From the doc: 'You can't recover (or remember) a zip's password? This program does it professionally. It is highly speed optimized - Up to 129,600,000,000 passwords/day on a modern Pentium II system. The program can run as a screensaver, has an heuristic type analysis, and has several different types of attacks. The program is fully customizable: you can set the password length (or length range) and the character set to be used to generate the passwords.'