Hi,
I have some data I think crypted by DES.I want to bruteforce it.So before reinventing the wheel,is there any software to bruteforce DES? like

Also if there is no such program what should be the strategy for bruteforce.AFAIK although key is 64 bit 8 bits used for parity so there are keys which gives same result.So we have to eliminate them too to decrerase key space to 56 bit.I will appreciate any tips on this subject.

Regards.

Well, it's almost as easy to write your own as to google for one. Here are ten different C implementations of DES from the applied crypto book:

http://www.mirrors.wiretapped.net/security/cryptography/literature/applied-crypto/

Any one of these will suit your needs. The trouble is, 56 bits is still a lot! It could take weeks or months on a single PC.

However, you could write to Paul Kocher at cryptography.com and ask how much he charges to rent the DEScrack machine he built. It'll do it in a couple of days.

Thanks for the links.I have already implemented DES routines from SSLeay package.I dont have any problem with it.I thought there is maybe some program written already for this purpose.Thanks again.

I have found another implemantation of DES which is written in MMX and using some technique called bitslice.I have tried to implement it but I failed.Could anybody with good understanding of this algorithm help to implement it?I have downloaded http://http.distributed.net/pub/dcti/source/archives/pub-20000502.zip.It has Des folder with such implemantaion.I have used obj files in it and tried to call


but it didnt worked.Thanks in advance.

Have you tried John the Ripper password cracker (http://www.openwall.com/john/)? It supports many brute-force cracking algorithm, includes DES, 3DES...