| 摘要 |
A method and apparatus for descrambling a television signal using a three tier encryption technique for the code used to descramble the signal. At the transmitter, a distribution key (41) is used to encrypt a session key. The encrypted session key (40.1) is transmitted in the digital data channel (40) of the television signal. The session key is also used to encrypt the descramble code (40.2) which is also transmitted in the data channel (40) of the television signal. At the receiver (42) the encrypted session key (43) is decrypted using a distribution key (41). The decrypted session key (43), is in turn used to decrypt the descramble code (44). The descramble code may then be used to descramble and/or decrypt other signals (45, 46, 47) in the receiver. |
