ToolsBench

Password Protect PDF

Add a password so only people who know it can open the PDF.

Processed on your device
Your files are processed in your browser and never uploaded.

How do I password-protect a PDF for free?

Open Protect PDF on Tools-Bench, add the file and type a password twice. Click Protect PDF to download a copy encrypted with AES-256, which nobody can open without that password. You can also block printing, copying or editing. It runs in your browser, so neither the PDF nor the password is uploaded.

About Protect PDF

A password is the simplest way to send a document only the right person can read: a payslip, a medical letter, a contract draft. This tool encrypts the PDF with AES-256 under a password you choose, so the file is unreadable to anyone without it, whether it’s forwarded by mistake or found on a shared drive. Unlike most online PDF lockers, it works inside your browser: neither the document nor the password is uploaded.

How to use Protect PDF

1
Add a PDF
Drop the document you want to lock.
2
Choose a password
Type it twice. If you like, stop people printing, copying or editing.
3
Protect and download
The encrypted copy is checked against your password, then saved to your device.

Frequently asked questions

Are my PDF and password uploaded anywhere?
No. The encryption runs on your device, with the open-source qpdf engine compiled to WebAssembly. The engine and its memory, password included, are thrown away as soon as your file is written. Nothing is logged, stored or sent.
How strong is the protection?
The PDF is encrypted with AES-256, the strongest method the PDF standard offers (PDF 2.0, revision 6). In practice the password is the weak point: a long passphrase of several words is far harder to guess than one short word.
Can people still print or copy a protected PDF?
Once they’ve opened it with the password, that depends on the permissions you set and on their app. Acrobat, Preview and Chrome honour the permissions; some other apps ignore them. Only the open password truly keeps people out.
I forgot the password. Can you recover it?
No, and nobody else can either: the password never reaches us, and AES-256 can’t be undone without it. Keep the original unprotected file, or save the password in a password manager.
Which apps can open the protected PDF?
Any current PDF reader: Adobe Acrobat and Reader, Apple Preview, Chrome, Edge, Firefox and the usual phone apps. Readers from before about 2010 don’t support this kind of AES-256.