XMSS public key algorithms for the Secure Shell (SSH) protocol
draft-mu-curdle-ssh-xmss-00

Document Type Active Internet-Draft (individual)
Last updated 2019-10-28
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf htmlized 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)
Internet Engineering Task Force                            L. Velvindron
Internet-Draft                                                 J. Daniel
Updates: RFC4253 (if approved)                             cyberstorm.mu
Intended status: Standards Track                        October 27, 2019
Expires: April 29, 2020

     XMSS public key algorithms for the Secure Shell (SSH) protocol
                      draft-mu-curdle-ssh-xmss-00

Abstract

   This document describes the use of the XMSS (XMSS: eXtended Merkle
   Signature Scheme) which is resistant to quantum computers attack, as
   a digital signature algorithm in the Secure Shell (SSH) protocol.

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 29, 2020.

Copyright Notice

   Copyright (c) 2019 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.

Velvindron & Daniel      Expires April 29, 2020                 [Page 1]
Internet-Draft                XMSS for SSH                  October 2019

1.  Introduction

   Secure Shell (SSH) [RFC4251] is a secure remote-login protocol.  It
   provides for an extensible variety of public key algorithms for
   identifying servers and users to one another.  XMSS [RFC8391] is a
   digital signature system.  OpenSSH 7.7 [OpenSSH-7.7] introduced
   support for using XMSS for server and user authentication and was
   then followed by other SSH implementations.

   This document describes the method implemented by OpenSSH and others,
   and formalizes its use of the name "ssh-xmss".

   [TO BE REMOVED: Please send comments on this draft to
   curdle@ietf.org.]

2.  Conventions Used in This Document

   The descriptions of key and signature formats use the notation
   introduced in [RFC4251], Section 3 [RFC4251] and the string data type
   from [RFC4251], Section 5 [RFC4251].

2.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119] RFC
   8174 [RFC8174] when, and only when, they appear in all capitals, as
   shown here.

3.  Public Key Algorithm

   This document describes a public key algorithm for use with SSH in
   accordance with [RFC4253], Section 6.6 [RFC4253].  The name of the
   algorithm is "ssh-xmss".  This algorithm only supports signing and
   not encryption.

   Standard implementations of SSH SHOULD implement these signature
   algorithms.

4.  Public Key Format

   The "ssh-xmss" key format has the following encoding:

   string    "ssh-xmss"
   string    key

   Here 'key' is the 32-octet public key described by [RFC8391],
   Section 4.1.7 [RFC8391].

Velvindron & Daniel      Expires April 29, 2020                 [Page 2]
Internet-Draft                XMSS for SSH                  October 2019

5.  Signature Algorithm

   Signatures are generated according to the procedure in [RFC8391],
   Section 4.1.8 [RFC8391].

6.  Signature Format

   The "ssh-xmss" key format has the following encoding:

   string    "ssh-xmss"
   string    signature

   Here 'signature' is the 64-octet signature produced in accordance
   with [RFC8391], Section 4.1.9 [RFC8391].

7.  Verification Algorithm

   XMSS signatures are verified according to the procedure in [RFC8391],
   Section 4.1.10 [RFC8391].

8.  SSHFP DNS resource records

   Usage and generation of SSHFP DNS resource record is described in
   [RFC4255].  This section illustrates the generation of SSHFP resource
   records for "ssh-xmss" keys and the document specifies the
   corresponding xmss code point to the "SSHFP RR Types for public key
   algorithms" IANA registry.

   The generation of SSHFP resource records for "ssh-xmss" keys is
Show full document text