Ed25519 and Ed448 Public Key Algorithms for the Secure Shell (SSH) Protocol
RFC 8709
Document | Type |
RFC - Proposed Standard
(February 2020; Errata)
Updates RFC 4253
|
|
---|---|---|---|
Authors | Ben Harris , Loganaden Velvindron | ||
Last updated | 2020-05-17 | ||
Replaces | draft-ietf-curdle-ssh-ed25519 | ||
Stream | IETF | ||
Formats | plain text html xml pdf htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Daniel Migault | ||
Shepherd write-up | Show (last changed 2019-06-05) | ||
IESG | IESG state | RFC 8709 (Proposed Standard) | |
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Benjamin Kaduk | ||
Send notices to | Daniel Migault <daniel.migaultf@ericsson.com> | ||
IANA | IANA review state | IANA OK - Actions Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) B. Harris Request for Comments: 8709 Updates: 4253 L. Velvindron Category: Standards Track cyberstorm.mu ISSN: 2070-1721 February 2020 Ed25519 and Ed448 Public Key Algorithms for the Secure Shell (SSH) Protocol Abstract This document describes the use of the Ed25519 and Ed448 digital signature algorithms in the Secure Shell (SSH) protocol. Accordingly, this RFC updates RFC 4253. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8709. Copyright Notice Copyright (c) 2020 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. Table of Contents 1. Introduction 2. Conventions Used in This Document 2.1. Requirements Language 3. Public Key Algorithm 4. Public Key Format 5. Signature Algorithm 6. Signature Format 7. Verification Algorithm 8. SSHFP DNS Resource Records 9. IANA Considerations 10. Security Considerations 11. References 11.1. Normative References 11.2. Informative References Acknowledgements Authors' Addresses 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 and was then followed by other SSH implementations. This document describes the method implemented by OpenSSH and others and formalizes the use of the name "ssh-ed25519". Additionally, this document describes the use of Ed448 and formalizes the use of the name "ssh-ed448". 2. Conventions Used in This Document The descriptions of key and signature formats use the notation introduced in [RFC4251], Section 3 and the string data type from [RFC4251], Section 5. 2.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [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, as per [RFC4253], Section 6.6. The name of the algorithm is "ssh- ed25519". This algorithm only supports signing and 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. Standard implementations of SSH SHOULD implement these signature algorithms. 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 in [RFC8032], Section 5.1.5. The "ssh-ed448" key format has the following encoding: string "ssh-ed448" string key Here, 'key' is the 57-octet public key described in [RFC8032], Section 5.2.5. 5. Signature Algorithm Signatures are generated according to the procedure in Sections 5.1.6 and 5.2.6 of [RFC8032]. 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. The "ssh-ed448" key format has the following encoding: string "ssh-ed448" string signature Here, 'signature' is the 114-octet signature produced in accordanceShow full document text