Protect PDF
Add a password to a PDF with AES-256 encryption. The file is encrypted on your device, so nothing is uploaded.
The PDF will be encrypted with AES-256 and will not open without this password. Keep it somewhere safe — it cannot be recovered.
Keep the password safe
The document is genuinely encrypted, which means it cannot be opened without the password — by you, by us, or by anyone else. There is no reset and no back door. That is what makes the protection worth having, and it is also why the password is asked for twice before the file is written.
Your file stays on your device
Encryption happens inside your browser. Neither the PDF nor the password is sent to a server — which is the point, since uploading a document to have it made private is a contradiction.
How to password-protect a PDF
- Drop your PDF into the box above, or click to choose it.
- Type a password, then type it again to confirm.
- Select Protect PDF, then download the result.
Frequently asked questions
Why is there no "prevent printing" option?
Because it would not be true. PDF can mark a document as not-to-be-printed or not-to-be-copied, but those flags are advisory: a reader is expected to honour them, and plenty simply do not. Offering a checkbox that promises a restriction which any number of free readers ignore would be selling a guarantee the format cannot make. The password, by contrast, is real encryption — the content is unreadable without it.
What encryption is used?
AES-256, the strongest scheme PDF defines. The older RC4 and AES-128 options are broken and deprecated, so they are not offered. The trade-off is that very old readers, predating PDF 2.0, will not open the result.
Can I change the password on a PDF that already has one?
Yes. Choose the file, enter its current password when asked, then set the new one. The result is encrypted with the new password only.
Does the document change in any other way?
No. Every page, font and image is preserved exactly. The only difference is that the file now asks for a password.
How do I remove the password later?
Use Unlock PDF, which removes a password you know.