ZTools › Secure

Protect PDF

Encrypt a PDF with a password (AES-256).

Protect PDF encrypts a document with AES-256 so it can only be opened with the password. The encryption happens in your browser, so the password and the file stay with you.

How to use Protect PDF

  1. Drop your PDF into the upload box, or click it to browse. The file stays on your device.
  2. Enter a password twice and click Protect.
  3. Click the button and the result downloads straight from your browser.

Questions

Is Protect PDF free?

Yes. Every tool on ZTools is free, with no limits, watermarks or sign-up.

Are my files uploaded to a server?

No. Protect PDF runs entirely in your browser using JavaScript and WebAssembly. Your files never leave your device and nothing is stored.

Does it work on my phone?

Yes. ZTools works in any modern browser on desktop, tablet or phone. Large files take longer on low-end devices because all the work happens locally.

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