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Re: [Cfrg] Elliptic Curves - signature scheme: randomised or not (ends on May 13th)

Simon Josefsson <simon@josefsson.org> Tue, 05 May 2015 14:22 UTC

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From: Simon Josefsson <simon@josefsson.org>
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Date: Tue, 05 May 2015 16:22:13 +0200
In-Reply-To: <5546032D.5070208@isode.com> (Alexey Melnikov's message of "Sun, 03 May 2015 12:14:53 +0100")
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Subject: Re: [Cfrg] Elliptic Curves - signature scheme: randomised or not (ends on May 13th)
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Alexey Melnikov <alexey.melnikov@isode.com> writes:

> 1. CFRG should stick to randomised signature schemes only.

No.

> 2. CFRG should adopt deterministic signature scheme only.

At this time, yes.

There are situations where you need non-determinism in a public-key
signature scheme to achieve certain properties.

I believe it will eventually be useful for the CFRG to recommend a
non-deterministic signature scheme that is better than RSA/DSA/ECDSA.

As Andy said, you can have a scheme that is secure in a deterministic
setting but still accept ranndomness to achieve a non-deterministic
signature, for wider applicability.

However the majority of applications under consideration today (e.g.,
PKIX, TLS, S/MIME, OpenPGP) would directly benefit from having a good
and easy to implement deterministic signature scheme, like EdDSA.

So I believe this should be the focus for the current agenda.

> 3. De-randomisation should be an optional feature for implementers to
> decide upon (i.e. both choices 1 and 2 allowed).

No.

/Simon

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