What is PDF password protection?

Password protection encrypts a PDF so it only opens after you type the password. The file can also carry permissions that tell PDF apps whether printing, copying text or editing is allowed.

Tool description

This tool adds a password to one PDF. Type the password twice, choose what people who open the file may do, and download the protected copy. The PDF is encrypted with AES-256, the strongest encryption the PDF format has.

Features

  • Encrypts with AES-256
  • Allows or blocks printing, copying and editing
  • Keeps the pages, text, links, form fields and document info
  • Runs in your browser: the file and the password are never uploaded

How permissions work

A blocked permission applies to everyone who opens the file with the password. PDFs also have a second password, the owner password, that lifts the restrictions. When you block something, the owner password is set to a long random one that nobody knows. When everything is allowed, your password is used for both.

Adobe Acrobat, web browsers and most PDF apps follow the permissions, but some tools ignore them. The password itself can't be skipped: without it the file stays encrypted.

Tips

  • Use a long password. Short ones can be guessed by software that tries millions of passwords.
  • Keep the password somewhere safe. Nobody can recover it for you.
  • Protect a PDF before you sign it. A digital signature is no longer valid once the file changes.