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Re: [Cfrg] On relative performance of Edwards v.s. Montgomery Curve25519, variable base

Kurt Roeckx <kurt@roeckx.be> Mon, 12 January 2015 21:46 UTC

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Date: Mon, 12 Jan 2015 22:46:43 +0100
From: Kurt Roeckx <kurt@roeckx.be>
To: Andrey Jivsov <crypto@brainhub.org>
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References: <54AA4AB9.70505@brainhub.org> <54AA5AD3.9020009@shiftleft.org> <54AAEEFC.9060309@brainhub.org>
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Subject: Re: [Cfrg] On relative performance of Edwards v.s. Montgomery Curve25519, variable base
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On Mon, Jan 05, 2015 at 12:07:24PM -0800, Andrey Jivsov wrote:
> 
> A common assumption is that we need point compression in ECDH, from which it
> follows that Montgomery representation is a wash for p ~ 2^256.
[...]
> This is fine for authenticated keys, e.g. because these will be distributed
> in X.509 certificates, DNS records, etc.

It's my understanding that at least for TLS the consensus is to
drop ECDH in favour of ephemeral versions only.  As far as I know
it's also very uncommon to see it in X509 certificates.  Are there
going to be uses of static ECDH?


Kurt

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