< draft-ietf-pkix-authorityclearanceconstraints-00.txt   draft-ietf-pkix-authorityclearanceconstraints-01.txt >
IETF PKIX Working Group Sean Turner Network Working Group Sean Turner
Internet Draft IECA Internet Draft IECA
Intended Status: Standard Track Santosh Chokhani Intended Status: Standard Track Santosh Chokhani
CygnaCom Solutions CygnaCom Solutions
Expires: April 30, 2009 October 31, 2008 Expires: September 4, 2009 March 4, 2009
Clearance Attribute and Authority Clearance Constraints Clearance Attribute and Authority Clearance Constraints
Certificate Extension Certificate Extension
draft-ietf-pkix-authorityclearanceconstraints-00.txt draft-ietf-pkix-authorityclearanceconstraints-01.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any This Internet-Draft is submitted to IETF in full conformance with the
applicable patent or other IPR claims of which he or she is aware provisions of BCP 78 and BCP 79.
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
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 groups may also distribute working documents as Internet- other 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 as "work in progress." material or to cite them other than as "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/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
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
This Internet-Draft will expire on April 30, 2009. This Internet-Draft will expire on September 4, 2009.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2008). Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Abstract Abstract
This document defines the syntax and semantics for the Clearance This document defines the syntax and semantics for the Clearance
attribute and the Authority Clearance Constraints extension in X.509 attribute and the Authority Clearance Constraints extension in X.509
certificates. The Clearance attribute is used to indicate the certificates. The Clearance attribute is used to indicate the
clearance held by the subject. The Clearance attribute may appear in clearance held by the subject. The Clearance attribute may appear in
the subject directory attributes extension of a public key the subject directory attributes extension of a public key
certificate or in the attributes field of an attribute certificate. certificate or in the attributes field of an attribute certificate.
The Authority Clearance Constraints certificate extension values in a The Authority Clearance Constraints certificate extension values in a
Trust Anchor (TA), CA public key certificates, and an Attribute Trust Anchor (TA), CA public key certificates, and an Attribute
Authority (AA) public key certificate in a public key certification Authority (AA) public key certificate in a public key certification
path constrain the effective Clearance of the subject. path constrain the effective Clearance of the subject.
Table of Contents Table of Contents
1. Introduction...................................................2 1. Introduction...................................................3
1.1. Terminology...............................................3 1.1. Terminology...............................................4
1.2. ASN.1 Syntax Notation.....................................3 1.2. ASN.1 Syntax Notation.....................................4
2. Clearance Attribute............................................4 2. Clearance Attribute............................................4
3. Authority Clearance Constraints Certificate Extension..........5 3. Authority Clearance Constraints Certificate Extension..........5
4. Clearance and Authority Clearance Constraints Processing in PKC6 4. Clearance and Authority Clearance Constraints Processing in
PKC............................................................6
4.1. Collecting Constraints....................................7 4.1. Collecting Constraints....................................7
4.1.1. Certification Path Processing........................7 4.1.1. Certification Path Processing........................7
5. Clearance and Authority Clearance Constraints Processing in AC11 4.1.1.1. Inputs..........................................8
5.1. Collecting Constraints...................................12 4.1.1.2. Initialization..................................8
5.1.1. Certification Path Processing.......................12 4.1.1.3. Basic Certificate Processing....................8
6. Computing Intersection of securityCategories..................13 4.1.1.4. Preparation for Certificate i+1.................9
7. Recommended securityCategories................................14 4.1.1.5. Wrap-up Procedure...............................9
8. Security Considerations.......................................14 4.1.1.5.1. Wrap Up Clearance..........................9
9. IANA Considerations...........................................15 4.1.1.6. Outputs........................................10
10. References...................................................15 5. Clearance and Authority Clearance Constraints Processing in
10.1. Normative References....................................15 AC............................................................10
10.2. Informative References..................................15 5.1. Collecting Constraints...................................11
Appendix A. ASN.1 Module.........................................16 5.1.1. Certification Path Processing.......................11
Author's Addresses...............................................18 5.1.1.1. Inputs.........................................11
Full Copyright Statement.........................................19 5.1.1.2. Initialization.................................11
Intellectual Property............................................19 5.1.1.3. Basic PKC Processing...........................12
5.1.1.4. Preparation for Certificate i+1................12
5.1.1.5. Wrap-up Procedure..............................12
5.1.1.5.1. Wrap Up Clearance.........................12
5.1.1.6. Outputs........................................12
6. Computing Intersection of permitted-clearances and
AuthorityClearanceConstraints extension.......................12
7. Computing Intersection of securityCategories..................14
8. Recommended securityCategories................................15
9. Security Considerations.......................................15
10. IANA Considerations..........................................15
11. References...................................................15
11.1. Normative References....................................15
11.2. Informative References..................................16
Appendix A. ASN.1 Module.........................................17
Author's Addresses...............................................19
1. Introduction 1. Introduction
Organizations that have implemented a security policy can issue Organizations that have implemented a security policy can issue
certificates that include an indication of the clearance values held certificates that include an indication of the clearance values held
by the subject. The Clearance attribute indicates the security by the subject. The Clearance attribute indicates the security
policy, the clearance levels held by the subject, and additional policy, the clearance levels held by the subject, and additional
authorization information held by the subject. This specification authorization information held by the subject. This specification
makes use of the ASN.1 syntax for clearance from [3281bis]. makes use of the ASN.1 syntax for clearance from [3281bis].
Clearance attribute may be placed in the Subject Directory extension Clearance attribute may be placed in the subject directory attributes
of a PKC or may be placed in a separate attribute certificate (AC). extension of a PKC or may be placed in a separate attribute
certificate (AC).
The placement of Clearance attribute in PKCs is desirable when the The placement of Clearance attribute in PKCs is desirable when the
credentials such as PKCs need to be revoked when the clearance credentials such as PKCs need to be revoked when the clearance
information changes or when clearance information is relatively information changes or when clearance information is relatively
static, and clearance information can be verified as part of PKC static, and clearance information can be verified as part of PKC
issuance process (e.g., using local databases). The placement of issuance process (e.g., using local databases). The placement of
Clearance attribute in PKCs may also be made to simplify the Clearance attribute in PKCs may also be made to simplify the
infrastructure, to reduce the infrastructure design cost, or to infrastructure, to reduce the infrastructure design cost, or to
reduce the infrastructure operations cost. An example of placement reduce the infrastructure operations cost. An example of placement
of Clearance attribute in PKCs in operational PKI is the Defense of Clearance attribute in PKCs in operational PKI is the Defense
Messaging Service. An example of placement of attributes in PKCs is Messaging Service. An example of placement of attributes in PKCs is
Qualified Certificates [RFC3739]. Qualified Certificates [RFC3739].
The placement of Clearance attribute in ACs is desirable when the The placement of Clearance attribute in ACs is desirable when the
clearance information is relatively dynamic and changes in the clearance information is relatively dynamic and changes in the
clearance information does not require revocation of credentials such clearance information does not require revocation of credentials such
as PKCs, or the clearance information can not be verified as part of as PKCs, or the clearance information can not be verified as part of
PKC issuance process. PKC issuance process.
Since [RFC3281] does not permit chain of ACs, the Authority Since [3281bis] does not permit chain of ACs, the Authority
Clearance Constraints extension may only appear in the PKCs of CA or Clearance Constraints extension may only appear in the PKCs of CA or
AA. The Authority Clearance Constraints extension may also appear AA. The Authority Clearance Constraints extension may also appear
in a TA or may be associated with a TA. in a TA or may be associated with a TA.
Some organizations have multiple TAs, CAs, and/or AAs and these Some organizations have multiple TAs, CAs, and/or AAs and these
organizations may wish to indicate to relying parties which clearance organizations may wish to indicate to relying parties which clearance
values from a particular TA, CA, or AA should be accepted. For values from a particular TA, CA, or AA should be accepted. For
example, consider the security policies described in [RFC3114], where example, consider the security policies described in [RFC3114], where
a security policy has been defined for Amoco with three security a security policy has been defined for Amoco with three security
classification values (HIGHLY CONFIDENTIAL, CONFIDENTIAL, and classification values (HIGHLY CONFIDENTIAL, CONFIDENTIAL, and
skipping to change at page 3, line 47 skipping to change at page 4, line 23
1.1. Terminology 1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1.2. ASN.1 Syntax Notation 1.2. ASN.1 Syntax Notation
All X.509 PKC [RFC5280] extensions are defined using ASN.1 [X.680]. All X.509 PKC [RFC5280] extensions are defined using ASN.1 [X.680].
All X.509 AC [RFC3281] extensions are defined using ASN.1 [X.680]. All X.509 AC [3281bis] extensions are defined using ASN.1 [X.680].
2. Clearance Attribute 2. Clearance Attribute
The Clearance attribute in a certificate indicates the clearances The Clearance attribute in a certificate indicates the clearances
held by the subject. It uses the clearance attribute syntax from held by the subject. It uses the clearance attribute syntax from
Section 4.4.6 of [3281bis], which is included below for convenience, Section 4.4.6 of [3281bis], which is included below for convenience,
in the Attributes field. A certificate MUST include either zero or in the Attributes field. A certificate MUST include either zero or
one instance of the Clearance attribute. If the Clearance attribute one instance of the Clearance attribute. If the Clearance attribute
is present, it must contain a single value. is present, it must contain a single value.
The following object identifier identifies the Clearance attribute The following object identifier identifies the Clearance attribute
(either in the subject directory attributes extension of a PKC or in (either in the subject directory attributes extension of a PKC or in
the Attributes field of an AC): the Attributes field of an AC):
id-at-clearance OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) id-at-clearance OBJECT IDENTIFIER ::= { joint-iso-ccitt(2)
ds(5) module(1) selected-attribute-types(5) clearance(55) } ds(5) attributeTypes(5) clearance(55) }
The ASN.1 syntax for the Clearance attribute is as follows [PKI-ASN]: The ASN.1 syntax for the Clearance attribute is as follows [PKI-ASN]:
Clearance ::= SEQUENCE { Clearance ::= SEQUENCE {
policyId OBJECT IDENTIFIER, policyId OBJECT IDENTIFIER,
classList ClassList DEFAULT {unclassified}, classList ClassList DEFAULT {unclassified},
securityCategories SET OF SecurityCategory OPTIONAL securityCategories SET OF SecurityCategory OPTIONAL
} }
ClassList ::= BIT STRING { ClassList ::= BIT STRING {
unmarked (0), unmarked (0),
unclassified (1), unclassified (1),
restricted (2), restricted (2),
confidential (3), confidential (3),
secret (4), secret (4),
topSecret (5) topSecret (5)
} }
SECURITY-CATEGORY ::= TYPE-IDENTIFIER SECURITY-CATEGORY ::= TYPE-IDENTIFIER
SecurityCategory ::= SEQUENCE { SecurityCategory ::= SEQUENCE {
type [0] type [0]
TYPE-IDENTIFIER.&id({SupportedSecurityCategories}), TYPE-IDENTIFIER.&id({SupportedSecurityCategories}),
value [1] value [1]
EXPLICIT TYPE-IDENTIFIER.&Type EXPLICIT TYPE-IDENTIFIER.&Type
({SupportedSecurityCategories}{@type}) ({SupportedSecurityCategories}{@type})
} }
The Clearance attribute takes its meaning from Section 4.4.6 of The Clearance attribute takes its meaning from Section 4.4.6 of
[RFC3281], which is repeated here for convenience: [3281bis], which is repeated here for convenience:
- policyId identifies the security policy to which the clearance - policyId identifies the security policy to which the clearance
relates. The policyId indicates the semantics of the classList relates. The policyId indicates the semantics of the classList
and securityCategory fields. and securityCategory fields.
- classlist identifies the security classifications. Six basic - classlist identifies the security classifications. Six basic
values are defined in bit positions 0 through 5 and more may be values are defined in bit positions 0 through 5 and more may be
defined by an organizational security policy. defined by an organizational security policy.
- securityCategories provides additional authorization information. - securityCategories provides additional authorization information.
skipping to change at page 5, line 40 skipping to change at page 6, line 14
Absence of this certificate extension in a TA, in a CA PKC, or in an Absence of this certificate extension in a TA, in a CA PKC, or in an
AA PKC indicates that clearance of the subject of the AC or the AA PKC indicates that clearance of the subject of the AC or the
subject of the last certificate in a PKC certification path subject of the last certificate in a PKC certification path
containing the TA, the CA or the AA is not constrained by the containing the TA, the CA or the AA is not constrained by the
respective TA, CA or AA. respective TA, CA or AA.
The following object identifier identifies the Authority Clearance The following object identifier identifies the Authority Clearance
Constraints certificate extension: Constraints certificate extension:
id-ce-authorityClearanceConstraints OBJECT IDENTIFIER ::= { id-pe-authorityClearanceConstraints OBJECT IDENTIFIER ::= {
id-TBSL } iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) pe(1) 21 }
The ASN.1 syntax for the Authority Clearance Constraints certificate The ASN.1 syntax for the Authority Clearance Constraints certificate
extension is as follows: extension is as follows:
AuthorityClearanceConstraints ::= SEQUENCE SIZE (1..MAX) OF AuthorityClearanceConstraints ::= SEQUENCE SIZE (1..MAX) OF
Clearance Clearance
The syntax for Authority Clearance Constraints certificate extension The syntax for Authority Clearance Constraints certificate extension
contains Clearance values that the CA or the AA asserts. The contains Clearance values that the CA or the AA asserts. The
sequence MUST NOT include more than one entry with the same policyId. sequence MUST NOT include more than one entry with the same policyId.
skipping to change at page 6, line 4 skipping to change at page 6, line 27
The ASN.1 syntax for the Authority Clearance Constraints certificate The ASN.1 syntax for the Authority Clearance Constraints certificate
extension is as follows: extension is as follows:
AuthorityClearanceConstraints ::= SEQUENCE SIZE (1..MAX) OF AuthorityClearanceConstraints ::= SEQUENCE SIZE (1..MAX) OF
Clearance Clearance
The syntax for Authority Clearance Constraints certificate extension The syntax for Authority Clearance Constraints certificate extension
contains Clearance values that the CA or the AA asserts. The contains Clearance values that the CA or the AA asserts. The
sequence MUST NOT include more than one entry with the same policyId. sequence MUST NOT include more than one entry with the same policyId.
This constraint is enforced during Clearance and Authority Clearance This constraint is enforced during Clearance and Authority Clearance
Constraints Processing described below. If more than one entry with Constraints Processing described below. If more than one entry with
the same policyId is present in AuthorityClearanceConstraints the same policyId is present in AuthorityClearanceConstraints
certificate extension, the certification path is rejected. In certificate extension, the certification path is rejected. In
addition, each Clearance attribute in the SEQUENCE must not contain addition, each Clearance attribute in the SEQUENCE must not contain
more than one value. more than one value.
4. Clearance and Authority Clearance Constraints Processing in PKC 4. Clearance and Authority Clearance Constraints Processing in PKC
This section describes the processing of certification path when This section describes the processing of certification path when
Clearance is asserted in PKC. Clearance is asserted in PKC.
Authority Clearance Constraints certificate extension and Clearance User input, Authority Clearance Constraints certificate extension,
attribute processing determines the effective clearance (henceforth and Clearance attribute processing determines the effective clearance
called effective-clearance) for the end PKC. Authority Clearance (henceforth called effective-clearance) for the end PKC. User input,
Constraints certificate extension in the TA and in each PKC up to but Authority Clearance Constraints certificate extension in the TA and
not including the end PKC in a PKC certification path impact the in each PKC up to but not including the end PKC in a PKC
effective-clearance. If there is more than one path to the end- certification path impact the effective-clearance. If there is more
entity PKC, each path is processed independently. The process than one path to the end-entity PKC, each path is processed
involves two steps: independently. The process involves two steps:
1) collecting the Authority Clearance Constraints; and 1) collecting the Authority Clearance Constraints; and
2) using Authority Clearance Constraints in the certification path 2) using Authority Clearance Constraints in the certification path
and the Clearance in the end PKC to determine the effective- and the Clearance in the end PKC to determine the effective-
clearance for the subject of the end PKC. clearance for the subject of the end PKC.
Assuming a certification path consisting of n PKCs, the effective- Assuming a certification path consisting of n PKCs, the effective-
clearance for the subject of the end PKC is the intersection of clearance for the subject of the end PKC is the intersection of
Clearance attribute in the subject PKC, Authority Clearance Clearance attribute in the subject PKC, Authority Clearance
Constraints, if present, in trust anchor and all Authority Clearance Constraints, if present, in trust anchor, user input, and all
Constraints present in intermediate PKCs. Any effective-clearance Authority Clearance Constraints present in intermediate PKCs. Any
calculation algorithm that performs this calculation and provides the effective-clearance calculation algorithm that performs this
same outcome as the one from the algorithm described herein is calculation and provides the same outcome as the one from the
considered compliant with the requirements of this RFC. algorithm described herein is considered compliant with the
requirements of this RFC.
When processing a certification path, Authority Clearance Constraints When processing a certification path, Authority Clearance Constraints
are maintained in one state variable: permitted-clearances. When are maintained in one state variable: permitted-clearances. When
processing begins, permitted-clearances is initialized to the special processing begins, permitted-clearances is initialized to the user
value all-clearances if Authority Clearance Constraints certificate input value or special value all-clearances if Authority Clearance
extension is not present in or associated with the trust anchor, Constraints user input is not provided. The permitted-clearances
otherwise this value is initialized to Authority Clearance state variable is updated by first processing Authority Clearance
Constraints associated with the trust anchor. The permitted- Constraints associated with the trust anchor, and then each time an
clearances state variable is updated each time an intermediate PKC intermediate PKC that contains an Authority Clearance Constraints
that contains an Authority Clearance Constraints certificate certificate extension in the path is processed.
extension in the path is processed.
When processing the end PKC, the value in the Clearance attribute in When processing the end PKC, the value in the Clearance attribute in
the end PKC is intersected with the permitted-clearances state the end PKC is intersected with the permitted-clearances state
variable. variable.
The output of Clearance attribute and Authority Clearance Constraint The output of Clearance attribute and Authority Clearance Constraint
certificate extensions processing is the effective-clearance, which certificate extensions processing is the effective-clearance, which
could also be an empty list; and success or failure with reason code could also be an empty list; and success or failure with reason code
for failure. for failure.
4.1. Collecting Constraints 4.1. Collecting Constraints
Authority Clearance Constraints are collected from the trust anchor Authority Clearance Constraints are collected from the user input,
and the intermediate PKCs in a certification path. the trust anchor and the intermediate PKCs in a certification path.
4.1.1. Certification Path Processing 4.1.1. Certification Path Processing
When processing Authority Clearance Constraints certificate extension When processing Authority Clearance Constraints certificate extension
for the purposes of validating Clearance attribute in the end PKC, for the purposes of validating Clearance attribute in the end PKC,
the processing described in this section or an equivalent algorithm the processing described in this section or an equivalent algorithm
MUST be included in the certification path validation. The MUST be included in the certification path validation. The
processing is presented as additions to the certification path processing is presented as additions to the certification path
validation algorithm described in section 6 of [RFC5280]. validation algorithm described in section 6 of [RFC5280]. Note that
this RFC is fully consistent with [RFC5280]; however, it augments
[RFC5280] with the following steps:
. Ability to provide and process Authority Clearance Constraints
as an additional input to the certification path processing
engine
. Requirement to process Authority Clearance Constraints present
with Trust anchor information.
4.1.1.1. Inputs 4.1.1.1. Inputs
User input may include AuthorityClearanceConstraints structure or
omit it.
Trust anchor information may include the Trust anchor information may include the
AuthorityClearanceConstraints structure to specify Authority AuthorityClearanceConstraints structure to specify Authority
Clearance Constraints for the trust anchor. The trust anchor may be Clearance Constraints for the trust anchor. The trust anchor may be
constrained or unconstrained. constrained or unconstrained.
4.1.1.2. Initialization 4.1.1.2. Initialization
Examine the trust anchor information and verify that it does not If user input includes AuthorityClearanceConstraints, set the
contain more than one instance of AuthorityClearanceConstraints permitted-clearances to the input value, otherwise,, set the
extension. If the trust anchor information contains more than one permitted-clearances to special value all-clearances.
instance of AuthorityClearanceConstraints extension, set effective-
clearance to an empty list, set error code to "multiple extension
instances", and exit with failure.
If any of the Clearance attributes in the
AuthorityClearanceConstraints extension contains more than one value,
set effective-clearance to an empty list, set error code to "multiple
values", and exit with failure.
Create a state variable named permitted-clearances. If the trust If any of the Clearance attributes in the permitted-clearances
anchor contains an AuthorityClearanceConstraints extension, then the contains more than one value, set effective-clearance to an empty
initial value of permitted-clearances is the list, set error code to "multiple values in input", and exit with
AuthorityClearanceConstraints extension from the trust anchor. failure.
Examine the permitted-clearances for the same Policy ID appearing Examine the permitted-clearances for the same Policy ID appearing
more then once. If a policyID appears more than once in the more then once. If a policyID appears more than once in the
permitted-clearances state variable, set effective-clearance to an permitted-clearances state variable, set effective-clearance to an
empty list, set error code to "multiple instances of same clearance", empty list, set error code to "multiple instances of same clearance",
and exit with failure. and exit with failure.
If the trust anchor does not contain an AuthorityClearanceConstraints If the trust anchor does not contain an AuthorityClearanceConstraints
extension, the permitted-clearances variable is assigned the special extension, continue at Section 4.1.1.3. Otherwise, execute the
value all-clearances. procedure described in Section 6 as an in-line macro by treating the
trust anchor as a PKC.
4.1.1.3. Basic Certificate Processing 4.1.1.3. Basic Certificate Processing
If the PKC is the last PKC (i.e., certificate n), skip the steps If the PKC is the last PKC (i.e., certificate n), skip the steps
listed in this section. listed in this section. Otherwise, execute the procedure described
in Section 6. as an in-line macro.
Examine the PKC and verify that it does not contain more than one
instance of AuthorityClearanceConstraints extension. If the PKC
contains more than one instance of AuthorityClearanceConstraints
extension, set effective-clearance to an empty list, set error code
to "multiple extension instances", and exit with failure.
If any of the Clearance attributes in the
AuthorityClearanceConstraints extension contains more than one value,
set effective-clearance to an empty list, set error code to "multiple
values", and exit with failure.
If the AuthorityClearanceConstraints certificate extension is not
present in the PKC, no action is taken, and the permitted-clearances
value is unchanged.
If the AuthorityClearanceConstraints certificate extension is present
in the PKC, set the variable temp-clearances to
AuthorityClearanceConstraints certificate extension. Examine the
temp-clearances for the same Policy ID appearing more then once. If
a policyID appears more than once in the temp-clearances state
variable, set effective-clearance to an empty list, set error code to
"multiple instances of same clearance", and exit with failure.
If the AuthorityClearanceConstraints certificate extension is present
in the PKC and permitted-clearances contains the all-clearances
special value, then assign permitted-clearances the value of the
temp-clearances.
If the AuthorityClearanceConstraints certificate extension is present
in the PKC and permitted-clearances does not contain the all-
clearances special value, take the intersection of temp-clearances
and permitted-clearances by repeating the following steps for each
clearance in the permitted-clearances state variable:
- If the policyID associated with the clearance is absent in the
temp-clearances, delete the clearance structure associated with
the policyID from the permitted-clearances state variable.
- If the policyID is present in the temp-clearances:
-- For every classList bit, assign the classList bit a value of
one (1) for the policyID in permitted-clearances state
variable if the bit is one (1) in both the permitted-
clearances state variable and the temp-clearances for that
policyID; otherwise assign the bit a value of zero (0).
-- If no bits are one (1) for the classList, delete the clearance
structure associated with the policyID from the permitted-
clearances state variable and skip the next step of processing
securityCategories.
-- For the policyID in permitted-clearances, set the
securityCategories to the intersection of securityCategories
for the policyID in permitted-clearances and in temp-
clearances using the algorithm described in Section 6. Note
that an empty SET is represented by simply omitting the SET.
4.1.1.4. Preparation for Certificate i+1 4.1.1.4. Preparation for Certificate i+1
No additional action associated with the Clearance attribute or No additional action associated with the Clearance attribute or
AuthorityClearanceConstraints certificate extensions is taken during AuthorityClearanceConstraints certificate extensions is taken during
this phase of certification path validation as described in section 6 this phase of certification path validation as described in section 6
of [RFC5280]. of [RFC5280].
4.1.1.5. Wrap-up Procedure 4.1.1.5. Wrap-up Procedure
skipping to change at page 11, line 11 skipping to change at page 10, line 29
clearance contains the effective clearance for the subject of the clearance contains the effective clearance for the subject of the
certification path. Processing also returns success or failure certification path. Processing also returns success or failure
indication and reason for failure, if applicable. indication and reason for failure, if applicable.
5. Clearance and Authority Clearance Constraints Processing in AC 5. Clearance and Authority Clearance Constraints Processing in AC
This section describes the processing of certification path when This section describes the processing of certification path when
Clearance is asserted in an AC. Relevant to processing are: one TA; Clearance is asserted in an AC. Relevant to processing are: one TA;
0 or more CA PKCs; 0 or 1 AA PKC; and 1 AC. 0 or more CA PKCs; 0 or 1 AA PKC; and 1 AC.
Authority Clearance Constraints certificate extension and Clearance User input, Authority Clearance Constraints certificate extension and
attribute processing determines the effective clearance (henceforth Clearance attribute processing determines the effective clearance
called effective-clearance) for the AC. Authority Clearance (henceforth called effective-clearance) for the AC. User input,
Constraints certificate extension in the TA and in each PKC up to and Authority Clearance Constraints certificate extension in the TA and
including the AA PKC in a certification path impact the effective- in each PKC up to and including the AA PKC in a certification path
clearance. If there is more than one path to the AA PKC, each path impact the effective-clearance. If there is more than one path to
is processed independently. The process involves two steps: the AA PKC, each path is processed independently. The process
involves two steps:
1) collecting the Authority Clearance Constraints; and 1) collecting the Authority Clearance Constraints; and
2) using Authority Clearance Constraints in the PKC certification 2) using Authority Clearance Constraints in the PKC certification
path and the Clearance in the AC to determine the effective- path and the Clearance in the AC to determine the effective-
clearance for the subject of the AC. clearance for the subject of the AC.
The effective-clearance for the subject of the AC is the intersection The effective-clearance for the subject of the AC is the intersection
of Clearance in the subject AC, Authority Clearance Constraints, if of Clearance in the subject AC, Authority Clearance Constraints, if
present, in trust anchor and all Authority Clearance Constraints present, in trust anchor, user input, and all Authority Clearance
present in PKC certification path from the TA to the AA. Any Constraints present in PKC certification path from the TA to the AA.
effective-clearance calculation algorithm that performs this Any effective-clearance calculation algorithm that performs this
calculation and provides the same outcome as the one from the calculation and provides the same outcome as the one from the
algorithm described herein is considered compliant with the algorithm described herein is considered compliant with the
requirements of this RFC. requirements of this RFC.
Authority Clearance Constraints is maintained in one state variable: Authority Clearance Constraints is maintained in one state variable:
permitted-clearances. When processing begins, permitted-clearances permitted-clearances. When processing begins, permitted-clearances
is initialized to the special value all-clearances if Authority is initialized to user input or special value all-clearances if
Clearance Constraints certificate extension is not present in or Authority Clearance Constraints user input is not provided. The
associated with the trust anchor, otherwise this value is initialized permitted-clearances state variable is updated by first processing
to Authority Clearance Constraints associated with the trust anchor. Authority Clearance Constraints associated with the trust anchor, and
The permitted-clearances state variable is updated each time a PKC then each time a PKC (other than AC holder PKC) that contains an
(other than AC holder PKC) that contains an Authority Clearance Authority Clearance Constraints certificate extension in the path is
Constraints certificate extension in the path is processed. processed.
When processing the AC, the value in the Clearance attribute in the When processing the AC, the value in the Clearance attribute in the
AC is intersected with the permitted-clearances state variable. AC is intersected with the permitted-clearances state variable.
The output of Clearance and Authority Clearance Constraint The output of Clearance and Authority Clearance Constraint
certificate extensions processing is the effective-clearance, which certificate extensions processing is the effective-clearance, which
could also be an empty list; and success or failure with reason code could also be an empty list; and success or failure with reason code
for failure. for failure.
5.1. Collecting Constraints 5.1. Collecting Constraints
Authority Clearance Constraints are collected from the trust anchor Authority Clearance Constraints are collected from the user input,
and all the PKCs in a PKC certification path. the trust anchor and all the PKCs in a PKC certification path.
5.1.1. Certification Path Processing 5.1.1. Certification Path Processing
When processing Authority Clearance Constraints certificate extension When processing Authority Clearance Constraints certificate extension
for the purposes of validating Clearance in the AC, the processing for the purposes of validating Clearance in the AC, the processing
described in this section or an equivalent algorithm MUST be included described in this section or an equivalent algorithm MUST be included
in the certification path validation. The processing is presented as in the certification path validation. The processing is presented as
additions to the PKC certification path validation algorithm additions to the PKC certification path validation algorithm
described in section 6 of [RFC5280] for the AA PKC certification path described in section 6 of [RFC5280] for the AA PKC certification path
and the algorithm described in section 5 of [RFC3281] for the AC and the algorithm described in section 5 of [3281bis] for the AC
validation. validation. Also see note related to [RFC5280 augmentation in
Section 4.1.1.
5.1.1.1. Inputs 5.1.1.1. Inputs
Same as Section 4.1.1.1. Same as Section 4.1.1.1.
In addition, let us assume that the PKC certification path for the AA In addition, let us assume that the PKC certification path for the AA
consists of n certificates. consists of n certificates.
5.1.1.2. Initialization 5.1.1.2. Initialization
skipping to change at page 13, line 19 skipping to change at page 12, line 38
5.1.1.5.1. Wrap Up Clearance 5.1.1.5.1. Wrap Up Clearance
Same as Section 4.1.1.5.1. Same as Section 4.1.1.5.1.
5.1.1.6. Outputs 5.1.1.6. Outputs
Same as Section 4.1.1.6. Same as Section 4.1.1.6.
In addition, apply AC processing rules described in Section 5 of In addition, apply AC processing rules described in Section 5 of
[RFC3281]. [3281bis].
6. Computing Intersection of securityCategories 6. Computing Intersection of permitted-clearances and
AuthorityClearanceConstraints extension
Examine the PKC and verify that it does not contain more than one
instance of AuthorityClearanceConstraints extension. If the PKC
contains more than one instance of AuthorityClearanceConstraints
extension, set effective-clearance to an empty list, set error code
to "multiple extension instances", and exit with failure.
If any of the Clearance attributes in the
AuthorityClearanceConstraints extension contains more than one value,
set effective-clearance to an empty list, set error code to "multiple
values", and exit with failure.
If the AuthorityClearanceConstraints certificate extension is not
present in the PKC, no action is taken, and the permitted-clearances
value is unchanged.
If the AuthorityClearanceConstraints certificate extension is present
in the PKC, set the variable temp-clearances to
AuthorityClearanceConstraints certificate extension. Examine the
temp-clearances for the same Policy ID appearing more then once. If
a policyID appears more than once in the temp-clearances state
variable, set effective-clearance to an empty list, set error code to
"multiple instances of same clearance", and exit with failure.
If the AuthorityClearanceConstraints certificate extension is present
in the PKC and permitted-clearances contains the all-clearances
special value, then assign permitted-clearances the value of the
temp-clearances.
If the AuthorityClearanceConstraints certificate extension is present
in the PKC and permitted-clearances does not contain the all-
clearances special value, take the intersection of temp-clearances
and permitted-clearances by repeating the following steps for each
clearance in the permitted-clearances state variable:
- If the policyID associated with the clearance is absent in the
temp-clearances, delete the clearance structure associated with
the policyID from the permitted-clearances state variable.
- If the policyID is present in the temp-clearances:
-- For every classList bit, assign the classList bit a value of
one (1) for the policyID in permitted-clearances state
variable if the bit is one (1) in both the permitted-
clearances state variable and the temp-clearances for that
policyID; otherwise assign the bit a value of zero (0).
-- If no bits are one (1) for the classList, delete the clearance
structure associated with the policyID from the permitted-
clearances state variable and skip the next step of processing
securityCategories.
-- For the policyID in permitted-clearances, set the
securityCategories to the intersection of securityCategories
for the policyID in permitted-clearances and in temp-
clearances using the algorithm described in Section 7. Note
that an empty SET is represented by simply omitting the SET.
7. Computing Intersection of securityCategories
This section describes how to compute the intersection of This section describes how to compute the intersection of
securityCategories A and B. It uses the state variable temp-set. securityCategories A and B. It uses the state variable temp-set.
Set the SET temp-set to empty. Set the SET temp-set to empty.
If SET A is empty (i.e., securityCategories is absent), return temp- If SET A is empty (i.e., securityCategories is absent), return temp-
set. set.
If SET B is empty (i.e., securityCategories is absent), return temp- If SET B is empty (i.e., securityCategories is absent), return temp-
skipping to change at page 14, line 20 skipping to change at page 15, line 5
SET B with the same Type OID. SET B with the same Type OID.
5. If the intersection is not empty, add and element containing the 5. If the intersection is not empty, add and element containing the
Type OID and intersection result as value to temp-set. Type OID and intersection result as value to temp-set.
6. If more elements remain in SET A, process the next element 6. If more elements remain in SET A, process the next element
starting with step 1. starting with step 1.
Return temp-set. Return temp-set.
7. Recommended securityCategories 8. Recommended securityCategories
This RFC also include a recommended securityCategories as follows: This RFC also include a recommended securityCategories as follows:
SecurityCategory ::= SEQUENCE { SecurityCategory ::= SEQUENCE {
type [0] OID id-TBSL, type [0] OID id-TBSL,
value [1] BIT STRING value [1] BIT STRING
} }
Note that Type specific intersection of two values for this Type will Note that Type specific intersection of two values for this Type will
be simply setting the bits that are set in both values. If the be simply setting the bits that are set in both values. If the
resulting intersection has none of the bits set, the intersection is resulting intersection has none of the bits set, the intersection is
considered empty. considered empty.
8. Security Considerations 9. Security Considerations
Certificate issuers must recognize that absence of the Certificate issuers must recognize that absence of the
AuthorityClearanceConstraints in a CA or AA certificate means that in AuthorityClearanceConstraints in a CA or AA certificate means that in
terms of the clearance, the subject Authority is not constrained. terms of the clearance, the subject Authority is not constrained.
Absence of Clearance attribute in a certificate means that the Absence of Clearance attribute in a certificate means that the
subject has not been assigned any clearance. subject has not been assigned any clearance.
If there is no Clearance associated with a TA, it means that the TA If there is no Clearance associated with a TA, it means that the TA
has not been assigned any clearance. has not been assigned any clearance.
If the local security policy considers the clearance held by a If the local security policy considers the clearance held by a
subject or those supported by a CA or AA to be sensitive, then the subject or those supported by a CA or AA to be sensitive, then the
Clearance attribute or Authority Clearance Constraints should only be Clearance attribute or Authority Clearance Constraints should only be
included if the subject's and Authority's certificate can be privacy included if the subject's and Authority's certificate can be privacy
protected. Also in this case, distribution of trust anchors and protected. Also in this case, distribution of trust anchors and
associated Authority Clearance Constraints extension or Clearance associated Authority Clearance Constraints extension or Clearance
must also be privacy protected. must also be privacy protected.
9. IANA Considerations 10. IANA Considerations
None. Please remove this section prior to publication as an RFC. None. Please remove this section prior to publication as an RFC.
10. References 11. References
10.1. Normative References 11.1. Normative References
[PKI-ASN] Hoffman, P., and J. Schaad, "New ASN.1 Modules for PKIX", [PKI-ASN] Hoffman, P., and J. Schaad, "New ASN.1 Modules for PKIX",
draft-ietf-pkix-new-asn1, work-in-progress. draft-ietf-pkix-new-asn1, work-in-progress.
/*** RFC EDITOR: Please replace PKI-ASN with RFCXYZA when draft-ietf-
pkix-new-asn1 is published.
[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.
[RFC3281] Farrell, S., and Housley, R., "An Internet Attribute
Certificate Profile for Authorization", RFC 3281, April
2002.
[3281bis] Farrell, S., Housely, R., and S. Turner, "An Internet [3281bis] Farrell, S., Housely, R., and S. Turner, "An Internet
Attribute Certificate Profile for Authorization: Update", Attribute Certificate Profile for Authorization: Update",
draft-ietf-pkix-3281update-01, work-in-progress. draft-ietf-pkix-3281update-04, work-in-progress.
/*** RFC EDITOR: Please replace 3281bis with RFCXYZA when draft-ietf-
pkix-3281update is published.
[RFC5280] Cooper, D. et. al., "Internet X.509 Public Key [RFC5280] Cooper, D. et. al., "Internet X.509 Public Key
Infrastructure Certificate and Certification Revocation Infrastructure Certificate and Certification Revocation
List (CRL) Profile", RFC 5280, May 2008. List (CRL) Profile", RFC 5280, May 2008.
[X.680] ITU-T Recommendation X.680 (2004) | ISO/IEC 8824-1:2004. [X.680] ITU-T Recommendation X.680 (2004) | ISO/IEC 8824-1:2004.
Information Technology - Abstract Syntax Notation One. Information Technology - Abstract Syntax Notation One.
10.2. Informative References 11.2. Informative References
[RFC3114] Nicolls, W., "Implementing Company Classification Policy [RFC3114] Nicolls, W., "Implementing Company Classification Policy
with S/MIME Security Label", RFC3114, May 2002. with S/MIME Security Label", RFC3114, May 2002.
[RFC3739] Santesson, S. et. al., "Internet X.509 Public Key [RFC3739] Santesson, S. et. al., "Internet X.509 Public Key
Infrastructure: Qualified Certificate Profile", RFC 3739, Infrastructure: Qualified Certificate Profile", RFC 3739,
March 2004. March 2004.
Appendix A. ASN.1 Module Appendix A. ASN.1 Module
This appendix provides the normative ASN.1 definitions for This appendix provides the normative ASN.1 definitions for
the structures described in this specification using ASN.1 as defined the structures described in this specification using ASN.1 as defined
in X.680. in X.680.
Clearance-AuthorityClearanceConstraints93 { id-TBSL } ClearanceConstraints { iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) mod(0) 46 }
DEFINITIONS IMPLICIT TAGS ::= DEFINITIONS IMPLICIT TAGS ::=
BEGIN BEGIN
-- EXPORTS ALL -- -- EXPORTS ALL --
IMPORTS IMPORTS
-- IMPORTS from [PKI-ASN] -- IMPORTS from [PKI-ASN]
skipping to change at page 16, line 46 skipping to change at page 17, line 47
id-mod-pkixCommon(43) id-mod-pkixCommon(43)
} }
; ;
-- Clearance attribute OID and syntax -- Clearance attribute OID and syntax
-- The following is a '93 version for clearance. -- The following is a '93 version for clearance.
-- It is included for convenience. -- It is included for convenience.
-- id-at-clearance OBJECT IDENTIFIER ::= -- id-at-clearance OBJECT IDENTIFIER ::=
-- { joint-iso-ccitt(2) ds(5) module(1) selected-attribute-types(5) -- { joint-iso-ccitt(2) ds(5) attributeTypes(5) clearance (55) }
-- clearance (55)
-- }
-- Clearance ::= SEQUENCE { -- Clearance ::= SEQUENCE {
-- policyId OBJECT IDENTIFIER, -- policyId OBJECT IDENTIFIER,
-- classList ClassList DEFAULT {unclassified}, -- classList ClassList DEFAULT {unclassified},
-- securityCategories SET OF SecurityCategory OPTIONAL -- securityCategories SET OF SecurityCategory OPTIONAL
-- } -- }
-- ClassList ::= BIT STRING { -- ClassList ::= BIT STRING {
-- unmarked (0), -- unmarked (0),
-- unclassified (1), -- unclassified (1),
-- restricted (2), -- restricted (2),
skipping to change at page 17, line 32 skipping to change at page 18, line 32
-- type [0] -- type [0]
-- TYPE-IDENTIFIER.&id({SupportedSecurityCategories}), -- TYPE-IDENTIFIER.&id({SupportedSecurityCategories}),
-- value [1] -- value [1]
-- EXPLICIT TYPE-IDENTIFIER.&Type -- EXPLICIT TYPE-IDENTIFIER.&Type
-- ({SupportedSecurityCategories}{@type}) -- ({SupportedSecurityCategories}{@type})
-- } -- }
-- Authority Clearance Constraints certificate extension OID -- Authority Clearance Constraints certificate extension OID
-- and syntax -- and syntax
id-ce-authorityClearanceConstraints OBJECT IDENTIFIER ::= { id-TBSL } id-pe-clearanceConstraints OBJECT IDENTIFIER ::=
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) pe(1) 21 }
authorityClearanceConstraints EXTENSION ::= { authorityClearanceConstraints EXTENSION ::= {
SYNTAX AuthorityClearanceConstraints SYNTAX AuthorityClearanceConstraints
IDENTIFIED BY id-ce-AuthorityClearanceConstraints IDENTIFIED BY id-pe-clearanceConstraints
} }
AuthorityClearanceConstraints ::= SEQUENCE SIZE (1..MAX) OF Clearance AuthorityClearanceConstraints ::= SEQUENCE SIZE (1..MAX) OF Clearance
END END
Author's Addresses Author's Addresses
Sean Turner Sean Turner
skipping to change at page 19, line 4 skipping to change at line 824
3057 Nutley Street, Suite 106 3057 Nutley Street, Suite 106
Fairfax, VA 22031 Fairfax, VA 22031
USA USA
EMail: turners@ieca.com EMail: turners@ieca.com
Santosh Chokhani Santosh Chokhani
CygnaCom Solutions, Inc. CygnaCom Solutions, Inc.
Email: SChokhani@cygnacom.com Email: SChokhani@cygnacom.com
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
 End of changes. 49 change blocks. 
177 lines changed or deleted 211 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/