INTERNET-DRAFT S. Moonesamy Intended Status: Informational Expires: March 4, 2015 August 31, 2014 Using 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 Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2014 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 (http://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 S. Moonesamy Expires March 4, 2015 [Page 1] INTERNET DRAFT Using ED25519 in SSHFP RRs August 31, 2014 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. S. Moonesamy Expires March 4, 2015 [Page 2] INTERNET DRAFT Using ED25519 in SSHFP RRs August 31, 2014 1. Introduction The Ed25519 [Ed25519] signature algorithm, specifically 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 Public Key with SHA-256 Fingerprint The SSHFP Resource Record for the ED25519 public key with SHA-256 fingerprint [FIPS180-4] would, for example, be: ssh.example.com IN SSHFP [TBD] 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 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 the following entry to the "SSHFP RR Types for public key algorithms" registry: +--------+-------------+------------+ S. Moonesamy Expires March 4, 2015 [Page 3] INTERNET DRAFT Using ED25519 in SSHFP RRs August 31, 2014 | Value | Description | Reference | +--------+-------------+------------+ | [TBD] | ED25519 | [RFCXXXX] | +--------+-------------+------------+ [RFC Editor Note: Please replace TBD with the value assigned by IANA and RFCXXXX to refer to this document.] 5. Acknowledgements Some of the text in this document was written by Ondrej Sury. The author would like to thank 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, . 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 S. Moonesamy Expires March 4, 2015 [Page 4] INTERNET DRAFT Using ED25519 in SSHFP RRs August 31, 2014 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 S. Moonesamy 76, Ylang Ylang Avenue Quatres Bornes Mauritius Email: sm+ietf@elandsys.com S. Moonesamy Expires March 4, 2015 [Page 5]