Protect PDF
Add a password
Sets a password that must be typed before the document will open, using AES-256 encryption. This happens entirely inside this page: neither the file nor the password is ever sent anywhere, which matters rather more for this tool than for most.
Questions
- Are my files uploaded anywhere?
- No. Every tool on this site runs entirely inside your browser using JavaScript — your file is never uploaded to a server, because there is no server. You can confirm it by opening your browser’s network tab, or by disconnecting from the internet once the page has loaded: the tool still works.
- Is my password sent to you?
- No, and it could not be even if we wanted it. The encryption runs as WebAssembly inside this page, so the password is typed into your own browser and used there. Nothing about it is transmitted, stored or logged. You can watch the network tab while you use the tool, or disconnect from the internet once the page has loaded — it still works.
- How strong is the encryption?
- AES-256, which is the strongest the PDF format defines and is not known to be breakable. The older 40-bit and 128-bit RC4 options that some tools still offer are broken, and we do not offer them. The real limit is your password: a short or common one can be guessed regardless of the cipher.
- What if I forget the password?
- Then the document cannot be opened, by you or by us. That is the point of encrypting it. There is no recovery, no back door and no reset — keep the password somewhere safe before you close the tab.
- What do the printing and copying options do?
- They ask PDF readers to disallow printing or text selection once the document is open. Be aware of what that is worth: those restrictions are enforced by the reader as a courtesy, not by the encryption, and a reader is free to ignore them. The password is the part that actually protects the file.
- Can I protect a PDF that already has a password?
- Not directly. Remove the existing password first with the unlock tool — which needs the current password — then protect it again with the new one.