Contrary to popular belief, Unix passwords cannot be decrypted. Unix
passwords are encrypted with a one way function. The login program
encrypts the text you enter at the "password:" prompt and compares
that encrypted string against the encrypted form of your password.
Password cracking software uses wordlists. Each word in the wordlist
is encrypted with each of the 2600 possible salt values and the
results are compared to the encrypted form of the target password.
The best cracking program for Unix passwords is currently Crack by
Alec Muffett. For PC-DOS, the best package to use is currently