Password-protect a PDF
Add a password to a PDF and encrypt it so only people with the password can open it. Free and private: encryption happens in your browser.
- Files never leave your device
- Free, no sign-up
- No watermark
About Protect PDF
Encrypt a PDF so it can only be opened with a password. It is the simplest way to protect a contract, a medical letter or a financial statement before you email it or put it on a shared drive. Encryption is done by qpdf, a well-established PDF engine, compiled to WebAssembly and running in your browser, so neither the document nor the password is uploaded.
How to use Protect PDF
- 1
Drop the PDF you want to protect.
- 2
Type a strong password and type it again to confirm.
- 3
Click Protect PDF.
- 4
Download the encrypted PDF and share the password through a different channel.
Why use this tool
- Real encryption with qpdf, not just a viewer flag.
- Password confirmation prevents typos that would lock you out.
- Works with any PDF reader that supports passwords, which is all of them.
- The file and password stay on your device.
- Free and unlimited.
Frequently asked questions
The PDF is encrypted with standard PDF encryption by qpdf. Use a long, unique password: the encryption is only as strong as the password.
It cannot be recovered. Keep an unprotected original or store the password in a password manager.
No. Every major PDF reader, including browsers, asks for the password and opens the file normally.
No. Share it by phone, text message or another channel so one intercepted email is not enough.
No. Encryption runs in your browser, so the PDF and password never leave your device.
Yes. It runs in any modern browser on Android and iOS as well as on Windows, macOS and Linux, with nothing to install.
Yes. There is no account, no watermark and no usage limit. The tool runs in your own browser, so there is no server cost to charge you for.
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