How do I crack substr hash?

[epixoip]

here's my stab at creating a program to crack this type of hash. not exceptionally good since it doesn't use sse2 or anything, but it is multithreaded and should be quite a bit faster than the other two that atom and undeath provided. seems to reliably find a collision in under a minute on my box.

http://bindshell.nl/pub/md5substr_mt.c

Code:

epixoip@db:~$ ./md5substr cafebabe Using 16 threads. Elapsed: 38s Progress: 3227859000/377149515625 (0.9%), Speed: 84.9 M/s cafebabe:t,gr>N epixoip@db:~$ ./md5substr deadfa11 Using 16 threads. Elapsed: 40s Progress: 3397629000/377149515625 (0.9%), Speed: 84.9 M/s deadfa11:G,vzY; epixoip@db:~$ ./md5substr deadbabe Using 16 threads. Elapsed: 32s Progress: 2718719000/377149515625 (0.7%), Speed: 85.0 M/s deadbabe:=+y51e epixoip@db:~$ ./md5substr ba5eba11 Using 16 threads. Elapsed: 33s Progress: 2803169000/377149515625 (0.7%), Speed: 84.9 M/s ba5eba11:),;~u` epixoip@db:~$ ./md5substr aaaaaaaa Using 16 threads. Elapsed: 20s Progress: 1698384000/377149515625 (0.5%), Speed: 84.9 M/s aaaaaaaa:8*pU]]