Network Working Group K. Zeilenga
Request for Comments: 4523 OpenLDAP Foundation
Obsoletes: 2252, 2256, 2587 June 2006
Category: Standards Track
Lightweight Directory Access Protocol (LDAP)
Schema Definitions for X.509 Certificates
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document describes schema for representing X.509 certificates,
X.521 security information, and related elements in directories
accessible using the Lightweight Directory Access Protocol (LDAP).
The LDAP definitions for these X.509 and X.521 schema elements
replace those provided in RFCs 2252 and 2256.
1. Introduction
This document provides LDAP [RFC4510] schema definitions [RFC4512]
for a subset of elements specified in X.509 [X.509] and X.521
[X.521], including attribute types for certificates, cross
certificate pairs, and certificate revocation lists; matching rules
to be used with these attribute types; and related object classes.
LDAP syntax definitions are also provided for associated assertion
and attribute values.
As the semantics of these elements are as defined in X.509 and X.521,
knowledge of X.509 and X.521 is necessary to make use of the LDAP
schema definitions provided herein.
This document, together with [RFC4510], obsoletes RFCs 2252 and 2256
in their entirety. The changes (in this document) made since RFC
2252 and RFC 2256 include:
- addition of pkiUser, pkiCA, and deltaCRL classes;
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RFC 4523 LDAP X.509 Schema June 2006
- update of attribute types to include equality matching rules in
accordance with their X.500 specifications;
- addition of certificate, certificate pair, certificate list,
and algorithm identifier matching rules; and
- addition of LDAP syntax for assertion syntaxes for these
matching rules.
This document obsoletes RFC 2587. The X.509 schema descriptions for
LDAPv2 [RFC1777] are Historic, as is LDAPv2 [RFC3494].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119].
Schema definitions are provided using LDAP description formats
[RFC4512]. Definitions provided here are formatted (line wrapped)
for readability.
2. Syntaxes
This section describes various syntaxes used in LDAP to transfer
certificates and related data types.
2.1. Certificate
( 1.3.6.1.4.1.1466.115.121.1.8 DESC 'X.509 Certificate' )
A value of this syntax is an X.509 Certificate [X.509, clause 7].
Due to changes made to the definition of a Certificate through time,
no LDAP-specific encoding is defined for this syntax. Values of this
syntax SHOULD be encoded using Distinguished Encoding Rules (DER)
[X.690] and MUST only be transferred using the ;binary transfer
option [RFC4522]; that is, by requesting and returning values using
attribute descriptions such as "userCertificate;binary".
As values of this syntax contain digitally signed data, values of
this syntax and the form of each value MUST be preserved as
presented.
2.2. CertificateList
( 1.3.6.1.4.1.1466.115.121.1.9 DESC 'X.509 Certificate List' )
A value of this syntax is an X.509 CertificateList [X.509, clause
7.3].
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RFC 4523 LDAP X.509 Schema June 2006
Due to changes made to the definition of a CertificateList through
time, no LDAP-specific encoding is defined for this syntax. Values
of this syntax SHOULD be encoded using DER [X.690] and MUST only be
transferred using the ;binary transfer option [RFC4522]; that is, by
requesting and returning values using attribute descriptions such as
"certificateRevocationList;binary".
As values of this syntax contain digitally signed data, values of
this syntax and the form of each value MUST be preserved as
presented.
2.3. CertificatePair
( 1.3.6.1.4.1.1466.115.121.1.10 DESC 'X.509 Certificate Pair' )
A value of this syntax is an X.509 CertificatePair [X.509, clause
11.2.3].
Due to changes made to the definition of an X.509 CertificatePair
through time, no LDAP-specific encoding is defined for this syntax.
Values of this syntax SHOULD be encoded using DER [X.690] and MUST
only be transferred using the ;binary transfer option [RFC4522]; that
is, by requesting and returning values using attribute descriptions
such as "crossCertificatePair;binary".
As values of this syntax contain digitally signed data, values of
this syntax and the form of each value MUST be preserved as
presented.
2.4. SupportedAlgorithm
( 1.3.6.1.4.1.1466.115.121.1.49
DESC 'X.509 Supported Algorithm' )
A value of this syntax is an X.509 SupportedAlgorithm [X.509, clause
11.2.7].
Due to changes made to the definition of an X.509 SupportedAlgorithm
through time, no LDAP-specific encoding is defined for this syntax.
Values of this syntax SHOULD be encoded using DER [X.690] and MUST
only be transferred using the ;binary transfer option [RFC4522]; that
is, by requesting and returning values using attribute descriptions
such as "supportedAlgorithms;binary".
As values of this syntax contain digitally signed data, values of
this syntax and the form of the value MUST be preserved as presented.
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RFC 4523 LDAP X.509 Schema June 2006
2.5. CertificateExactAssertion
( 1.3.6.1.1.15.1 DESC 'X.509 Certificate Exact Assertion' )
A value of this syntax is an X.509 CertificateExactAssertion [X.509,
clause 11.3.1]. Values of this syntax MUST be encoded using the
Generic String Encoding Rules (GSER) [RFC3641]. Appendix A.1
provides an equivalent Augmented Backus-Naur Form (ABNF) [RFC4234]
grammar for this syntax.
2.6. CertificateAssertion
( 1.3.6.1.1.15.2 DESC 'X.509 Certificate Assertion' )
A value of this syntax is an X.509 CertificateAssertion [X.509,
clause 11.3.2]. Values of this syntax MUST be encoded using GSER
[RFC3641]. Appendix A.2 provides an equivalent ABNF [RFC4234]
grammar for this syntax.
2.7. CertificatePairExactAssertion
( 1.3.6.1.1.15.3
DESC 'X.509 Certificate Pair Exact Assertion' )
A value of this syntax is an X.509 CertificatePairExactAssertion
[X.509, clause 11.3.3]. Values of this syntax MUST be encoded using
GSER [RFC3641]. Appendix A.3 provides an equivalent ABNF [RFC4234]
grammar for this syntax.
2.8. CertificatePairAssertion
( 1.3.6.1.1.15.4 DESC 'X.509 Certificate Pair Assertion' )
A value of this syntax is an X.509 CertificatePairAssertion [X.509,
clause 11.3.4]. Values of this syntax MUST be encoded using GSER
[RFC3641]. Appendix A.4 provides an equivalent ABNF [RFC4234]
grammar for this syntax.
2.9. CertificateListExactAssertion
( 1.3.6.1.1.15.5
DESC 'X.509 Certificate List Exact Assertion' )
A value of this syntax is an X.509 CertificateListExactAssertion
[X.509, clause 11.3.5]. Values of this syntax MUST be encoded using
GSER [RFC3641]. Appendix A.5 provides an equivalent ABNF grammar for
this syntax.
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RFC 4523 LDAP X.509 Schema June 2006
2.10. CertificateListAssertion
( 1.3.6.1.1.15.6 DESC 'X.509 Certificate List Assertion' )
A value of this syntax is an X.509 CertificateListAssertion [X.509,
clause 11.3.6]. Values of this syntax MUST be encoded using GSER
[RFC3641]. Appendix A.6 provides an equivalent ABNF [RFC4234]
grammar for this syntax.
2.11. AlgorithmIdentifier
( 1.3.6.1.1.15.7 DESC 'X.509 Algorithm Identifier' )
A value of this syntax is an X.509 AlgorithmIdentifier [X.509, Clause
7]. Values of this syntax MUST be encoded using GSER [RFC3641].
Appendix A.7 provides an equivalent ABNF [RFC4234] grammar for this
syntax.
3. Matching Rules
This section introduces a set of certificate and related matching
rules for use in LDAP. These rules are intended to act in accordance
with their X.500 counterparts.
3.1. certificateExactMatch
The certificateExactMatch matching rule compares the presented
certificate exact assertion value with an attribute value of the
certificate syntax as described in clause 11.3.1 of [X.509].
( 2.5.13.34 NAME 'certificateExactMatch'
DESC 'X.509 Certificate Exact Match'
SYNTAX 1.3.6.1.1.15.1 )
3.2. certificateMatch
The certificateMatch matching rule compares the presented certificate
assertion value with an attribute value of the certificate syntax as
described in clause 11.3.2 of [X.509].
( 2.5.13.35 NAME 'certificateMatch'
DESC 'X.509 Certificate Match'
SYNTAX 1.3.6.1.1.15.2 )
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RFC 4523 LDAP X.509 Schema June 2006
3.3. certificatePairExactMatch
The certificatePairExactMatch matching rule compares the presented
certificate pair exact assertion value with an attribute value of the
certificate pair syntax as described in clause 11.3.3 of [X.509].
( 2.5.13.36 NAME 'certificatePairExactMatch'
DESC 'X.509 Certificate Pair Exact Match'
SYNTAX 1.3.6.1.1.15.3 )
3.4. certificatePairMatch
The certificatePairMatch matching rule compares the presented
certificate pair assertion value with an attribute value of the
certificate pair syntax as described in clause 11.3.4 of [X.509].
( 2.5.13.37 NAME 'certificatePairMatch'
DESC 'X.509 Certificate Pair Match'
SYNTAX 1.3.6.1.1.15.4 )
3.5. certificateListExactMatch
The certificateListExactMatch matching rule compares the presented
certificate list exact assertion value with an attribute value of the
certificate pair syntax as described in clause 11.3.5 of [X.509].
( 2.5.13.38 NAME 'certificateListExactMatch'
DESC 'X.509 Certificate List Exact Match'
SYNTAX 1.3.6.1.1.15.5 )
3.6. certificateListMatch
The certificateListMatch matching rule compares the presented
certificate list assertion value with an attribute value of the
certificate pair syntax as described in clause 11.3.6 of [X.509].
( 2.5.13.39 NAME 'certificateListMatch'
DESC 'X.509 Certificate List Match'
SYNTAX 1.3.6.1.1.15.6 )
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RFC 4523 LDAP X.509 Schema June 2006
3.7. algorithmIdentifierMatch
The algorithmIdentifierMatch mating rule compares a presented
algorithm identifier with an attribute value of the supported
algorithm as described in clause 11.3.7 of [X.509].
( 2.5.13.40 NAME 'algorithmIdentifier'
DESC 'X.509 Algorithm Identifier Match'
SYNTAX 1.3.6.1.1.15.7 )
4. Attribute Types
This section details a set of certificate and related attribute types
for use in LDAP.
4.1. userCertificate
The userCertificate attribute holds the X.509 certificates issued to
the user by one or more certificate authorities, as discussed in
clause 11.2.1 of [X.509].
( 2.5.4.36 NAME 'userCertificate'
DESC 'X.509 user certificate'
EQUALITY certificateExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.8 )
As required by this attribute type's syntax, values of this attribute
are requested and transferred using the attribute description
"userCertificate;binary".
4.2. cACertificate
The cACertificate attribute holds the X.509 certificates issued to
the certificate authority (CA), as discussed in clause 11.2.2 of
[X.509].
( 2.5.4.37 NAME 'cACertificate'
DESC 'X.509 CA certificate'
EQUALITY certificateExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.8 )
As required by this attribute type's syntax, values of this attribute
are requested and transferred using the attribute description
"cACertificate;binary".
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RFC 4523 LDAP X.509 Schema June 2006
4.3. crossCertificatePair
The crossCertificatePair attribute holds an X.509 certificate pair,
as discussed in clause 11.2.3 of [X.509].
( 2.5.4.40 NAME 'crossCertificatePair'
DESC 'X.509 cross certificate pair'
EQUALITY certificatePairExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.10 )
As required by this attribute type's syntax, values of this attribute
are requested and transferred using the attribute description
"crossCertificatePair;binary".
4.4. certificateRevocationList
The certificateRevocationList attribute holds certificate lists, as
discussed in 11.2.4 of [X.509].
( 2.5.4.39 NAME 'certificateRevocationList'
DESC 'X.509 certificate revocation list'
EQUALITY certificateListExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.9 )
As required by this attribute type's syntax, values of this attribute
are requested and transferred using the attribute description
"certificateRevocationList;binary".
4.5. authorityRevocationList
The authorityRevocationList attribute holds certificate lists, as
discussed in 11.2.5 of [X.509].
( 2.5.4.38 NAME 'authorityRevocationList'
DESC 'X.509 authority revocation list'
EQUALITY certificateListExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.9 )
As required by this attribute type's syntax, values of this attribute
are requested and transferred using the attribute description
"authorityRevocationList;binary".
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4.6. deltaRevocationList
The deltaRevocationList attribute holds certificate lists, as
discussed in 11.2.6 of [X.509].
( 2.5.4.53 NAME 'deltaRevocationList'
DESC 'X.509 delta revocation list'
EQUALITY certificateListExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.9 )
As required by this attribute type's syntax, values of this attribute
MUST be requested and transferred using the attribute description
"deltaRevocationList;binary".
4.7. supportedAlgorithms
The supportedAlgorithms attribute holds supported algorithms, as
discussed in 11.2.7 of [X.509].
( 2.5.4.52 NAME 'supportedAlgorithms'
DESC 'X.509 supported algorithms'
EQUALITY algorithmIdentifierMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.49 )
As required by this attribute type's syntax, values of this attribute
MUST be requested and transferred using the attribute description
"supportedAlgorithms;binary".
5. Object Classes
This section details a set of certificate-related object classes for
use in LDAP.
5.1. pkiUser
This object class is used in augment entries for objects that may be
subject to certificates, as defined in clause 11.1.1 of [X.509].
( 2.5.6.21 NAME 'pkiUser'
DESC 'X.509 PKI User'
SUP top AUXILIARY
MAY userCertificate )
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RFC 4523 LDAP X.509 Schema June 2006
5.2. pkiCA
This object class is used to augment entries for objects that act as
certificate authorities, as defined in clause 11.1.2 of [X.509]
( 2.5.6.22 NAME 'pkiCA'
DESC 'X.509 PKI Certificate Authority'
SUP top AUXILIARY
MAY ( cACertificate $ certificateRevocationList $
authorityRevocationList $ crossCertificatePair ) )
5.3. cRLDistributionPoint
This class is used to represent objects that act as CRL distribution
points, as discussed in clause 11.1.3 of [X.509].
( 2.5.6.19 NAME 'cRLDistributionPoint'
DESC 'X.509 CRL distribution point'
SUP top STRUCTURAL
MUST cn
MAY ( certificateRevocationList $
authorityRevocationList $ deltaRevocationList ) )
5.4. deltaCRL
The deltaCRL object class is used to augment entries to hold delta
revocation lists, as discussed in clause 11.1.4 of [X.509].
( 2.5.6.23 NAME 'deltaCRL'
DESC 'X.509 delta CRL'
SUP top AUXILIARY
MAY deltaRevocationList )
5.5. strongAuthenticationUser
This object class is used to augment entries for objects
participating in certificate-based authentication, as defined in
clause 6.15 of [X.521]. This object class is deprecated in favor of
pkiUser.
( 2.5.6.15 NAME 'strongAuthenticationUser'
DESC 'X.521 strong authentication user'
SUP top AUXILIARY
MUST userCertificate )
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RFC 4523 LDAP X.509 Schema June 2006
5.6. userSecurityInformation
This object class is used to augment entries with needed additional
associated security information, as defined in clause 6.16 of
[X.521].
( 2.5.6.18 NAME 'userSecurityInformation'
DESC 'X.521 user security information'
SUP top AUXILIARY
MAY ( supportedAlgorithms ) )
5.7. certificationAuthority
This object class is used to augment entries for objects that act as
certificate authorities, as defined in clause 6.17 of [X.521]. This
object class is deprecated in favor of pkiCA.
( 2.5.6.16 NAME 'certificationAuthority'
DESC 'X.509 certificate authority'
SUP top AUXILIARY
MUST ( authorityRevocationList $
certificateRevocationList $ cACertificate )
MAY crossCertificatePair )
5.8. certificationAuthority-V2
This object class is used to augment entries for objects that act as
certificate authorities, as defined in clause 6.18 of [X.521]. This
object class is deprecated in favor of pkiCA.
( 2.5.6.16.2 NAME 'certificationAuthority-V2'
DESC 'X.509 certificate authority, version 2'
SUP certificationAuthority AUXILIARY
MAY deltaRevocationList )
6. Security Considerations
General certificate considerations [RFC3280] apply to LDAP-aware
certificate applications. General LDAP security considerations
[RFC4510] apply as well.
While elements of certificate information are commonly signed, these
signatures only protect the integrity of the signed information. In
the absence of data integrity protections in LDAP (or lower layer,
e.g., IPsec), a server is not assured that client certificate request
(or other request) was unaltered in transit. Likewise, a client
cannot be assured that the results of the query were unaltered in
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RFC 4523 LDAP X.509 Schema June 2006
transit. Hence, it is generally recommended that implementations
make use of authentication and data integrity services in LDAP
[RFC4513][RFC4511].
7. IANA Considerations
7.1. Object Identifier Registration
The IANA has registered an LDAP Object Identifier [RFC4520] for use
in this technical specification.
Subject: Request for LDAP OID Registration
Person & email address to contact for further information:
Kurt Zeilenga