure Configuration of IP Routers, with
Detailed Instructions for Cisco Systems Routers", version
1.0g, C4-054R-00, 20 April 2001, available at
http://www.nsa.gov.
[Russ] Russell, D. et al, Chapter 10 ("TEMPEST") of "Computer
Security Basics", ISBN 0-937175-71-4, 1991. Security Basics", ISBN 0-937175-71-4, 1991.
[SAML] Organization for the Advancement of Structured Information [SAML] Organization for the Advancement of Structured Information
Standards (OASIS), "Assertions and Protocol for the OASIS Standards (OASIS), "Assertions and Protocol for the OASIS
Security Assertion Markup Language (SAML)", version 1.1, 2 Security Assertion Markup Language (SAML)", version 1.1, 2
Sep 2003. September 2003.
[Sand] R. Sandhu et al, "Role-Based Access Control Models", in [Sand] Sandhu, R. et al, "Role-Based Access Control Models", in
"IEEE Computer", vol. 29, no.2, Feb 1996, pp. 38-47. "IEEE Computer", vol. 29, no.2, February 1996, pp. 38-47.
[Schn] B. Schneier, "Applied Cryptography Second Edition", John [Schn] Schneier, B., "Applied Cryptography Second Edition", John
Wiley & Sons, Inc., New York, 1996. Wiley & Sons, Inc., New York, 1996.
[SDNS3] U.S. DoD, NSA, "Secure Data Network Systems, Security [SDNS3] U.S. DoD, NSA, "Secure Data Network Systems, Security
Protocol 3 (SP3)", document SDN.301, Revision 1.5, 15 May Protocol 3 (SP3)", document SDN.301, Revision 1.5, 15 May
1989. 1989.
[SDNS4] ---, ---, "Security Protocol 4 (SP4)", document SDN.401, [SDNS4] ---, ---, "Security Protocol 4 (SP4)", document SDN.401,
Revision 1.2, 12 Jul 1988. Revision 1.2, 12 July 1988.
[SDNS7] ---, ---, "Secure data Network System, Message Security [SDNS7] ---, ---, "Secure data Network System, Message Security
Protocol (MSP)", document SDN.701, Revision 4.0, 7 Jun 1996, Protocol (MSP)", SDN.701, Revision 4.0, 7 June 1996, with
with Corrections to Message Security Protocol, SDN.701, Rev "Corrections to Message Security Protocol, SDN.701, Rev 4.0,
4.0", 96-06-07, 30 Aug, 1996. 96-06-07", 30 Aug, 1996.
[SET1] MasterCard and Visa, "SET Secure Electronic Transaction [SET1] MasterCard and Visa, "SET Secure Electronic Transaction
Specification, Book 1: Business Description", ver. 1.0, 31 Specification, Book 1: Business Description", version 1.0,
May 1997. 31 May 1997.
[SET2] ---, "SET Secure Electronic Transaction Specification, Book [SET2] ---, "SET Secure Electronic Transaction Specification, Book
2: Programmer's Guide", ver. 1.0, 31 May 1997. 2: Programmer's Guide", version 1.0, 31 May 1997.
[SKEME] H. Krawczyk, H., "SKEME: A Versatile Secure Key Exchange [SKEME] Krawczyk, H., "SKEME: A Versatile Secure Key Exchange
Mechanism for Internet", in "Proceedings of the 1996 Mechanism for Internet", in "Proceedings of the 1996
Symposium on Network and Distributed Systems Security". Symposium on Network and Distributed Systems Security".
[SKIP] "SKIPJACK and KEA Algorithm Specifications", ver. 2.0, 22 [SKIP] "SKIPJACK and KEA Algorithm Specifications", version 2.0, 22
May 1998 (available from NIST Computer Security Resource May 1998, and "Clarification to the SKIPJACK Algorithm
Center). Specification", 9 May 2002 (available from NIST Computer
Security Resource Center).
[SP12] NIST, "An Introduction to Computer Security: The NIST [SP12] NIST, "An Introduction to Computer Security: The NIST
Handbook", Special Publication 800-12. Handbook", Special Publication 800-12.
[SP14] M. Swanson et al (NIST), "Generally Accepted Principles and [SP14] Swanson, M. et al (NIST), "Generally Accepted Principles and
Practices for Security Information Technology Systems", --- Practices for Security Information Technology Systems", ---
800-14, Sep 1996. 800-14, September 1996.
[SP15] W. Burr et al (NIST), "Minimum Interoperability [SP15] Burr, W. et al (NIST), "Minimum Interoperability
Specification for PKI Components (MISPC), Version 1", --- Specification for PKI Components (MISPC), Version 1", ---
800-15, Sep 1997. 800-15, September 1997.
[SP22] A. Rukhin et al (NIST), "A Statistical Test Suite for Random [SP22] Rukhin, A. et al (NIST), "A Statistical Test Suite for
and Pseudorandom Number Generators for Cryptographic Random and Pseudorandom Number Generators for Cryptographic
Applications", --- 800-15, 15 May 2001. Applications", --- 800-15, 15 May 2001.
[SP27] G. Stoneburner et al (NIST), "Engineering Principles for [SP27] Stoneburner, G. et al (NIST), "Engineering Principles for
Information Technology Security (A Baseline for Achieving Information Technology Security (A Baseline for Achieving
Security)", --- 800-27 Rev A, June 2004. Security)", --- 800-27 Rev A, June 2004.
[SP28] W. Jansen (NIST), "Guidelines on Active Content and Mobile [SP28] Jansen, W. (NIST), "Guidelines on Active Content and Mobile
Code", --- 800-28, Oct 2001. Code", --- 800-28, October 2001.
[SP30] G. Stoneburner et al (NIST), "Risk Management Guide for [SP30] Stoneburner, G. et al (NIST), "Risk Management Guide for
Information Technology Systems", --- 800-30, Oct 2001. Information Technology Systems", --- 800-30, October 2001.
[SP31] R. Bace et al (NIST), "Intrusion Detection Systems", --- [SP31] Bace, R. et al (NIST), "Intrusion Detection Systems", ---
800-31. 800-31.
[SP32] D. Kuhn (NIST), "Introduction to Public Key Technology and [SP32] Kuhn, D. (NIST), "Introduction to Public Key Technology and
the Federal PKI Infrastructure ", --- 800-32, 26 Feb 2001. the Federal PKI Infrastructure ", --- 800-32, 26 February
2001.
[SP33] G. Stoneburner (NIST), "Underlying Technical Models for [SP33] Stoneburner, G. (NIST), "Underlying Technical Models for
Information Technology Security", --- 800-33, Dec 2001. Information Technology Security", --- 800-33, December 2001.
[SP37] R. Ross et al (NIST), "Guide for the Security Certification [SP37] Ross, R. et al (NIST), "Guide for the Security Certification
and Accreditation of Federal Information Systems", --- 800- and Accreditation of Federal Information Systems", --- 800-
37, May 2004 37, May 2004
[SP41] J. Wack et al (NIST), "Guidelines on Firewalls and Firewall [SP41] Wack. J. et al (NIST), "Guidelines on Firewalls and Firewall
Policy", --- 800-41, Jan 2002. Policy", --- 800-41, January 2002.
[SP42] J. Wack et al (NIST), "Guideline on Network Security [SP42] ---, "Guideline on Network Security Testing", --- 800-42,
Testing", --- 800-42, Oct 2003. October 2003.
[SP56] NIST, "Recommendations on Key Establishment Schemes", Draft [SP56] NIST, "Recommendations on Key Establishment Schemes", Draft
2.0, --- 800-63, Jan 2003. 2.0, --- 800-63, January 2003.
[SP57] NIST, "Recommendation for Key Management", Part 1 "General [SP57] ---, "Recommendation for Key Management", Part 1 "General
Guideline" and Part 2 "Best Practices for Key Management Guideline" and Part 2 "Best Practices for Key Management
Organization", --- 800-57, Jan 2003. Organization", --- 800-57, DRAFT, January 2003.
[SP61] T. Grance et al (NIST), "Computer Security Incident Handling [SP61] Grance, T. et al (NIST), "Computer Security Incident
Guide", --- 800-57, Jan 2003. Handling Guide", --- 800-57, January 2003.
[SP63] W. Burr et al (NIST), "Electronic Authentication Guideline", [SP63] Burr, W. et al (NIST), "Electronic Authentication
--- 800-63, Jun 2004 Guideline", --- 800-63, June 2004
[SP67] W. Barker (NIST), "Recommendation for the Triple Data [SP67] Barker, W. (NIST), "Recommendation for the Triple Data
Encryption Algorithm (TDEA) Block Cipher", --- 800-67, May Encryption Algorithm (TDEA) Block Cipher", --- 800-67, May
2004 2004
[Stei] J. Steiner et al, "Kerberos: An Authentication Service for [Stal] Stallings, W., "Local Networks", 1987, ISBN 0-02-415520-9.
Open Network Systems" in "Usenix Conference Proceedings",
Feb 1988.
[Weis] C. Weissman, "Blacker: Security for the DDN: Examples of A1 [Stei] Steiner, J. et al, "Kerberos: An Authentication Service for
Open Network Systems", in "Usenix Conference Proceedings",
February 1988.
[Weis] Weissman, C., "Blacker: Security for the DDN: Examples of A1
Security Engineering Trades", in "Symposium on Security and Security Engineering Trades", in "Symposium on Security and
Privacy", IEEE Computer Society Press, May 1992, pp. 286- Privacy", IEEE Computer Society Press, May 1992, pp. 286-
292. 292.
[X400] International Telecommunications Union--Telecommunication [X400] International Telecommunications Union -- Telecommunication
Standardization Sector (formerly "CCITT"), Recommendation Standardization Sector (formerly "CCITT"), Recommendation
X.400, "Message Handling Services: Message Handling System X.400, "Message Handling Services: Message Handling System
and Service Overview". and Service Overview".
[X500] ---, Recommendation X.500, "Information Technology--Open [X419] ---, "Message Handling Systems: Protocol Specifications",
Systems Interconnection--The Directory: Overview of ITU-T Recommendation X.419. (Equivalent to ISO 10021-6).
[X420] ---, ---: "Interpersonal Messaging System", ITU-T
Recommendation X.420. (Equivalent to ISO 10021-7.).
[X500] ---, Recommendation X.500, "Information Technology -- Open
Systems Interconnection -- The Directory: Overview of
Concepts, Models, and Services". (Equivalent to ISO 9594-1.) Concepts, Models, and Services". (Equivalent to ISO 9594-1.)
[X501] ---, Recommendation X.501, "Information Technology--Open [X501] ---, Recommendation X.501, ---: "Models".
Systems Interconnection--The Directory: Models".
[X509] ---, Recommendation X.509, "Information Technology--Open [X509] ---, Recommendation X.509, ---: "Authentication Framework",
Systems Interconnection--The Directory: Authentication COM 7-250-E Revision 1, 23 February 2001. (Equivalent to ISO
Framework", COM 7-250-E Revision 1, 23 Feb 2001. (Equivalent 9594-8.)
to ISO 9594-8.)
[X519] ---, Recommendation X.519, "Information Technology--Open [X519] ---, Recommendation X.519, ---: "Protocol Specifications".
Systems Interconnection--The Directory: Protocol
Specifications".
[X520] ---, Recommendation X.520, "Information Technology--Open [X520] ---, Recommendation X.520, ---: "Selected Attribute Types".
Systems Interconnection--The Directory: Selected Attribute
Types".
[X680] ---, Recommendation X.680, "Information Technology--Abstract [X680] ---, Recommendation X.680, "Information Technology --
Syntax Notation One (ASN.1)--Specification of Basic Abstract Syntax Notation One (ASN.1) -- Specification of
Notation", 15 Nov 1994. (Equivalent to ISO/IEC 8824-1.) Basic Notation", 15 November 1994. (Equivalent to ISO/IEC
8824-1.)
[X690] ---, Recommendation X.690, "Information Technology--ASN.1 [X690] ---, Recommendation X.690, "Information Technology -- ASN.1
Encoding Rules--Specification of Basic Encoding Rules (BER), Encoding Rules -- Specification of Basic Encoding Rules
Canonical Encoding Rules (CER) and Distinguished Encoding (BER), Canonical Encoding Rules (CER) and Distinguished
Rules (DER)", 15 Nov 1994. (Equivalent to ISO/IEC 8825-1.) Encoding Rules (DER)", 15 November 1994. (Equivalent to
ISO/IEC 8825-1.)
6. Security Considerations 6. Security Considerations
This document mainly defines security terms and recommends how to use This document mainly defines security terms and recommends how to use
them. It also provides limited tutorial information about security them. It also provides limited tutorial information about security
aspects of Internet protocols, but it not describe in detail the aspects of Internet protocols, but it does not describe in detail the
vulnerabilities of or threats to specific protocols and does not vulnerabilities of, or threats to, specific protocols and does not
definitively describe mechanisms that protect specific protocols. definitively describe mechanisms that protect specific protocols.
7. Acknowledgments 7. Acknowledgments
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
George Huff had a good idea! [Huff] George Huff had a good idea! [Huff]
8. Author's Address 8. Author's Address
Please address all comments to: Please address all comments to:
Robert W. Shirey BBN Technologies Robert W. Shirey BBN Technologies
E-mail: rshirey@bbn.com Suite 400, Mail Stop 30/6B1 E-mail: rshirey@bbn.com Suite 400, Mail Stop 30/6B1
1300 Seventeenth Street North 1300 Seventeenth Street North
Arlington, VA 22209-3801 USA Arlington, VA 22209-3801 USA
9. Full Copyright Statement 9. Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE IS SPONSORED "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE IS SPONSORED
BY, THE INTERNET SOCIETY, AND THE INTERNET ENGINEERING TASK FORCE BY, THE INTERNET SOCIETY, AND THE INTERNET ENGINEERING TASK FORCE
DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL
NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE. OR FITNESS FOR A PARTICULAR PURPOSE.
Expiration Date: 20 February 2004. Expiration Date: 9 September 2005.
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