Design And Implementation Of Conditional Access System Based On DVB-C

Pay-TV is becoming more and more popular nowadays in that it can better satisfy customers'requirements in respect of diversification and specialization.The core technology of Pay-TV is encryption by which the customers'rights and interests are well protected .Conditional Access System is a tool to ensure that payment is received in return for the program content they provide.The thesis mainly discusses the design and the implementation of conditional access system based on DVB-C. Firstly, it introduces the development and actuality of Digital TV .secondly, the composition and principle of conditional access system are described and encryption mechanism is analysed concretely.Thirdly, it emphasizes the implementation of condiontal access sytem, symmetrical encryption arithmetic (DES) is adopted by such a system considering its speediness.In order to guarantee fair competition in Pay-TV industry,simulcrypt and multicrypt are recommended in the design of a conditional access system. Simulcrypt allows two CA systems to work side by side, transmitting separate entitlement messages to two separate types of STB, with different CA systems. It also gives the multiplex provider the opportunity to increase his viewer base by cooperating with other multiplex operators. simulcrypt is the same thing but within a single multiplex, thus giving the multiplex operator some leverage with the CA suppliers.Finally,several correlative technologies are briefly refered in this thesis,such as demodulation and channel decoding,embeded real-time OS,middleware and so on.Conditional access system introduced in this thesis has brought commercial value for our cooperative company and highly appraised by users.