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Versions: (draft-bjh21-ssh-ed25519) 00 01

Internet Engineering Task Force                                B. Harris
Internet-Draft
Updates: 4250 (if approved)                                L. Velvindron
Intended status: Standards Track                              Hackers.mu
Expires: February 7, 2018                                 August 6, 2017


    Ed25519 public key algorithm for the Secure Shell (SSH) protocol
                    draft-ietf-curdle-ssh-ed25519-01

Abstract

   This document describes the use of the Ed25519 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 http://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 February 7, 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





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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.  Ed25519 [RFC8032] is a
   digital signature system.  OpenSSH 6.5 [OpenSSH-6.5] introduced
   support for using Ed25519 for server and user authentication.
   Compatible support for Ed25519 has since been added to other SSH
   implementations.

   This document describes the method implemented by OpenSSH and others,
   and formalizes its use of the name "ssh-ed25519".

   [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].

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-ed25519".  This algorithm only supports signing and
   not encryption.

4.  Public Key Format

   The "ssh-ed25519" key format has the following encoding:

   string    "ssh-ed25519"
   string    key

   Here 'key' is the 32-octet public key described by [RFC8032],
   Section 5.1.5 [RFC8032].

5.  Signature Algorithm

   Signatures are generated according to the procedure in [RFC8032],
   Section 5.1.6 [RFC8032].








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6.  Signature Format

   The "ssh-ed25519" key format has the following encoding:

   string    "ssh-ed25519"
   string    signature

   Here 'signature' is the 64-octet signature produced in accordance
   with [RFC8032], Section 5.1.6 [RFC8032].

7.  Verification Algorithm

   Signatures are verified according to the procedure in [RFC8032],
   Section 5.1.7 [RFC8032].

8.  SSHFP DNS resource records

   The generation of SSHFP resource records for "ssh-ed25519" keys is
   described in [RFC7479].

9.  IANA Considerations

   This document augments the Public Key Algorithm Names in [RFC4250],
   Section 4.6.2 [RFC4250].

   IANA is requested to add to the Public Key Algorithm Names registry
   [IANA-PKA] with the following entry:

                   Public Key Algorithm Name Reference
                   ------------------------- ----------
                   ssh-ed25519               This Draft

   [TO BE REMOVED: This registration should take place at the following
   location: <http://www.iana.org/assignments/ssh-parameters/ssh-
   parameters.xhtml#ssh-parameters-19>]

10.  Security Considerations

   The security considerations in [RFC4251], Section 9 [RFC4251] apply
   to all SSH implementations, including those using Ed25519.

   The security considerations in [RFC8032], Section 8 [RFC8032] apply
   to all uses of Ed25519, including those in SSH.








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11.  Acknowledgements

   The OpenSSH implementation of Ed25519 in SSH was written by Markus
   Friedl.

12.  References

12.1.  Normative References

   [RFC4250]  Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Protocol Assigned Numbers", RFC 4250,
              DOI 10.17487/RFC4250, January 2006,
              <http://www.rfc-editor.org/info/rfc4250>.

   [RFC4251]  Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Protocol Architecture", RFC 4251, DOI 10.17487/RFC4251,
              January 2006, <http://www.rfc-editor.org/info/rfc4251>.

   [RFC4253]  Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
              January 2006, <http://www.rfc-editor.org/info/rfc4253>.

   [RFC8032]  Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
              Signature Algorithm (EdDSA)", RFC 8032,
              DOI 10.17487/RFC8032, January 2017,
              <http://www.rfc-editor.org/info/rfc8032>.

12.2.  Informative References

   [IANA-PKA]
              Internet Assigned Numbers Authority (IANA), "Secure Shell
              (SSH) Protocol Parameters: Public Key Algorithm Names",
              May 2017, <http://www.iana.org/assignments/ssh-parameters/
              ssh-parameters.xhtml#ssh-parameters-19>.

   [OpenSSH-6.5]
              Friedl, M., Provos, N., de Raadt, T., Steves, K., Miller,
              D., Tucker, D., Rice, T., and B. Lindstrom, "OpenSSH 6.5
              release notes", January 2014,
              <http://www.openssh.com/txt/release-6.5>.

   [RFC7479]  Moonesamy, S., "Using Ed25519 in SSHFP Resource Records",
              RFC 7479, DOI 10.17487/RFC7479, March 2015,
              <http://www.rfc-editor.org/info/rfc7479>.







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Authors' Addresses

   Ben Harris
   2A Eachard Road
   CAMBRIDGE  CB3 0HY
   UNITED KINGDOM

   Email: bjh21@bjh21.me.uk


   Loganaden Velvindron
   Hackers.mu
   88, Avenue De Plevitz
   Roches Brunes
   Mauritius

   Email: logan@hackers.mu


































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