Lock a PDF with a real password.
Drop in a PDF, set a password, and get back an AES-256 encrypted copy that needs it to open — built right here in the tab, nothing uploaded.
Drag a PDF here, or click to browse
PDF files only — processed entirely on your device
- 1
Add your PDF
Drag it in, or click the box to choose a file from your device.
- 2
Set a password
Type it twice so there's no risk of a typo locking you out.
- 3
Download the encrypted copy
It's encrypted in your browser and ready in a second or two.
Good to know
Is my PDF uploaded anywhere?
No. Encryption happens with JavaScript (and WebAssembly) running in your browser tab. Your file never touches a server — you could disconnect from the internet after the page loads and it would still work.
Is this real encryption?
Yes — this applies genuine AES-256 PDF encryption using MuPDF (compiled to WebAssembly), the same open-source engine behind MuPDF's desktop and command-line tools. The password you set is required to open the file in Acrobat, Preview, browsers, and any other standards-compliant PDF reader.
What kind of password protection is this?
The password you set is used as both the PDF's "user" password (required to open the file) and its "owner" password (required to change permissions), so one password fully protects the file. We don't currently expose separate printing/copying restrictions — anyone with the password gets full access, same as most simple PDF password tools.
Can I use this to remove a password instead?
No — this tool only adds a password to a PDF that doesn't already have one. If your PDF is already encrypted, this tool can't re-protect or strip it.