Conditional Access System
A Conditional Access System is an electronic system that aims to restrict the viewing of premium television content to paying subscribers only. There are many different Conditional Access Systems. Generally speaking a Conditional Access System will require a receiver/STB, with an appropriate Conditional Access Module (CAM) armed with the correct smart card. There are a wide varieties of encryption systems used to protect digital TV content from unauthorized viewing, such as Nagravision, Viaccess, MediaGuard, Conax and KeyFly, with a variable level of reliability from a security perspective.