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Date: Thu, 6 Dec 2012 22:42:17 +0530
From: Sayantan Datta <std2048@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: bitslice DES on GPU

On Thu, Dec 6, 2012 at 10:26 PM, magnum <john.magnum@...hmail.com> wrote:

> On 6 Dec, 2012, at 17:38 , Sayantan Datta <std2048@...il.com> wrote:
> > I did the following:
> >
> > Set up two hard coded kernels with same salt. Bit reversed a constant at
> only one position in one of the kernel. Using this loop,
> >
> >  //kernel 1
> > for(i=0; i< binary_size;i++){
> >       iptr = binary + i;
> >       if(*iptr== 0xf0000000) printf("Found:%d\n",i);
> >     }
> > //kernel 2
> > for(i=0; i< binary_size;i++){
> >       iptr = binary + i ;
> >       if(*iptr== 0x0000000f ) printf("Found:%d\n",i);
> >     }
> >
> > where 'iptr' is int pointer , 'binary' is char pointer and 'binary_size'
> is size in bytes.
> >
> > Now comparing the two sets of found locations, I should be able to
> pinpoint at least one  common location. However it seems that there are no
> common location between them!!
> >
> > Is this approach OK?
>
>
> I know some people "binary patch" AMD kernels for BFI and stuff but I
> always thought they actually patch IL code in an ELF binary file and then
> load that. This will of course be a lot faster than actually recompiling so
> it might be a better alternative (of course vendor dependant, but I think
> that currently goes for any method).
>
> I bet Milen would know for sure how to proceed.
>
> magnum
>

I doubt he is following this thread , is he there in IRC and by what name?

Regards,
Sayantan

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