Protect a PDF with a password, or unlock one you already know the password to — using real AES-256 encryption. It runs entirely in your browser through qpdf compiled to WebAssembly, so your document and password are never uploaded.
Protecting adds an open password (and, optionally, restrictions on printing and copying). Unlocking takes an encrypted PDF plus its password and gives you back a clean, decrypted copy.
Frequently asked questions
Is it free?
Yes — free, no sign-up, no watermark.
Is my PDF or password uploaded?
No. Encryption runs locally via qpdf-wasm; nothing leaves the page.
What encryption is used?
Real AES-256 — the same standard desktop PDF tools use.
Can I remove a password I know?
Yes. Switch to Unlock, enter the current password, and download a decrypted copy.