wdiff rfc7479.original rfc7479.txt


INTERNET-DRAFT
Internet Engineering Task Force (IETF)                      S. Moonesamy
Intended Status: Informational
Expires:
Request for Comments: 7479                                    March 4, 2015                                   August 31, 2014
Category: Informational
ISSN: 2070-1721

                Using ED25519 Ed25519 in SSHFP Resource Records
                    draft-moonesamy-sshfp-ed25519-02

Abstract

   The Ed25519 signature algorithm has been implemented in OpenSSH.
   This document updates the IANA "SSHFP RR Types for public key
   algorithms" registry by adding an algorithm number for Ed25519.

Status of this This Memo

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   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents not an Internet Standards Track specification; it is
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Copyright and License Notice

   Copyright (c) 2014 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1. Introduction ....................................................2
   2. Ed25519 Public Key with SHA-256 Fingerprint .....................2
   3. Security Considerations .........................................3
   4. IANA Considerations .............................................3
   5. References ......................................................3
      5.1. Normative References .......................................3
      5.2. Informative References .....................................3
   Acknowledgements ...................................................3
   Author's Address ...................................................4

1.  Introduction

   The Ed25519 [Ed25519] signature algorithm, specifically Ed25519-SHA-
   512,
   Ed25519-SHA-512, has been implemented in OpenSSH.  RFC 4255 [RFC4255]
   defines a DNS resource record, "SSHFP", which can be used to publish
   a fingerprint of the SSH server public key in the DNS.  This document
   updates the IANA "SSHFP RR Types for public key algorithms" registry
   by adding an algorithm number for Ed25519 [Ed25519].

2. ED25519  Ed25519 Public Key with SHA-256 Fingerprint

   The encoding of Ed25519 public keys is described in [Ed25519].  In
   brief, an Ed25519 public key is a 32-octet value representing a
   255-bit y-coordinate of an elliptic curve point, and a sign bit
   indicating the corresponding x-coordinate.

   The SSHFP Resource Record for the ED25519 Ed25519 public key with SHA-256
   fingerprint [FIPS180-4] would, for example, be:

      ssh.example.com IN SSHFP [TBD] 4 2 ( a87f1b687ac0e57d2a081a2f2826723
                                     34d90ed316d2b818ca9580ea384d924
                                     01 )

   [RFC Editor Note: Please replace TBD with the value assigned by
   IANA.]

   The following body of the public key file was used as input to
   generate the above fingerprint:

    ssh-ed25519
    AAAAC3NzaC1lZDI1NTE5AAAAIGPKSUTyz1HwHReFVvD5obVsALAgJRNarH4TRpNePnAS

   The opaque octet string output produced is placed as-is as is in the RDATA
   fingerprint field.

3.  Security Considerations

   The overall security of using SSHFP for SSH host key verification is
   dependent on the security policies of the SSH host administrator and
   DNS zone administrator (in transferring the fingerprint), detailed
   aspects of how verification is done in the SSH implementation, and in
   the client's diligence in accessing the DNS in a secure manner.
   Please refer to RFC 4255 [RFC4255] for a discussion of the security
   considerations.

4.  IANA Considerations

   IANA is requested to add has added the following entry to the "SSHFP RR Types for public
   key algorithms" registry:

      +--------+-------------+------------+
      | Value  | Description |  Reference |
      +--------+-------------+------------+
      |  [TBD]   4    |    ED25519    Ed25519  | [RFCXXXX] [RFC7479]  |
      +--------+-------------+------------+

   [RFC Editor Note: Please replace TBD with the value assigned by IANA

5.  References

5.1.  Normative References

   [Ed25519]    Bernstein, D. J., Lange T., Schwabe P., and RFCXXXX to refer B-Y. Yang,
                "High-Speed High-Security Signatures", Journal of
                Cryptographic Engineering, Vol. 2, September 26, 2011.

   [RFC4255]    Schlyter, J. and W. Griffin, "Using DNS to this document.]

5. Securely
                Publish Secure Shell (SSH) Key Fingerprints", RFC 4255,
                January 2006, <http://www.rfc-editor.org/info/rfc4255>.

5.2.  Informative References

   [FIPS180-4]  National Institute of Standards and Technology, "Secure
                Hash Standard (SHS)", FIPS PUB 180-4, March 2012,
                <http://csrc.nist.gov/publications/fips/fips180-4/
                fips-180-4.pdf>.

Acknowledgements

   Some of the text in this document was written by Ondrej Sury.  The
   author would like to thank Richard Barnes, Damien Miller, Yoav Nir,
   and Paul Wouters for their feedback.  Rene Struik provided advice
   about the usage of Ed25519.  Stephen Farrell, as Security Area
   Director, reviewed the code point request.

6.  References

6.1.  Normative References

   [RFC4255]  Schlyter, J. and W. Griffin, "Using DNS to Securely
              Publish Secure Shell (SSH) Key Fingerprints", RFC 4255,
              January 2006.

6.2.  Informative References

   [Ed25519]  Bernstein, D. J., Lange T., Schwabe P., Yang B-Y., High-
              Speed High-Security Signatures, Journal of Cryptographic
              Engineering, Vol. 2, September 26, 2011

   [FIPS180-4]  National Institute of Standards and Technology, "Secure
              Hash Standard (SHS)", FIPS PUB 180-4, March 2012,
              <http://csrc.nist.gov/publications/fips/fips180-4/fips180-
              4_final.pdf>.

Appendix A: Changes

[RFC Editor Note: Please remove this appendix]

A.1 Changes since version 00

   o  Text about usage policy removed from Section 2

   o  SHA-1 Fingerprint removed

A.2 Changes since version 01

   o  Appendix B lists the implementation status of the Ed25519
      signature algorithm.

   o  Added an example in Section 2 of the public key file used to
      generate the fingerprint.

Appendix B: Implementation Status

[RFC Editor Note: Please remove this appendix]

This section records the status of known implementations of the
signature algorithm referenced by this specification at the time of
posting of this Internet-Draft.

The Ed25519 signature algorithm, specifically Ed25519-SHA-512, has been
implemented in OpenSSH (http://www.openssh.org) and it is featured in
production version (http://www.openssh.com/txt/release-6.5).  The
software is distributed under a BSD license.

The Ed25519 signature algorithm has also been implemented in Tera Term
(http://sourceforge.jp/ticket/browse.php?group_id=1412&tid=33263).  The
software is distributed under a BSD license.

Authors' Addresses

Author's Address

   S. Moonesamy
   76, Ylang Ylang Avenue
   Quatres Bornes
   Mauritius

   Email:

   EMail: sm+ietf@elandsys.com