Algorithm Identifiers for Ed25519, Ed448, X25519 and X448 for use in the Internet X.509 Public Key Infrastructure
draft-ietf-curdle-pkix-08
Network Working Group S. Josefsson
Internet-Draft SJD AB
Intended status: Standards Track J. Schaad
Expires: October 20, 2018 August Cellars
April 18, 2018
Algorithm Identifiers for Ed25519, Ed448, X25519 and X448 for use in the
Internet X.509 Public Key Infrastructure
draft-ietf-curdle-pkix-08
Abstract
This document specifies algorithm identifiers and ASN.1 encoding
formats for Elliptic Curve constructs using the curve25519 and
curve448 curves. The signature algorithms covered are Ed25519 and
Ed448. The key agreement algorithm covered are X25519 and X448. The
encoding for Public Key, Private Key and EdDSA digital signature
structures is provided.
Status of This Memo
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This Internet-Draft will expire on October 20, 2018.
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Copyright (c) 2018 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Terminology . . . . . . . . . . . . . . . . . . 3
3. Curve25519 and Curve448 Algorithm Identifiers . . . . . . . . 3
4. Subject Public Key Fields . . . . . . . . . . . . . . . . . . 4
5. Key Usage Bits . . . . . . . . . . . . . . . . . . . . . . . 5
6. EdDSA Signatures . . . . . . . . . . . . . . . . . . . . . . 6
7. Private Key Format . . . . . . . . . . . . . . . . . . . . . 6
8. Human Readable Algorithm Names . . . . . . . . . . . . . . . 8
9. ASN.1 Module . . . . . . . . . . . . . . . . . . . . . . . . 8
10. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Example Ed25519 Public Key . . . . . . . . . . . . . . . 10
10.2. Example X25519 Certificate . . . . . . . . . . . . . . . 11
10.3. Examples of Ed25519 Private Key . . . . . . . . . . . . 13
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
13. Security Considerations . . . . . . . . . . . . . . . . . . . 15
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
14.1. Normative References . . . . . . . . . . . . . . . . . . 15
14.2. Informative References . . . . . . . . . . . . . . . . . 16
Appendix A. Invalid Encodings . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
In [RFC7748], the elliptic curves curve25519 and curve448 are
described. They are designed with performance and security in mind.
The curves may be used for Diffie-Hellman and Digital Signature
operations.
[RFC7748] describes the operations on these curves for the Diffie-
Hellman operation. A convention has developed that when these two
curves are used with the Diffie-Hellman operation, they are referred
to as X25519 and X448. This RFC defines the ASN.1 Object Identifiers
(OIDs) for the operations X25519 and X448 along with the associated
parameters. The use of these OIDs is described for public and
private keys.
In [RFC8032] the elliptic curve signature system Edwards-curve
Digital Signature Algorithm (EdDSA) is described along with a
recommendation for the use of the curve25519 and curve448. EdDSA has
defined two modes, the PureEdDSA mode without pre-hashing, and the
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