Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Sat, 8 Jun 2013 22:50:29 +0530
From: Sayantan Datta <std2048@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: limits within mscash2

Hi,

On Sat, Jun 8, 2013 at 10:40 PM, <jfoug@....net> wrote:

> Changing the opencl_mscash2 format to allow for salts (user names) longer
> than 19 bytes will take more work.  Ideally, this would be done 'prior' to
> jumping into GPU code.  The salt is ONLY used on iteration #0.  This
> iteration really should be pulled back into the crypt_all function, likely
> done right after the DCC function, but before calling the pbkdf2. Then
> instead of providing the salt to the pbkdf2 function, the 'results' of
> iteration 0 would be provided.  Thus, in the gpu code, iterations 1 to
> 10240 would be done (but not the first). This will have no impact on
> overall speed,  AND will keep the GPU code faster, only doing 1 block
> sha1's, BUT allow multiple block SHA1 code for that very first iteration
> where the salt value is used.


Yes it allows for 22 char salts :). Thank you very much. Probably I can
also make it support 128 byte salts. Mostly some changes need to be made in
pbkdf2_preprocess kernel. The pbkdf2_iter kernel does 1 to 10240
iterations.

Regards,
Sayantan

Content of type "text/html" skipped

Powered by blists - more mailing lists

Your e-mail address:

Powered by Openwall GNU/*/Linux - Powered by OpenVZ