PDF Unlock is a simple tool which can remove the password from multiple PDFs in a single operation.
The program isn't a cracking tool. You must know the document password for it to work, and the same password must apply to every file.
The main advantage here is speed and ease of use. Drag and drop your source PDFs, enter the common password, click "Unlock" and the unlocked versions will be saved in the source folder (file.pdf > file_unlocked.pdf).
You can optionally save the unlocked files to a new folder, or even overwrite the originals, although we wouldn't recommend it-- if the unlock process fails for some reason, your document could be lost.
PDF Unlock doesn't do much, but its single function works very well, and it can unprotect an entire folder of PDFs in a click.