Processed on your device — never uploaded
Protect PDF with a password
Add password encryption (RC4 128-bit)
Drop a file here, or browse
.pdf — processed on your device, never uploaded
How it works
- 1
Drop the PDF to protect.
- 2
Choose a strong password (it stays on your device).
- 3
Download the encrypted PDF — it will ask for the password when opened.
Why FoldPDF
- Files processed 100% locally — verifiable in DevTools
- No file size or daily usage limits
- No watermarks, no accounts, no paywalls
- Works offline once loaded
Frequently asked questions
Is this protect pdf tool really free?+
Yes — every FoldPDF tool is free with no file limits, watermarks, or sign-up. Processing runs on your own device, so it costs us nothing to serve.
Are my files uploaded to a server?+
No. Files are processed entirely inside your browser using WebAssembly. You can verify with your browser's developer tools that no file data is transmitted.
How does protect pdf work?+
Encrypt your PDF with a password using the classic PDF Standard security handler (RC4 128-bit). The file is encrypted locally — your password never leaves the device.