Password Protect PDF

Encrypt a PDF so it cannot be opened without a password. PDF supports two separate passwords and they do different jobs: the user password is required to open the document at all, while the owner password leaves it readable but controls what the reader is permitted to do. Setting the user password is what actually protects the contents - the encryption is real, and there is no way to recover the file if the password is lost.

How to password protect a PDF

  1. Upload the PDF you want to protect.
  2. Set a user password to require one for opening, an owner password to restrict permissions, or both.
  3. Choose the encryption key length.
  4. Apply and download the encrypted PDF.

Frequently asked questions

What is the difference between the user and owner passwords?

The user password is needed to open the file. The owner password does not restrict opening - it governs permissions such as printing and copying, and lets whoever knows it change those settings later.

Which key length should I use?

The longest offered, unless you must support a very old reader. AES-256 is the current standard; the shorter legacy options exist for compatibility rather than security.

Can I recover a PDF if I forget the password?

No. The encryption is genuine and there is no recovery path or back door. Remove PDF Password requires you to supply the current password - it does not break the encryption.

Is the owner password alone enough to protect a document?

No. Permission restrictions are advisory and many readers ignore them, so the content stays fully readable. Use the user password when the content itself must be protected.

Other security and signing tools

Files are uploaded over an encrypted connection and processed on CoonTool's own server, not in your browser. The working copy is deleted automatically once the job is done, and in any case within 24 hours. Nothing is stored permanently and no account is required.