Network Working Group D. Cooper Internet-Draft NIST Updates: 3281 (if approved) September 29, 2006 Expires: March 2007 Authority Information Access Attribute Certificate Extension draft-cooper-pkix-aiaac-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware 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 Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This document updates RFC 3281 by specifying the use of the id-ad- caIssuers access method of the Authority Information Access extension in an attribute certificate (AC). The Authority Information Access extension is defined in RFC 3280 and RFC 3281 specifies the use of the id-ad-ocsp access method of the Authority Information Access extension in attribute certificates. When present in an attribute certificate, the id-ad-caIssuers access method provides a means of discovering and retrieving the public key certificate of the attribute certificate's issuer. Cooper Expires March 2007 [Page 1] Internet-Draft AIA AC September 29, 2006 Table of Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . 2 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . 2 2 Authority Information Access AC Extension . . . . . . . . 3 3 References . . . . . . . . . . . . . . . . . . . . . . . 4 3.1 Normative References . . . . . . . . . . . . . . . . . 4 3.2 Informative References . . . . . . . . . . . . . . . . 5 4 Intellectual Property Rights . . . . . . . . . . . . . . 5 5 Security Considerations . . . . . . . . . . . . . . . . . 6 6 IANA Considerations . . . . . . . . . . . . . . . . . . . 6 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . 6 Full Copyright Statement . . . . . . . . . . . . . . . . . . 6 1 Introduction [RFC 3281] specifies the validation of attribute certificates. As part of the validation process, the verifier must ensure that the attribute certificate (AC) signature is cryptographically correct and must verify the AC issuer's entire public key certificate (PKC) certification path in accordance with [RFC 3280]. Methods of finding the PKC of the AC issuer are currently available, such as through an accessible directory location. Directory lookup requires existence and access to a directory that has been populated with all of the necessary certificates. [RFC 3280] provides for discovery of certificates needed to construct a certification path through the Authority Information Access extension, where the id-ad-caIssuers access method may specify one or more accessLocation fields that reference CA certificates associated with the certificate containing this extension. This document enables the use of the id-ad-caIssuers access method of the Authority Information Access extension in ACs, enabling an AC checking application to use the access method (id-ad-caIssuers) to locate certificates that may be used to verify the signature on the attribute certificate. 1.1 Terminology 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]. Cooper Expires March 2007 [Page 2] Internet-Draft AIA AC September 29, 2006 2 Authority Information Access AC Extension This section defines the use of the id-ad-caIssuers access method of the Authority Information Access extension in an attribute certificate. The syntax and semantics defined in [RFC 3280] for the certificate extension are also used for the AC extension. This extension MUST NOT be marked critical. This extension MUST be identified by the extension object identifier (OID) defined in RFC 3280 (1.3.6.1.5.5.7.1.1), and the AuthorityInfoAccessSyntax MUST be used to form the extension value. For convenience, the ASN.1 [X.680] definition of the Authority Information Access extension is repeated below. id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 } AuthorityInfoAccessSyntax ::= SEQUENCE SIZE (1..MAX) OF AccessDescription AccessDescription ::= SEQUENCE { accessMethod OBJECT IDENTIFIER, accessLocation GeneralName } id-ad OBJECT IDENTIFIER ::= { id-pkix 48 } id-ad-caIssuers OBJECT IDENTIFIER ::= { id-ad 2 } id-ad-ocsp OBJECT IDENTIFIER ::= { id-ad 1 } When the id-ad-caIssuers access method is used in an AC, at least one instance of AccessDescription SHOULD specify an accessLocation that is an HTTP [RFC 1738] or Lightweight Directory Access Protocol (LDAP) [RFC 4516] Uniform Resource Identifier (URI). Where the information is available via HTTP or FTP, accessLocation MUST be a uniformResourceIdentifier and the URI MUST point to a certificate containing file. The certificate file MUST contain either a single Distinguished Encoding Rules (DER) [X.690] encoded certificate (indicated by the .cer file extension) or a collection of certificates (indicated by the .p7c file extension): .cer A single DER encoded certificate as specified in [RFC 2585]. .p7c A BER or DER "certs-only" CMS message as specified in [RFC 2797]. Cooper Expires March 2007 [Page 3] Internet-Draft AIA AC September 29, 2006 Conforming applications that support HTTP or FTP for accessing certificates MUST be able to accept .cer files and SHOULD be able to accept .p7c files. HTTP server implementations accessed via the URI SHOULD use the appropriate MIME content-type for the certificate containing file. Specifically, the HTTP server SHOULD use the content-type application/pkix-cert [RFC 2585] for a single DER encoded certificate and application/pkcs7-mime [RFC 2797] for "certs-only" CMS messages. Consuming clients may use the MIME type and file extension as a hint to the file content, but should not depend solely on the presence of the correct MIME type or file extension in the server response. When the accessLocation is a directoryName, the information is to be obtained by the application from whatever directory server is locally configured. When the AC issuer is not a CA, as required by [RFC 3281], the desired certificate is stored in the userCertificate attribute as specified in [RFC 4523]. When the AC issuer is also a CA, the desired certificate may be stored in the cACertificate and/or crossCertificatePair attributes. The protocol that an application uses to access the directory (e.g., DAP or LDAP) is a local matter. Where the information is available via LDAP, the accessLocation SHOULD be a uniformResourceIdentifier. The URI MUST specify a distinguishedName and attribute(s) and SHOULD specify a host name (e.g., ldap://ldap.example.com/cn=example%20AA,dc=example,dc=com? userCertificate;binary). Omitting the host name (e.g., ldap:///cn=example%20AA,dc=example,dc=com?userCertificate;binary) has the effect of specifying the use of whatever LDAP server is locally configured. The URI MUST list appropriate attribute descriptions for one or more attributes holding certificates or cross-certificate pairs. 3 References 3.1 Normative References [RFC 1738] Berners-Lee, T., L. Masinter and M. McCahill, "Uniform Resource Locators (URL)", RFC 1738, December 1994. [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC 2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key Infrastructure Operational Protocols: FTP and HTTP", RFC 2585, May 1999. Cooper Expires March 2007 [Page 4] Internet-Draft AIA AC September 29, 2006 [RFC 2797] Myers, M., X. Liu, J. Schaad and J. Weinstein, "Certificate Management Messages over CMS", RFC 2797, April 2000. [RFC 3280] Housley, R., W. Polk, W. Ford and D. Solo, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3280, April 2002. [RFC 3281] Farrell, S. and R. Housley, "An Internet Attribute Certificate Profile for Authorization", RFC 3281, April 2002. [RFC 4516] Smith, M. and T. Howes, "Lightweight Directory Access Protocol (LDAP): Uniform Resource Locator", RFC 4516, June 2006. [RFC 4523] Zeilenga, K., "Lightweight Directory Access Protocol (LDAP) Schema Definitions for X.509 Certificates", June 2006. 3.2 Informative References [X.680] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002, Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation. [X.690] ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002, Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER). 4 Intellectual Property Rights 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 Cooper Expires March 2007 [Page 5] Internet-Draft AIA AC September 29, 2006 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. 5 Security Considerations Implementers should be aware of risks involved if the Authority Information Access extensions of corrupted attribute certificates contain links to malicious code. Implementers should always take the steps of validating the retrieved data to ensure that the data is properly formed. 6 IANA Considerations Extensions in certificates are identified using object identifiers. The objects are defined in an arc delegated by IANA to the PKIX Working Group. No further action by IANA is necessary for this document or any anticipated updates. 7 Authors' Addresses David Cooper National Institute of Standards and Technology 100 Bureau Drive, Mail Stop 8930 Gaithersburg, MD 20899-8930 USA EMail: david.cooper@nist.gov Full Copyright Statement 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. Cooper Expires March 2007 [Page 6] Internet-Draft AIA AC September 29, 2006 This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. In addition, the ASN.1 modules presented may be used in whole or in part without inclusion of the copyright notice. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process shall be followed, or as required to translate it into languages other than English. Cooper Expires March 2007 [Page 7]