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Date: Sun, 12 Aug 2012 20:46:48 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: bitslice DES on GPU (was: DES_BS_ASM in DES_bs_b.c)

Hi Sayantan,

On Sun, Aug 12, 2012 at 02:07:11PM +0530, Sayantan Datta wrote:
> What should be the value of DES_BS parameter for a gpu ? I mean which s-box
> file out of three should I use for gpu implementation ? Also could you
> explain the parameters latency ,regs and triop in those s-boxes.

It is way too early for that - you can use any one of the three files
with any settings to get things working first - but since you asked:

sboxes-s.c is meant to be right for ATI/AMD GPUs, provided that you make
use of bitselect() (define the vsel() macro to use it).

sboxes.c is meant to be right for NVIDIA (and we'll replace this file
with one that has even more suitable S-boxes later).  andn is thus set
to 0, triop should be set to 1.

latency and regs will need to be experimented with.  Optimal settings
for these will probably depend on your higher-level code revision, on
its other settings, and on GPU type.

Alexander

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