may be interesting for someone...

"In short, the RainbowCrack tool is a hash cracker. While a traditional brute force cracker try all possible plaintexts one by one in cracking time, RainbowCrack works in another way. It precompute all possible plaintext - ciphertext pairs in advance and store them in the file so called "rainbow table". It may take a long time to precompute the tables, but once the one time precomputation is finished, you will always be able to crack the ciphertext covered by the rainbow tables in seconds."

http://www.antsight.com/zsl/rainbowcrack/#action

Regards,

this seems only be a good idea when small passwords are used. the time you waste on cracking a hash will be the same, unless you or someone else has already rainbow tables computed. but what if i use a 20 byte password hashed with SHA1 for example? you need damn a lot time to pre-compute all that tables - maybe start a project like seti@home? ;-)

if you only need 1 password it's useless,otherwise...may be.
for examplen/offline application(haven't tried it):
http://sarcaprj.wayreth.eu.org/
or when you have much time preparing but not much time searching for the password...
Regards,

This technique is as old as the hills. The whole point of adding salt to the hash in crypt(3) (the program that hashes the passwords in passwd) was to defeat this kind of thing.

yeah i know,it's in the manual.
as old as the street ,new version.
a story:
http://www.giac.org/practical/GCIH/Mike_Mahurin_GCIH.pdf
sorry if boring...
Regards,

Ho Ho Ho

Just Thought I would drag this old thread back out again.
Perhaps to add a little data and see if anyone has somemore to contribute since things have changed a little.
Online search for Alpha-Number passwords by hash (LM:NT)hxxp://lasecwww.epfl.ch/~oechslin/projects/ophcrack/

Anyone have any other links