What if both dictionary and brute-force attacks failed?
Have a look at other product we have: Advanced Office Password Breaker (AOPB). Because of U.S. crypto export regulations, the key length in RC4 algorithm used for encrypting the document is only 40 bits, and that means that the total number of possible encryption keys is 2^40 = 1,099,511,627,776. So instead of testing all possible passwords, AOPB test all possible encryption keys. And once the key is found, it decrypts the document, so the password is no longer required to open it. Decryption is still not instant, but recovery time is very reasonable (usually, a few days). Moreover, this method provides 100% success rate regardless the password length. For example, if the speed is one million passwords per second (as for Athlon XP 1800+), the program will work about 305 hours or about 13 days – and this is maximum.
