RFC 2587
Internet X.509 Public Key Infrastructure LDAPv2 Schema
Pages: 8
Obsoleted by: 4523
Obsoleted by: 4523
Network Working Group S. Boeyen Request for Comments: 2587 Entrust Category: Standards Track T. Howes Netscape P. Richard Xcert June 1999 Internet X.509 Public Key Infrastructure LDAPv2 Schema 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 (1999). All Rights Reserved.1. Abstract
The schema defined in this document is a minimal schema to support PKIX in an LDAPv2 environment, as defined in RFC 2559. Only PKIX- specific components are specified here. LDAP servers, acting as PKIX repositories should support the auxiliary object classes defined in this specification and integrate this schema specification with the generic and other application-specific schemas as appropriate, depending on the services to be supplied by that server. The key words 'MUST', 'SHALL', 'REQUIRED', 'SHOULD', 'RECOMMENDED', and 'MAY' in this document are to be interpreted as described in RFC 2119.2. Introduction
This specification is part of a multi-part standard for development of a Public Key Infrastructure (PKI) for the Internet. LDAPv2 is one mechanism defined for access to a PKI repository. Other mechanisms, such as http, are also defined. If an LDAP server, accessed by LDAPv2 is used to provide a repository, the minimum requirement is that the repository support the addition of X.509 certificates to directory
entries. Certificate Revocation List (CRL)is one mechanism for publishing revocation information in a repository. Other mechanisms, such as http, are also defined. This specification defines the attributes and object classes to be used by LDAP servers acting as PKIX repositories and to be understood by LDAP clients communicating with such repositories to query, add, modify and delete PKI information. Some object classes and attributes defined in X.509 are duplicated here for completeness. For end entities and Certification Authorities (CA), the earlier X.509 defined object classes mandated inclusion of attributes which are optional for PKIX. Also, because of the mandatory attribute specification, this would have required dynamic modification of the object class attribute should the attributes not always be present in entries. For these reasons, alternative object classes are defined in this document for use by LDAP servers acting as PKIX repositories.3. PKIX Repository Objects
The primary PKIX objects to be represented in a repository are: - End Entities - Certification Authorities (CA) These objects are defined in RFC 2459.3.1. End Entities
For purposes of PKIX schema definition, the role of end entities as subjects of certificates is the major aspect relevant to this specification. End entities may be human users, or other types of entities to which certificates may be issued. In some cases, the entry for the end entity may already exist and the PKI-specific information is added to the existing entry. In other cases the entry may not exist prior to the issuance of a certificate, in which case the entity adding the certificate may also need to create the entry. Schema elements used to represent the non PKIX aspects of an entry, such as the structural object class used to represent organizational persons, may vary, depending on the particular environment and set of applications served and are outside the scope of this specification. The following auxiliary object class MAY be used to represent certificate subjects:
pkiUser OBJECT-CLASS ::= {
SUBCLASS OF { top}
KIND auxiliary
MAY CONTAIN {userCertificate}
ID joint-iso-ccitt(2) ds(5) objectClass(6) pkiUser(21)}
userCertificate ATTRIBUTE ::= {
WITH SYNTAX Certificate
EQUALITY MATCHING RULE certificateExactMatch
ID joint-iso-ccitt(2) ds(5) attributeType(4) userCertificate(36) }
An end entity may obtain one or more certificates from one or more
Certification Authorities. The userCertificate attribute MUST be
used to represent these certificates in the directory entry
representing that user.
3.2. Certification Authorities
As with end entities, Certification Authorities are typically
represented in directories as auxiliary components of entries
representing a more generic object, such as organizations,
organizational units etc. The non PKIX-specific schema elements for
these entries, such as the structural object class of the object, are
outside the scope of this specification.
The following auxiliary object class MAY be used to represent
Certification Authorities:
pkiCA OBJECT-CLASS ::= {
SUBCLASS OF { top}
KIND auxiliary
MAY CONTAIN {cACertificate |
certificateRevocationList |
authorityRevocationList |
crossCertificatePair }
ID joint-iso-ccitt(2) ds(5) objectClass(6) pkiCA(22)}
cACertificate ATTRIBUTE ::= {
WITH SYNTAX Certificate
EQUALITY MATCHING RULE certificateExactMatch
ID joint-iso-ccitt(2) ds(5) attributeType(4) cACertificate(37) }
crossCertificatePairATTRIBUTE::={
WITH SYNTAX CertificatePair
EQUALITY MATCHING RULE certificatePairExactMatch
ID joint-iso-ccitt(2) ds(5) attributeType(4) crossCertificatePair(40)}
The cACertificate attribute of a CA's directory entry shall be used
to store self-issued certificates (if any) and certificates issued to
this CA by CAs in the same realm as this CA.
The forward elements of the crossCertificatePair attribute of a CA's
directory entry shall be used to store all, except self-issued
certificates issued to this CA. Optionally, the reverse elements of
the crossCertificatePair attribute, of a CA's directory entry may
contain a subset of certificates issued by this CA to other CAs.
When both the forward and the reverse elements are present in a
single attribute value, issuer name in one certificate shall match
the subject name in the other and vice versa, and the subject public
key in one certificate shall be capable of verifying the digital
signature on the other certificate and vice versa.
When a reverse element is present, the forward element value and the
reverse element value need not be stored in the same attribute value;
in other words, they can be stored in either a single attribute value
or two attribute values.
In the case of V3 certificates, none of the above CA certificates
shall include a basicConstraints extension with the cA value set to
FALSE.
The definition of realm is purely a matter of local policy.
certificateRevocationListATTRIBUTE::={
WITH SYNTAX CertificateList
EQUALITY MATCHING RULE certificateListExactMatch
ID joint-iso-ccitt(2) ds(5) attributeType(4)
certificateRevocationList(39)}
The certificateRevocationList attribute, if present in a particular
CA's entry, contains CRL(s) as defined in RFC 2459.
authorityRevocationListATTRIBUTE::={
WITH SYNTAX CertificateList
EQUALITY MATCHING RULE certificateListExactMatch
ID joint-iso-ccitt(2) ds(5) attributeType(4)
authorityRevocationList(38)}
The authorityRevocationList attribute, if present in a particular
CA's entry, includes revocation information regarding certificates
issued to other CAs.
3.2.1. CRL distribution points
CRL distribution points are an optional mechanism, specified in RFC 2459, which MAY be used to distribute revocation information. A patent statement regarding CRL distribution points can be found at the end of this document. If a CA elects to use CRL distribution points, the following object class is used to represent these. cRLDistributionPoint OBJECT-CLASS::= { SUBCLASS OF { top } KIND structural MUST CONTAIN { commonName } MAY CONTAIN { certificateRevocationList | authorityRevocationList | deltaRevocationList } ID joint-iso-ccitt(2) ds(5) objectClass(6) cRLDistributionPoint(19) } The certificateRevocationList and authorityRevocationList attributes are as defined above. The commonName attribute and deltaRevocationList attributes, defined in X.509, are duplicated below. commonName ATTRIBUTE::={ SUBTYPE OF name WITH SYNTAX DirectoryString ID joint-iso-ccitt(2) ds(5) attributeType(4) commonName(3) } deltaRevocationList ATTRIBUTE ::= { WITH SYNTAX CertificateList EQUALITY MATCHING RULE certificateListExactMatch ID joint-iso-ccitt(2) ds(5) attributeType(4) deltaRevocationList(53) }3.2.2. Delta CRLs
Delta CRLs are an optional mechanism, specified in RFC 2459, which MAY be used to enhance the distribution of revocation information. If a CA elects to use delta CRLs, the following object class is used to represent these.
deltaCRL OBJECT-CLASS::= {
SUBCLASS OF { top }
KIND auxiliary
MAY CONTAIN { deltaRevocationList }
ID joint-iso-ccitt(2) ds(5) objectClass(6) deltaCRL(23) }
4. Security Considerations
Since the elements of information which are key to the PKI service
(certificates and CRLs) are both digitally signed pieces of
information, no additional integrity service is REQUIRED.
Security considerations with respect to retrieval, addition,
deletion, and modification of the information supported by this
schema definition are addressed in RFC 2559.
5. References
[1] Yeong, Y., Howes, T. and S. Kille, "Lightweight Directory Access
Protocol", RFC 1777, March 1995.
[2] Bradner, S., "Key Words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
6 Intellectual Property Rights
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7. Authors' Addresses
Sharon Boeyen Entrust Technologies Limited 750 Heron Road Ottawa, Ontario Canada K1V 1A7 EMail: sharon.boeyen@entrust.com Tim Howes Netscape Communications Corp. 501 E. Middlefield Rd. Mountain View, CA 94043 USA EMail: howes@netscape.com Patrick Richard Xcert Software Inc. Suite 1001, 701 W. Georgia Street P.O. Box 10145 Pacific Centre Vancouver, B.C. Canada V7Y 1C6 EMail: patr@xcert.com
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