| 摘要 |
PURPOSE:To obtain the correct TV signal for specified contractors by transmitting the signal which indicates the program together with the TV signal and designating algorithm at the scrambler and disc rumble. CONSTITUTION:At the broadcast station 21 side, the tear code is supplied to the key file 27 and output Ki works as the key Ki of the cipher device 29. Output of the cipher device 29 becomes the key Ks of the scrambler 25. The TV signal is transmitted by encryption at the scrambler 25 and the signal is supplied to the receiver 23 through the artificial satellite 20. The receiving signal is separated to the TV signal and bit row, and the tier code is separated at the separator 33. The tier code is supplied to the key module 35, this output becomes the key of the cipher device 31, alternating algorithm is designated and the TV signal is regenerated. The pay TV system is obtained which is impossible to intercept. |
