CONDITIONAL ACCESS SYSTEM
A conditional access system comprising a host configured to receive an incoming data stream and to supply this incoming data stream to a conditional access module, the conditional access module being configured to process the incoming data stream and to provide a corresponding output stream to the host, characterized in that the host and the conditionalaccess module are configured to engage in an authentication protocol with each other upon detection of a code embedded in the output stream.
1 . A conditional access system comprising a host configured to receive an incoming data stream and to supply this incoming data stream to a conditional access module, the conditional access module being configured to process the incoming data stream and to provide a corresponding output stream to the host, characterized in that the host and the conditional access module are configured to engage in an authentication protocol with each other upon detection of a code embedded in the incoming data stream or in the output stream.
2 . The system of claim 1 , in which the conditional access module is configured to embed the code in the output stream before providing the output stream to the host, and in that the host is configured to initiate the authentication protocol with the conditional access module upon detecting the code embedded in the output stream.
3 . The system of claim 2 , in which the host is further configured to abort the reception of the output stream upon detecting the code embedded in the output stream.
4 . The system of claim 1 , in which the conditional access module is configured to initiate the authentication protocol with the host upon detecting the code embedded in the output stream.
5 . The system of claim 4 , in which the conditional access module is configured to refrain from providing the output stream to the host until the authentication protocol has successfully been completed.
6 . The system of claim 4 , in which the conditional access module is configured to revoke the host upon a failure to successfully authenticate the host.
7 . The system of claim 1 , in which the conditional access module is configured to scramble the output stream using a key agreed upon in the authentication protocol and to supply the scrambled output stream to the host.
8 . The system of claim 1 , in which the host is configured to embed a further code, unique for the host, in the output stream provided by the conditional access module.
9 . The system of claim 1 , in which the code has been embedded in the output stream by means of a watermark.
10 . The system of claim 1 , in which the host is configured to detect the embedded code in the input data stream.
11 . The system of claim 1 , in which the embedded code indicates the presence of at least one information element in the incoming data stream, and in which the host is configured to restrict its interaction with the conditional access module upon detection of the embedded code and failure to retrieve the at least one information element from the output stream provided by the conditional access module to the host.
12 . The system of claim 1 , in which an authentication element for the embedded code is provided together with the embedded code.