Protect PDF
Secure your PDF with a user password (to open) and an optional owner password (for full permissions). Uses strong encryption. 100% browser-based — your file and passwords never leave your device.
Other PDF Tools
About Protect PDF
Secure your PDF documents with password protection. Add a user password (to open the file) and an optional owner password (for full permissions). Uses strong encryption to keep your sensitive documents safe. Everything runs in your browser — your file and passwords never leave your device.
Frequently Asked Questions
What's the difference between a user password and an owner password?
The user password (also called the 'open' password) is required to view the PDF. The owner password controls permissions — printing, editing, copying. You can set one or both depending on your needs.
What encryption does the tool use?
The tool applies AES-128 or AES-256 encryption depending on the PDF version. Both are industry-standard and used by banks and governments.
Is my password sent to a server?
No. Your password and file are processed entirely in your browser. Nothing is transmitted — ever.
Can I password-protect a PDF on my phone?
Yes. FastConvert works in any mobile browser. Open the page, upload your PDF, set your password, and download the encrypted file — no app needed.