GSS-API Key Exchange with SHA2
draft-ietf-curdle-gss-keyex-sha2-05

Document Type Active Internet-Draft (curdle WG)
Last updated 2018-04-06 (latest revision 2018-02-22)
Replaces draft-ssorce-gss-keyex-sha2
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication
Document shepherd Daniel Migault
Shepherd write-up Show (last changed 2018-02-23)
IESG IESG state AD Evaluation::Revised I-D Needed
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Responsible AD Eric Rescorla
Send notices to Daniel Migault <daniel.migault@ericsson.com>
Internet Engineering Task Force                                 S. Sorce
Internet-Draft                                                  H. Kario
Updates: 4462 (if approved)                                Red Hat, Inc.
Intended status: Standards Track                            Feb 22, 2018
Expires: August 26, 2018

                     GSS-API Key Exchange with SHA2
                  draft-ietf-curdle-gss-keyex-sha2-05

Abstract

   This document specifies additions and amendments to RFC4462.  It
   defines a new key exchange method that uses SHA-2 for integrity and
   deprecates weak DH groups.  The purpose of this specification is to
   modernize the cryptographic primitives used by GSS Key Exchanges.

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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 26, 2018.

Copyright Notice

   Copyright (c) 2018 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
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Sorce & Kario            Expires August 26, 2018                [Page 1]
Internet-Draft               GSS Keyex SHA2                     Feb 2018

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Document Conventions  . . . . . . . . . . . . . . . . . . . .   3
   4.  New Diffie-Hellman Key Exchange methods . . . . . . . . . . .   3
     4.1.  gss-group14-sha256-*  . . . . . . . . . . . . . . . . . .   3
     4.2.  gss-group15-sha512-*  . . . . . . . . . . . . . . . . . .   3
     4.3.  gss-group16-sha512-*  . . . . . . . . . . . . . . . . . .   4
     4.4.  gss-group17-sha512-*  . . . . . . . . . . . . . . . . . .   4
     4.5.  gss-group18-sha512-*  . . . . . . . . . . . . . . . . . .   4
   5.  New Elliptic Curve Diffie-Hellman Key Exchange methods  . . .   4
     5.1.  Generic GSS-API Key Exchange with ECDH  . . . . . . . . .   4
     5.2.  ECDH Key Exchange Methods . . . . . . . . . . . . . . . .  11
       5.2.1.  gss-nistp256-sha256-* . . . . . . . . . . . . . . . .  12
       5.2.2.  gss-nistp384-sha384-* . . . . . . . . . . . . . . . .  12
       5.2.3.  gss-nistp521-sha512-* . . . . . . . . . . . . . . . .  12
       5.2.4.  gss-curve25519-sha256-* . . . . . . . . . . . . . . .  12
       5.2.5.  gss-curve448-sha512-* . . . . . . . . . . . . . . . .  13
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
     7.1.  New Finite Field DH mechanisms  . . . . . . . . . . . . .  13
     7.2.  New Elliptic Curve DH mechanisms  . . . . . . . . . . . .  13
     7.3.  GSSAPI Delegation . . . . . . . . . . . . . . . . . . . .  14
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   SSH GSS-API Methods [RFC4462] allows the use of GSSAPI for
   authentication and key exchange in SSH.  It defines three exchange
   methods all based on DH groups and SHA-1.  This document updates
   RFC4462 with new methods intended to support environments that desire
   to use the SHA-2 cryptographic hash functions.

2.  Rationale

   Due to security concerns with SHA-1 [RFC6194] and with MODP groups
   with less than 2048 bits [NIST-SP-800-131Ar1]  we propose the use of
   the SHA-2 based hashes with DH group14, group15, group16, group17 and
   group18 [RFC3526].  Additionally we add support for key exchange
   based on Elliptic Curve Diffie Hellman with NIST P-256, P-384 and
   P-521 as well as X25519 and X448 curves.  Following the rationale of
   [RFC8268] only SHA-256 and SHA-512 hashes are used for DH groups.
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