< draft-ietf-precis-saslprepbis-14.txt   draft-ietf-precis-saslprepbis-15.txt >
PRECIS P. Saint-Andre PRECIS P. Saint-Andre
Internet-Draft &yet Internet-Draft &yet
Obsoletes: 4013 (if approved) A. Melnikov Obsoletes: 4013 (if approved) A. Melnikov
Intended status: Standards Track Isode Ltd Intended status: Standards Track Isode Ltd
Expires: September 3, 2015 March 2, 2015 Expires: October 16, 2015 April 14, 2015
Preparation, Enforcement, and Comparison of Internationalized Strings Preparation, Enforcement, and Comparison of Internationalized Strings
Representing Usernames and Passwords Representing Usernames and Passwords
draft-ietf-precis-saslprepbis-14 draft-ietf-precis-saslprepbis-15
Abstract Abstract
This document describes methods for handling Unicode strings This document describes updated methods for handling Unicode strings
representing usernames and passwords. The methods specified in this representing usernames and passwords. The previous approach was
document provide a more sustainable approach to the handling of known as SASLprep (RFC 4013) and was based on Stringprep (RFC 3454).
internationalized usernames and passwords than the previous approach, The methods specified in this document provide a more sustainable
known as SASLprep (RFC 4013) and based on Stringprep (RFC 3454). approach to the handling of internationalized usernames and
This document obsoletes RFC 4013. passwords. The PRECIS framework, RFC YYYY, obsoletes RFC 3454, and
this document obsoletes RFC 4013.
[[ NOTE TO RFC EDITOR: please replace "YYYY" in the previous
paragraph with the RFC number assigned to draft-ietf-precis-
framework. ]]
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
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 as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 3, 2015. This Internet-Draft will expire on October 16, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 15 skipping to change at page 2, line 22
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Usernames . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Usernames . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. UsernameCaseMapped Profile . . . . . . . . . . . . . . . 5 3.2. UsernameCaseMapped Profile . . . . . . . . . . . . . . . 5
3.2.1. Preparation . . . . . . . . . . . . . . . . . . . . . 5 3.2.1. Preparation . . . . . . . . . . . . . . . . . . . . . 6
3.2.2. Enforcement . . . . . . . . . . . . . . . . . . . . . 6 3.2.2. Enforcement . . . . . . . . . . . . . . . . . . . . . 6
3.2.3. Comparison . . . . . . . . . . . . . . . . . . . . . 6 3.2.3. Comparison . . . . . . . . . . . . . . . . . . . . . 6
3.3. UsernameCasePreserved Profile . . . . . . . . . . . . . . 6 3.3. UsernameCasePreserved Profile . . . . . . . . . . . . . . 6
3.3.1. Preparation . . . . . . . . . . . . . . . . . . . . . 7 3.3.1. Preparation . . . . . . . . . . . . . . . . . . . . . 7
3.3.2. Enforcement . . . . . . . . . . . . . . . . . . . . . 7 3.3.2. Enforcement . . . . . . . . . . . . . . . . . . . . . 7
3.3.3. Comparison . . . . . . . . . . . . . . . . . . . . . 7 3.3.3. Comparison . . . . . . . . . . . . . . . . . . . . . 7
3.4. Case Mapping vs. Case Preservation . . . . . . . . . . . 7 3.4. Case Mapping vs. Case Preservation . . . . . . . . . . . 7
3.5. Application-Layer Constructs . . . . . . . . . . . . . . 9 3.5. Application-Layer Constructs . . . . . . . . . . . . . . 9
3.6. Examples . . . . . . . . . . . . . . . . . . . . . . . . 9 3.6. Examples . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Passwords . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4. Passwords . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. OpaqueString Profile . . . . . . . . . . . . . . . . . . 11 4.2. OpaqueString Profile . . . . . . . . . . . . . . . . . . 12
4.2.1. Preparation . . . . . . . . . . . . . . . . . . . . . 12 4.2.1. Preparation . . . . . . . . . . . . . . . . . . . . . 12
4.2.2. Enforcement . . . . . . . . . . . . . . . . . . . . . 12 4.2.2. Enforcement . . . . . . . . . . . . . . . . . . . . . 12
4.2.3. Comparison . . . . . . . . . . . . . . . . . . . . . 13 4.2.3. Comparison . . . . . . . . . . . . . . . . . . . . . 13
4.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 13 4.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 13
5. Use in Application Protocols . . . . . . . . . . . . . . . . 14 5. Use in Application Protocols . . . . . . . . . . . . . . . . 14
6. Migration . . . . . . . . . . . . . . . . . . . . . . . . . . 14 6. Migration . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1. Usernames . . . . . . . . . . . . . . . . . . . . . . . . 14 6.1. Usernames . . . . . . . . . . . . . . . . . . . . . . . . 15
6.2. Passwords . . . . . . . . . . . . . . . . . . . . . . . . 15 6.2. Passwords . . . . . . . . . . . . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
7.1. UsernameCaseMapped Profile . . . . . . . . . . . . . . . 17 7.1. UsernameCaseMapped Profile . . . . . . . . . . . . . . . 17
7.2. UsernameCasePreserved Profile . . . . . . . . . . . . . . 17 7.2. UsernameCasePreserved Profile . . . . . . . . . . . . . . 18
7.3. OpaqueString Profile . . . . . . . . . . . . . . . . . . 18 7.3. OpaqueString Profile . . . . . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18 8. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8.1. Password/Passphrase Strength . . . . . . . . . . . . . . 18 8.1. Password/Passphrase Strength . . . . . . . . . . . . . . 19
8.2. Identifier Comparison . . . . . . . . . . . . . . . . . . 19 8.2. Identifier Comparison . . . . . . . . . . . . . . . . . . 19
8.3. Reuse of PRECIS . . . . . . . . . . . . . . . . . . . . . 19 8.3. Reuse of PRECIS . . . . . . . . . . . . . . . . . . . . . 19
8.4. Reuse of Unicode . . . . . . . . . . . . . . . . . . . . 19 8.4. Reuse of Unicode . . . . . . . . . . . . . . . . . . . . 19
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
9.1. Normative References . . . . . . . . . . . . . . . . . . 19 9.1. Normative References . . . . . . . . . . . . . . . . . . 20
9.2. Informative References . . . . . . . . . . . . . . . . . 20 9.2. Informative References . . . . . . . . . . . . . . . . . 20
Appendix A. Differences from RFC 4013 . . . . . . . . . . . . . 21 Appendix A. Differences from RFC 4013 . . . . . . . . . . . . . 22
Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 22 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
Usernames and passwords are widely used for authentication and Usernames and passwords are widely used for authentication and
authorization on the Internet, either directly when provided in authorization on the Internet, either directly when provided in
plaintext (as in the SASL PLAIN mechanism [RFC4616] or the HTTP Basic plaintext (as in the SASL PLAIN mechanism [RFC4616] or the HTTP Basic
scheme [RFC2617] / [I-D.ietf-httpauth-basicauth-update]) or scheme [I-D.ietf-httpauth-basicauth-update]) or indirectly when
indirectly when provided as the input to a cryptographic algorithm provided as the input to a cryptographic algorithm such as a hash
such as a hash function (as in the SASL SCRAM mechanism [RFC5802] or function (as in the SASL SCRAM mechanism [RFC5802] or the HTTP Digest
the HTTP Digest scheme [RFC2617] / [I-D.ietf-httpauth-digest]). scheme [I-D.ietf-httpauth-digest]).
To increase the likelihood that the input and comparison of usernames To increase the likelihood that the input and comparison of usernames
and passwords will work in ways that make sense for typical users and passwords will work in ways that make sense for typical users
throughout the world, this document defines rules for preparing, throughout the world, this document defines rules for preparing,
enforcing, and comparing internationalized strings that represent enforcing, and comparing internationalized strings that represent
usernames and passwords. Such strings consist of characters from the usernames and passwords. Such strings consist of characters from the
Unicode character set [Unicode], with special attention to characters Unicode character set [Unicode], with special attention to characters
outside the ASCII range [RFC20]. The rules for handling such strings outside the ASCII range [RFC20]. The rules for handling such strings
are specified through profiles of the string classes defined in the are specified through profiles of the string classes defined in the
PRECIS framework specification [I-D.ietf-precis-framework]. PRECIS framework specification [I-D.ietf-precis-framework].
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The methods defined here might be applicable wherever usernames or The methods defined here might be applicable wherever usernames or
passwords are used. However, the methods are not intended for use in passwords are used. However, the methods are not intended for use in
preparing strings that are not usernames (e.g., email addresses and preparing strings that are not usernames (e.g., email addresses and
LDAP distinguished names), nor in cases where identifiers or secrets LDAP distinguished names), nor in cases where identifiers or secrets
are not strings (e.g., keys and certificates) or require specialized are not strings (e.g., keys and certificates) or require specialized
handling. handling.
This document obsoletes RFC 4013 (the "SASLprep" profile of This document obsoletes RFC 4013 (the "SASLprep" profile of
stringprep [RFC3454]) but can be used by technologies other than the stringprep [RFC3454]) but can be used by technologies other than the
Simple Authentication and Security Layer (SASL) [RFC4422], such as Simple Authentication and Security Layer (SASL) [RFC4422], such as
HTTP authentication [RFC2617] / [I-D.ietf-httpauth-basicauth-update] HTTP authentication as specified in
/ [I-D.ietf-httpauth-digest]. [I-D.ietf-httpauth-basicauth-update] and [I-D.ietf-httpauth-digest].
2. Terminology 2. Terminology
Many important terms used in this document are defined in Many important terms used in this document are defined in
[I-D.ietf-precis-framework], [RFC5890], [RFC6365], and [Unicode]. [I-D.ietf-precis-framework], [RFC5890], [RFC6365], and [Unicode].
The term "non-ASCII space" refers to any Unicode code point having a The term "non-ASCII space" refers to any Unicode code point having a
general category of "Zs", with the exception of U+0020 (here called general category of "Zs", with the exception of U+0020 (here called
"ASCII space"). "ASCII space").
As used here, the term "password" is not literally limited to a word; As used here, the term "password" is not literally limited to a word;
i.e., a password could be a passphrase consisting of more than one i.e., a password could be a passphrase consisting of more than one
word, perhaps separated by spaces or other such characters. word, perhaps separated by spaces, punctuation, or other non-
alphanumeric characters.
Some SASL mechanisms (e.g., CRAM-MD5, DIGEST-MD5, and SCRAM) specify Some SASL mechanisms (e.g., CRAM-MD5, DIGEST-MD5, and SCRAM) specify
that the authentication identity used in the context of such that the authentication identity used in the context of such
mechanisms is a "simple user name" (see Section 2 of [RFC4422] as mechanisms is a "simple user name" (see Section 2 of [RFC4422] as
well as [RFC4013]). Various application technologies also assume well as [RFC4013]). Various application technologies also assume
that the identity of a user or account takes the form of a username that the identity of a user or account takes the form of a username
(e.g., authentication for the HyperText Transfer Protocol [RFC2617] / (e.g., authentication for the HyperText Transfer Protocol as
[I-D.ietf-httpauth-basicauth-update] / [I-D.ietf-httpauth-digest]), specified in [I-D.ietf-httpauth-basicauth-update] and
whether or not they use SASL. Note well that the exact form of a [I-D.ietf-httpauth-digest]), whether or not they use SASL. Note well
username in any particular SASL mechanism or application technology that the exact form of a username in any particular SASL mechanism or
is a matter for implementation and deployment, and that a username application technology is a matter for implementation and deployment,
does not necessarily map to any particular application identifier and that a username does not necessarily map to any particular
(such as the localpart of an email address). application identifier (such as the localpart of an email address).
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. [RFC2119].
3. Usernames 3. Usernames
3.1. Definition 3.1. Definition
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; an "idbyte" is a byte used to represent a ; an "idbyte" is a byte used to represent a
; UTF-8 encoded Unicode code point that can be ; UTF-8 encoded Unicode code point that can be
; contained in a string that conforms to the ; contained in a string that conforms to the
; PRECIS "IdentifierClass" ; PRECIS "IdentifierClass"
; ;
All code points and blocks not explicitly allowed in the PRECIS All code points and blocks not explicitly allowed in the PRECIS
IdentifierClass are disallowed; this includes private use characters, IdentifierClass are disallowed; this includes private use characters,
surrogate code points, and the other code points and blocks that were surrogate code points, and the other code points and blocks that were
defined as "Prohibited Output" in [RFC4013]. In addition, common defined as "Prohibited Output" in [RFC4013]. In addition, common
constructions such as "user@example.com" are allowed as usernames constructions such as "user@example.com" (e.g., the Network Access
under this specification, as they were under [RFC4013]. Identifier from [I-D.ietf-radext-nai]) are allowed as usernames under
this specification, as they were under [RFC4013].
Implementation Note: The username construct defined in this Implementation Note: The username construct defined in this
document does not necessarily match what all deployed applications document does not necessarily match what all deployed applications
might refer to as a "username" or "userid", but instead provides a might refer to as a "username" or "userid", but instead provides a
relatively safe subset of Unicode characters that can be used in relatively safe subset of Unicode characters that can be used in
existing SASL mechanisms and SASL-using application protocols, and existing SASL mechanisms and SASL-using application protocols, and
even in most application protocols that do not currently use SASL. even in most application protocols that do not currently use SASL.
A username MUST NOT be zero bytes in length. This rule is to be A username MUST NOT be zero bytes in length. This rule is to be
enforced after any normalization and mapping of code points. enforced after any normalization and mapping of code points.
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3.3.3. Comparison 3.3.3. Comparison
An entity that performs comparison of two strings according to this An entity that performs comparison of two strings according to this
profile MUST prepare each string and enforce the rules specified in profile MUST prepare each string and enforce the rules specified in
the previous two sections. The two strings are to be considered the previous two sections. The two strings are to be considered
equivalent if they are an exact octet-for-octet match (sometimes equivalent if they are an exact octet-for-octet match (sometimes
called "bit-string identity"). called "bit-string identity").
3.4. Case Mapping vs. Case Preservation 3.4. Case Mapping vs. Case Preservation
In order to accomodate the widest range of username constructs in In order to accommodate the widest range of username constructs in
applications, this document defines two username profiles: applications, this document defines two username profiles:
UsernameCaseMapped and UsernameCasePreserved. UsernameCaseMapped and UsernameCasePreserved. These two profiles
differ only in the Case Mapping Rule, and are otherwise identical.
Case mapping is a matter for the application protocol, protocol Case mapping is a matter for the application protocol, protocol
implementation, or end deployment. In general, this document implementation, or end deployment. In general, this document
suggests that it is preferable to apply the UsernameCaseMapped suggests that it is preferable to apply the UsernameCaseMapped
profile and therefore perform case mapping, since not doing so can profile and therefore perform case mapping, since not doing so can
lead to false positives during authentication and authorization (as lead to false positives during authentication and authorization (as
described in [RFC6943]) and can result in confusion among end users described in [RFC6943]) and can result in confusion among end users
given the prevalence of case mapping in many existing protocols and given the prevalence of case mapping in many existing protocols and
applications. However, there can be good reasons to apply the applications. However, there can be good reasons to apply the
UsernameCasePreserved profile and thus not perform case mapping, such UsernameCasePreserved profile and thus not perform case mapping, such
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whether case mapping is to be applied to authorization whether case mapping is to be applied to authorization
identifiers. Such "SASL application protocols" SHOULD delay any identifiers. Such "SASL application protocols" SHOULD delay any
case mapping of authorization identifiers to the last possible case mapping of authorization identifiers to the last possible
moment, which happens to necessarily be on the server side (this moment, which happens to necessarily be on the server side (this
enables decisions about case mapping to be a matter of deployment enables decisions about case mapping to be a matter of deployment
policy). In keeping with [RFC4422], SASL application protocols policy). In keeping with [RFC4422], SASL application protocols
are not to apply this or any other profile to authentication are not to apply this or any other profile to authentication
identifiers. identifiers.
o Application protocols that do not use SASL (such as HTTP o Application protocols that do not use SASL (such as HTTP
authentication with the Basic and Digest schemes [RFC2617] / authentication with the Basic and Digest schemes as specified in
[I-D.ietf-httpauth-basicauth-update] / [I-D.ietf-httpauth-digest]) [I-D.ietf-httpauth-basicauth-update] and
but that directly re-use this profile MUST specify whether and [I-D.ietf-httpauth-digest]) but that directly re-use this profile
when case mapping is to be applied to authentication identifiers MUST specify whether and when case mapping is to be applied to
and authorization identifiers. Such "non-SASL application authentication identifiers and authorization identifiers. Such
protocols" SHOULD delay any case mapping to the last possible "non-SASL application protocols" SHOULD delay any case mapping to
moment, such as when doing a lookup by username, username the last possible moment, such as when doing a lookup by username,
comparisons, or generating a cryptographic salt from a username username comparisons, or generating a cryptographic salt from a
(if the last possible moment happens on the server, then decisions username (if the last possible moment happens on the server, then
about case mapping can be a matter of deployment policy). decisions about case mapping can be a matter of deployment
policy).
If the specification for a SASL mechanism, SASL application protocol, If the specification for a SASL mechanism, SASL application protocol,
or non-SASL application protocol uses the UsernameCaseMapped profile, or non-SASL application protocol uses the UsernameCaseMapped profile,
it MUST clearly describe whether case mapping is to be applied at the it MUST clearly describe whether case mapping is to be applied at the
level of the protocol itself, implementations thereof, or service level of the protocol itself, implementations thereof, or service
deployments (all of these approaches can be legitimate depending on deployments (all of these approaches can be legitimate depending on
the application in question). the application in question).
3.5. Application-Layer Constructs 3.5. Application-Layer Constructs
Both the UsernameCaseMapped and UsernameCasePreserved profiles allow Both the UsernameCaseMapped and UsernameCasePreserved profiles enable
an application protocol, implementation, or deployment to create an application protocol, implementation, or deployment to create
application-layer constructs such as "user@domain" or "Firstname application-layer constructs such as a space-separated set of names
Middlename Lastname". One example of the former is the Network like "Firstname Middlename Lastname". Although such a construct is
Access Identifier specified in [I-D.ietf-radext-nai]. (Such not a PRECIS profile (since U+0020 SPACE is not allowed in the
constructs are possible because the PRECIS IdentifierClass allows any IdentifierClass), it can be created at the application layer because
ASCII7 character, because spaces can be used to separate userpart U+0020 SPACE can be used as a separator between instances of the
instances, and because domain names as specified in [RFC5890] and PRECIS IdentifierClass (or a profile thereof).
[RFC5892] are a subset of the PRECIS IdentifierClass.)
3.6. Examples 3.6. Examples
The following examples illustrate a small number of userparts (not The following examples illustrate a small number of userparts (not
usernames) that are consistent with the format defined above (note usernames) that are consistent with the format defined above (note
that the characters < and > are used here to delineate the actual that the characters < and > are used here to delineate the actual
userparts and are not part of the userpart strings). userparts and are not part of the userpart strings).
Table 1: A sample of legal userparts Table 1: A sample of legal userparts
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+--------------------------+---------------------------------+ +--------------------------+---------------------------------+
| 5 | <&#x3A3;> | A userpart of GREEK CAPITAL | | 5 | <&#x3A3;> | A userpart of GREEK CAPITAL |
| | | LETTER SIGMA (U+03A3) | | | | LETTER SIGMA (U+03A3) |
+--------------------------+---------------------------------+ +--------------------------+---------------------------------+
| 6 | <&#x3C3;> | A userpart of GREEK SMALL | | 6 | <&#x3C3;> | A userpart of GREEK SMALL |
| | | LETTER SIGMA (U+03C3) | | | | LETTER SIGMA (U+03C3) |
+--------------------------+---------------------------------+ +--------------------------+---------------------------------+
| 7 | <&#x3C2;> | A userpart of GREEK SMALL | | 7 | <&#x3C2;> | A userpart of GREEK SMALL |
| | | LETTER FINAL SIGMA (U+03C2) | | | | LETTER FINAL SIGMA (U+03C2) |
+--------------------------+---------------------------------+ +--------------------------+---------------------------------+
Several points are worth noting. Regarding examples 2 and 3: Several points are worth noting. Regarding examples 2 and 3:
although in German the character esszett (LATIN SMALL LETTER SHARP S, although in German the character eszett (LATIN SMALL LETTER SHARP S,
U+00DF) can mostly be used interchangeably with the two characters U+00DF) can mostly be used interchangeably with the two characters
"ss", the userparts in these examples are different and (if desired) "ss", the userparts in these examples are different and (if desired)
a server would need to enforce a registration policy that disallows a server would need to enforce a registration policy that disallows
one of them if the other is registered. Regarding examples 5, 6, and one of them if the other is registered. Regarding examples 5, 6, and
7: optional case-mapping of GREEK CAPITAL LETTER SIGMA (U+03A3) to 7: optional case-mapping of GREEK CAPITAL LETTER SIGMA (U+03A3) to
lowercase (i.e., to GREEK SMALL LETTER SIGMA, U+03C3) during lowercase (i.e., to GREEK SMALL LETTER SIGMA, U+03C3) during
comparison would result in matching the userparts in examples 5 and comparison would result in matching the userparts in examples 5 and
6; however, because the PRECIS mapping rules do not account for the 6; however, because the PRECIS mapping rules do not account for the
special status of GREEK SMALL LETTER FINAL SIGMA (U+03C2), the special status of GREEK SMALL LETTER FINAL SIGMA (U+03C2), the
userparts in examples 5 and 7 or examples 6 and 7 would not be userparts in examples 5 and 7 or examples 6 and 7 would not be
skipping to change at page 13, line 36 skipping to change at page 14, line 21
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
| 13| <Correct Horse Battery Staple> | Different from example 12 | | 13| <Correct Horse Battery Staple> | Different from example 12 |
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
| 14| <&#x3C0;&#xDF;&#xE5;> | Non-ASCII letters are OK | | 14| <&#x3C0;&#xDF;&#xE5;> | Non-ASCII letters are OK |
| | | (e.g., GREEK SMALL LETTER | | | | (e.g., GREEK SMALL LETTER |
| | | PI, U+03C0) | | | | PI, U+03C0) |
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
| 15| <Jack of &#x2666;s> | Symbols are OK (e.g., BLACK | | 15| <Jack of &#x2666;s> | Symbols are OK (e.g., BLACK |
| | | DIAMOND SUIT, U+2666) | | | | DIAMOND SUIT, U+2666) |
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
| 16| <foo&#x1680;bar> | OGHAM SPACE MARK, U+1680, is |
| | | mapped to U+0020 and thus |
| | | the full string is mapped to |
| | | <foo bar> |
+------------------------------------+------------------------------+
The following examples illustrate strings that are not valid The following example illustrates a strings that is not a valid
passwords because they violate the format defined above. password because it violates the format defined above.
Table 4: A sample of strings that violate the password rules Table 4: A string that violates the password rules
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
| # | Password | Notes | | # | Password | Notes |
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
| 16| <foo&#x1680;bar> | Non-ASCII space (here, OGHAM |
| | | SPACE MARK, U+1680) is not |
| | | allowed |
+------------------------------------+------------------------------+
| 17| <my cat is a &#x9;by> | Controls are disallowed | | 17| <my cat is a &#x9;by> | Controls are disallowed |
+------------------------------------+------------------------------+ +------------------------------------+------------------------------+
5. Use in Application Protocols 5. Use in Application Protocols
This specification defines only the PRECIS-based rules for handling This specification defines only the PRECIS-based rules for handling
of strings conforming to the UsernameCaseMapped and of strings conforming to the UsernameCaseMapped and
UsernameCasePreserved profiles of the PRECIS IdentifierClass, and UsernameCasePreserved profiles of the PRECIS IdentifierClass, and
strings conforming to the OpaqueString profile of the PRECIS strings conforming to the OpaqueString profile of the PRECIS
FreeformClass. It is the responsibility of an application protocol FreeformClass. It is the responsibility of an application protocol
skipping to change at page 19, line 44 skipping to change at page 20, line 24
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003. 10646", STD 63, RFC 3629, November 2003.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008. Specifications: ABNF", STD 68, RFC 5234, January 2008.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
RFC 5890, August 2010.
[RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in
Internationalization in the IETF", BCP 166, RFC 6365,
September 2011.
[Unicode] The Unicode Consortium, "The Unicode Standard", [Unicode] The Unicode Consortium, "The Unicode Standard",
2015-present, <http://www.unicode.org/versions/latest/>. 2015-present, <http://www.unicode.org/versions/latest/>.
[Unicode7.0] [Unicode7.0]
The Unicode Consortium, "The Unicode Standard, Version The Unicode Consortium, "The Unicode Standard, Version
7.0.0", 2014, 7.0.0", 2014,
<http://www.unicode.org/versions/Unicode7.0.0/>. <http://www.unicode.org/versions/Unicode7.0.0/>.
9.2. Informative References 9.2. Informative References
[I-D.ietf-httpauth-basicauth-update] [I-D.ietf-httpauth-basicauth-update]
Reschke, J., "The 'Basic' HTTP Authentication Scheme", Reschke, J., "The 'Basic' HTTP Authentication Scheme",
draft-ietf-httpauth-basicauth-update-07 (work in draft-ietf-httpauth-basicauth-update-07 (work in
progress), February 2015. progress), February 2015.
[I-D.ietf-httpauth-digest] [I-D.ietf-httpauth-digest]
Shekh-Yusef, R., Ahrens, D., and S. Bremer, "HTTP Digest Shekh-Yusef, R., Ahrens, D., and S. Bremer, "HTTP Digest
Access Authentication", draft-ietf-httpauth-digest-14 Access Authentication", draft-ietf-httpauth-digest-18
(work in progress), February 2015. (work in progress), April 2015.
[I-D.ietf-radext-nai] [I-D.ietf-radext-nai]
DeKok, A., "The Network Access Identifier", draft-ietf- DeKok, A., "The Network Access Identifier", draft-ietf-
radext-nai-15 (work in progress), December 2014. radext-nai-15 (work in progress), December 2014.
[RFC20] Cerf, V., "ASCII format for network interchange", RFC 20, [RFC20] Cerf, V., "ASCII format for network interchange", RFC 20,
October 1969. October 1969.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC3454] Hoffman, P. and M. Blanchet, "Preparation of [RFC3454] Hoffman, P. and M. Blanchet, "Preparation of
Internationalized Strings ("stringprep")", RFC 3454, Internationalized Strings ("stringprep")", RFC 3454,
December 2002. December 2002.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, March 2003. 4rev1", RFC 3501, March 2003.
[RFC4013] Zeilenga, K., "SASLprep: Stringprep Profile for User Names [RFC4013] Zeilenga, K., "SASLprep: Stringprep Profile for User Names
and Passwords", RFC 4013, February 2005. and Passwords", RFC 4013, February 2005.
skipping to change at page 20, line 50 skipping to change at page 21, line 33
Authentication and Security Layer (SASL)", RFC 4422, June Authentication and Security Layer (SASL)", RFC 4422, June
2006. 2006.
[RFC4616] Zeilenga, K., "The PLAIN Simple Authentication and [RFC4616] Zeilenga, K., "The PLAIN Simple Authentication and
Security Layer (SASL) Mechanism", RFC 4616, August 2006. Security Layer (SASL) Mechanism", RFC 4616, August 2006.
[RFC5802] Newman, C., Menon-Sen, A., Melnikov, A., and N. Williams, [RFC5802] Newman, C., Menon-Sen, A., Melnikov, A., and N. Williams,
"Salted Challenge Response Authentication Mechanism "Salted Challenge Response Authentication Mechanism
(SCRAM) SASL and GSS-API Mechanisms", RFC 5802, July 2010. (SCRAM) SASL and GSS-API Mechanisms", RFC 5802, July 2010.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
RFC 5890, August 2010.
[RFC5891] Klensin, J., "Internationalized Domain Names in [RFC5891] Klensin, J., "Internationalized Domain Names in
Applications (IDNA): Protocol", RFC 5891, August 2010. Applications (IDNA): Protocol", RFC 5891, August 2010.
[RFC5892] Faltstrom, P., "The Unicode Code Points and
Internationalized Domain Names for Applications (IDNA)",
RFC 5892, August 2010.
[RFC5893] Alvestrand, H. and C. Karp, "Right-to-Left Scripts for [RFC5893] Alvestrand, H. and C. Karp, "Right-to-Left Scripts for
Internationalized Domain Names for Applications (IDNA)", Internationalized Domain Names for Applications (IDNA)",
RFC 5893, August 2010. RFC 5893, August 2010.
[RFC5894] Klensin, J., "Internationalized Domain Names for [RFC5894] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Background, Explanation, and Applications (IDNA): Background, Explanation, and
Rationale", RFC 5894, August 2010. Rationale", RFC 5894, August 2010.
[RFC6120] Saint-Andre, P., "Extensible Messaging and Presence [RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Core", RFC 6120, March 2011. Protocol (XMPP): Core", RFC 6120, March 2011.
[RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in
Internationalization in the IETF", BCP 166, RFC 6365,
September 2011.
[RFC6943] Thaler, D., "Issues in Identifier Comparison for Security [RFC6943] Thaler, D., "Issues in Identifier Comparison for Security
Purposes", RFC 6943, May 2013. Purposes", RFC 6943, May 2013.
[UTS39] The Unicode Consortium, "Unicode Technical Standard #39: [UTS39] The Unicode Consortium, "Unicode Technical Standard #39:
Unicode Security Mechanisms", July 2012, Unicode Security Mechanisms", July 2012,
<http://unicode.org/reports/tr39/>. <http://unicode.org/reports/tr39/>.
Appendix A. Differences from RFC 4013 Appendix A. Differences from RFC 4013
This document builds upon the PRECIS framework defined in This document builds upon the PRECIS framework defined in
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