| 摘要 |
PURPOSE:To detect the noncoincidence of keys at a receiving station without decreasing the packet transmission capacity of transmitting information concerning the satellite data broadcasting system for ciphering and transmitting the transmitting information. CONSTITUTION:In the satellite data broadcasting system provided with a center station A and a receiving station B, the center station is provided with a key version number generating means 4 to generate and transmit the number of versions for network keys, key information generating means 2 to generate key information by ciphering the network keys and adding the version number of key, and key edition number fetching function 31 added to a frame control code generating section 3. The receiving station is provided with a key information receiving means 6 to separate the key version number from the inputted key information and to store it, and key version number collating means 7 to collate the key information receiving means with the respective key version number extracted at a frame control code extracting section 5 and to output the collated result. |
