Limited broadcast system

An IC card with a data processing function for use in a receiving station which receives enciphered service information together with destination information from an information service station of a limited broadcast system, said destination information designating destination stations to which a data reception right for the enciphered service information is given, said enciphered service information being deciphered by using a common key obtained from said destination information at said received station, said IC card comprising:

• means for receiving destination information from said receiving station;
• means for storing position information designating a bit position in said received destination information to be checked;
• means for confirming data reception right by referring the status of said destination information at the bit position designated by said position information;
• means for generating a common key by using said received destination information in response to the confirmation result of said data reception right;
• and
• means for supplying said common key to said receiving station.

A receiving station for receiving enciphered service information together with group identification information, destination information and an enciphered group secret key(P) from an information service station of a limited broadcast system, said destination information designating destination stations within a group specified by said group identification information to which a data reception right for the enciphered service information is given, said enciphered service information being produced by enciphering service information by a secret key(L) and said enciphered group secret key(P) being generated by enciphering said secret key(L) by L group common key(K) generated from said destination information comprising:

• means for receiving said enciphered service information, group identification information and destination information transmitted from said service station;
• means for confirming data reception right by referring said group identification information and destination information received by said receiving means;
• means for generating a group common key(K) by using said received destination information and generating the secret key(L) from said generated group common key(K) and said received enciphered group secret key(P) if said data reception right was confirmed by said confirming means;
• and
• means for deciphering said received enciphered service information by using said generated secret key(L).

A receiving station for receiving limited broadcast information together with destination information from an information broadcast system, said destination information being presented in a form of a bit pattern including a plurality of bits for designating receiving stations available to the limited broadcast information, the receiving station comprising:

• means for receiving said destination information and said limited broadcast information from said information broadcast system;
• means for confirming information utilization right by referring to the status of said received destination information at a predetermined bit position assigned to the receiving station;
• and
• means for processing said received limited broadcast information for the purpose of use in response to the confirmation result of said information utilization right.

An IC card with a data processing function for use in a receiving station which receives limited broadcast information together with destination information from a limited information broadcast system, said destination information being presented in a form of a bit pattern including a plurality of bits for designating receiving stations available to the limited broadcast information, said IC card comprising:

• means for receiving the bit pattern of said destination information from said receiving station;
• means for storing position information designating a bit position in said received destination information to be checked;
• means for confirming information utilization right by referring the status of said destination information at the bit position designated by said position information;
• and
• means for responding to the result of said confirming of the information utilization right to said receiving station.

A receiving station for receiving limited broadcast information together with group identification information and destination information from an information broadcast system, said destination information being presented in a form of a bit pattern including a plurality of bits affectire within a group specified by said group identification information and designating receiving stations available to the limited broadcast information, the receiving station comprising:

• means for receiving said group identification information, destination information and said limited broadcast information from said information broadcast system;
• means for confirming information utilization right by checking said group identification information and the status of said received destination information at a predetermined bit position assigned to the receiving station;
• and
• means for processing said received limited broadcast information for the purpose of use in response to the confirmation result of said information utilization right.

An IC card with a data processing function for use in a receiving station which receives limited broadcast information together with group identification information and destination information from a limited information broadcast system, said destination information being presented in a form of a bit pattern including a plurality of bits effective within a group specified by said group identification information and designating receiving stations available to the limited broadcast information, said IC card comprising:

• means for receiving said group identification information and the bit pattern of said destination information from said receiving station;
• means for storing group identification information and position information designating a bit position in said received destination information to be checked;
• means for confirming information utilization right by comparing said stored group identification information and said received group identification information and by checking the status of said received destination information at the bit position designated by said position information;
• and
• means for responding to the result of said confirming of the information utilization right to said receiving station.