Edwards-curve Digital Signature Algorithm (EdDSA)
draft-irtf-cfrg-eddsa-01

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Replaces draft-josefsson-eddsa-ed25519
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Network Working Group                                       S. Josefsson
Internet-Draft                                                    SJD AB
Intended status: Informational                              I. Liusvaara
Expires: June 11, 2016                                       Independent
                                                        December 9, 2015

           Edwards-curve Digital Signature Algorithm (EdDSA)
                        draft-irtf-cfrg-eddsa-01

Abstract

   The elliptic curve signature scheme Edwards-curve Digital Signature
   Algorithm (EdDSA) is described.  The algorithm is instantiated with
   recommended parameters for the Curve25519 and Curve448 curves.  An
   example implementation and test vectors are provided.

   NOTE: Anything not about Ed25519 in this document is premature and
   there is at least one FIXME that makes some things unimplementable.

Status of This Memo

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   This Internet-Draft will expire on June 11, 2016.

Copyright Notice

   Copyright (c) 2015 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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   (http://trustee.ietf.org/license-info) in effect on the date of
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Josefsson & Liusvaara     Expires June 11, 2016                 [Page 1]
Internet-Draft          EdDSA: Ed25519 and Ed448           December 2015

   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Notation and Conventions  . . . . . . . . . . . . . . . . . .   4
   3.  EdDSA Algorithm . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Encoding  . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Keys  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.3.  Sign  . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.4.  Verify  . . . . . . . . . . . . . . . . . . . . . . . . .   7
   4.  PureEdDSA, HashEdDSA and Naming . . . . . . . . . . . . . . .   7
   5.  EdDSA Instances . . . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Ed25519ph and Ed25519 . . . . . . . . . . . . . . . . . .   8
       5.1.1.  Modular arithmetic  . . . . . . . . . . . . . . . . .   8
       5.1.2.  Encoding  . . . . . . . . . . . . . . . . . . . . . .   9
       5.1.3.  Decoding  . . . . . . . . . . . . . . . . . . . . . .   9
       5.1.4.  Point addition  . . . . . . . . . . . . . . . . . . .  10
       5.1.5.  Key Generation  . . . . . . . . . . . . . . . . . . .  10
       5.1.6.  Sign  . . . . . . . . . . . . . . . . . . . . . . . .  11
       5.1.7.  Verify  . . . . . . . . . . . . . . . . . . . . . . .  12
     5.2.  Ed448ph and Ed448 . . . . . . . . . . . . . . . . . . . .  12
       5.2.1.  Modular arithmetic  . . . . . . . . . . . . . . . . .  12
       5.2.2.  Encoding  . . . . . . . . . . . . . . . . . . . . . .  12
       5.2.3.  Decoding  . . . . . . . . . . . . . . . . . . . . . .  13
       5.2.4.  Point addition  . . . . . . . . . . . . . . . . . . .  13
       5.2.5.  Key Generation  . . . . . . . . . . . . . . . . . . .  14
       5.2.6.  Sign  . . . . . . . . . . . . . . . . . . . . . . . .  14
       5.2.7.  Verify  . . . . . . . . . . . . . . . . . . . . . . .  15
   6.  Ed25519 Python illustration . . . . . . . . . . . . . . . . .  15
   7.  Test Vectors  . . . . . . . . . . . . . . . . . . . . . . . .  20
     7.1.  Test Vectors for Ed25519  . . . . . . . . . . . . . . . .  20
     7.2.  Test Vectors for Ed25519ph  . . . . . . . . . . . . . . .  23
     7.3.  Test Vectors for Ed448  . . . . . . . . . . . . . . . . .  23
     7.4.  Test Vectors for Ed448ph  . . . . . . . . . . . . . . . .  23
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  23
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  23
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  23
     10.1.  Side-channel leaks . . . . . . . . . . . . . . . . . . .  23
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