Studies On The Technologies Of Conditional Access And Smart-Card-Based Ca Functional Separation

As is known to all, the conversion from analog TV to Digital TV is the inexorable trend. Analog TV users can either by new digital televisions or by set top boxes to watch digital programs, while the STB is a preferred choose of the masses. Being a kernel equipment of DTV technology, Conditional Access can manage and control the customers'entitlements, guarantee the interests of service providers and network operator, and set up a safe platform of providing new services by encrypting the programs. However, the current experimental operating of DTV is a bundling mode of the STB and the smart card, which leads to an abnormal industrial structure that the cable network operator choose a conditional access system, the STB manufacturer have STBs custom-made for one operator, and the operator monopolize the sell of STBs.To solve the disadvantages of the bundled mode, the ministry of information industry brings up the"Conditional Access functional separation"as an industrial policy, and calls for bid as a project supported by"Electronic Development Fund"in order to encourage the research and development. The application of CA functional separation are expected to remove the bottleneck of STB mass-production for manufacturer, to benefit the customers, and to comb up the industrial chain among CATV operators, DTV manufactures and CA system providers.Based on the work of the actual research and development, the dissertation presents all the key technologies of the"Smart-card-based CA functional separation". It is arranged as: Firstly, the principles and kernel technology of conditional access are analyzed. The conditional access technology is studied from related CA working mechanism, common structure, CA kernel structure and working mechanism on the receiver side, and the synchronization. A software simulation of head-end CA system is implemented. The all-round study of CA technologies builds a feasibility foundation of smart-card-based CA functional separation. Secondly, based on the implemented SW CA system platform, there are some research on key distribution and MPEG2 scrambling technology. Based on D.Naor's complete subtree algorithm and subset difference algorithm for full binary tree, a new four-level key management scheme is presented which can dynamically entitle the customers and greatly save the bandwidth usage.Moreover, with the analysis of DVB, ATSC and IPCA scrambling algorithm, a mechanism is illustrated which combines with the MPEG2 encoding characteristics and supports down-bit-rate transparent scrambling, and the reference algorithms are used to show the subjective and objective effects.Subsequently, the overall design and system architecture of smart-card-based CA functional separation is proposed. All the key technologies are described in application background, concrete content, and implementation method. The key technologies include the communication protocol, the virtual CA message filtering, the identification method, and the safety channel function. To implement the safety module, a DLP-based security protocol and an ECC-based security protocol are presented to carry out the smart-card authentication, safety channel and STB-smartcard pairing, which are followed by security analysis.Consequently, after the introduction of the CA-functional-separation receiver and smart card implementation, a new business model-"multi-service providers + single network operator + one CA functional separation card"is proposed. The implementation scheme for the new mode is presented based on the CA functional separation platform, and it can bring smart-card-based CA functional separation into full play and with the combination of the current two-level CA mode. We proposed a"one card"CASS solution which is more open, secure, and easy to update compared with the existing proprietary smart-card-based CASS. Meanwhile, the cost is much less than a CI PCMCIA module.The market benefits from the proposed system at least from the following four aspects. For the STB manufacturers, the manufacturing bottleneck caused by porting different kinds of proprietary CASS is broken. Manufacturers are able to mass-produce standard decoders with no need for permission from any CA system vendors.For the service providers, they can easily switch from one CA system to another and update their systems. All of these will be entirely under their control. For customers, they can buy STBs of whatever brands they like in a more affordable manner, or change their service provider at the cost of no more than a new smart card.For the CA vendors, the"one card"CASS solution saves the cost comparing to a CI PC card. The openness and high interoperability of the new solution makes a CA vendor's product more competitive in the market.