| 摘要 |
The invention relates to a conditional access system. In a conditional access system, a service provider supplies the user with access conditions relating to various modes of access (for example the "subscriber" mode or else the "pay per view" mode) and user entitlements relating to these various access conditions. The smartcard which the service provider delivers to each user comprises a program making it possible to validate the access conditions and the user's entitlements, to compare the validated access conditions with the user's validated entitlements and, depending on the result of the comparison, to execute management operations relating to certain services. According to the invention, the modes of access take the form of access mode descriptors each consisting of a descriptor of a comparison operation and of a descriptor of a management operation. The smartcard comprises an interpreter module which determines the authorized modes of access and, for each authorized mode of access, searches for the descriptor of the mode of access and performs the comparison and management operations. The conditional access system according to the invention allows the access mode descriptors in the user's smartcard to be modified by downloading. <IMAGE> <IMAGE> |
