Lock PDF

Protect your PDF with a password using AES-256 encryption in your browser. Enter and confirm a password, then download the locked document.

The interactive workspace loads here. Enable JavaScript to select and process files on your device.

How to use Lock PDF

  1. Choose an unprotected PDF, up to 50 MB.
  2. Enter a password and enter it again to confirm. Save it somewhere safe.
  3. Choose Lock PDF, download the result and check it opens with your password.

Frequently asked questions

Does the downloaded PDF really require a password?

Yes. The tool uses AES-256 PDF encryption. A compatible reader asks for the password before opening the document.

Can PDFDesk recover my password?

No. Keep your password separately in a safe place. Passwords and document contents are not sent to a PDFDesk processing server.

Can I lock a PDF that already has a password?

Unlock it first using the existing password. Then use Lock PDF to protect the unencrypted copy. Existing digital signatures may become invalid.

Files in this workspace are processed in your browser. Keep the original and check the result before sharing. The total input limit is 50 MB; large tasks may exceed your device memory.

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