PDF Encryptor - Version 4.0 With this encryption tool, you can encrypt your pdf files into exe files that can only be opened when a Read Password is provided (PC-binding or No PC-binding), and users can only open the encrypted pdf files after obtaining the Read Password provided by you. You can choose encryption type :[ Non-binding ] -- All computer,One password. (Use "Create Read Password" function to create Read Password, Enter "00000-00000-00000" as Machine ID);[ PC-binding ] -- One computer,One password,you only need to encrypt files one time. (Use "Create Read Password" function to create Read Password);[ Protect only ] -- pdf2exe only. How do I know the machine ID of the user's computer?