Digital TV conditional access system and method of using the same for transmitting and receiving digital data

A digital TV conditional access system comprising an authentication server, a conditional access front-end module, and a receiver module, wherein

• said authentication server, upon production thereof, communicates bidirectionally with and authenticates said receiver module to generate a unique ID number of the receiver module and authentication information of the receiver module, said ID number and said authentication information being recorded to a data base, said ID number functioning as a basis for conditional addressing, wherein the receiver module comprises a main chip, a security chip, and a memory chip, said main chip is matched with said security chip by an algorithm and each other's information and common information are recorded:
• said main chip is matched with said memory chip by an algorithm and each other's information and common information are recorded:
• said security chip is matched with said memory chip by an algorithm and each other's information and common information are recorded;
• said conditional access front-end module communicates bidirectionally with said data base, collects the authentication information of said receiver module from said data base, encrypts entitlement management message of said receiver module, and transmits said entitlement management message encrypted with the authentication information to said receiver module by an addressing mode;
• said conditional access front-end module further comprises an entitlement control message generator and connects to an external download port;
• and
• said receiver module receives a scrambled program with the help of said ID number and said authentication information, wherein said receiver firstly examines the match of said main chip with said security chip, the match of said main chip with said memory chip, and the match of said security chip with said memory chip;
• upon success, an effective entitlement management message is filtered out according to ID of said receiver, and a secret key of said entitlement management message is calculated according to the matched information;
• said entitlement management message is decrypted, and corresponding processes are performed according to the result of the decryption.