Network Working Group P. Saint-Andre Internet-Draft Jabber Software Foundation Expires: December 3, 2003 J. Hildebrand Jabber, Inc. June 04, 2003 Nodeprep: A Stringprep Profile for Node Identifiers in XMPP draft-ietf-xmpp-nodeprep-03 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. This Internet-Draft will expire on December 3, 2003. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document defines a stringprep profile for node identifiers in the Extensible Messaging and Presence Protocol (XMPP). Saint-Andre & Hildebrand Expires December 3, 2003 [Page 1] Internet-Draft Nodeprep June 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Discussion Venue . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Intellectual Property Notice . . . . . . . . . . . . . . . . . 3 2. Character Repertoire . . . . . . . . . . . . . . . . . . . . . 5 3. Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Normalization . . . . . . . . . . . . . . . . . . . . . . . . 7 5. Prohibited Output . . . . . . . . . . . . . . . . . . . . . . 8 6. Bidirectional Characters . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 Normative References . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 12 A. Revision History . . . . . . . . . . . . . . . . . . . . . . . 13 A.1 Changes from draft-ietf-xmpp-nodeprep-02 . . . . . . . . . . . 13 A.2 Changes from draft-ietf-xmpp-nodeprep-01 . . . . . . . . . . . 13 A.3 Changes from draft-ietf-xmpp-nodeprep-00 . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . 14 Saint-Andre & Hildebrand Expires December 3, 2003 [Page 2] Internet-Draft Nodeprep June 2003 1. Introduction This document, which defines a profile of stringprep (RFC 3454 [1]), specifies processing rules that will enable users to enter internationalized node identifiers in XMPP (see XMPP Core [2]) and have the highest chance of getting the content of the strings correct. These processing rules are intended only for XMPP node identifiers (which are often associated with usernames), and are not intended for arbitrary text. This profile defines the following, as required by RFC 3454 [1]: o The intended applicability of the profile: internationalized node identifiers within XMPP o The character repertoire that is the input and output to stringprep: Unicode 3.2, specified in section 2 o The mappings used: specified in section 3 o The Unicode normalization used: specified in section 4 o The characters that are prohibited as output: specified in section 5 o Bidirectional character handling: specified in section 6 1.1 Terminology This document inherits the terminology defined in XMPP Core [2]. The capitalized 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]. 1.2 Discussion Venue The authors welcome discussion and comments related to the topics presented in this document. The preferred forum is the mailing list, for which archives and subscription information are available at . 1.3 Intellectual Property Notice This document is in full compliance with all provisions of Section 10 Saint-Andre & Hildebrand Expires December 3, 2003 [Page 3] Internet-Draft Nodeprep June 2003 of RFC 2026. Parts of this specification use the term "jabber" for identifying namespaces and other protocol syntax. Jabber[tm] is a registered trademark of Jabber, Inc. Jabber, Inc. grants permission to the IETF for use of the Jabber trademark in association with this specification and its successors, if any. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 4] Internet-Draft Nodeprep June 2003 2. Character Repertoire This profile uses Unicode 3.2 with the list of unassigned code points being Table A.1, both defined in Appendix A of RFC 3454 [1]. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 5] Internet-Draft Nodeprep June 2003 3. Mapping This profile specifies mapping using the following tables from RFC 3454 [1]: Table B.1 Table B.2 Saint-Andre & Hildebrand Expires December 3, 2003 [Page 6] Internet-Draft Nodeprep June 2003 4. Normalization This profile specifies using Unicode normalization form KC, as described in RFC 3454 [1]. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 7] Internet-Draft Nodeprep June 2003 5. Prohibited Output This profile specifies prohibiting use of the following tables from RFC 3454 [1]. Table C.1.1 Table C.1.2 Table C.2.1 Table C.2.2 Table C.3 Table C.4 Table C.5 Table C.6 Table C.7 Table C.8 Table C.9 In addition, the following Unicode characters are also prohibited: #x22 (") #x26 (&) #x27 (') #x2F (/) #x3A (:) #x3C (<) #x3E (>) #x40 (@) Saint-Andre & Hildebrand Expires December 3, 2003 [Page 8] Internet-Draft Nodeprep June 2003 6. Bidirectional Characters This profile specifies checking bidirectional strings as described in section 6 of RFC 3454 [1]. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 9] Internet-Draft Nodeprep June 2003 7. Security Considerations The Unicode and ISO/IEC 10646 repertoires have many characters that look similar. In many cases, users of security protocols might do visual matching, such as when comparing the names of trusted third parties. Because it is impossible to map similar-looking characters without a great deal of context such as knowing the fonts used, stringprep does nothing to map similar-looking characters together nor to prohibit some characters because they look like others. A node identifier can be employed as one part of an entity's address in XMPP. One common usage is as the username of an instant messaging user; another is as the name of a multi-user chat room; and many other kinds of entities could use node identifiers as part of their addresses. The security of such services could be compromised based on different interpretations of the internationalized node identifier; for example, a user entering a single internationalized node identifier could access another user's account information, or a user could gain access to an otherwise restricted chat room or service. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 10] Internet-Draft Nodeprep June 2003 8. IANA Considerations This is a profile of stringprep. If and when it becomes an RFC, it should be registered in the stringprep profile registry maintained by the IANA [4]. Name of this profile: Nodeprep RFC in which the profile is defined: This document Indicator whether or not this is the newest version of the profile: This is the first version of Nodeprep Saint-Andre & Hildebrand Expires December 3, 2003 [Page 11] Internet-Draft Nodeprep June 2003 Normative References [1] Hoffman, P. and M. Blanchet, "Preparation of Internationalized Strings ("stringprep")", RFC 3454, December 2002. [2] Saint-Andre, P. and J. Miller, "XMPP Core", draft-ietf-xmpp-core-13 (work in progress), June 2003. [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [4] Internet Assigned Numbers Authority, "Internet Assigned Numbers Authority", January 1998, . Authors' Addresses Peter Saint-Andre Jabber Software Foundation EMail: stpeter@jabber.org URI: http://www.jabber.org/people/stpeter.php Joe Hildebrand Jabber, Inc. EMail: jhildebrand@jabber.com URI: http://www.jabber.org/people/hildjj.php Saint-Andre & Hildebrand Expires December 3, 2003 [Page 12] Internet-Draft Nodeprep June 2003 Appendix A. Revision History Note to RFC Editor: please remove this entire appendix, and the corresponding entries in the table of contents, prior to publication. A.1 Changes from draft-ietf-xmpp-nodeprep-02 o Provided additional examples of node identifier usage. o Made several small editorial changes. A.2 Changes from draft-ietf-xmpp-nodeprep-01 o Made small editorial changes to address RFC Editor requirements. A.3 Changes from draft-ietf-xmpp-nodeprep-00 o Clarified references to Unicode 3.2 and unassigned code points. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 13] Internet-Draft Nodeprep June 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication 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 implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. 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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 Saint-Andre & Hildebrand Expires December 3, 2003 [Page 14] Internet-Draft Nodeprep June 2003 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Saint-Andre & Hildebrand Expires December 3, 2003 [Page 15]