rfc2459.txt

PKIX的RFC英文文档

Network Working Group                                         R. Housley
Request for Comments: 2459                                        SPYRUS
Category: Standards Track                                        W. Ford
                                                                VeriSign
                                                                 W. Polk
                                                                    NIST
                                                                 D. Solo
                                                                Citicorp
                                                            January 1999


                Internet X.509 Public Key Infrastructure
                      Certificate and CRL Profile

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.

Abstract

   This memo profiles the X.509 v3 certificate and X.509 v2 CRL for use
   in the Internet.  An overview of the approach and model are provided
   as an introduction.  The X.509 v3 certificate format is described in
   detail, with additional information regarding the format and
   semantics of Internet name forms (e.g., IP addresses).  Standard
   certificate extensions are described and one new Internet-specific
   extension is defined.  A required set of certificate extensions is
   specified.  The X.509 v2 CRL format is described and a required
   extension set is defined as well.  An algorithm for X.509 certificate
   path validation is described. Supplemental information is provided
   describing the format of public keys and digital signatures in X.509
   certificates for common Internet public key encryption algorithms
   (i.e., RSA, DSA, and Diffie-Hellman).  ASN.1 modules and examples are
   provided in the appendices.

   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 RFC 2119.





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RFC 2459        Internet X.509 Public Key Infrastructure    January 1999


   Please send comments on this document to the [e-mail] mail
   list.



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   1  Introduction ................................................    5
   2  Requirements and Assumptions ................................    6
   2.1  Communication and Topology ................................    6
   2.2  Acceptability Criteria ....................................    7
   2.3  User Expectations .........................................    7
   2.4  Administrator Expectations ................................    7
   3  Overview of Approach ........................................    7
   3.1  X.509 Version 3 Certificate ...............................    9
   3.2  Certification Paths and Trust .............................   10
   3.3  Revocation ................................................   12
   3.4  Operational Protocols .....................................   13
   3.5  Management Protocols ......................................   13
   4  Certificate and Certificate Extensions Profile ..............   15
   4.1  Basic Certificate Fields ..................................   15
   4.1.1  Certificate Fields ......................................   16
   4.1.1.1  tbsCertificate ........................................   16
   4.1.1.2  signatureAlgorithm ....................................   16
   4.1.1.3  signatureValue ........................................   17
   4.1.2  TBSCertificate ..........................................   17
   4.1.2.1  Version ...............................................   17
   4.1.2.2  Serial number .........................................   18
   4.1.2.3  Signature .............................................   18
   4.1.2.4  Issuer ................................................   18
   4.1.2.5  Validity ..............................................   21
   4.1.2.5.1  UTCTime .............................................   22
   4.1.2.5.2  GeneralizedTime .....................................   22
   4.1.2.6  Subject ...............................................   22
   4.1.2.7  Subject Public Key Info ...............................   23
   4.1.2.8  Unique Identifiers ....................................   24
   4.1.2.9 Extensions .............................................   24
   4.2  Certificate Extensions ....................................   24
   4.2.1  Standard Extensions .....................................   25
   4.2.1.1  Authority Key Identifier ..............................   25
   4.2.1.2  Subject Key Identifier ................................   26
   4.2.1.3  Key Usage .............................................   27
   4.2.1.4  Private Key Usage Period ..............................   29
   4.2.1.5  Certificate Policies ..................................   29
   4.2.1.6  Policy Mappings .......................................   31
   4.2.1.7  Subject Alternative Name ..............................   32



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   4.2.1.8  Issuer Alternative Name ...............................   34
   4.2.1.9  Subject Directory Attributes ..........................   34
   4.2.1.10  Basic Constraints ....................................   35
   4.2.1.11  Name Constraints .....................................   35
   4.2.1.12  Policy Constraints ...................................   37
   4.2.1.13  Extended key usage field .............................   38
   4.2.1.14  CRL Distribution Points ..............................   39
   4.2.2  Private Internet Extensions .............................   40
   4.2.2.1  Authority Information Access ..........................   41
   5  CRL and CRL Extensions Profile ..............................   42
   5.1  CRL Fields ................................................   43
   5.1.1  CertificateList Fields ..................................   43
   5.1.1.1  tbsCertList ...........................................   44
   5.1.1.2  signatureAlgorithm ....................................   44
   5.1.1.3  signatureValue ........................................   44
   5.1.2  Certificate List "To Be Signed" .........................   44
   5.1.2.1  Version ...............................................   45
   5.1.2.2  Signature .............................................   45
   5.1.2.3  Issuer Name ...........................................   45
   5.1.2.4  This Update ...........................................   45
   5.1.2.5  Next Update ...........................................   45
   5.1.2.6  Revoked Certificates ..................................   46
   5.1.2.7  Extensions ............................................   46
   5.2  CRL Extensions ............................................   46
   5.2.1  Authority Key Identifier ................................   47
   5.2.2  Issuer Alternative Name .................................   47
   5.2.3  CRL Number ..............................................   47
   5.2.4  Delta CRL Indicator .....................................   48
   5.2.5  Issuing Distribution Point ..............................   48
   5.3  CRL Entry Extensions ......................................   49
   5.3.1  Reason Code .............................................   50
   5.3.2  Hold Instruction Code ...................................   50
   5.3.3  Invalidity Date .........................................   51
   5.3.4  Certificate Issuer ......................................   51
   6  Certificate Path Validation .................................   52
   6.1  Basic Path Validation .....................................   52
   6.2  Extending Path Validation .................................   56
   7  Algorithm Support ...........................................   57
   7.1  One-way Hash Functions ....................................   57
   7.1.1  MD2 One-way Hash Function ...............................   57
   7.1.2  MD5 One-way Hash Function ...............................   58
   7.1.3  SHA-1 One-way Hash Function .............................   58
   7.2  Signature Algorithms ......................................   58
   7.2.1  RSA Signature Algorithm .................................   59
   7.2.2  DSA Signature Algorithm .................................   60
   7.3  Subject Public Key Algorithms .............................   60
   7.3.1  RSA Keys ................................................   61
   7.3.2  Diffie-Hellman Key Exchange Key .........................   61



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RFC 2459        Internet X.509 Public Key Infrastructure    January 1999


   7.3.3  DSA Signature Keys ......................................   63
   8  References ..................................................   64
   9  Intellectual Property Rights ................................   66
   10  Security Considerations ....................................   67
   Appendix A.  ASN.1 Structures and OIDs .........................   70
   A.1 Explicitly Tagged Module, 1988 Syntax ......................   70
   A.2 Implicitly Tagged Module, 1988 Syntax ......................   84
   Appendix B.  1993 ASN.1 Structures and OIDs ....................   91
   B.1 Explicitly Tagged Module, 1993 Syntax ......................   91
   B.2 Implicitly Tagged Module, 1993 Syntax ......................  108
   Appendix C.  ASN.1 Notes .......................................  116
   Appendix D.  Examples ..........................................  117
   D.1  Certificate ...............................................  117
   D.2  Certificate ...............................................  120
   D.3  End-Entity Certificate Using RSA ..........................  123
   D.4  Certificate Revocation List ...............................  126
   Appendix E.  Authors' Addresses ................................  128
   Appendix F.  Full Copyright Statement ..........................  129

































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RFC 2459        Internet X.509 Public Key Infrastructure    January 1999


1  Introduction

   This specification is one part of a family of standards for the X.509
   Public Key Infrastructure (PKI) for the Internet.  This specification
   is a standalone document; implementations of this standard may
   proceed independent from the other parts.

   This specification profiles the format and semantics of certificates
   and certificate revocation lists for the Internet PKI.  Procedures
   are described for processing of certification paths in the Internet
   environment.  Encoding rules are provided for popular cryptographic
   algorithms.  Finally, ASN.1 modules are provided in the appendices
   for all data structures defined or referenced.

   The specification describes the requirements which inspire the
   creation of this document and the assumptions which affect its scope
   in Section 2.  Section 3 presents an architectural model and
   describes its relationship to previous IETF and ISO/IEC/ITU
   standards.  In particular, this document's relationship with the IETF
   PEM specifications and the ISO/IEC/ITU X.509 documents are described.

   The specification profiles the X.509 version 3 certificate in Section
   4, and the X.509 version 2 certificate revocation list (CRL) in
   Section 5. The profiles include the identification of ISO/IEC/ITU and
   ANSI extensions which may be useful in the Internet PKI. The profiles
   are presented in the 1988 Abstract Syntax Notation One (ASN.1) rather
   than the 1994 syntax used in the ISO/IEC/ITU standards.

   This specification also includes path validation procedures in
   Section 6.  These procedures are based upon the ISO/IEC/ITU
   definition, but the presentation assumes one or more self-signed
   trusted CA certificates.  Implementations are required to derive the
   same results but are not required to use the specified procedures.

   Section 7 of the specification describes procedures for
   identification and encoding of public key materials and digital
   signatures.  Implementations are not required to use any particular
   cryptographic algorithms.  However, conforming implementations which
   use the identified algorithms are required to identify and encode the
   public key materials and digital signatures as described.

   Finally, four appendices are provided to aid implementers.  Appendix
   A contains all ASN.1 structures defined or referenced within this
   specification.  As above, the material is presented in the 1988
   Abstract Syntax Notation One (ASN.1) rather than the 1994 syntax.
   Appendix B contains the same information in the 1994 ASN.1 notation
   as a service to implementers using updated toolsets.  However,
   Appendix A takes precedence in case of conflict.  Appendix C contains



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RFC 2459        Internet X.509 Public Key Infrastructure    January 1999


   notes on less familiar features of the ASN.1 notation used within
   this specification.  Appendix D contains examples of a conforming
   certificate and a conforming CRL.