Re: [TLS] I-D Action: draft-ietf-tls-curve25519-00.txt

Simon Josefsson <simon@josefsson.org> Mon, 15 June 2015 21:40 UTC

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From: Simon Josefsson <simon@josefsson.org>
To: Martin Thomson <martin.thomson@gmail.com>
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Date: Mon, 15 Jun 2015 23:40:11 +0200
In-Reply-To: <CABkgnnWsHXvgojKMBz9aOE4rhDdP5fPP1VYnvj7Gs06VggaG1g@mail.gmail.com> (Martin Thomson's message of "Mon, 15 Jun 2015 14:22:35 -0700")
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Subject: Re: [TLS] I-D Action: draft-ietf-tls-curve25519-00.txt
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Martin Thomson <martin.thomson@gmail.com> writes:

> On 15 June 2015 at 14:12, Simon Josefsson <simon@josefsson.org> wrote:
>>> I would suggest claiming that this point format is "uncompressed" and the
>>> only point format for Curve25519.
>>
>> I'm happy to do that.  Anyone against?  If I understand correctly, I
>> would drop most of the montgomery_x_le ECPointFormat registration and
>> instead say: use ECPointFormat "uncompressed" and send the public-key
>> formatted as follows [...].
>
> The CFRG draft defines 25519 to take a 32 byte string.  Use that
> directly.  Just *claim* that it's uncompressed.
>
> You don't have to add a 4 at the front, or mess around with forms.
> Just define (by reference to draft-irtf-cfrg-curves, preferably) the
> format.  We have plenty of contextual information available in TLS, we
> just need the bytes.

I agree!  Committed as follows:

https://gitlab.com/jas/ietf-tls-newcurves/commit/e7b449ee5af70c2a0851f617ce225f93cc86d993#diff-1

/Simon