Network Working Group P. Saint-Andre
Internet-Draft Jabber Software Foundation
Expires: August 4, 2003 J. Hildebrand
Jabber, Inc.
February 03, 2003
Nodeprep: A Stringprep Profile for Node Identifiers in XMPP
draft-ietf-xmpp-nodeprep-00
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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This Internet-Draft will expire on August 4, 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
References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 12
Full Copyright Statement . . . . . . . . . . . . . . . . . . . 13
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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 for XMPP node
identifiers only, and not 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
of RFC 2026. Parts of this specification use the term "jabber" for
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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, as defined in Appendix A.1 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.
Node identifiers are commonly employed as the username of users who
connect to XMPP servers for instant messaging and presence services.
The security of such services could be compromised if a user entering
a single internationalized node identifier could access another
user's account information based on different interpretations of the
internationalized node identifier.
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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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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-
02, work in progress)", February 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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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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