Research And Application Of The Bidirectional Conditional Access Technology

With the rapid development of the Cable Radio Television network technology and telecommunications networks, in particular, with the triple play was officially launched in 2010, many radio and television began to worry about the use of CA’s security. Traditional smart card CA or non card CA, their security depend on the bundle with the chip, the more complex and harder to chip hardware, the higher security to the corresponding bundle of CA. But the biggest problem faced to the traditional CA technologies:algorithms and keys is that it must be stored in a stream or a set-top box memory chips, so once fast enough to crack the method, there is still a security risk. The two-way conditional access system (CAS) is a two-way real-time authentication conditional access system, the principle is that the CA Access Server in the radio and television in the front-end system goes through the IP network and IP module descrambler terminal STB IP module connects to the IP module and the descrambler of the set-top box is connected to the descrambler which is connected through the cable TV network and broadcasting headband system. User authentication information, key information, user authorization information, management information, all go through a two-way backhaul network to reach the terminal set-top boxes. The bidirectional CA algorithm and key dynamic replacement via online download, when the system is attacked by hackers, it can update through online download into another new CA system, so crack this CA system will lose its significance.This paper focuses on the bidirectional conditional access system in IP-based networks in the digital cable TV and carries out a detailed study and design. First, described the research background and research status of the conditional access system, meanwhile gave a relatively brief description of the trends of the conditional access system; Second, gave a more detailed research to the conditional access technology, and took more thorough research to the hierarchical structure of the conditional access system, works in-depth exposition, DES algorithm encryption algorithm,3DES algorithms and public key encryption algorithm; Again, according to the understanding of conditional access technology and related technologies, I did a more in-depth research to the basic components of the bidirectional-way conditional access system and its basic framework; Finally, based on an understanding of the basic components and the basic framework of the bidirectional conditional access system, the whole system is applied to the cable set-top box, for each module, because the entire system is relatively large, the author mainly did more comprehensive research and design to the user receiving end system throughout the module, tested verification and improvement of the system, from the test, we can find that the system can basically achieve the desired functional requirements.The results of this study as an exploration of the CA for two-way digital TV, this paper writes about the digital TV terminal authentication function for two-way CA research and design has a certain practical value.