Protect a PDF with a password
Lock a PDF so it can only be opened with your password. Encryption runs inside your browser, so the document and the password never travel over the internet.
Everything runs on your device. Nothing you add or type is sent to any server.
How to use it
- 01
Drop your PDF into the box above, or click it to choose a file.
- 02
Type a password, then type it again to confirm. Use Show to check what you typed.
- 03
Optionally untick printing, copying or editing to restrict what people can do after opening it.
- 04
Press Protect PDF. The locked copy downloads with -protected added to its name; your original file is not changed.
What the password does
The open password encrypts the whole document with AES-256, the encryption method of the current PDF standard (PDF 2.0). Without the password, the pages, text and images cannot be read; a PDF reader asks for it before showing anything. Nothing else about the file changes: text stays sharp and searchable, images keep their quality and page sizes stay the same.
Choose something you will remember or store it in a password manager. We never see or store your password, so there is no way for us to recover it or unlock the file for you.
Printing, copying and editing limits
Restrictions are stored inside the encrypted file and PDF readers are supposed to respect them: they grey out Print, block selecting text, or refuse changes. They are not as strong as the password itself, because a reader has to choose to obey them, and some software ignores them. Use them as a polite barrier, and rely on the open password to keep the content private.
Good uses
Protect bank statements, salary slips, ID copies, contracts or medical reports before emailing them or saving them to a shared drive. Send the password through a different channel, for example a phone call or a separate message, so one leaked message does not expose both.
Frequently asked questions
Is my file uploaded anywhere?
No. The encryption engine (qpdf, compiled to WebAssembly) is downloaded from this site when you choose a file, then runs on your device. Your PDF and password are never sent anywhere.
Will every PDF reader open the protected file?
AES-256 is part of the current PDF standard, so PDF apps that follow it can open the file. Very old readers made before it may not; if someone cannot open it, ask them to update their PDF app.
I forgot the password. Can you unlock it?
No. The password is never sent to us, and a well-chosen AES-256 password cannot be guessed in practice. Keep the original unprotected file somewhere safe.
My PDF already has a password. Can I change it?
Yes. Remove the old password with Unlock PDF first (you need to know it), then protect the unlocked copy with a new password here.