Re: [Cfrg] A downside of deterministic DL signatures?

Bodo Moeller <bmoeller@acm.org> Tue, 29 July 2014 21:20 UTC

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Date: Tue, 29 Jul 2014 17:19:55 -0400
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From: Bodo Moeller <bmoeller@acm.org>
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Subject: Re: [Cfrg] A downside of deterministic DL signatures?
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Right. I don't think that deterministic signatures should be required. I
think having the ephemeral scalar depend on the message is an (often
useful) implementation technique, but probably not something to be imposed
as a protocol variant in its own right.

Bodo



2014-07-29 16:58 GMT-04:00 Dan Brown <dbrown@certicom.com>:

> ‎In ECDSA or Schnorr, if the ephemeral private key k depends on the
> message bring signed, precomputation of kG, an efficiency advantage
> (reduced latency?), and possibly effective side channel countermeasure
> (harder to time precomputation), seems precluded. Not being an efficiency
> or side channel expert, I ask: Does this downside sound right?
>
> If so, deterministic signatures ought to be a SHOULD or MAY, not a MUST
> (or none of the above, since thus is not an interoperability issue).
>
> Best regards,
>
> -- Dan
>
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