Internet DRAFT - draft-nir-ipsecme-eddsa
draft-nir-ipsecme-eddsa
Network Working Group Y. Nir
Internet-Draft Check Point
Intended status: Standards Track April 8, 2016
Expires: October 10, 2016
Using Edwards-curve Digital Signature Algorithm (EdDSA) in the Internet
Key Exchange (IKEv2)
draft-nir-ipsecme-eddsa-00
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
2. The "Identity" Hash Identifier . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Normative References . . . . . . . . . . . . . . . . . . . . 3
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
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 a
signature phase, which makes sense because most signature algorithms
either cannot sign messages bigger than their key or truncate
messages bigger than their key.
[I.D-eddsa] defines signature algorithms that do not require 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 message is available at once.
[I.D-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 OIDs for these
two signature methods. To signal within IKE that no hashing needs to
be done. 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].
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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 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 there is no good reason
to hash where the signature algorithm does not require it (or does it
internally), so the "Identity" value SHOULD be the only one used 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>.
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[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]
Josefsson, S., "Using Curve25519 and Curve448 in PKIX",
March 2016, <https://tools.ietf.org/html/draft-ietf-
curdle-pkix-newcurves-00>.
Author's Address
Yoav Nir
Check Point Software Technologies Ltd.
5 Hasolelim st.
Tel Aviv 6789735
Israel
EMail: ynir.ietf@gmail.com
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