Protect PDF
Add a password to a PDF with strong AES-256 encryption and control printing and copying permissions.
Private by design: your files are processed inside your browser and are never uploaded to our server.
About Protect PDF
Add a password before you email salary slips, ID copies or contracts. Files are encrypted with AES-256, and you can also block printing, copying or editing.
How to use Protect PDF
- Step 1Select your file(s) or drag and drop them into the box.
- Step 2Choose the Protect PDF settings you want.
- Step 3Click the button and download your result.
Questions & answers
How strong is the encryption?
It uses AES-256, the same standard used by banks. A long password with letters and numbers is very hard to break.
Is Protect PDF free?
Yes. Every tool on this site is free to use, with no signup, no watermark and no daily limit.
Are my files uploaded to a server?
No. Your files are processed inside your own browser on your device. They are never uploaded, so nobody else can see them.
Is there a file size limit?
There is no fixed limit. Because processing happens on your device, very large files depend on your phone or computer memory. Most files up to a few hundred MB work fine.
Does it work with password-protected PDFs?
Yes. If a PDF needs a password to open, the tool asks for it and then works normally. The password never leaves your browser.
Does it work on mobile?
Yes. It works in Chrome, Safari, Edge and Firefox on Android, iPhone, Windows and Mac.