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LM (LanMan) support?

PostPosted: Mon Jul 06, 2009 7:40 am
by snakeoilsteve
Hi all,

I was wondering if there were any plans to integrate LM (LanMan) support into the brute forcers? Although LM is slower, the keyspace is much smaller and would be very useful for whittling hashes down from a large list. Apologies if this has been discussed before, I couldn't search for lm (as search terms have to be at least 3 characters on the site).

Thanks.

Re: LM (LanMan) support?

PostPosted: Mon Jul 06, 2009 1:53 pm
by Bitweasil
I haven't put in the time to write a DES/LM module for CUDA yet.

I suspect since it's encrypting a constant value with a varying key, there may be some nice optimizations.

Also, I've not worked out if lookup tables (in shared memory) would be fastest, or if bitslicing (very high register count) would be faster.

Adding LM support would be fairly trivial if someone provided some nice LM hash code.

Re: LM (LanMan) support?

PostPosted: Mon Jul 06, 2009 6:10 pm
by blazer
lm is aging and not used much "i wonder why", i guess adding support for it would be a waste of time. Though it would be interesting to see the effects of GPU and DES. Any Rough estimates ?

Re: LM (LanMan) support?

PostPosted: Mon Jul 06, 2009 9:52 pm
by neinbrucke
blazer wrote:lm is aging and not used much

are you on the same planet as i am? :p

Re: LM (LanMan) support?

PostPosted: Tue Jul 07, 2009 3:03 pm
by mrCracker
neinbrucke wrote:
blazer wrote:lm is aging and not used much

are you on the same planet as i am? :p


No way he can be. EVERYONE uses LM. (the number of those who has disabled LM support compared to all those still using it supports my opinion... :-))

I would LOVE to see LM support, but i can't even make a decent windows shell script that outputs "hello, world!" to your screen....

Re: LM (LanMan) support?

PostPosted: Wed Jul 08, 2009 1:37 pm
by blazer
i guess i'm wrong then. :(

Re: LM (LanMan) support?

PostPosted: Thu Jul 09, 2009 5:27 pm
by 1epi
you could always use rainbow tables : http://tbhost.eu/rt.php?algorithm=1

Re: LM (LanMan) support?

PostPosted: Sun Jul 12, 2009 8:29 am
by snakeoilsteve
Bitweasil wrote:Also, I've not worked out if lookup tables (in shared memory) would be fastest, or if bitslicing (very high register count) would be faster.
Adding LM support would be fairly trivial if someone provided some nice LM hash code.


IANAC (I Am Not A Cryptographer) but from some googling it seems that bitslice DES is the way to optimise LM. http://www.darkside.com.au/bitslice/ has some bitslice DES code. JtR (http://www.openwall.com/john/) has a bitsliced-based LM implementation but I'm not sure how readable the source is as it's heavily optimised for specific architectures.

On my 8600GS I get 25 million LM hashes/sec on Elcomsoft Distributed Password Recovery versus 5 on Cain, but the key space is so much lower with LM. I suspect that there'd be some enormous speed gains on a GTX295.

Does the above help?