CA system for broadcast DTV using multiple keys for different service providers and service areas

摘要

A method for managing access to scrambled broadcast or transmitted events received from a variety of service providers (including broadcast television networks, cable television networks, digital satellite systems). In one preferred embodiment, each service provider employs a different public key for encrypting the access information message, and each smart card includes the corresponding private keys for the public keys, thereby permitting a user to access events from various service providers without changing the smart card.