Date: Wed, 5 Dec 2012 23:38:23 +0400 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: Re: bitslice DES on GPU Hi Sayantan, It's great that you're continuing work on this. Thank you! On Wed, Dec 5, 2012 at 1:24 PM, Sayantan Datta <std2048@...il.com> wrote: > I am working on patching the source at run time. We need to be patching binary, not source. For example, you could find the pointers to patch by looking for their known values, then making sure their count is as expected. You'd record their addresses in an array. Then reuse that array to patch them each time a new salt it set. > However it seems that > during benchmark , salt is changed every time before a crypt all() call is > made. This is negatively affecting the benchmark results because every > time the salt is changed we need to rebuild the kernel which is very slow. > So is it possible to run the benchmark without changing the salt every time > ? In real world cracking how often is the salt changed ? It's changed once per crypt_all() call as well, except in the special case when we're cracking hashes with only one salt (then it's not changed). The salt changes are made infrequent enough by keeping keys_per_crypt large enough. Rebuilding from source is just too slow, though. On Wed, Dec 05, 2012 at 11:57:41PM +0530, Sayantan Datta wrote: > I have managed to solve the above problem by storing the all the kernels > corresponding to different salt in host memory. Hence there is no need to > rebuild kernel every time the salt is changed. However the amount of memory > used can be quite high depending upon the number of different salts loaded. > I have posted the patch in git repo. Curious. How much memory is consumed per salt? How much is consumed when all 4096 salts are present? And how long does it take to build the 4096 kernels? (If this takes too long to measure, then provide the number e.g. for 41 or 410.) Thanks again, Alexander
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.