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Date: Fri, 5 Oct 2012 00:17:33 +0200
From: magnum <>
Subject: Re: Office2013 OpenCL

On 4 Oct, 2012, at 23:41 , Claudio André <> wrote:
> 2012/10/4 magnum <>:
>> BTW it does around 44 million SHA-2 per second on the 570 and over 75 million on HD7970. Are those speeds fair or lousy? There is a huge need for private memory so I have no idea how to get it faster.
> Well, i tried once to compare raw 512 and 512crypt. Then, i realized
> that on sha512crypt i measure rounds (not 'digest' operations,
> 'neigher' blocks operations). Not sure if i am clear here, but your
> number seems to be ok if i can compare your solution with mine.
> Anyway, i will try to think about it while looking at the code.

I'm counting calls to the actual digest function. For the office formats this is the same as the iteration count but for RAR it depends on password length - it's originally 256K update()'s which turns out as 94224 blocks at a password length of 6 characters. So the huge difference between RAR and Office 2010 (100K rounds) speeds is just due to overhead in RAR, it's very GPU unfriendly, while Office is very GPU friendly.

BTW my formats do not have any update() and sometimes no init() nor final() either. And no endian swaps within sha_block(). I use very lean and raw digest functions with context in the output buffer if needed. The caller builds the buffer in order to avoid swapping back and forth. It matters when you do a 100,000 rounds... BTW, I also use to len sha_block() work directly on the input buffer instead of copying it, but that means it's destroyed after the call so any re-use of input must be re-built.

Note that Office 2010 and Office 2013 is exactly the same, except the former use SHA-1 and the latter use SHA-512. So I currently do 2.1 billion sha1/s on 7970 but only 75 million sha2/s.


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