Encrypt PDF
Add real password protection using AES-256 - the only cipher ISO 32000-2 still recommends. Set an open password, optionally separate owner permissions for printing and copying. Everything happens in this browser; the password is never sent or stored.
- Processed locally in your browser
- No watermark
- No sign-up
- Works offline
Processed locally in your browser. Encrypted with AES-256, the algorithm ISO 32000-2 recommends. Your password is used only inside this browser tab — it is never sent anywhere or stored. Re-encrypting a signed PDF normally invalidates its existing cryptographic signatures.
Choose a PDF or drop it here
One PDF · encrypted locally
How it works
- 1Open a PDF.
- 2Choose a strong password and confirm it.
- 3Optionally adjust reader permissions like printing or copying.
- 4Download the encrypted file - the password cannot be recovered later.
Your privacy
This tool runs entirely inside your browser using JavaScript and Web Workers. Your document is never uploaded to any server — you can even disconnect from the internet and keep working once the page has loaded.
Frequently asked questions
▸How strong is this encryption?
AES-256 with revision 6 security handler, exactly what the PDF standard recommends. There is no backdoor and no recovery if you lose the password.
▸What do permissions control?
Whether viewers allow printing, copying text, editing or commenting. Note that permission flags are advisory - a determined user with tools can bypass them; the open password is the real protection.