Re: [Cfrg] New names for draft-ladd-safecurves

Robert Ransom <rransom.8774@gmail.com> Tue, 21 January 2014 04:25 UTC

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Date: Mon, 20 Jan 2014 20:25:23 -0800
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From: Robert Ransom <rransom.8774@gmail.com>
To: Mike Hamburg <mike@shiftleft.org>
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Cc: "cfrg@irtf.org" <cfrg@irtf.org>, Jon Callas <jon@callas.org>
Subject: Re: [Cfrg] New names for draft-ladd-safecurves
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On 1/20/14, Mike Hamburg <mike@shiftleft.org> wrote:

> I suppose in that case we should be using curves with a small A or (A-2)/4
> in Montgomery form instead of small d in Edwards form, because you need to
> multiply by A more often: Edwards representations are probably fastest with
> Niels+Extended coordinates at that size so they almost never multiply by d.

The Montgomery-form ladder is as efficient for small-integer
Edwards-form d as it is for small-integer Montgomery-form parameter
((A-2)/4 or (A+2)/4).


Robert Ransom