Password protect a PDF with AES-256

This is genuine encryption using the PDF 2.0 security handler — not a permissions flag that readers can ignore. The file will not open anywhere without the password.

Open the free Protect PDF tool

Free · No upload · No sign-up · No watermark

How to protect a PDF

  1. Open the editor and load your PDF.
  2. Set a password in the document options.
  3. Save — the downloaded file is encrypted with AES-256.

Questions

What if I forget the password?
It cannot be recovered. AES-256 has no back door, so keep the password somewhere safe.
Which readers can open it?
Any modern reader that supports PDF 2.0 encryption, such as Adobe Acrobat and the built-in viewers in Chrome, Edge and Firefox.
Is my file uploaded?
No. The whole job runs inside your browser tab, so the document never leaves your device. You can even disconnect from the internet once the page has loaded.

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