SCRAM-SHA-256 and SCRAM-SHA-256-PLUS SASL Mechanisms
draft-hansen-scram-sha256-00

Abstract

This document registers the SASL mechanisms SCRAM-SHA-256 and SCRAM-SHA-256-PLUS. It also updates RFC 5802 in minor ways.

Status of This Memo

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Copyright Notice

Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. SCRAM-SHA-256 and SCRAM-SHA-256-PLUS
• 3. IANA Considerations
• 4. Acknowledgements
• 5. References
• 5.1. Normative References
• 5.2. Informative References
• Author's Address

1. Introduction

This document registers the SASL mechanisms SCRAM-SHA-256 and SCRAM-SHA-256-PLUS.

The registration form for the SCRAM is also updated.

Note: this paragraph may be removed before publication.
This document was written because [RFC5802] requires that new SASL mechanisms in the SCRAM family be subject to IETF review. This document is being discussed on the kitten@ietf.org mailing list.

2. SCRAM-SHA-256 and SCRAM-SHA-256-PLUS

The SCRAM-SHA-256 and SCRAM-SHA-256-PLUS SASL mechanism are defined in the same way that SCRAM-SHA-1 and SCRAM-SHA-1-PLUS are defined in [RFC5802], except that the hash function for HMAC() and H() uses SHA-256 instead of SHA-1 [RFC6234].

For the SCRAM-SHA-256/SCRAM-SHA-256-PLUS SASL mechanisms, servers SHOULD announce a hash iteration-count of at least 4096.
!!!!!!!!!!!!!!!! Note that the appropriate value to specify here is being actively discussed. !!!!!!!!!!!!!!!!

The GSS-API mechanism OID for SCRAM-SHA-256 is [to be assigned by IANA] (see Section 3).

This is a simple example of a SCRAM-SHA-256 authentication exchange when the client doesn't support channel bindings (username 'user' and password 'pencil' are used):

C:

n,,n=user,r=rOprNGfwEbeRWgbNEkqO

S:

r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,
s=W22ZaJ0SNY7soEsUEjb6gQ==,i=4096

C:

c=biws,r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,
p=dHzbZapWIk4jUhN+Ute9ytag9zjfMHgsqmmiz7AndVQ=

S:

v=6rriTRBi23WpRR/wtup+mMhUZUn/dB5nLTJRsjl95G4=

3. IANA Considerations

The IANA registry for the SCRAM family of SASL mechanisms is updated as follows:

• To: iana@iana.org
  Subject: Registration of a new SASL family SCRAM
• SASL mechanism name (or prefix for the family): SCRAM-*
  Security considerations: Section 7 of [RFC5802]
  Published specification (optional, recommended): [RFC5802]
  Person & email address to contact for further information: IETF KITTEN WG kitten@ietf.org
  Intended usage: COMMON
  Owner/Change controller: IESG iesg@ietf.org
  Note: Members of this family MUST be explicitly registered using the "IETF Review" [RFC5226] registration procedure. Reviews MUST be requested on the KITTEN mailing list kitten@ietf.org (or a successor designated by the responsible Security AD).
• Note to future SCRAM-mechanism designers: each new SCRAM-SASL mechanism MUST be explicitly registered with IANA and MUST comply with SCRAM-mechanism naming convention defined in Section 4 of [RFC5802].
• IANA has added the following entries to the SASL Mechanism registry established by [RFC4422]:
• To: iana@iana.org
  Subject: Registration of a new SASL mechanism SCRAM-SHA-256
• SASL mechanism name (or prefix for the family): SCRAM-SHA-256
  Security considerations: Section 7 of [RFC5802]
  Published specification (optional, recommended): [RFC5802]
  Person & email address to contact for further information: IETF KITTEN WG kitten@ietf.org
  Intended usage: COMMON
  Owner/Change controller: IESG iesg@ietf.org
  Note:
• To: iana@iana.org
  Subject: Registration of a new SASL mechanism SCRAM-SHA-256-PLUS
• SASL mechanism name (or prefix for the family): SCRAM-SHA-256-PLUS
  Security considerations: Section 7 of [RFC5802]
  Published specification (optional, recommended): [RFC5802]
  Person & email address to contact for further information: IETF KITTEN WG kitten@ietf.org
  Intended usage: COMMON
  Owner/Change controller: IESG iesg@ietf.org
  Note:
• IANA needs to assign a GSS-API mechanism OID for SCRAM-SHA-256 from the iso.org.dod.internet.security.mechanisms prefix (see the "SMI Security for Mechanism Codes" registry).

4. Acknowledgements

This document benefited from discussions on the KITTEN WG mailing list. The author would like to specially thank ...

5. References

5.1. Normative References

5.2. Informative References

Author's Address