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Date: Mon, 8 Aug 2011 07:29:41 +0400
From: Solar Designer <>
Subject: Re: John with Radeon graphical card supports?

On Sun, Aug 07, 2011 at 10:43:30AM -0500, Richard Miles wrote:
> I'm interested in buy 2 or 3 of the cheap Radeon graphical cards to
> speed up my brute force password cracking. I love john the ripper, so
> I want to use it. There is a way to make john the ripper works with
> this graphical cards? Even with 2 or 3 at the same time? Maybe a third
> party patch?

Unfortunately, there's currently no JtR patch that would achieve
reasonable performance on AMD/ATI GPUs.  There are some patches in
development (see below), but they're not reasonable for actual use yet.
Hopefully, things will improve soon.  We'll see.

Things are better for NVidia GPUs, where patches by Lukas Odzioba adding
CUDA code for some "slow" hashes achieve reasonable performance.  We
actually used john-1.7.8-allcuda-0.2.diff for phpass hashes in the
KoreLogic contest.  This patch may be found here:

Lukas is currently working on implementing "slow" hashes in OpenCL as
well, which is supposed to work for AMD/ATI GPUs.  You can already find
his john-1.7.8-cryptmd5opencl_0.1.diff on the wiki (URL above).  The wiki page also mentions OpenCL
support for SHA256-crypt, but somehow I don't see this patch on the
wiki.  Lukas?

There's also a patch implementing several "fast" hashes in OpenCL, by
Alain Espinosa, Dhiru Kholia, and Samuele Tonon - "OpenCL support for
cracking NT, raw-MD4, raw-MD5, NSLDAP and raw-SHA1 hashes",
john-1.7.8-jumbo-5-opencl-1.diff.bz2.  This should work on AMD/ATI
cards (in fact, that's what the authors test it on).  However, it only
achieves performance comparable to that of using several CPU cores at
once, probably not exceeding that of one quad-core CPU.  Somewhat
invasive changes will be needed to JtR core to avoid this bottleneck for
"fast" hashes.  We intend to approach this later.


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