AUTHENTICATION OF SERVICE IN CONDITIONAL ACCESS SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a cable TV system which provides conditional access to services. SOLUTION: This cable TV system includes a head end from which service "instances" or programs are broadcasted and a plurality of set-top units which receive the instances and selectively decrypt the instances in order to display them for a system subscriber. The service instances are encrypted by using public keys and/or private keys provided by a service provider or a center authority agent. The keys used by the set top for selective decryption may also have a public or secret characteristic. These keys are allocated again at different points of time. Thus, the cable TV system in which the risk of infringement activities is minimized is provided. COPYRIGHT: (C)2010,JPO&INPIT