draft-ietf-curdle-ssh-ed25519-01.txt   draft-ietf-curdle-ssh-ed25519-02.txt 
Internet Engineering Task Force B. Harris Internet Engineering Task Force B. Harris
Internet-Draft Internet-Draft
Updates: 4250 (if approved) L. Velvindron Updates: 4250 (if approved) L. Velvindron
Intended status: Standards Track Hackers.mu Intended status: Standards Track Hackers.mu
Expires: February 7, 2018 August 6, 2017 Expires: August 7, 2018 February 3, 2018
Ed25519 public key algorithm for the Secure Shell (SSH) protocol Ed25519 public key algorithm for the Secure Shell (SSH) protocol
draft-ietf-curdle-ssh-ed25519-01 draft-ietf-curdle-ssh-ed25519-02
Abstract Abstract
This document describes the use of the Ed25519 digital signature This document describes the use of the Ed25519 digital signature
algorithm in the Secure Shell (SSH) protocol. algorithm in the Secure Shell (SSH) protocol.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on February 7, 2018. This Internet-Draft will expire on August 7, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
1. Introduction 1. Introduction
Secure Shell (SSH) [RFC4251] is a secure remote-login protocol. It Secure Shell (SSH) [RFC4251] is a secure remote-login protocol. It
provides for an extensible variety of public key algorithms for provides for an extensible variety of public key algorithms for
identifying servers and users to one another. Ed25519 [RFC8032] is a identifying servers and users to one another. Ed25519 [RFC8032] is a
digital signature system. OpenSSH 6.5 [OpenSSH-6.5] introduced digital signature system. OpenSSH 6.5 [OpenSSH-6.5] introduced
support for using Ed25519 for server and user authentication. support for using Ed25519 for server and user authentication.
Compatible support for Ed25519 has since been added to other SSH Compatible support for Ed25519 has since been added to other SSH
implementations. implementations. Ed448 [RFC8032] is another digital signature
system.
This document describes the method implemented by OpenSSH and others, This document describes the method implemented by OpenSSH and others,
and formalizes its use of the name "ssh-ed25519". and formalizes its use of the name "ssh-ed25519". Additionally, it
also describes the use of Ed448 and formalizes its use of the name
"ssh-ed448".
[TO BE REMOVED: Please send comments on this draft to [TO BE REMOVED: Please send comments on this draft to
curdle@ietf.org.] curdle@ietf.org.]
2. Conventions Used in This Document 2. Conventions Used in This Document
The descriptions of key and signature formats use the notation The descriptions of key and signature formats use the notation
introduced in [RFC4251], Section 3 [RFC4251] and the string data type introduced in [RFC4251], Section 3 [RFC4251] and the string data type
from [RFC4251], Section 5 [RFC4251]. from [RFC4251], Section 5 [RFC4251].
3. Public Key Algorithm 3. Public Key Algorithm
This document describes a public key algorithm for use with SSH in This document describes a public key algorithm for use with SSH in
accordance with [RFC4253], Section 6.6 [RFC4253]. The name of the accordance with [RFC4253], Section 6.6 [RFC4253]. The name of the
algorithm is "ssh-ed25519". This algorithm only supports signing and algorithm is "ssh-ed25519". This algorithm only supports signing and
not encryption. not encryption.
Additionally, this document describes another public key algorithm.
The name of the algorithm is "ssh-ed448". This algorithm only
supports signing and not encryption.
4. Public Key Format 4. Public Key Format
The "ssh-ed25519" key format has the following encoding: The "ssh-ed25519" key format has the following encoding:
string "ssh-ed25519" string "ssh-ed25519"
string key string key
Here 'key' is the 32-octet public key described by [RFC8032], Here 'key' is the 32-octet public key described by [RFC8032],
Section 5.1.5 [RFC8032]. Section 5.1.5 [RFC8032].
The "ssh-ed448" key format has the following encoding:
string "ssh-ed448"
string key
Here 'key' is the 57-octet public key described by [RFC8032],
Section 5.2.5 [RFC8032].
5. Signature Algorithm 5. Signature Algorithm
Signatures are generated according to the procedure in [RFC8032], Signatures are generated according to the procedure in [RFC8032],
Section 5.1.6 [RFC8032]. Section 5.2.6 [RFC8032].
6. Signature Format 6. Signature Format
The "ssh-ed25519" key format has the following encoding: The "ssh-ed25519" key format has the following encoding:
string "ssh-ed25519" string "ssh-ed25519"
string signature string signature
Here 'signature' is the 64-octet signature produced in accordance Here 'signature' is the 64-octet signature produced in accordance
with [RFC8032], Section 5.1.6 [RFC8032]. with [RFC8032], Section 5.1.6 [RFC8032].
The "ssh-ed448" key format has the following encoding:
string "ssh-ed448"
string signature
Here 'signature' is the 57-octet signature produced in accordance
with [RFC8032], Section 5.2.6 [RFC8032].
7. Verification Algorithm 7. Verification Algorithm
Signatures are verified according to the procedure in [RFC8032], ED25519 signatures are verified according to the procedure in
Section 5.1.7 [RFC8032]. [RFC8032], Section 5.1.7 [RFC8032].
ED448 signatures are verified according to the procedure in
[RFC8032], Section 5.2.7 [RFC8032].
8. SSHFP DNS resource records 8. SSHFP DNS resource records
The generation of SSHFP resource records for "ssh-ed25519" keys is The generation of SSHFP resource records for "ssh-ed25519" keys is
described in [RFC7479]. described in [RFC7479].
The generation of SSHFP resource records for "ssh-ed448" keys is
described in .
9. IANA Considerations 9. IANA Considerations
This document augments the Public Key Algorithm Names in [RFC4250], This document augments the Public Key Algorithm Names in [RFC4250],
Section 4.6.2 [RFC4250]. Section 4.6.2 [RFC4250].
IANA is requested to add to the Public Key Algorithm Names registry IANA is requested to add to the Public Key Algorithm Names registry
[IANA-PKA] with the following entry: [IANA-PKA] with the following entry:
Public Key Algorithm Name Reference Public Key Algorithm Name Reference
------------------------- ---------- ------------------------- ----------
ssh-ed25519 This Draft ssh-ed25519 This Draft
ssh-ed448 This Draft
[TO BE REMOVED: This registration should take place at the following [TO BE REMOVED: This registration should take place at the following
location: <http://www.iana.org/assignments/ssh-parameters/ssh- location: <http://www.iana.org/assignments/ssh-parameters/ssh-
parameters.xhtml#ssh-parameters-19>] parameters.xhtml#ssh-parameters-19>]
10. Security Considerations 10. Security Considerations
The security considerations in [RFC4251], Section 9 [RFC4251] apply The security considerations in [RFC4251], Section 9 [RFC4251] apply
to all SSH implementations, including those using Ed25519. to all SSH implementations, including those using Ed25519 and Ed448.
The security considerations in [RFC8032], Section 8 [RFC8032] apply The security considerations in [RFC8032], Section 8 [RFC8032] apply
to all uses of Ed25519, including those in SSH. to all uses of Ed25519 and Ed448 including those in SSH.
11. Acknowledgements 11. Acknowledgements
The OpenSSH implementation of Ed25519 in SSH was written by Markus The OpenSSH implementation of Ed25519 in SSH was written by Markus
Friedl. Friedl.
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC4250] Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH) [RFC4250] Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)
Protocol Assigned Numbers", RFC 4250, Protocol Assigned Numbers", RFC 4250,
DOI 10.17487/RFC4250, January 2006, DOI 10.17487/RFC4250, January 2006,
<http://www.rfc-editor.org/info/rfc4250>. <https://www.rfc-editor.org/info/rfc4250>.
[RFC4251] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) [RFC4251] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Protocol Architecture", RFC 4251, DOI 10.17487/RFC4251, Protocol Architecture", RFC 4251, DOI 10.17487/RFC4251,
January 2006, <http://www.rfc-editor.org/info/rfc4251>. January 2006, <https://www.rfc-editor.org/info/rfc4251>.
[RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) [RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253, Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
January 2006, <http://www.rfc-editor.org/info/rfc4253>. January 2006, <https://www.rfc-editor.org/info/rfc4253>.
[RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital [RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
Signature Algorithm (EdDSA)", RFC 8032, Signature Algorithm (EdDSA)", RFC 8032,
DOI 10.17487/RFC8032, January 2017, DOI 10.17487/RFC8032, January 2017,
<http://www.rfc-editor.org/info/rfc8032>. <https://www.rfc-editor.org/info/rfc8032>.
12.2. Informative References 12.2. Informative References
[IANA-PKA] [IANA-PKA]
Internet Assigned Numbers Authority (IANA), "Secure Shell Internet Assigned Numbers Authority (IANA), "Secure Shell
(SSH) Protocol Parameters: Public Key Algorithm Names", (SSH) Protocol Parameters: Public Key Algorithm Names",
May 2017, <http://www.iana.org/assignments/ssh-parameters/ May 2017, <http://www.iana.org/assignments/ssh-parameters/
ssh-parameters.xhtml#ssh-parameters-19>. ssh-parameters.xhtml#ssh-parameters-19>.
[OpenSSH-6.5] [OpenSSH-6.5]
Friedl, M., Provos, N., de Raadt, T., Steves, K., Miller, Friedl, M., Provos, N., de Raadt, T., Steves, K., Miller,
D., Tucker, D., Rice, T., and B. Lindstrom, "OpenSSH 6.5 D., Tucker, D., Rice, T., and B. Lindstrom, "OpenSSH 6.5
release notes", January 2014, release notes", January 2014,
<http://www.openssh.com/txt/release-6.5>. <http://www.openssh.com/txt/release-6.5>.
[RFC7479] Moonesamy, S., "Using Ed25519 in SSHFP Resource Records", [RFC7479] Moonesamy, S., "Using Ed25519 in SSHFP Resource Records",
RFC 7479, DOI 10.17487/RFC7479, March 2015, RFC 7479, DOI 10.17487/RFC7479, March 2015,
<http://www.rfc-editor.org/info/rfc7479>. <https://www.rfc-editor.org/info/rfc7479>.
Authors' Addresses Authors' Addresses
Ben Harris Ben Harris
2A Eachard Road 2A Eachard Road
CAMBRIDGE CB3 0HY CAMBRIDGE CB3 0HY
UNITED KINGDOM UNITED KINGDOM
Email: bjh21@bjh21.me.uk Email: bjh21@bjh21.me.uk
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