Recover PDF Password is a password cracking app for the Mac. It can be used to recover passwords that prevent you from opening a PDF file. It can do this in two different ways: by using a brute-force attack or a dictionary-based attack. The brute-force attack tries every combination of characters one after the other, and given enough time, it can crack down most passwords. The second option uses a text file with common words and tries to open the document with that. You have to have a long and well-though word list for this type of attack to work.
One great thing about this app is that it REALLY lets you customize these attacks. For example, if you choose to use the brute-force attack, you can specify the password length, use a template, and choose which characters you want to include in the attack. You can manually add characters as well.
In my testing, I encrypted a PDF file using Mac OS X's built-in PDF encryption tool. I used "dada123" as my password. The estimate time for completion was of "more than a day". I let it work for 15 minutes and nothing happened. The speed at which the app can work depends on your hardware, so the better the computer, the faster it will go.
The demo version will let you find passwords, but it will only show the first few characters of it.
- Very customizable
- Two different modes