Lightweight Directory Access Protocol (LDAP) Schema for Storing Salted Challenge Response Authentication Mechanism (SCRAM) Secrets
RFC 5803

 
Document Type RFC - Informational (July 2010; Errata)
Was draft-melnikov-sasl-scram-ldap (individual in sec area)
Last updated 2013-03-02
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IESG IESG state RFC 5803 (Informational)
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Send notices to alexey.melnikov@isode.com, draft-melnikov-sasl-scram-ldap@ietf.org
Internet Engineering Task Force (IETF)                       A. Melnikov
Request for Comments: 5803                                 Isode Limited
Category: Informational                                        July 2010
ISSN: 2070-1721

 Lightweight Directory Access Protocol (LDAP) Schema for Storing Salted
      Challenge Response Authentication Mechanism (SCRAM) Secrets

Abstract

   This memo describes how the "authPassword" Lightweight Directory
   Access Protocol (LDAP) attribute can be used for storing secrets used
   by the Salted Challenge Response Authentication Message (SCRAM)
   mechanism in the Simple Authentication and Security Layer (SASL)
   framework.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5803.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Melnikov                      Informational                     [Page 1]
RFC 5803          LDAP Schema for Storing SCRAM Secrets        July 2010

Table of Contents

   1. Overview ........................................................2
   2. Conventions Used in This Document ...............................3
   3. Security Considerations .........................................3
   4. Acknowledgements ................................................4
   5. Normative References ............................................4

1.  Overview

   This document describes how the authPassword LDAP attribute
   [AUTHPASS] can be used for storing secrets used by [SCRAM] Simple
   Authentication and Security Layer [RFC4422] Mechanisms.

      The "scheme" part of the authPassword attribute is the SCRAM
      mechanism name (always without the "-PLUS" suffix), e.g., "SCRAM-
      SHA-1".  See [SCRAM] for the exact syntax of SCRAM mechanism
      names.

      The "authInfo" part of the authPassword attribute is the iteration
      count (iter-count in the ABNF below), followed by ":" and base64-
      encoded [BASE64] salt.

      The "authValue" part of the authPassword attribute is the base64-
      encoded [BASE64] StoredKey [SCRAM], followed by ":" and base64-
      encoded [BASE64] ServerKey [SCRAM].

   Syntax of the attribute can be expressed using ABNF [RFC5234].  Non-
   terminal references in the following ABNF are defined in either
   [AUTHPASS], [RFC4422], or [RFC5234].

       scram-mech     = "SCRAM-SHA-1" / scram-mech-ext
                      ; Complies with ABNF for <scheme>
                      ; defined in [AUTHPASS].

       scram-authInfo = iter-count ":" salt
                      ; Complies with ABNF for <authInfo>
                      ; defined in [AUTHPASS].

       scram-authValue = stored-key ":" server-key
                      ; Complies with ABNF for <authValue>
                      ; defined in [AUTHPASS].

       iter-count   = %x31-39 *DIGIT
                      ; SCRAM iteration count.
                      ; A positive number without leading zeros.

       salt         = <base64-encoded value>

Melnikov                      Informational                     [Page 2]
RFC 5803          LDAP Schema for Storing SCRAM Secrets        July 2010

       stored-key   = <base64-encoded value>
                      ; See definition in [SCRAM].

       server-key   = <base64-encoded value>
                      ; See definition in [SCRAM].

       scram-mech-ext = "SCRAM-" 1*9mech-char
                      ; Other SCRAM mechanisms registered
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