pdf encrypt Converter - Version 5.1 PDF Encrypt software is a very flexible and powerful program, it allows you to encrypt (using standard 40-bit or 128-bit or AES encryption) existing PDFs, set permissions, add user and owner password. For example you can encrypt a PDF without allowing to print it. The button to print the file will be disabled in Acrobat Reader application, you can also encrypt a PDF to allow the user to read it only if he knows the correct password. There are two passwords you can apply to a PDF. The first is the owner password, Opening a PDF with this password will allow you full access to the PDF when a user password has been assigned as well. This means that even if printing was disabled you will still be able to print the PDF when using this password. No password will be prompted for when opening the PDF if you secure it with only an owner password. The second is the user password, Opening a PDF with this password will restrict you based on how the PDF was password protected (printing may be disabled, for instance).