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[WajdyEssam]

Hello, I'm newbie in GPU programming , and i work on brute force RAR Password Recovery on ATI Stream Processor using brook+ language, but i see that the kernel written in brook+ language doesn't allow any calling to normal functions (except kernel functions) , my questions is :

1) how to use unrar.dll (to unrar archive files) API in this situation? and is this the only way to program RAR password recovery?

2) what about crack and ElcomSoft software that use GPU , how they work ?

3) what exactly the role for the function work inside GPU (ATI Stream processor or CUDA) in this program?

4) is nVidia/CUDA technology is easier/more flexible than ATI/brook+ language ?

Thanks in advance .

[empty_knapsack]

0) There is already RAR Password Recovery for ATI GPUs www.golubev.com/rargpu.htm

1)  It isn't enough to use unrar.dll as it's way too slow (as it doesn't optimized for password checking at all). You're need to redone and include some unrar parts directly into your code (luckily unrar's source code is available).

2, 3) ElcomSoft doesn't support GPU for archives. Crark offloads only password -> key generation to GPU (as it most time consuming part). And password -> key generation only requires several thousands SHA1 transformations. The kernel code itself running on GPU isn't too complex. Though preparing data for each SHA1 isn't so easy because of the algorithm used.

4) Yes, CUDA is easier to use. And ATI's GPUs are significantly faster on integer operations. That's the dilemma.