Protect PDF
Encrypt a PDF with a strong password so only people who know it can open the file. All encryption runs locally.
or drop PDF file here
Drop a PDF to protect
The password never leaves your browser. We can’t see it or recover it.
- Files never leave your device
- Instant, no upload wait
- Free, no sign-up
Add a password to a PDF
Password-protecting a PDF is one of the simplest forms of document security available. It is not unbreakable — no password is — but it does mean that someone who intercepts the file in transit, or finds it left on a shared drive, cannot casually open it.
Because this tool runs in your browser, the unprotected source PDF is never sent over the network. We apply 128-bit AES encryption to the document in memory and offer the protected version as a download. The password itself is typed only here, never transmitted.
Choosing a good password
- Use a long passphrase, not a short complex string.
- Avoid anything that appears elsewhere in the document.
- Send the password through a different channel from the file itself.
Note: PDF encryption is supported by Acrobat, Preview, Chrome, Firefox, and every major mobile reader. Older command-line tools may need to be passed the password explicitly.
Frequently asked questions
- Standard PDF AES-style encryption keyed to the password you provide. The password never leaves your device.