Internet-Draft David Chadwick PKIX WG University of Salford Intended Category: Standards Track Expires: 18 January 2004 18 July 2003 LDAPv3 DN strings for use with PKIs STATUS OF THIS MEMO This document is an Internet-Draft and is in full conformance with all the provisions of Section 10 of RFC2026 [1]. 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/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Comments and suggestions on this document are encouraged. Comments on this document should be sent to the LDAPEXT working group discussion list: ietf-pkix@imc.org or directly to the author. ABSTRACT RFC 2253 [2] standardises a set of strings that can be used to represent attribute types in LDAP distinguished names. This list is does not cover the full set of attribute types used in the distinguished names of issuers and subjects in public key certificates. This document standardises the strings needed for these additional attribute types. It also defines the Permanent Identifier attribute type which may be used to identify objects. 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 [3]. 1. Introduction X.501 [9] defines distinguished names in ASN.1 [10], where each attribute type of a RDN is identified using an object identifier. The encoding of distinguished names is both verbose and non-user friendly. RFC 2253 [2] standardises a set of strings for a limited number of attribute types that can be used in the LDAP encoding of X.500 distinguished names. This makes the LDAP encoding of distinguished names more compact and user friendly. The limited number of attribute types was initially chosen as they were thought to be sufficient for building a global DIT. These attribute types are: String X.500 AttributeType ------------------------------ CN commonName L localityName ST stateOrProvinceName O organizationName OU organizationalUnitName C countryName STREET streetAddress DC domainComponent UID userid RFC 2253 made provision for additional attribute types to be registered with IANA, should this become necessary. In fact, no additional attribute types were ever registered as it was thought that none were needed. The revision of RFC 2253 [5] removed the requirements for an IANA register and states that additional attribute types should be represented by their object identifiers. RFC 3039 [4] lists the following attribute types that may be used to create subject and issuer distinguished names: countryName; commonName; surname; givenName; pseudonym; serialNumber; organizationName; organizationalUnitName; stateOrProvinceName localityName and postalAddress. The observant reader will notice that the serialNumber, pseudonym, surname, givenName, and postalAddress attribute types are missing from the RFC 2253 set and consequently do not have standardised strings for use in LDAP distinguished names. Another example is the emailAddress attribute. 2. Additional LDAP String Definitions This document defines the following additional strings that SHOULD be used to represent their respective attribute types in LDAP distinguished names, as given in the following table: String X.500 AttributeType ---------------------------------- SERIALNUMBER serialNumber ADDR postalAddress PSEUDO pseudonym GN givenName SN surname T title MAIL mail/rfc822Mailbox PI permanentIdentifier X509SN x509serialNumber ISSUER x509issuer ISSUERSN x509issuerSerial UPDATE x509crlThisUpdate Note. The strings are case insensitive as far as LDAPv3 is concerned Note. The string ADDR was borrowed from RFC 2846 [8] rather than inventing a new one to represent the same information (an unformatted postal address). 3. Permanent Identifier Attribute Type The definition for the permanentIdentifier attribute type is: (definition to be added here or in another ID/standard) 4. Security Considerations The following security considerations are specific to the handling of distinguished names. LDAP security considerations are discussed in [6] and other documents comprising the LDAP Technical Specification [7]. 5. IANA Considerations The IANA-maintained "Directory Systems Names" registry [IANADSN] of valid keywords for well known attributes used in the LDAPv2 string representation of a distinguished name [11] was made Historic by [12]. If this IANA registry were to be re-activated, the contents of this document could be placed in this registry. 6. Acknowledgements None at present 7. Copyright Copyright (C) The Internet Society (date). All Rights Reserved. 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. 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 must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. 8. References [1] S. Bradner. "The Internet Standards Process -- Revision 3", RFC 2026, October 1996. [2] Wahl, M., Kille, S., Howes, T. "Lightweight Directory Access Protocol (v3): UTF-8 String Representation of Distinguished Names", RFC2253, December 1997. [3] S.Bradner. "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [4] Santesson,S., Polk, W., Barzin, P., Nystrom, M. "Internet X.509 Public Key Infrastructure Qualified Certificates Profile", RFC 3039, Jan 2001 [5] K. Zeilenga. "LDAP: String Representation of Distinguished Names". ,l March 2002 [6] J. Sermersheim (editor), "LDAP: The Protocol", , a work in progress. [7] K. Zeilenga (editor), "LDAP: Technical Specification Road Map", , a work in progress. [8] C. Allocchio. "GSTN Address Extensions in E-mail Services" RFC 2846, June 2000 [9] ISO/IEC 9594-2/ ITU-T X.501 (2002) "The Directory - Models". [10] ITU-T Recommendation X.680 (1997) | ISO/IEC 8824-1:1998, Information Technology - Abstract Syntax Notation One (ASN.1): Specification of Basic Notation [11] S.Kille. "A String Representation of Distinguished Names". RFC 1779 March 1995. [12] K.Zeilenga "Lightweight Directory Access Protocol version 2 (LDAPv2)to Historic Status", RFC 3494, March 2003 9. Authors Address David Chadwick IS Institute University of Salford Salford M5 4WT England Email: d.w.chadwick@salford.ac.uk Tel: +44 161 295 5351