What encryption does this PDF protector use?
It uses AES-128 password protection.
Protect PDF
Encrypt your PDF with AES-128 password protection in your browser.
Drag & drop PDF files here
or click to browse
How to protect a PDF with a password
Add AES-128 password protection to a PDF in your browser.
Choose a PDF
Open the Protect PDF tool and select the PDF you want to secure.
Enter a password
Enter a password, then enter it again in the confirmation field.
Protect the PDF
Select Protect PDF to create the password-protected document.
What password can I use?
Use 1–32 single-byte characters; characters outside the Latin-1 range are not supported.
Can I protect an already encrypted PDF?
No. This tool does not re-protect a PDF that is already encrypted.