Research On The Algorithm For Authorization And Secret Key Management In CA System Of Mobile TV

Mobile digital TV standards had been determined by our country in the second half of 2006. Along with the issue of fees, mobile digital TV will continue to develop, that means how to protect the interests of operators. Therefore, it is important to research and implement CA system in the mobile TV field.CA structure of the system can still use the digital TV CA system based on DVB standards framework. Mobile digital television has many features, like smaller bandwidth, a number of users and so on. But the existed digital TV CA system generally support millions of users, and use relatively large bandwidth. The most important factor affect the performance of a CA is the authority and efficiency of algorithms. So we need to research the digital TV existing mandates and key management algorithms. We improved the algorithms to meet the needs of mobile television.Three key distribution mechanism is used in traditional digital TV system. Based on this mechanism, users are grouped to distribute authorized information. Through research and calculation of this algorithm, the system is found in excessive volume of data transmission when there are many users, and can not meet the demand of Mobile TV. This paper presents an improved algorithm that still based on three key distribution mechanisms, while apply the logic ideological of LKH in key management and improve it according to the characteristics of CA system. Addressing methods such as subset boundaries and addressing coding in authority addressing. It is confirmed that the improved algorithm can greatly reduce the volume of data transmission when there are many users and improve the performance of CA system from theoretical and practical aspects. Finally take the test that simulates the situation of many users and low bandwidth of Mobile TV. It is proved that the CA system which uses the algorithm can meet the needs of mobile television perfectly.