Research Of The CA System Of The Middleware In The Integrated Service Terminal

A neo-type HFC network was put forward by the author's supervisor, in order to solve the"funnel effect"of original HFC network. The neo-type HFC network makes full use of the advantages in HFC network and improves the channel capacity, which is fit for providing broadband integrated services. An integrated service termination by customers is used to connect the neo-type HFC network, to realize the receiving programs of digital TV, dial-up IP phone and Internet service. The application of neo-type HFC network and such integrated service termination are expected to bear an extensive prospect. The author puts emphasis on studying the CAS in the integrated service termination.Based on authorization, controlling and management of the customers, the CAS of digital TV aims to realize the payment service in digital broadcast system. In this case, CAS can not only bring economic return to providers, but also provide more and higher quality services for consumers. First, the thesis gives a detailed analysis on the running mode of digital TV, the functional demand, composing and related protocol of CAS. Then it further analyses the network environment and the software, hardware environment in the IST. And the project of CAS for integrated service termination is advanced, grounded on present technology states home and abroad, as well as the current CAS technology of set-top-box. This project not only achieves the whole functions required by CAS, but also receiving multi-programs of digital TV only with one CAS in the termination at the same time, which hence reduces the cost of the equipment.This project designed in this paper divides the CAS into three parts: CA process module, smartcard interface module and costumer interface module. By means of the advantages of multitask process, four process tasks in CA process module are designed to filter and parse the encrypted message sent from the commencement, so that the termination may finish the authorization and decryption in time. And then the encrypted message to smartcard is sent for decrypting through smartcard interface module, and next the descrambler is set based on the decrypted results to complete the descrambling the program stream, which enables the termination to normally display the programs. By virtue of the communicating protocol of smartcard and some software module regarding the protocol in the software platform, the interactive function between smartcard and IST in application layer is realized, accomplishing the communication between integrated services and smartcard. The interaction between CA system and customers is realized by calling OSD functions and smartcard interface in user interface of this system.This thesis tests the functions of the designed software. The experimental result proves that the CAS in designed IST can accurately extract the message streams for decrypting, thereby realizing the expected function.CAS is a complex system, and IST is a neo-type equipment, so further research is necessary in order to improve the technology standards. The paper also brings forward some suggestions for future studies on CA.