Conditional Access
Conditional access (CA) is a technology used to control access to DTV services to authorized users by encrypting the transmitted programs. CA has been used for years for pay-TV services. There are numerous ATSC and DVB compliant CA systems available for a broadcaster to choose from. The CA system provider provides the equipment and software to the broadcaster who then implements the CA system into his equipment. CA is not designed solely for DTV. It can be used for digital radio broadcasts, digital data broadcasts, and non-broadcast information and interactive services. A CA system consists of several basic components: