How to Protect a PDF with a Password
Learn the difference between open passwords, owner settings and real PDF encryption.
Use real PDF encryption
Password protection should be implemented through the PDF encryption model, not a JavaScript prompt or password stored in metadata. The Protect PDF workflow is designed around QPDF encryption.
Open and owner passwords
An open password controls document opening. An owner password controls protection settings and permissions. Usage permissions are not absolute DRM; conforming viewers enforce them.
Do not lose the password
The site does not provide password cracking. Keep a secure record of important passwords and preserve an unencrypted original when appropriate.