Ophcrack is a Windows password cracker based on a time-memory trade-off using rainbow tables. This is a new variant of Hellman's original trade-off, with better performance.

Ophcrack will recover 99.9% of alphanumeric passwords in a matter of seconds

Here are some key features of "Ophcrack":

· Cracks LM and NTLM hashes.
· Free tables available for alphanumeric LM hashes.
· Loads hashes from local SAM, remote SAM.
· Loads hashes from encrypted SAM recovered from a Windows partition, Vista included.