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Re: [Cfrg] Elliptic Curves - poll on specific curve around 256bit work factor (ends on February 23rd)

Stephen Farrell <stephen.farrell@cs.tcd.ie> Wed, 18 February 2015 22:44 UTC

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Date: Wed, 18 Feb 2015 22:44:27 +0000
From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
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Subject: Re: [Cfrg] Elliptic Curves - poll on specific curve around 256bit work factor (ends on February 23rd)
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On 18/02/15 10:51, Alexey Melnikov wrote:
> CFRG chairs are starting another poll:
> 
> Q3: (For people who want CFRG to recommend a curve at 256bit level) Is
> bandwidth cost of going to p521 worth the speed win over primes closer
> to 512 bits?

I'd be fine with anything significantly stronger than the 128-bit work
factor so would definitely not be arguing that precisely 512 bit long
primes are needed. (I'd actually be fine with any of the "more than
192 bit WF" curves, including the 4xx bit long prime options.)

I don't think the bandwidth cost in terms of bits-sent-over-the-wire is
at all significant if it came to considering 521 vs. 512 bit primes.

S.


> 
> 
> Once this issues is settled, we will be discussing implementation
> specifics and coordinate systems for Diffie-Hellman. We will then make
> decisions on signature schemes. Please don't discuss any of these future
> topics at this time.
> 
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