The Hashed Token SASL Mechanism
draft-schmaus-kitten-sasl-ht-01

Document Type Active Internet-Draft (individual)
Last updated 2017-09-29
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Common Authentication Technology Next Generation              F. Schmaus
Internet-Draft                                                  C. Egger
Intended status: Experimental           University of Erlangen-Nuremberg
Expires: April 2, 2018                                September 29, 2017

                    The Hashed Token SASL Mechanism
                    draft-schmaus-kitten-sasl-ht-01

Abstract

   This document specifies a SASL mechanism designed to be used with
   short-lived, exclusively ephemeral tokens.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on April 2, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (https://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.

Schmaus & Egger           Expires April 2, 2018                 [Page 1]
Internet-Draft                                            September 2017

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions and Terminology . . . . . . . . . . . . . . .   3
     1.2.  Applicability . . . . . . . . . . . . . . . . . . . . . .   3
   2.  The HT-* Family of Mechanisms . . . . . . . . . . . . . . . .   3
   3.  The HT Mechanism  . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Initiator First Message . . . . . . . . . . . . . . . . .   4
     3.2.  Final Responder Message . . . . . . . . . . . . . . . . .   5
   4.  Compliance with SASL Mechanism Requirements . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   This section specifies the the family of Hashed Token (HT-*) SASL
   mechanisms.  It provides hash agility, mutual authentication and is
   secured by channel binding.

   This mechanism was designed to be used with short-lived tokens for
   quick, one round-trip, re-authentication of a previous session.
   Clients are supposed to request such tokens from the server after
   being authenticated using a "strong" SASL mechanism (e.g.  SCRAM).
   Hence a typical sequence of actions using SASL-HT may look like the
   following:

      A) Client authenticates using a strong mechanism (e.g., SCRAM)
      B) Client requests secret SASL-HT token
         <normal client-server interaction here>
      C) Connection between client and server gets interrupted
         (e.g., WiFi <-> GSM switch)
      D) Client resumes previous session using the token from B
      E) Client requests secret SASL-HT token
         [goto C]

   An example application protocol specific extension based on SASL-HT
   is [XEP-ISR-SASL2].

   Since the token is not salted, and only one hash iteration is used,
   the HT-* mechanism is not suitable to protect long-lived shared
   secrets (e.g. "passwords").  You may want to look at [RFC5802] for
   that.

Schmaus & Egger           Expires April 2, 2018                 [Page 2]
Internet-Draft                                            September 2017

1.1.  Conventions and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
Show full document text