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INTERNET-DRAFT                           Editor: Kurt D. Zeilenga
Intended Category: Standards Track            OpenLDAP Foundation
Expires in six months                            24 February 2003

        SASLprep: Stringprep profile for user names and passwords

Status of Memo

  This document is an Internet-Draft and is in full conformance with all
  provisions of Section 10 of RFC2026.

  This document is intended to be, after appropriate review and
  revision, submitted to the RFC Editor as a Standards Track document.
  Distribution of this memo is unlimited.  Technical discussion of this
  document will take place on the IETF SASL mailing list
  <ietf-sasl@imc.org>.  Please send editorial comments directly to the
  document editor <Kurt@OpenLDAP.org>.

  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
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  Copyright 2003, The Internet Society.  All Rights Reserved.

  Please see the Copyright section near the end of this document for
  more information.


  This document describes how to prepare Unicode strings representing
  user names and passwords for comparison.  The document defines the
  "SASLprep" "stringprep" profile to be used for both user names and
  passwords.  This profile is intended to be used by Simple
  Authentication and Security Layer (SASL) mechanisms (such as PLAIN,
  CRAM-MD5, and DIGEST-MD5) as well as other protocols exchanging user

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  names and/or passwords.

1. Introduction

  The use of simple user names and passwords in authentication and
  authorization is pervasive on the Internet.  To increase the
  likelyhood that user name and password input and comparsion work in
  ways that make sense for typical users throughout the world, this
  document defines rules for preparing internationalized user names and
  passwords for comparison.  For simplicity and implementation ease, a
  single algorithm is defined for both user names and passwords.

  This document defines the "SASLprep" profile of the "stringprep"
  protocol [StringPrep].

  The profile is designed for use in Simple Authentication and Security
  Layer ([SASL]) mechanisms such as [PLAIN].  It may be applicable
  elsewhere user names and passwords are used.  This profile is not
  intended to be used for arbitrary text.

1.1. Conventions

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  document are to be interpreted as described in BCP 14 [RFC2119].

  Character names in this document use the notation for code points and
  names from the Unicode Standard [Unicode].  For example, the letter
  "a" may be represented as either <U+0061> or <LATIN SMALL LETTER A>.
  In the lists of mappings and the prohibited characters, the "U+" is
  left off to make the lists easier to read.  The comments for character
  ranges are shown in square brackets (such as "[CONTROL CHARACTERS]")
  and do not come from the standard.

  Note: a glossary of terms used in Unicode can be found in [Glossary].
  Information on the Unicode character encoding model can be found in

2. The SASLprep profile

  This section defines the "SASLprep" profile.  This profile is intended
  to be used to prepare strings representing user names and passwords.

2.1. Character Repertoire

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  This profile uses Unicode 3.2, as defined in [StringPrep, A.1].

2.2. Mapping

  This profile specifies:
    - non-ASCII space characters [StringPrep, C.1.2] are to be mapped to
      SPACE (U+0020), and

    - the "commonly mapped to nothing" characters [StringPrep, B.1] are
      to be mapped to nothing.

2.3. Normalization

  This profile specifies using Unicode normalization form KC, as
  described in Section 4 of [StringPrep].

2.4. Prohibited Output

  This profile specifies the following characters:

    - Non-ASCII space characters [StringPrep, C.1.2],
    - ASCII control charcters [StringPrep, C.2.1],
    - Non-ASCII control characters [StringPrep, C.2.2],
    - Private Use [StringPrep, C.3],
    - Non-character code points [StringPrep, C.4],
    - Surrogate code points [StringPrep, C.5],
    - Inappropriate for plain text [StringPrep, C.6],
    - Inappropriate for canonical representation [StringPrep, C.7],
    - Change display properties or are deprecated [StringPrep, C.8], and
    - Tagging characters [StringPrep, C.9].

  are prohibited output.

2.5. Bidirectional characters

  This profile specifies checking bidirectional strings as described in
  [StringPrep, Section 6].

2.6. Unassigned Code Points

  This profile specifies [StringPrep, A.1] table as its list of
  unassigned code points.

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3. IANA Considerations

  This document details the "SASLprep" profile of [StringPrep] protocol.
  Upon Standards Action, it should be registered in the stringprep
  profile registry.

      Name of this profile: SASLprep
      RFC in which the profile is defined: This RFC
      Indicator whether or not this is the newest version of the
      profile: This is the first version of the User Name profile.

5. Acknowledgement

      This document borrows text from "Preparation of Internationalized
      Strings ('stringprep')" and "Nameprep: A Stringprep Profile for
      Internationalized Domain Names", both by Paul Hoffman and Marc

6. Normative References

  [Keywords]   S. Bradner, "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14 (also RFC 2119), March 1997.

  [StringPrep] P. Hoffman, M. Blanchet, "Preparation of
               Internationalized Strings ("stringprep")", RFC 3454,
               December 2002.

  [SASL]       J. Myers, "Simple Authentication and Security Layer
               (SASL)", draft-myers-saslrev-xx.txt (a work in progress).

7. Informative References

  [Unicode]    The Unicode Consortium. The Unicode Standard, Version
               3.2.0 is defined by The Unicode Standard, Version 3.0
               (Reading, MA, Addison-Wesley, 2000. ISBN 0-201-61633-5),
               as amended by the Unicode Standard Annex #27: Unicode 3.1
               (http://www.unicode.org/reports/tr27/) and by the Unicode
               Standard Annex #28: Unicode 3.2

  [Glossary]   Unicode Glossary, <http://www.unicode.org/glossary/>.

  [CharModel]  Unicode Technical Report;17, Character Encoding Model.

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  [CRAM-MD5]   L. Nerenberg, "The CRAM-MD5 SASL Mechanism",
               draft-nerenberg-sasl-crammd5-xx.txt (a work in progress).

  [PLAIN]      K. Zeilenga, "The Plain SASL Mechanism",
               draft-ietf-sasl-plain-xx.txt (a work in progress).

  [DIGEST-MD5] P. Leach, C. Newman, A. Melnikov, "Using Digest
               Authentication as a SASL Mechanism",
               draft-ietf-sasl-rfc2831bis-xx.txt (a work in progress).

8. Editor's Address

  Kurt Zeilenga
  OpenLDAP Foundation

  Email: kurt@OpenLDAP.org

Full Copyright Statement

  Copyright 2003, The Internet Society.  All Rights Reserved.

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  This document and the information contained herein is provided on an

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