PDFKey Pro, the Mac and Windows utility to unlock password-protected PDFs. PDFKey Pro 4.0 is distributed as shareware. Try it for free for OS X or for Windows. If you like it, pay only USD 24.99 for a license.
PDFKey Pro is used by simply dragging one or more files, or even an entire folder, onto the PDFKey Pro. You can even use it in shell scripts.
PDFKey Pro reads your PDF files with printing or copying passwords set and then creates exact replicas of the PDFs, but without the passwords.
For PDF files that have a viewing password set, PDFKey Pro will read your PDF file and create an unlocked exact replica of the PDF removing the password, although you must supply this password beforehand.
Locking is as simple as unlocking. You will be prompted with a dialog to set your passwords and an exact, but protected, copy of the PDFs will be created.
The included command line tools allow you to insert PDFKey Pro in complex workflows. PDFKey Pro can process entire folders of PDF files without requiring user intervention.
PDFKey Pro is not compatible with DRM’ed eBooks from eStores. PDFKey Pro is designed to help you work with PDF files when you’ve lost your password, or when you need to process your PDFs all at once.
It is not designed to crack DRM.