RFC 4523

Lightweight Directory Access Protocol (LDAP) Schema Definitions for X.509 Certificates

📅 published June 2006, from ietf

Network Working Group RFC 4523 ✨ Lightweight Directory Access Protocol (LDAP) Schema Definitions for X.509 Certificates

okay bestie, so this is RFC 4523 🎀. It's a Standards Track doc from June 2006, written by K. Zeilenga of the OpenLDAP Foundation. It obsoletes RFC 2252, RFC 2256 and RFC 2587 💅, and it doesn't update anything. Its whole job is giving LDAP directories the schema for X.509 certificates and X.521 security info. Let's go 🦋

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 (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 💖

okay so this doc gives us LDAP [RFC4510] schema definitions [RFC4512] for a subset of the stuff in X.509 [X.509] and X.521 [X.521]. That covers attribute types for certificates, cross certificate pairs, and certificate revocation lists, plus matching rules for those attribute types and the related object classes. It also gives LDAP syntax definitions for the associated assertion and attribute values 🫶

the semantics are all defined in X.509 and X.521, so you NEED to know those two to use these LDAP schema definitions. no shortcuts, bestie 😭

this doc, together with [RFC4510], obsoletes RFCs 2252 and 2256 in their entirety. Here's what changed since RFC 2252 and RFC 2256 ✨

  • addition of pkiUser, pkiCA, and deltaCRL classes;
  • 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 doc also obsoletes RFC 2587. The X.509 schema descriptions for LDAPv2 [RFC1777] are Historic, and so 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 here use LDAP description formats [RFC4512]. The definitions are formatted (line wrapped) for readability 🍓

2. Syntaxes 🎀

this section covers the various syntaxes LDAP uses 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].

since the definition of a Certificate has changed over 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 means requesting and returning values using attribute descriptions such as "userCertificate;binary" 💅

values of this syntax contain digitally signed data, so 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].

same deal as before: the CertificateList definition has changed through time, so no LDAP-specific encoding is defined. Values of this syntax SHOULD be encoded using DER [X.690] and MUST only be transferred using the ;binary transfer option [RFC4522]. So you request and return them using attribute descriptions such as "certificateRevocationList;binary" 🫶

these values contain digitally signed data too, so 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].

no LDAP-specific encoding is defined for this syntax, because the X.509 CertificatePair definition has changed over time. Values of this syntax SHOULD be encoded using DER [X.690] and MUST only be transferred using the ;binary transfer option [RFC4522]. That's requesting and returning values with attribute descriptions such as "crossCertificatePair;binary" 🍓

digitally signed data again, so 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].

the SupportedAlgorithm definition has changed over time, so no LDAP-specific encoding is defined here. Values of this syntax SHOULD be encoded using DER [X.690] and MUST only be transferred using the ;binary transfer option [RFC4522]. So request and return them with attribute descriptions such as "supportedAlgorithms;binary" 💖

digitally signed data means values of this syntax and the form of the value MUST be preserved as presented 💀

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 gives 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 gives 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 gives 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 gives 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 gives an equivalent ABNF grammar for this syntax 🍓

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 gives 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 gives 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. They're meant to act in line 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 )

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 )

3.7. algorithmIdentifierMatch 🍓

the algorithmIdentifierMatch matching 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 🎀

okay so cACertificate is where the X.509 certs issued to the certificate authority (CA) live 🏛️✨ see clause 11.2.2 of [X.509] for the full lore.

   ( 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 )

because of this attribute type's syntax, the values get requested and transferred using the attribute description cACertificate;binary 💌

4.3. crossCertificatePair 💜

crossCertificatePair holds an X.509 certificate pair 👯‍♀️ check out clause 11.2.3 of [X.509] if you want the deets.

   ( 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 )

same deal as before: the syntax says values get requested and transferred as crossCertificatePair;binary 🦋

4.4. certificateRevocationList 🚫

the certificateRevocationList attribute holds certificate lists, which is giving "naughty list for certs" energy 😭 see 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 )

values get requested and transferred as certificateRevocationList;binary 🌸

4.5. authorityRevocationList 🏰

the authorityRevocationList attribute also holds certificate lists, just from the authority side 👑 see 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 )

and yep, the values are requested and transferred as authorityRevocationList;binary ✨

4.6. deltaRevocationList 🌈

deltaRevocationList holds certificate lists too (we see you, certificate lists, you're everywhere 💅) see 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 )

this one is a little bossier 👀 values of this attribute MUST be requested and transferred using the attribute description deltaRevocationList;binary 🔥

4.7. supportedAlgorithms 🧠

supportedAlgorithms holds supported algorithms, which is basically the menu of crypto this entry can do 🍓 see 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 )

values of this attribute MUST be requested and transferred using the attribute description supportedAlgorithms;binary 🫶

5. Object Classes 🧚

this section is the lineup of certificate-related object classes you can 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 )

5.2. pkiCA 🏛️

this object class augments 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 represents 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 augments 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 augments entries for objects taking part in certificate-based authentication, as defined in clause 6.15 of [X.521] 🙈 heads up, it's deprecated in favor of pkiUser, so pkiUser is the one to pick now 💅

   ( 2.5.6.15 NAME 'strongAuthenticationUser'
        DESC 'X.521 strong authentication user'
        SUP top AUXILIARY
        MUST userCertificate )

5.6. userSecurityInformation 🛡️

this object class augments 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 augments entries for objects that act as certificate authorities, as defined in clause 6.17 of [X.521] 👑 it's deprecated in favor of pkiCA, so again, pkiCA is the cool kid now 🌸

   ( 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 one is the version 2 of the object class above, and it's also used to augment entries for objects that act as certificate authorities, as defined in clause 6.18 of [X.521] 🎀 deprecated in favor of pkiCA too, bestie 😭

   ( 2.5.6.16.2 NAME 'certificationAuthority-V2'
        DESC 'X.509 certificate authority, version 2'
        SUP certificationAuthority AUXILIARY
        MAY deltaRevocationList )

6. Security Considerations 🔒

okay, serious moment, babe 🥺 general certificate considerations [RFC3280] apply to LDAP-aware certificate applications, and general LDAP security considerations [RFC4510] apply as well. read those too!!

while elements of certificate information are commonly signed, those signatures only protect the integrity of the signed information 🫣 without data integrity protections in LDAP (or a lower layer, e.g., IPsec), a server is not assured that a client certificate request (or other request) was unaltered in transit. and the other way around: a client cannot be assured that the results of the query were unaltered in transit 😱 so, it is generally recommended that implementations make use of authentication and data integrity services in LDAP [RFC4513][RFC4511]. protect your requests, protect your results, protect your whole vibe 🛡️💖

7. IANA Considerations 📋

7.1. Object Identifier Registration 🆔

the IANA has registered an LDAP Object Identifier [RFC4520] for use in this technical specification ✨ here's the paperwork:

   Subject: Request for LDAP OID Registration
   Person & email address to contact for further information:
       Kurt Zeilenga <kurt@OpenLDAP.org>
   Specification: RFC 4523
   Author/Change Controller: IESG
   Comments:
       Identifies the LDAP X.509 Certificate schema elements
        introduced in this document.

7.2. Descriptor Registration 📝

the IANA has updated the LDAP Descriptor registry [RFC44520] as shown below 💅 the table is the star of the show:

   Subject: Request for LDAP Descriptor Registration
   Descriptor (short name): see table
   Object Identifier: see table
   Person & email address to contact for further information:
       Kurt Zeilenga <kurt@OpenLDAP.org>
   Usage: see table
   Specification: RFC 4523
   Author/Change Controller: IESG

   algorithmIdentifierMatch     M 2.5.13.40
   authorityRevocationList      A 2.5.4.38 *
   cACertificate                A 2.5.4.37 *
   cRLDistributionPoint         O 2.5.6.19 *
   certificateExactMatch        M 2.5.13.34
   certificateListExactMatch    M 2.5.13.38
   certificateListMatch         M 2.5.13.39
   certificateMatch             M 2.5.13.35
   certificatePairExactMatch    M 2.5.13.36
   certificatePairMatch         M 2.5.13.37
   certificateRevocationList    A 2.5.4.39 *
   certificationAuthority       O 2.5.6.16 *
   certificationAuthority-V2    O 2.5.6.16.2 *
   crossCertificatePair         A 2.5.4.40 *
   deltaCRL                     O 2.5.6.23 *
   deltaRevocationList          A 2.5.4.53 *
   pkiCA                        O 2.5.6.22 *
   pkiUser                      O 2.5.6.21 *
   strongAuthenticationUser     O 2.5.6.15 *
   supportedAlgorithms          A 2.5.4.52 *
   userCertificate              A 2.5.4.36 *
   userSecurityInformation      O 2.5.6.18 *

   * Updates previous registration

8. Acknowledgements 💌

this document is based on X.509, a product of the ITU-T 🌍 a bunch of the LDAP schema definitions were based on those found in RFCs 2252 and 2256, both products of the IETF ASID WG 🙌 the ABNF productions in Appendix A were provided by Steven Legg 🧚 and additional material was borrowed from prior works by David Chadwick and Steven Legg to refine the LDAP X.509 schema. the real MVPs 🏆🫶

9. References 📚

9.1. Normative References 🎀

  • [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
  • [RFC3641] Legg, S., "Generic String Encoding Rules (GSER) for ASN.1 Types", RFC 3641, October 2003.
  • [RFC4510] Zeilenga, K., Ed., "Lightweight Directory Access Protocol (LDAP): Technical Specification Road Map", RFC 4510, June 2006.
  • [RFC4512] Zeilenga, K., "Lightweight Directory Access Protocol (LDAP): Directory Information Models", RFC 4512, June 2006.
  • [RFC4522] Legg, S., "Lightweight Directory Access Protocol (LDAP): The Binary Encoding Option", RFC 4522, June 2006.
  • [X.509] International Telecommunication Union - Telecommunication Standardization Sector, "The Directory: Authentication Framework", X.509(2000).
  • [X.521] International Telecommunication Union - Telecommunication Standardization Sector, "The Directory: Selected Object Classes", X.521(2000).
  • [X.690] International Telecommunication Union - Telecommunication Standardization Sector, "Specification of ASN.1 encoding rules: Basic Encoding Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER)", X.690(2002) (also ISO/IEC 8825-1:2002).

9.2. Informative References ✨

  • [RFC1777] Yeong, W., Howes, T., and S. Kille, "Lightweight Directory Access Protocol", RFC 1777, March 1995.
  • [RFC2156] Kille, S., "MIXER (Mime Internet X.400 Enhanced Relay): Mapping between X.400 and RFC 822/MIME", RFC 2156, January 1998.
  • [RFC3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3280, April 2002.
  • [RFC3494] Zeilenga, K., "Lightweight Directory Access Protocol version 2 (LDAPv2) to Historic Status", RFC 3494, March 2003.
  • [RFC3642] Legg, S., "Common Elements of Generic String Encoding Rules (GSER) Encodings", RFC 3642, October 2003.
  • [RFC4234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005.
  • [RFC4511] Sermersheim, J., Ed., "Lightweight Directory Access Protocol (LDAP): The Protocol", RFC 4511, June 2006.
  • [RFC4513] Harrison, R. Ed., "Lightweight Directory Access Protocol (LDAP): Authentication Methods and Security Mechanisms", RFC 4513, June 2006.
  • [RFC4520] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) Considerations for the Lightweight Directory Access Protocol (LDAP)", BCP 64, RFC 4520, June 2006.

Appendix A. 🧚

Heads up: this appendix is informative. 🫶

This appendix gives you the ABNF [RFC4234] grammars for the GSER-based [RFC3641] LDAP-specific encodings that are specified in this document. These grammars were produced using, and rely on, Common Elements for GSER Encodings [RFC3642]. 🎀

A.1. CertificateExactAssertion 🦋

CertificateExactAssertion = "{" sp cea-serialNumber ","
     sp cea-issuer sp "}"

cea-serialNumber = id-serialNumber msp CertificateSerialNumber
cea-issuer = id-issuer msp Name

id-serialNumber =
     %x73.65.72.69.61.6C.4E.75.6D.62.65.72 ; 'serialNumber'
id-issuer = %x69.73.73.75.65.72 ; 'issuer'

Name = id-rdnSequence ":" RDNSequence
id-rdnSequence = %x72.64.6E.53.65.71.75.65.6E.63.65 ; 'rdnSequence'

CertificateSerialNumber = INTEGER

A.2. CertificateAssertion 🌸

CertificateAssertion = "{" [ sp ca-serialNumber ]
     [ sep sp ca-issuer ]
     [ sep sp ca-subjectKeyIdentifier ]
     [ sep sp ca-authorityKeyIdentifier ]
     [ sep sp ca-certificateValid ]
     [ sep sp ca-privateKeyValid ]
     [ sep sp ca-subjectPublicKeyAlgID ]
     [ sep sp ca-keyUsage ]
     [ sep sp ca-subjectAltName ]
     [ sep sp ca-policy ]
     [ sep sp ca-pathToName ]
     [ sep sp ca-subject ]
     [ sep sp ca-nameConstraints ] sp "}"

ca-serialNumber = id-serialNumber msp CertificateSerialNumber
ca-issuer = id-issuer msp Name
ca-subjectKeyIdentifier = id-subjectKeyIdentifier msp
     SubjectKeyIdentifier
ca-authorityKeyIdentifier = id-authorityKeyIdentifier msp
     AuthorityKeyIdentifier

ca-certificateValid = id-certificateValid msp Time
ca-privateKeyValid = id-privateKeyValid msp GeneralizedTime
ca-subjectPublicKeyAlgID = id-subjectPublicKeyAlgID msp
     OBJECT-IDENTIFIER
ca-keyUsage = id-keyUsage msp KeyUsage
ca-subjectAltName = id-subjectAltName msp AltNameType
ca-policy = id-policy msp CertPolicySet
ca-pathToName = id-pathToName msp Name
ca-subject = id-subject msp Name
ca-nameConstraints = id-nameConstraints msp NameConstraintsSyntax

id-subjectKeyIdentifier =
     %x73.75.62.6A.65.63.74.4B.65.79.49.64.65.6E.74.69.66.69.65.72
     ; 'subjectKeyIdentifier'
id-authorityKeyIdentifier =
     %x61.75.74.68.6F.72.69.74.79.4B.65.79.49.64.65.6E.74.69.66.69.65.72
     ; 'authorityKeyIdentifier'
id-certificateValid = %x63.65.72.74.69.66.69.63.61.74.65.56.61.6C.69.64
     ; 'certificateValid'
id-privateKeyValid = %x70.72.69.76.61.74.65.4B.65.79.56.61.6C.69.64
     ; 'privateKeyValid'
id-subjectPublicKeyAlgID  =
     %x73.75.62.6A.65.63.74.50.75.62.6C.69.63.4B.65.79.41.6C.67.49.44
     ; 'subjectPublicKeyAlgID'
id-keyUsage = %x6B.65.79.55.73.61.67.65 ; 'keyUsage'
id-subjectAltName = %x73.75.62.6A.65.63.74.41.6C.74.4E.61.6D.65
     ; 'subjectAltName'
id-policy = %x70.6F.6C.69.63.79 ; 'policy'
id-pathToName = %x70.61.74.68.54.6F.4E.61.6D.65 ; 'pathToName'
id-subject = %x73.75.62.6A.65.63.74 ; 'subject'
id-nameConstraints = %x6E.61.6D.65.43.6F.6E.73.74.72.61.69.6E.74.73
     ; 'nameConstraints'

SubjectKeyIdentifier = KeyIdentifier

KeyIdentifier = OCTET-STRING

AuthorityKeyIdentifier = "{" [ sp aki-keyIdentifier ]
     [ sep sp aki-authorityCertIssuer ]
     [ sep sp aki-authorityCertSerialNumber ] sp "}"

aki-keyIdentifier = id-keyIdentifier msp KeyIdentifier
aki-authorityCertIssuer = id-authorityCertIssuer msp GeneralNames

GeneralNames = "{" sp GeneralName *( "," sp GeneralName ) sp "}"
GeneralName  = gn-otherName
     / gn-rfc822Name
     / gn-dNSName
     / gn-x400Address
     / gn-directoryName
     / gn-ediPartyName
     / gn-uniformResourceIdentifier
     / gn-iPAddress
     / gn-registeredID

gn-otherName = id-otherName ":" OtherName
gn-rfc822Name = id-rfc822Name ":" IA5String
gn-dNSName = id-dNSName ":" IA5String
gn-x400Address = id-x400Address ":" ORAddress
gn-directoryName = id-directoryName ":" Name
gn-ediPartyName = id-ediPartyName ":" EDIPartyName
gn-iPAddress = id-iPAddress ":" OCTET-STRING
gn-registeredID = gn-id-registeredID ":" OBJECT-IDENTIFIER

gn-uniformResourceIdentifier = id-uniformResourceIdentifier
     ":" IA5String

id-otherName = %x6F.74.68.65.72.4E.61.6D.65 ; 'otherName'
gn-id-registeredID = %x72.65.67.69.73.74.65.72.65.64.49.44
     ; 'registeredID'

OtherName = "{" sp on-type-id "," sp on-value sp "}"
on-type-id = id-type-id msp OBJECT-IDENTIFIER
on-value = id-value msp Value
     ;; <Value> as defined in Section 3 of [RFC3641]

id-type-id = %x74.79.70.65.2D.69.64 ; 'type-id'
id-value = %x76.61.6C.75.65 ; 'value'

ORAddress = dquote *SafeIA5Character dquote
SafeIA5Character = %x01-21 / %x23-7F / ; ASCII minus dquote
     dquote dquote ; escaped double quote
dquote = %x22 ; '"' (double quote)

;; Note: The <ORAddress> rule encodes the x400Address component
;; of a GeneralName as a character string between double quotes.
;; The character string is first derived according to Section 4.1
;; of [RFC2156], and then any embedded double quotes are escaped
;; by being repeated. This resulting string is output between
;; double quotes.

EDIPartyName = "{" [ sp nameAssigner "," ] sp partyName sp "}"
nameAssigner = id-nameAssigner msp DirectoryString
partyName = id-partyName msp DirectoryString
id-nameAssigner = %x6E.61.6D.65.41.73.73.69.67.6E.65.72
     ; 'nameAssigner'

id-partyName    = %x70.61.72.74.79.4E.61.6D.65 ; 'partyName'

aki-authorityCertSerialNumber = id-authorityCertSerialNumber
     msp CertificateSerialNumber

id-keyIdentifier = %x6B.65.79.49.64.65.6E.74.69.66.69.65.72
     ; 'keyIdentifier'
id-authorityCertIssuer =
     %x61.75.74.68.6F.72.69.74.79.43.65.72.74.49.73.73.75.65.72
     ; 'authorityCertIssuer'

id-authorityCertSerialNumber = %x61.75.74.68.6F.72.69.74.79.43
     %x65.72.74.53.65.72.69.61.6C.4E.75.6D.62.65.72
     ; 'authorityCertSerialNumber'

Time = time-utcTime / time-generalizedTime
time-utcTime = id-utcTime ":" UTCTime
time-generalizedTime = id-generalizedTime ":" GeneralizedTime
id-utcTime = %x75.74.63.54.69.6D.65 ; 'utcTime'
id-generalizedTime = %x67.65.6E.65.72.61.6C.69.7A.65.64.54.69.6D.65
     ; 'generalizedTime'

KeyUsage = BIT-STRING / key-usage-bit-list
key-usage-bit-list = "{" [ sp key-usage *( "," sp key-usage ) ] sp "}"

;; Note: The <key-usage-bit-list> rule encodes the one bits in
;; a KeyUsage value as a comma separated list of identifiers.

key-usage = id-digitalSignature
     / id-nonRepudiation
     / id-keyEncipherment
     / id-dataEncipherment
     / id-keyAgreement
     / id-keyCertSign
     / id-cRLSign
     / id-encipherOnly
     / id-decipherOnly

id-digitalSignature = %x64.69.67.69.74.61.6C.53.69.67.6E.61.74
     %x75.72.65 ; 'digitalSignature'
id-nonRepudiation   = %x6E.6F.6E.52.65.70.75.64.69.61.74.69.6F.6E
     ; 'nonRepudiation'
id-keyEncipherment  = %x6B.65.79.45.6E.63.69.70.68.65.72.6D.65.6E.74
     ; 'keyEncipherment'
id-dataEncipherment = %x64.61.74.61.45.6E.63.69.70.68.65.72.6D.65.6E
     %x74 ; "dataEncipherment'
id-keyAgreement     = %x6B.65.79.41.67.72.65.65.6D.65.6E.74
     ; 'keyAgreement'

id-keyCertSign      = %x6B.65.79.43.65.72.74.53.69.67.6E
     ; 'keyCertSign'
id-cRLSign          = %x63.52.4C.53.69.67.6E ; "cRLSign"
id-encipherOnly     = %x65.6E.63.69.70.68.65.72.4F.6E.6C.79
     ; 'encipherOnly'
id-decipherOnly     = %x64.65.63.69.70.68.65.72.4F.6E.6C.79
     ; 'decipherOnly'

AltNameType = ant-builtinNameForm / ant-otherNameForm

ant-builtinNameForm = id-builtinNameForm ":" BuiltinNameForm
ant-otherNameForm = id-otherNameForm ":" OBJECT-IDENTIFIER

id-builtinNameForm = %x62.75.69.6C.74.69.6E.4E.61.6D.65.46.6F.72.6D
     ; 'builtinNameForm'
id-otherNameForm   = %x6F.74.68.65.72.4E.61.6D.65.46.6F.72.6D
     ; 'otherNameForm'

BuiltinNameForm  = id-rfc822Name
     / id-dNSName
     / id-x400Address
     / id-directoryName
     / id-ediPartyName
     / id-uniformResourceIdentifier
     / id-iPAddress
     / id-registeredId

id-rfc822Name = %x72.66.63.38.32.32.4E.61.6D.65 ; 'rfc822Name'
id-dNSName = %x64.4E.53.4E.61.6D.65 ; 'dNSName'
id-x400Address  = %x78.34.30.30.41.64.64.72.65.73.73 ; 'x400Address'
id-directoryName = %x64.69.72.65.63.74.6F.72.79.4E.61.6D.65
     ; 'directoryName'
id-ediPartyName  = %x65.64.69.50.61.72.74.79.4E.61.6D.65
     ; 'ediPartyName'
id-iPAddress = %x69.50.41.64.64.72.65.73.73 ; 'iPAddress'
id-registeredId = %x72.65.67.69.73.74.65.72.65.64.49.64
     ; 'registeredId'

id-uniformResourceIdentifier = %x75.6E.69.66.6F.72.6D.52.65.73.6F.75
     %x72.63.65.49.64.65.6E.74.69.66.69.65.72
     ; 'uniformResourceIdentifier'

CertPolicySet = "{" sp CertPolicyId *( "," sp CertPolicyId ) sp "}"
CertPolicyId = OBJECT-IDENTIFIER

NameConstraintsSyntax = "{" [ sp ncs-permittedSubtrees ]
     [ sep sp ncs-excludedSubtrees ] sp "}"

ncs-permittedSubtrees = id-permittedSubtrees msp GeneralSubtrees
ncs-excludedSubtrees = id-excludedSubtrees  msp GeneralSubtrees

id-permittedSubtrees =
     %x70.65.72.6D.69.74.74.65.64.53.75.62.74.72.65.65.73
     ; 'permittedSubtrees'
id-excludedSubtrees =
     %x65.78.63.6C.75.64.65.64.53.75.62.74.72.65.65.73
     ; 'excludedSubtrees'

GeneralSubtrees = "{" sp GeneralSubtree
     *( "," sp GeneralSubtree ) sp "}"
GeneralSubtree  = "{" sp gs-base
     [ "," sp gs-minimum ]
     [ "," sp gs-maximum ] sp "}"

gs-base = id-base msp GeneralName
gs-minimum = id-minimum msp BaseDistance
gs-maximum = id-maximum msp BaseDistance

id-base = %x62.61.73.65 ; 'base'
id-minimum = %x6D.69.6E.69.6D.75.6D ; 'minimum'
id-maximum = %x6D.61.78.69.6D.75.6D ; 'maximum'

BaseDistance = INTEGER-0-MAX

A.3. CertificatePairExactAssertion 💜

CertificatePairExactAssertion = "{" [ sp cpea-issuedTo ]
     [sep sp cpea-issuedBy ] sp "}"
;; At least one of <cpea-issuedTo> or <cpea-issuedBy> MUST be present.

cpea-issuedTo = id-issuedToThisCAAssertion msp
     CertificateExactAssertion
cpea-issuedBy = id-issuedByThisCAAssertion msp
     CertificateExactAssertion

id-issuedToThisCAAssertion = %x69.73.73.75.65.64.54.6F.54.68.69.73
     %x43.41.41.73.73.65.72.74.69.6F.6E ; 'issuedToThisCAAssertion'
id-issuedByThisCAAssertion = %x69.73.73.75.65.64.42.79.54.68.69.73
     %x43.41.41.73.73.65.72.74.69.6F.6E ; 'issuedByThisCAAssertion'

A.4. CertificatePairAssertion 🌈

CertificatePairAssertion = "{" [ sp cpa-issuedTo ]
     [sep sp cpa-issuedBy ] sp "}"
;; At least one of <cpa-issuedTo> and <cpa-issuedBy> MUST be present.

cpa-issuedTo = id-issuedToThisCAAssertion msp CertificateAssertion
cpa-issuedBy = id-issuedByThisCAAssertion msp CertificateAssertion

A.5. CertificateListExactAssertion ✨

okay so this one is the exact-match version of a CRL assertion 🧚 it's giving very specific energy: an issuer, a thisUpdate, and an optional distribution point, all wrapped in curly braces 🎀

CertificateListExactAssertion = "{" sp clea-issuer ","
     sp clea-thisUpdate
     [ "," sp clea-distributionPoint ] sp "}"

clea-issuer = id-issuer msp Name
clea-thisUpdate = id-thisUpdate msp Time
clea-distributionPoint = id-distributionPoint msp
     DistributionPointName

id-thisUpdate = %x74.68.69.73.55.70.64.61.74.65 ; 'thisUpdate'
id-distributionPoint =
     %x64.69.73.74.72.69.62.75.74.69.6F.6E.50.6F.69.6E.74
     ; 'distributionPoint'

DistributionPointName = dpn-fullName / dpn-nameRelativeToCRLIssuer

dpn-fullName = id-fullName ":" GeneralNames
dpn-nameRelativeToCRLIssuer = id-nameRelativeToCRLIssuer ":"
     RelativeDistinguishedName

id-fullName = %x66.75.6C.6C.4E.61.6D.65 ; 'fullName'
id-nameRelativeToCRLIssuer = %x6E.61.6D.65.52.65.6C.61.74.69.76.65
     %x54.6F.43.52.4C.49.73.73.75.65.72 ; 'nameRelativeToCRLIssuer'

The distribution point can be spelled out either as a full name or as a name relative to the CRL issuer. Both options are just labelled choices, so pick the one that fits your data 💅

A.6. CertificateListAssertion 🦋

This is the non-exact cousin 💜 every field is optional, so you can match on whichever bits you care about: the issuer, the CRL number range, the reason flags, the date and time, the distribution point, or the authority key identifier. Literally a buffet 🍓

CertificateListAssertion = "{" [ sp cla-issuer ]
     [ sep sp cla-minCRLNumber ]
     [ sep sp cla-maxCRLNumber ]
     [ sep sp cla-reasonFlags ]
     [ sep sp cla-dateAndTime ]
     [ sep sp cla-distributionPoint ]
     [ sep sp cla-authorityKeyIdentifier ] sp "}"

cla-issuer = id-issuer msp Name
cla-minCRLNumber = id-minCRLNumber msp CRLNumber
cla-maxCRLNumber = id-maxCRLNumber msp CRLNumber
cla-reasonFlags = id-reasonFlags msp ReasonFlags
cla-dateAndTime = id-dateAndTime msp Time

cla-distributionPoint = id-distributionPoint msp
     DistributionPointName

cla-authorityKeyIdentifier = id-authorityKeyIdentifier msp
     AuthorityKeyIdentifier

id-minCRLNumber = %x6D.69.6E.43.52.4C.4E.75.6D.62.65.72
     ; 'minCRLNumber'
id-maxCRLNumber = %x6D.61.78.43.52.4C.4E.75.6D.62.65.72
     ; 'maxCRLNumber'
id-reasonFlags = %x72.65.61.73.6F.6E.46.6C.61.67.73 ; 'reasonFlags'
id-dateAndTime = %x64.61.74.65.41.6E.64.54.69.6D.65 ; 'dateAndTime'

CRLNumber = INTEGER-0-MAX

ReasonFlags = BIT-STRING
     / "{" [ sp reason-flag *( "," sp reason-flag ) ] sp "}"

reason-flag = id-unused
     / id-keyCompromise
     / id-cACompromise
     / id-affiliationChanged
     / id-superseded
     / id-cessationOfOperation
     / id-certificateHold
     / id-privilegeWithdrawn
     / id-aACompromise

id-unused = %x75.6E.75.73.65.64 ; 'unused'
id-keyCompromise = %x6B.65.79.43.6F.6D.70.72.6F.6D.69.73.65
     ; 'keyCompromise'
id-cACompromise = %x63.41.43.6F.6D.70.72.6F.6D.69.73.65
     ; 'cACompromise'
id-affiliationChanged =
     %x61.66.66.69.6C.69.61.74.69.6F.6E.43.68.61.6E.67.65.64
     ; 'affiliationChanged'
id-superseded = %x73.75.70.65.72.73.65.64.65.64 ; 'superseded'
id-cessationOfOperation =
     %x63.65.73.73.61.74.69.6F.6E.4F.66.4F.70.65.72.61.74.69.6F.6E
     ; 'cessationOfOperation'
id-certificateHold = %x63.65.72.74.69.66.69.63.61.74.65.48.6F.6C.64
     ; 'certificateHold'
id-privilegeWithdrawn =
     %x70.72.69.76.69.6C.65.67.65.57.69.74.68.64.72.61.77.6E
     ; 'privilegeWithdrawn'

id-aACompromise = %x61.41.43.6F.6D.70.72.6F.6D.69.73.65
     ; 'aACompromise'

The reason flags come in two flavours: a BIT-STRING, or a braced list of named flags. The named ones include unused, keyCompromise, cACompromise, affiliationChanged, superseded, cessationOfOperation, certificateHold, privilegeWithdrawn and aACompromise 🔥

A.7. AlgorithmIdentifier 👑

last one, bestie 🫶 this is the algorithm plus optional parameters, wrapped up nice and tidy

AlgorithmIdentifier = "{" sp ai-algorithm
     [ "," sp ai-parameters ] sp "}"

ai-algorithm = id-algorithm msp OBJECT-IDENTIFIER
ai-parameters = id-parameters msp Value
id-algorithm = %x61.6C.67.6F.72.69.74.68.6D ; 'algorithm'
id-parameters = %x70.61.72.61.6D.65.74.65.72.73 ; 'parameters'

Author's Address 🌸

Kurt D. Zeilenga OpenLDAP Foundation

EMail: Kurt@OpenLDAP.org

Copyright (C) The Internet Society (2006).

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 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.

Acknowledgement 💜

Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA).

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