Algorithm Identifiers for Ed25519, Ed448, X25519 and X448 for use in the Internet X.509 Public Key Infrastructure
draft-ietf-curdle-pkix-08

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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

   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
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   This Internet-Draft will expire on October 20, 2018.

Copyright Notice

   Copyright (c) 2018 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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   (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

Josefsson & Schaad      Expires October 20, 2018                [Page 1]
Internet-Draft            Safe curves for X.509               April 2018

   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
   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