Question 1

Is my file uploaded?

Accepted Answer

No. The PDF is locked inside this browser tab, and the page's security policy blocks it from sending data anywhere. Your original file is not touched.

Question 2

Is my password sent anywhere?

Accepted Answer

No. The password stays in this browser tab. It goes to the locking engine on this page and nowhere else. The page never saves or logs it, and the fields are cleared as soon as you use them.

Question 3

What if I forget the password?

Accepted Answer

Then nobody can open the file again, not even this site. A strong password can't be guessed or recovered. Keep the password somewhere safe, and keep an unlocked copy of the original if you may need it.

Question 4

Which programs can open it?

Accepted Answer

Any current PDF program that supports 256-bit AES: Adobe Acrobat and Reader, Preview on Mac, Chrome, Edge, Firefox and most phone apps. Very old programs may not open it.

Question 5

Do the print, copy and change choices lock the file?

Accepted Answer

No. They are a request that most PDF programs follow, and some ignore. The password is what keeps the file closed. Choose a long password that is hard to guess.

Runs	In your browser. Your files stay on your device.
Engine	qpdf 11, compiled to WebAssembly
Encryption	256-bit AES
First load	1.3 MB, then cached by your browser
Works offline	Yes, once the page has loaded
Licence	AGPL-3.0
Added	13 October 2026
Built by	Sapience Design
Source	tools/pdf/protect

Lock a PDF with a password

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Set a password

Save it

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