| 摘要 |
PROBLEM TO BE SOLVED: To realize viewing restriction for non-independent broadcast (general broadcast) at a relatively low cost.SOLUTION: An independent broadcast transmitter 14 sends out non-scrambled independent broadcast contents together with an EMM including viewing permission time information addressed to a card adapter of a television receiver 21 of a viewing restriction cancellation object. A card adapter 24 stores the viewing permission time information in a nonvolatile manner when detecting that the viewing permission time information is included in the EMM addressed to itself, and updates the residual time of viewing permission time indicated by the viewing permission time information every time of detecting ECM sent out from the television receiver 21 to an IC card 26 for digital broadcast viewing. The card adapter 24 allows transmission of a descrambling key based on the ECM from the IC card 26 to the television receiver 21 when the residual time is not zero according to the reception of the ECM, and sends out an invalid descrambling key to the television receiver 21 instead of the IC card 26 after the residual time becomes zero. |
