Re: [Cfrg] On the use of Montgomery form curves for key agreement

Benjamin Black <b@b3k.us> Tue, 02 September 2014 21:33 UTC

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From: Benjamin Black <b@b3k.us>
Date: Tue, 2 Sep 2014 14:33:34 -0700
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To: Stephen Farrell <stephen.farrell@cs.tcd.ie>
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Cc: "cfrg@ietf.org" <cfrg@ietf.org>
Subject: Re: [Cfrg] On the use of Montgomery form curves for key agreement
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Why would new cipher suites be required to use new curves? Do you mean new
named curve code points rather than cipher suites?

Though our reasons are different, it sounds like we agree on leaving wire
formats to the WGs.


On Tue, Sep 2, 2014 at 1:30 AM, Stephen Farrell <stephen.farrell@cs.tcd.ie>;
wrote:

>
> Just on this point...
>
> On 02/09/14 02:50, Benjamin Black wrote:
> > The various working groups and standards bodies have already answered the
> > question of what goes on the wire.
>
> That's not correct. When CFRG finish doing a great job here, then
> the TLS WG will have to assign new codepoints for ciphersuites and
> there is nothing stopping them defining new encodings at that point
> if that's needed. That'd just not be a big deal. And the same is
> true of other IETF activities. So what goes on the wire should be
> a non-issue for this discussion really.
>
> There is a connection with Russ' point about code re-use, but that's
> much better considered in the way Russ framed it, as an implementation
> issue and not as a protocol issue. Note that I'm not saying here that
> I share Russ' concerns or conclusions, (not having implemented any
> ECC myself) but I do think his question is the right one to ask.
>
> S.
>