Good evening boys n' girls!

I've been looking to find an equivalent program of APDFPR (Advanced PDF Password Recovery by Elcomsoft) for Linux lateley. All that I've found was PDFDecrypt which I personally think isn't a complete software at all. It works without a GUI and the most important function is missing: If no userpassword is set, all restriction can be removed and thus resulting in a fully usable PDF.

Do you know of any great Programs that implement a variety of features like (passsword-mask-attack, instant decrypting) of locked PDFs (either OpenSource or Commercial) for *nix based systems? Please let me know.