Protect a PDF with a password
Sending a bank statement, a salary slip or an ID scan? Lock it with a password first. Choose the PDF, type a password twice and save a copy that only opens with it. The file never leaves your device.
The tool above works in your browser: your files stay on your device and are not uploaded. The steps below are for this tool.
How to put a password on a PDF
- Choose your PDF in the tool above, or drop it on the box.
- Type the password in New password, then type it again in the second box. Tick Show password to check what you typed.
- Press Protect PDF.
- Download the new copy. It asks for the password every time it opens. Your original file is not changed.
The password is used only in this browser tab to lock the file. It is not stored or sent anywhere, and neither is the PDF.
How strong is the lock?
The tool uses AES with a 256-bit key, the strongest encryption the PDF format offers, through qpdf, a widely used open-source PDF program that runs inside your browser. How safe the file is depends mostly on your password: a long one with words and numbers that nobody could guess, such as a short sentence, is far better than a name or a date of birth.
Current versions of Adobe Acrobat Reader, the PDF viewers built into Chrome, Edge, Firefox and Safari, and the usual phone PDF viewers open AES-256 files. Very old PDF programs, from before about 2010, may not.
If you forget the password
Nobody can recover it, including us: we never see it. Keep the original, unlocked file somewhere safe, or write the password down before you send the protected copy. To share the password, use a different channel from the file, for example send the PDF by email and the password by text message.
Removing the password later
If you know the password, you can save a copy without it with Unlock PDF. A PDF that already has a password must be unlocked before you can protect it with a new one.
Questions
Is my PDF or password uploaded?
No. The PDF is locked in your browser and stays on your device. The password is never stored or sent.
Can I still print or copy text after I protect a PDF?
Yes. Anyone who knows the password can read, print and copy from the file as before. The tool adds an open password and no other restrictions.
How long should the password be?
The tool needs at least 4 characters, but longer is much safer. Use 10 or more characters, or a short sentence that only you and the receiver know.
Does protecting a PDF make it bigger?
Hardly. The encrypted copy is usually about the same size as the original.