The Design And Realization Of Conditional Access Solution With Model Of Host And Module Separately

The essential intention of Conditional Access System (CAS) is to achieve pay-TV of the digital broadcast system by means of subscriber management and authorization control. So CAS is the key technology to realize the pay-TV and interact-TV.Based on composite technology in transport layer, paper describes the production and structure of transport stream in MPEG-2 standard, MPEG-2 program special information and conditional access definition in service information from DVB standard. Composite technology supplies the possibility for the realization of conditional access, and the relative definitions for conditional access in standard supplies the feasibility of conditional access. Then paper analyses the working theory of normal conditional access system, and gives the realization frame for conditional access system. Based on the structure of conditional access system, paper analyses each software module's function, realization theory and relative algorithm research. Also paper discusses the security of current conditional access system and relative recovery measure, introduces the composite and transport technology relative to CA system in MPEG-2/DVB standard.According to the complete research on CA system theory and relative technology, paper introduces traditional conditional access realization method: simulcrypt and multicrypt, analyses the localization of simulcrypt and the complexity of multicrypt in terms of the design model of host and module separately. And then from practicability and integration, paper analyses a new style of conditional access method: serial conditional access technology, describes its difference and connection with traditional conditional access, and its advantage when used to model of host and module separately. Also paper researches the function and realization theory of serial conditional access. Through analyzing some important software module, paper gives the course of the serial conditional access realization on set top box. Finally, the system test content for serial conditional access and the solution for the problem in test are given.