Click to upload or drag & drop a PDF
A single PDF file · processed locally
What does this actually do?
This encrypts the entire PDF with AES-256 — a real, modern encryption standard, the same one Adobe Acrobat itself offers, not a cosmetic "restriction" that any PDF reader can ignore. Once protected, the file cannot be opened in any PDF viewer without the password, on any device. The encryption runs via qpdf, a widely-used open-source PDF library, compiled to WebAssembly so it runs entirely on your device.
Keep your password somewhere safe
Because this is real encryption processed entirely in your browser, there is no "forgot password" option and no way for anyone — including us — to recover a lost password later. Store it in a password manager or somewhere else safe before you close this tab. If you already have a password-protected PDF and need to remove it, use Unlock PDF instead — that also requires knowing the current password.
Frequently asked questions
How strong is this password protection?
It uses AES-256, the current standard for strong encryption, the same algorithm banks and governments rely on and the same one built into Adobe Acrobat's own password protection. The weak link is always the password itself — a short or common password can still be guessed, so choose something long and unique.
What happens if I forget the password?
The PDF becomes permanently unreadable to anyone without it, including you. There's no backdoor or recovery mechanism — that's exactly what makes the encryption real. Store the password somewhere safe before you need the file again.
Can I remove the password later?
Yes — use the Unlock PDF tool, which removes protection from a PDF given its current password. It can't remove a password it doesn't know, by design.
Is my PDF uploaded anywhere when I use this tool?
No. Encryption happens entirely in your browser using a WebAssembly build of qpdf — your file and password are never sent to a server.