Search for: Any password, User password or Owner password. Select this option to instruct the program which particular password to search for; look at About PDF encryption chapter first. And here are a few recommendations for different cases:
|•||Your file is not encrypted at all. It doesn't matter what do you select: when you try to run the attack, the program will note you that it is nothing to do.|
|•||Your file has only "owner" password set. You'll get a notification message that the file can be decrypted now, but you can still search for the original password. Select to search for Owner password only; you can also search for Any password, but the speed will be lower.|
|•||Your file has both "user" and "owner" passwords set, and they're the same (typically, you don't know that in advance, but as noted above, the "owner" password is set to the same value as "user" one just by default). The best solution here is to search for User password only, as far as it is the fastest.|
|•||Both "user" and "owner" passwords are set, but they're different. You can search for any of them, or for both at the same time. Please take in mind that searching for User password is the fastest, for Owner password – almost two time slower, and for Any password – the slowest. So that's up to you what to select. There is a chance that one of these passwords is much shorter/simpler than the other one, but again, you don't know that in advance. We'd recommend to set Any password first (for example, with the dictionary attack, and up to 4-5 chars with brute-force attack), and then look for User password, but in extended range (e.g. up to 7 chars).|
Mask symbol: used for Mask attack.
Use code optimized for: (Non-MMX processors / Intel PII/PIII/Celeron / AMD Athlon / Intel P4 SSE2 / Intel Core/Core2): force APDFPR to use the code specially optimized for the given CPUs. The program detects your CPU and tries to select the proper code automatically, but you may want to play with that option if you've got any other CPU.
GPU Manager: calls GPU Manager (separate progham installed with APDFPR), that allows to set what GPU(s) (graphic processors) the program can run the brute-force attack on, so providing hardware acceleration. The list of compatible video cards is available at NVIDIA web site. Please note that GPU acceleration is available only for PDF files with 256-bit AES encryption.