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Re: [Cfrg] Conclusions: poll about curve around 256bit work factor

Simon Josefsson <simon@josefsson.org> Tue, 24 February 2015 12:39 UTC

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From: Simon Josefsson <simon@josefsson.org>
To: Kurt Roeckx <kurt@roeckx.be>
References: <4927ECAD-1E54-419C-A2DC-1D29BE9E1839@isode.com> <20150223212253.GB27739@roeckx.be>
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Date: Tue, 24 Feb 2015 13:39:08 +0100
In-Reply-To: <20150223212253.GB27739@roeckx.be> (Kurt Roeckx's message of "Mon, 23 Feb 2015 22:22:53 +0100")
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Subject: Re: [Cfrg] Conclusions: poll about curve around 256bit work factor
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Kurt Roeckx <kurt@roeckx.be> writes:

> On Mon, Feb 23, 2015 at 08:58:54PM +0000, Alexey Melnikov wrote:
>> From responses and discussions on the mailing list it is clear that
>> there is rough consensus against using curve 512-C. However, part of
>> the responders said that they prefer 521 (the original Q3 asked),
>> while other responded to extended list suggested by Phillip.
>> 
>> Based on answers chairs declare CFRG consensus against the curve 512
>> being in the CFRG recommendation at the 256 WF level. Other curves
>> (521, 448, etc) still remain as contenders for the CFRG
>> recommendation.
>
> Could you next time please ask what you want really want to ask?

+1

The question that was asked was:

 "Is bandwidth cost of going to p521 worth the speed win over primes
  closer to 512 bits?"

and now my (and others') answer to that questions is used to make a
consensus call on the following statement:

  "against the curve 512 being in the CFRG recommendation at the 256 WF
  level"

My opinion on the first question cannot be extrapolated to cover the
second statement.

/Simon

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