Lock PDF
Password protect your PDF and restrict what others can do with it.
Drop your PDF here
or click to select from your computer
🔒 File stays in your browser — never uploaded
Password Settings
If set, readers must enter this to open the file.
Controls permissions (printing, editing, copying).
Restrict Permissions
ℹ️ PDF encryption uses 128-bit RC4 via pdf-lib. For maximum compatibility set both passwords. All processing happens locally — passwords are never sent anywhere.
Encrypting…
Advanced PDF Protection & Encryption
The Lock PDF security suite encrypts your documents locally using strong industry-standard security algorithms. We compile and run encryption libraries directly in your web browser, ensuring that neither your document nor your selected password ever touches a remote server.
Configure two separate security levels:
- Open Password: Prevents unauthorized users from opening or viewing the document content.
- Owner Password (Permissions): Blocks modifications, copying of text/images, printing, or adding annotations, even if the user can open and view the PDF.
Use our client-side encryption utility to securely manage data permissions for personal or enterprise files on any desktop or mobile device.