SASLprep: Stringprep Profile for User Names and Passwords
RFC 4013
Document | Type |
RFC - Proposed Standard
(March 2005; Errata)
Obsoleted by RFC 7613
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Author | Kurt Zeilenga | ||
Last updated | 2020-01-21 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4013 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Russ Housley | ||
Send notices to | (None) |
Network Working Group K. Zeilenga Request for Comments: 4013 OpenLDAP Foundation Category: Standards Track February 2005 SASLprep: Stringprep Profile for User Names and Passwords Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document describes how to prepare Unicode strings representing user names and passwords for comparison. The document defines the "SASLprep" profile of the "stringprep" algorithm 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 simple user 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 likelihood that user name and password input and comparison 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. The algorithm assumes all strings are comprised of characters from the Unicode [Unicode] character set. This document defines the "SASLprep" profile of the "stringprep" algorithm [StringPrep]. The profile is designed for use in Simple Authentication and Security Layer ([SASL]) mechanisms, such as [PLAIN], [CRAM-MD5], and [DIGEST-MD5]. It may be applicable where simple user names and Zeilenga Standards Track [Page 1] RFC 4013 SASLprep February 2005 passwords are used. This profile is not intended for use in preparing identity strings that are not simple user names (e.g., email addresses, domain names, distinguished names), or where identity or password strings that are not character data, or require different handling (e.g., case folding). This document does not alter the technical specification of any existing protocols. Any specification that wishes to use the algorithm described in this document needs to explicitly incorporate this document and provide precise details as to where and how this algorithm is used by implementations of that specification. 2. The SASLprep Profile This section defines the "SASLprep" profile of the "stringprep" algorithm [StringPrep]. This profile is intended for use in preparing strings representing simple user names and passwords. This profile uses Unicode 3.2 [Unicode]. 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 [CharModel]. 2.1. Mapping This profile specifies: - non-ASCII space characters [StringPrep, C.1.2] that can be mapped to SPACE (U+0020), and - the "commonly mapped to nothing" characters [StringPrep, B.1] that can be mapped to nothing. 2.2. Normalization This profile specifies using Unicode normalization form KC, as described in Section 4 of [StringPrep]. Zeilenga Standards Track [Page 2] RFC 4013 SASLprep February 2005 2.3. Prohibited Output This profile specifies the following characters as prohibited input: - Non-ASCII space characters [StringPrep, C.1.2] - ASCII control characters [StringPrep, C.2.1] - Non-ASCII control characters [StringPrep, C.2.2] - Private Use characters [StringPrep, C.3] - Non-character code points [StringPrep, C.4] - Surrogate code points [StringPrep, C.5] - Inappropriate for plain text characters [StringPrep, C.6] - Inappropriate for canonical representation characters [StringPrep, C.7] - Change display properties or deprecated charactersShow full document text