[Beowulf] NVIDIA GPUs, CUDA, MD5, and "hobbyists"

Jakob Oestergaard jakob at unthought.net
Wed Jun 18 15:45:23 PDT 2008


On Wed, Jun 18, 2008 at 10:14:28PM +0200, Vincent Diepeveen wrote:
> Prentice,
> 
> No one doubts your collegue.
> 

Ok the following has nothing to do with any part of the discussion, but I just
needed to get this out  :)

...
> So this experiment of your high esteemed collegue is an example of an  
> application that you do not want to buy those cards for.

For attacks against password hashes (and similar) this is very useful.

You generate strings, hash them, compare the hash to your target value.  If it
matches, you've found your source string (password).

Disks are never involved.

Your brute-force of md5 (or something similar) will run as fast as the string
generators (processors) allow. Some time ago I looked into buying an FPGA card
to speed up a bitsliced 3des to brute force certain hashes, but never actually
got around to doing this.  From an algorithmic point of view, though, this
could have rocked seriously on even a low end FPGA  :)

The point being; this is a useful application. Even though the md5
implementation may just have been "for show" and not intended as a final
product, it is very close to something that has direct uses.

And sure, no, people won't buy GPUs to speed up the occational file hashing
with md5sum, and I'm sure that wasn't the intention either  :)

-- 

 / jakob




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