INTERNET-DRAFT Kurt D. Zeilenga Intended Category: Standards Track OpenLDAP Foundation Expires in six months 4 May 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 . Please send editorial comments directly to the document editor . 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 . The list of Internet-Draft Shadow Directories can be accessed at . Copyright 2003, The Internet Society. All Rights Reserved. Please see the Copyright section near the end of this document for more information. Abstract 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 Zeilenga SASLprep [Page 1] INTERNET-DRAFT draft-ietf-sasl-saslprep-01.txt 4 May 2003 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 simple user names and passwords are used. This profile is not intended to be used for arbitrary text. This profile is also not intended to be used to prepare identity strings which are not simple user names (e.g., e-mail addresses, domain names, distinguished names). 1.1. Conventions 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 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 or . 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 [CharModel]. 2. The SASLprep profile This section defines the "SASLprep" profile. This profile is intended to be used to prepare strings representing simple user names and Zeilenga SASLprep [Page 2] INTERNET-DRAFT draft-ietf-sasl-saslprep-01.txt 4 May 2003 passwords. This profile uses Unicode 3.2, as defined in [StringPrep, A.1]. 2.1. Mapping This profile specifies: - non-ASCII space characters [StringPrep, C.1.2] be mapped to SPACE (U+0020), and - the "commonly mapped to nothing" characters [StringPrep, B.1] be mapped to nothing. 2.2. Normalization This profile specifies using Unicode normalization form KC, as described in Section 4 of [StringPrep]. 2.3. 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. 2.4. Bidirectional characters This profile specifies checking bidirectional strings as described in [StringPrep, Section 6]. 2.5. Unassigned Code Points Zeilenga SASLprep [Page 3] INTERNET-DRAFT draft-ietf-sasl-saslprep-01.txt 4 May 2003 This profile specifies [StringPrep, A.1] table as its list of unassigned code points. 3. IANA Considerations This document details the "SASLprep" profile of [StringPrep] protocol. Upon Standards Action the profile 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 Blanchet. 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). [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 (http://www.unicode.org/reports/tr28/). 7. Informative References [Glossary] Unicode Glossary, . Zeilenga SASLprep [Page 4] INTERNET-DRAFT draft-ietf-sasl-saslprep-01.txt 4 May 2003 [CharModel] Unicode Technical Report;17, Character Encoding Model. . [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. 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 AUTHORS, 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. Zeilenga SASLprep [Page 5]