Protect PDF
Encrypt PDF files with user and owner passwords
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âī¸ How It Works
Upload a PDF, set a user password to restrict access, and optionally define an owner password. If the file is already encrypted, enter its current password. Click 'Protect & Download' to save the secured PDF.
â Frequently Asked Questions
What's the difference between user and owner passwords?
The user password is required to open the PDF. The owner password controls permissions and full access. If not set, it defaults to the user password.
Can I protect an already encrypted PDF?
Yes. Provide the existing password first, then set new passwords to re-encrypt the file.
Are my files uploaded anywhere?
No. All encryption happens locally in your browser. Your files and passwords never leave your device.
Does the Protect PDF work offline?
Yes, the Protect PDF is fully functional offline. Because this tool runs entirely in your browser, no data is ever uploaded to external servers. Once the page is loaded, you can seamlessly continue using it without an active internet connection. You can also install Knicknaks as a Progressive Web App (PWA) for native-like offline access.