Password Protect a PDF
Password protect a PDF free. Add an AES-256 open password so the file can't be opened without it — all in your browser, nothing uploaded.
Runs in your browserNothing uploadedFree · no signup
Drop a PDF here, or click to chooseChoose a PDF, set a password, then download the protected copy.
Frequently asked questions
- How strong is the encryption?
- AES-256, written as revision 6 of the PDF encryption handler — the strongest the PDF format defines, and the same class of encryption used for disks and network traffic. Streams, strings and the whole file are encrypted with it. Older 40-bit and RC4 modes are deliberately not offered: they are broken, and a file using them is protected in appearance only.
- What happens if I forget the password?
- The file cannot be opened again — by this tool or any other. Your password is what derives the encryption key, and no copy of that key is stored anywhere in the document, so without the password the pages are genuinely unreadable rather than merely hidden. Nothing is kept on our side either, because nothing is sent to us. Save the password in a password manager before you download.
- Is my PDF uploaded to a server?
- No. The file is encrypted in your browser, and neither the document nor the password ever leaves your device — which is the point, since a tool that asks you to upload a file and a password to protect it has already defeated the purpose.