HeyPDF
All tools

Protect PDF

Add password protection to a PDF with AES-128 encryption. Encryption happens in your browser — your file and password never leave your device.

Drop a PDF file here
We'll add password protection with AES-128 encryption — entirely in your browser.

How to use Protect PDF

  1. 1
    Drop a PDF file.
  2. 2
    Choose a strong password and optional permission restrictions.
  3. 3
    Click Protect PDF — download the encrypted file.

FAQ

What encryption is used?

PDFs are encrypted with AES-128 (the standard for password-protected PDFs). Any PDF reader that supports password-protected files will be able to open them.

Is my password sent anywhere?

No. Encryption happens entirely in your browser. Neither your PDF nor your password is uploaded to a server.

What's the difference between user and owner password?

A user password is required to open the document. An owner password controls what users can do (print, copy, edit). HeyPDF sets both to the same value for simplicity.

Can I remove the password later?

Yes — open the protected PDF in any PDF reader with the password, then re-save it without protection (or use a future Unlock PDF tool here).