Re: [TLS] I-D Action: draft-ietf-tls-curve25519-01.txt

[Hubert Kario <[e-mail]>]

On Monday 06 July 2015 04:48:14 [e-mail] wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories. This draft is a work item of the Transport Layer Security
> Working Group of the IETF.
> 
>         Title           : Curve25519 and Curve448 for Transport Layer
> Security (TLS) Authors         : Simon Josefsson
>                           Manuel Pegourie-Gonnard
> 	Filename        : draft-ietf-tls-curve25519-01.txt
> 	Pages           : 11
> 	Date            : 2015-07-06
> 
> Abstract:
>    This document specifies the use of Curve25519 and Curve448 for
>    ephemeral key exchange in the Transport Layer Security (TLS) and
>    Datagram TLS (DTLS) protocols.  It updates RFC 5246 (TLS 1.2) and RFC
>    4492 (Elliptic Curve Cryptography for TLS).

As is described in secion 5.1. of RFC 4492, and then reiterated in 
section 2.2. of this draft - the elliptic_curves (a.k.a. supported_groups) 
guides both the ECDH curves and curves understandable by peer for ECDSA 
signatures.

As Curve25519 and Curve448 can only be used for ECDHE, maybe they should be 
defined/named in the registry as such, to remove any ambiguity[1]:

         enum {
              Curve25519_ecdh(TBD1),
              Curve448_ecdh(TBD2),
         } NamedCurve;


 1 - to not redo the mistake of diffie-hellman-group1-"really-group2"-sha1 in 
     SSH: https://tools.ietf.org/html/rfc4253#section-8.1 when the 25519 and 
     448 are defined for some form of ECDSA
-- 
Regards,
Hubert Kario
Quality Engineer, QE BaseOS Security team
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purkyňova 99/71, 612 45, Brno, Czech Republic