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1995-12-11 - Re: Timing Cryptanalysis Attack

Header Data

From: Tom Weinstein <tomw@netscape.com>
To: cypherpunks@toad.com
Message Hash: 7a6dde9b743e6d9e04b77cbfc9b4a01b3390d405aace874297630e9723a0814d
Message ID: <30CC02F5.4487@netscape.com>
Reply To: <199512110845.JAA25564@utopia.hacktic.nl>
UTC Datetime: 1995-12-11 10:27:46 UTC
Raw Date: Mon, 11 Dec 1995 18:27:46 +0800

Raw message

From: Tom Weinstein <tomw@netscape.com>
Date: Mon, 11 Dec 1995 18:27:46 +0800
To: cypherpunks@toad.com
Subject: Re: Timing Cryptanalysis Attack
In-Reply-To: <199512110845.JAA25564@utopia.hacktic.nl>
Message-ID: <30CC02F5.4487@netscape.com>
MIME-Version: 1.0
Content-Type: text/plain


Eric Young wrote:
> 
> I for one will probably add a flag for conditional compilation of my
> bignumber library so that it will take constant time.  This may be a
> %10 slow down (using small windows exponentiation) which is trivial
> compared to the %30 speedup I will probably get when I implement a
> faster mod function :-).

Careful.  Even if you can make the number of executed instructions the
same, you still have to worry about timing differences due to branches
and the way the hardware multiplier handles different operands.

-- 
Sure we spend a lot of money, but that doesn't mean | Tom Weinstein
we *do* anything.  --  Washington DC motto          | tomw@netscape.com

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