12-08-2011, 10:42 AM
well, not trillion years to brute-force. more like 180 years on a hd5970. 256^8 is big, but sha1 is computed pretty fast (3200M/s). also note that if your plaintext is of size 64 its required to do an additional sha1 transform. in best case, this lowers speed to 1600M/s.