Re: [Cfrg] Side channel attack and Edwards curves...

Samuel Neves <samuel.c.p.neves@gmail.com> Thu, 06 July 2017 00:36 UTC

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From: Samuel Neves <samuel.c.p.neves@gmail.com>
Date: Thu, 6 Jul 2017 01:35:29 +0100
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Subject: Re: [Cfrg] Side channel attack and Edwards curves...
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Coron's countermeasures [1, §5]---the first and third one, in
particular---work well with Montgomery coordinates.

[1] http://www.jscoron.fr/publications/dpaecc.pdf

On Thu, Jul 6, 2017 at 1:07 AM, Tony Arcieri <bascule@gmail.com> wrote:
> On Wed, Jul 5, 2017 at 4:16 PM, Phillip Hallam-Baker <phill@hallambaker.com>
> wrote:
>>
>> You can blind in either. But if you are going to blind then a lot of the
>> advantages of Montgomery start to collapse. because you have to do that add
>> stage.
>
>
> What if you blinded kP with r using:
>
>     r*([k r^-1]*P)
>
> which only requires inversions?
>
> --
> Tony Arcieri
>
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