Re: [Cfrg] On relative performance of Edwards v.s. Montgomery Curve25519, variable base

Michael Hamburg <mike@shiftleft.org> Tue, 06 January 2015 00:07 UTC

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From: Michael Hamburg <mike@shiftleft.org>
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Date: Mon, 5 Jan 2015 16:07:42 -0800
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References: <54AA4AB9.70505@brainhub.org> <54AA5AD3.9020009@shiftleft.org> <54AAEEFC.9060309@brainhub.org> <EBF3EC55-3057-496A-8BAE-7EAD405518A7@shiftleft.org> <54AB194A.6020104@brainhub.org> <322BA3AD-7F5F-4A77-ADBA-7E5260DC690A@shiftleft.org>
To: Andrey Jivsov <crypto@brainhub.org>
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Subject: Re: [Cfrg] On relative performance of Edwards v.s. Montgomery Curve25519, variable base
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> On Jan 5, 2015, at 4:04 PM, Michael Hamburg <mike@shiftleft.org>; wrote:
> 
> 
>> On Jan 5, 2015, at 3:07 PM, Andrey Jivsov <crypto@brainhub.org <mailto:crypto@brainhub.org>> wrote:
>> The method uses window exponentiation-style scalar multiplication with doubling for each bit. The data-dependent decisions are done for additions, which are additional ~ 50% of these. The fix may lower the performance gap, but I think it will be within these 15%.
> 
> The difference is about 15% in my code.

Sorry, I meant 12%.

— Mike