| 摘要 |
PURPOSE: A conditional access system and method are provided to allow only a user having authentication key information to receive and watch broadcasting programs by scrambling a broadcasting signal using a mathematical function having a solution given as the authentication key information. CONSTITUTION: A conditional access system includes a subscriber authentication unit and a conditional access module. The subscriber authentication unit includes an encoding key storage(115) unit for storing the solution of a mathematical function as authentication key information required for receiving a scrambled broadcasting signal, a function generator(113) for generating mathematical functions having the solution, a scrambler(110) for scrambling a broadcasting signal, subscriber information and broadcasting service information using the mathematical functions, and a broadcasting signal transmitter(117) for transmitting the scrambled broadcasting stream. The conditional access module includes a broadcasting signal receiver(122) for receiving the scrambled broadcasting stream, a decoding key storage unit(124) for storing the solution of mathematical functions as the authentication key information, a subscriber information storage unit(126) for storing subscriber information, and a descrambler(120) for descrambling the received broadcasting stream using the solution stored in the decoding key storage unit, confirming whether the received subscriber information is identical to the subscriber information stored in the subscriber information storage unit, and selecting only a broadcasting signal corresponding to service allowed to a corresponding subscriber to transmit the broadcasting signal to a broadcasting receiver(128). |
