wdiff draft-nir-ipsecme-eddsa-00.txt draft-nir-ipsecme-eddsa-01.txt

Network Working Group Y. Nir
Internet-Draft Check Point
Intended status: Standards Track April 8, June 11, 2016
Expires: October 10, December 13, 2016

Using Edwards-curve Digital Signature Algorithm (EdDSA) in the Internet
Key Exchange (IKEv2)
draft-nir-ipsecme-eddsa-00
draft-nir-ipsecme-eddsa-01

Abstract

This document describes the use of the Edwards-curve digital
signature algorithm in the IKEv2 protocol.

Status of This Memo

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions Used in This Document . . . . . . . . . . . . 2 3
2. The "Identity" Hash Identifier . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Normative References . . . . . . . . . . . . . . . . . . . . 3
Appendix A. ASN.1 Objects . . . . . . . . . . . . . . . . . . . 5
A.1. ASN.1 Object for Ed25519 . . . . . . . . . . . . . . . . 5
A.2. ASN.1 Object for Ed448 . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 5

1. Introduction

The Internet Key Exchange protocol [RFC7296] can use arbitrary
signature algorithms as described in [RFC7427]. The latter RFC
defines the SIGNATURE_HASH_ALGORITHMS notification where each side of
the IKE negotiation lists its supported hash algorithms. This
assumes that all signature schemes involve a hashing phase before followed
by a signature phase, which makes phase. This made sense because most signature
algorithms either cannot sign messages bigger than their key or
truncate messages bigger than their key.

[I.D-eddsa]

EdDSA ([I.D-eddsa]) defines signature algorithms methods that do not require pre-
hashing
pre-hashing of the message. Unlike other methods, these signature
algorithms accept
arbitrary-sized messages, so no pre-hashing is required. These
methods are called Ed25519 and Ed448, which respectively use the
Edwards 25519 and the Edwards 448 ("Goldilocks") curves. Although
that document also defines pre-hashed versions of these algorithm,
those versions are not recommended for protocols where the entire to-be-signed to-
be-signed message is available at once.

[I.D-eddsa]

EdDSA defines the binary format of the signatures that should be used
in the "Signature Value" field of the Authentication Data Format in
section 3. [I.D-pkix-newcurves] defined The "EdDSA, Ed25519, Ed448, Curve25519 and Curve448 for
X.509" document ([I.D-curdle-pkix]) defines the OIDs object identifiers
(OIDs) for these
two signature methods. To For convenience, these OIDs are
repeated in Appendix A.

In order to signal within IKE that no hashing needs to be done. A done, we
define a new value has to be signalled in the SIGNATURE_HASH_ALGORITHMS notification,
one that indicates that no hashing is performed.

1.1. Conventions Used in This Document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].

2. The "Identity" Hash Identifier

This document defines a new value called "Identity" (value TBA by
IANA) in the hash algorithm registry for use in the
SIGNATURE_HASH_ALGORITHMS notification. Inserting this new value
into the notification indicates that the receiver supports at least
one signature algorithm that accepts arbitrary-sized messages such as
Ed25519 and Ed448.

Ed25519 and Ed448 are only defined with the Identity hash, and MUST
NOT be sent to a receiver that has not indicated support for the
"Identity" hash.

The pre-hashed versions of Ed25519 and Ed448 (Ed25519ph and Ed448ph
respectively) SHOULD NOT be used in IKE.

3. Security Considerations

The new "Identity" value is needed only for signature algorithms that
accept an arbitrary-sized input. It MUST NOT be used if none of the
supported algorithms has this property. OTOH On the other hand there is
no good reason to hash pre-hash the inputs where the signature algorithm
either does not require it (or does it
internally), so or performs a hash internally. For this
reason implementations SHOULD have the "Identity" value in the
SIGNATURE_HASH_ALGORITHMS notification when they support EdDSA.
Implementations SHOULD be NOT have other hash algorithms in the only one used
notification if all of the supported signature algorithms have this property.

4. IANA Considerations

IANA is requested to assign a new value from the "IKEv2 Hash
Algorithms" registry with name "Identity" and this document as
reference.

5. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.

[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <http://www.rfc-editor.org/info/rfc7296>.

[RFC7427] Kivinen, T. and J. Snyder, "Signature Authentication in
the Internet Key Exchange Version 2 (IKEv2)", RFC 7427,
DOI 10.17487/RFC7427, January 2015,
<http://www.rfc-editor.org/info/rfc7427>.

[I.D-eddsa]
Josefsson, S. and I. Liusvaara, "Edwards-curve Digital
Signature Algorithm (EdDSA)", March 2016,
<https://tools.ietf.org/id/draft-irtf-cfrg-eddsa-05.html>.

[I.D-pkix-newcurves]

[I.D-curdle-pkix]
Josefsson, S., "Using "EdDSA, Ed25519, Ed448, Curve25519 and
Curve448 in PKIX",
March for X.509", April 2016, <https://tools.ietf.org/html/draft-ietf-
curdle-pkix-newcurves-00>.
<https://tools.ietf.org/html/draft-ietf-curdle-pkix-00>.

Appendix A. ASN.1 Objects

The normative reference for the ASN.1 objects for Ed25519 and Ed448
is in [I.D-curdle-pkix]. They are repeated below for convenience.

A.1. ASN.1 Object for Ed25519

id-Curve25519 OBJECT IDENTIFIER ::= { 1.3.101.110 }

Parameters are absent.

Binary encoding: TBA

A.2. ASN.1 Object for Ed448

id-Curve448 OBJECT IDENTIFIER ::= { 1.3.101.111 }

Parameters are absent.

Binary encoding: TBA

Author's Address

Yoav Nir
Check Point Software Technologies Ltd.
5 Hasolelim st.
Tel Aviv 6789735
Israel

EMail: ynir.ietf@gmail.com