Protect PDF
Lock a PDF with a password using AES-256 encryption. Runs locally in your browser — no uploads.
Frequently asked questions
What does the Protect PDF tool do?
Lock a PDF with a password using AES-256 encryption. It runs entirely client-side — nothing is uploaded to a server.
Is my file private?
Yes — processing happens locally in your browser tab using the Canvas API and WebAssembly, so your file never leaves your device.
Is there a cost or file size limit?
It's free with no upload limit. Processing time depends on your device and the size of your file rather than any imposed cap.