Free · Private · In your browser

Protect PDF

Set a user password required to open the PDF.

Drop your files here, or click to browse
Processed on your device — nothing is uploaded

How your files are handled

We built these tools so you never have to wonder where your documents go. Here is exactly what happens when you use them.

  • Your files are processed entirely in your browser using open-source libraries (pdf-lib, PDF.js, and others).
  • Nothing is uploaded to our servers. We have no backend that receives, stores, or scans your documents.
  • We cannot see, store, or access your files — not during processing, not after, not ever.
  • Processing uses your device's memory and CPU. Large files may take longer, especially on phones and tablets.
  • All tools are free with no paywall tricks, no hourly task limits, and no watermarks on your output files.

How it works

Three simple steps. Your files never leave your device, and the result downloads straight to your computer or phone.

Frequently asked questions

Common questions about privacy, pricing, and how these tools work.

More security tools

Other free PDF utilities that work the same way — private, in-browser, no sign-up.

How to protect PDF

Protect PDF encrypts your document with a password so it cannot be opened without it. You can also set whether printing and copying text are allowed.

  1. Add your PDF; encryption is performed on your device with no upload.
  2. Enter and confirm a password, and choose whether to allow printing and copying.
  3. Click Encrypt PDF, which then self-checks that the file is truly locked.
  4. Preview the content and download the genuinely encrypted PDF.

Everything happens in your browser — your file is never uploaded, and there is no sign-up, watermark, or limit.

Frequently asked questions

Are my files uploaded to a server?

No. Every tool runs entirely in your browser using open-source libraries, so your file is processed on your own device and is never uploaded. We have no backend that receives, stores, or scans your documents.

Is it really free, and will there be a watermark?

Yes. There is no account, no sign-up, and no hourly limit, and the tools never add a watermark to your output. UnboundPDF is free and is not affiliated with Adobe.

Does it work on a phone or tablet?

Yes. The tools run in any modern mobile browser as well as on desktop. Because the work uses your device's own memory and processor, very large files simply take longer on phones.

How strong is the protection?

The PDF is encrypted with AES, and the tool runs a self-check to confirm the output will not open without the password before handing it to you.

What happens if I forget the password?

It cannot be recovered. The encryption is real, so store the password somewhere safe; without it, the file cannot be opened.

Why can I still preview the document after encrypting?

The preview shows your original content for reference, but the file that downloads is the encrypted version that asks for the password when opened.