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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://
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   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).












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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































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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
   <xmppwg@jabber.org> mailing list, for which archives and subscription
   information are available at <http://www.jabber.org/cgi-bin/mailman/
   listinfo/xmppwg/>.

1.3 Intellectual Property Notice

   This document is in full compliance with all provisions of Section 10



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   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.














































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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].















































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3. Mapping

   This profile specifies mapping using the following tables from RFC
   3454 [1]:

      Table B.1

      Table B.2











































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4. Normalization

   This profile specifies using Unicode normalization form KC, as
   described in RFC 3454 [1].















































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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 (@)







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6. Bidirectional Characters

   This profile specifies checking bidirectional strings as described in
   section 6 of RFC 3454 [1].















































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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.































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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


































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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, <http://www.iana.org/>.


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






















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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.































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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.

   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
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   developing Internet standards in which case the procedures for
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   followed, or as required to translate it into languages other than
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   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   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



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   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.











































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