SCRAM-SHA-512 and SCRAM-SHA-512-PLUS Simple Authentication and Security Layer (SASL) Mechanisms
draft-melnikov-scram-sha-512-00

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Network Working Group                                   A. Melnikov, Ed.
Internet-Draft                                                 Isode Ltd
Intended status: Standards Track                            May 14, 2020
Expires: November 15, 2020

SCRAM-SHA-512 and SCRAM-SHA-512-PLUS Simple Authentication and Security
                        Layer (SASL) Mechanisms
                    draft-melnikov-scram-sha-512-00

Abstract

   This document registers the Simple Authentication and Security Layer
   (SASL) mechanisms SCRAM-SHA-512 and SCRAM-SHA-512-PLUS.

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   This Internet-Draft will expire on November 15, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Key Word Definitions  . . . . . . . . . . . . . . . . . . . .   2
   3.  SCRAM-SHA-512 and SCRAM-SHA-512-PLUS  . . . . . . . . . . . .   2
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   This document registers the SASL [RFC4422] mechanisms SCRAM-SHA-512
   and SCRAM-SHA-512-PLUS.  SHA-512 has stronger security properties
   than SHA-1, and it is expected that SCRAM mechanisms based on it will
   have greater predicted longevity than the SCRAM mechanisms based on
   SHA-1.

2.  Key Word Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all

3.  SCRAM-SHA-512 and SCRAM-SHA-512-PLUS

   The SCRAM-SHA-512 and SCRAM-SHA-512-PLUS SASL mechanisms 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-512 instead of SHA-1 [RFC6234].

   For the SCRAM-SHA-512 and SCRAM-SHA-512-PLUS SASL mechanisms, the
   hash iteration-count announced by a server SHOULD be at least 4096.

   The GSS-API mechanism OID for SCRAM-SHA-512 is 1.3.6.1.5.5.<TBD> (see
   Section 5).

   This is a simple example of a SCRAM-SHA-512 authentication exchange
   when the client doesn't support channel bindings.  The username
   'user' and password 'pencil' are being used.

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4.  Security Considerations

   The security considerations from [RFC5802] still apply.

   To be secure, either SCRAM-SHA-512-PLUS and SCRAM-SHA-1-PLUS MUST be
   used over a TLS channel that has had the session hash extension
   [RFC7627] negotiated, or session resumption MUST NOT have been used.

   See [RFC4270] and [RFC6194] for reasons to move from SHA-1 to a
   strong security mechanism like SHA-512.

   The strength of this mechanism is dependent in part on the hash
   iteration-count, as denoted by "i" in [RFC5802].  As a rule of thumb,
   the hash iteration-count should be such that a modern machine will