Abstract: An improved authentication system is disclosed. In one class of embodiments, the system utilizes the distance between a user's cell phone and client's computer as an authenticating factor in an access control mechanism. Users attempting to log on to a system without their cell phone being nearby are granted low or zero usage rights, while users attempting to log on to a system when their cell phone is nearby are granted high or full rights. In some embodiments, an image that contains encoded information unique to that company's website is served to the user for use in verifying the authenticity of a website. In a class of embodiments, the system is programmed to restrict access if a correct response to a cryptographic authentication challenge is not provided. A non-binary authentication system is also disclosed. This non-binary system allows users to have partial access to a system.