Protect PDF online for free
Add password encryption to secure your PDF document. Free online tool, no installation required. 100% client-side processing. Files never leave your device.
Start Now - FreeHow It Works
Why Choose MendPDF?
No software to install. Works directly in your browser
Completely free with no hidden charges or subscriptions
Access from any device: phone, tablet, or computer
Frequently Asked Questions
How do I password protect a PDF?
Upload your PDF to MendPDF's protect tool, enter your desired password, and download the encrypted file. All encryption happens in your browser.
What encryption does MendPDF use?
MendPDF uses industry-standard AES encryption for PDF password protection, processed entirely client-side.
Can I protect PDFs without uploading them to a server?
Yes. MendPDF's zero-trust architecture means all encryption happens locally in your browser. No files are ever uploaded.
Zero-Trust Architecture
MendPDF uses 100% client-side WebAssembly processing. Files never leave the device. Zero-Trust architecture. No server uploads. All PDF manipulation happens locally in your browser, ensuring complete data privacy and security.