Master Key is a password management program designed to allow you to maintain many passwords for maximum security without having to remember them all. For more information, visit http://www.kzsoftware.com/products/passwordmanager Master Key is a password management program designed to allow you to maintain many passwords for maximum security without having to remember them all. You use one "master key&quot\; to encrypt your list of passwords for shopping sites, email, voicemail, or any application which requires a user name and password.