【作者】 冯小川；

【导师】 景晓军；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2008， 硕士

【摘要】 数字电视的蓬勃发展为广大用户提供了视频点播、按次付费、信息点播等更优质的服务,也为服务提供商和网络运营商提供了更好的服务平台,而作为数字电视的重要部分的条件接收(ConditionalAccess,CA)系统是实现数字电视服务的必要条件。其保障了节目提供商,网络运营商和用户三方的利益。CA系统通过加密技术的支持、良好的系统设计及严格的法规,从技术和法律的角度维护用户的合法权益,保证运营商的利益。本文在对CA系统各个方面综述的基础上,主要完成了以下三部分工作:1.介绍了条件接收系统中涉及到的加密技术;详细分析了条件接收系统的原理和安全体系结构,其中包括CA系统的组成、原理、框架以及安全体系结构。2.引入了IP-CA的概念,提出了基于IP网的条件接收系统设计方案,该方案不仅根据《数字电视广播条件接收系统规范》制定的标准控制加扰器对原始传输流进行加扰,而且利用基于IP网的密钥分发系统代替传统的IC卡,实现对用户的认证、授权和计费管理。3.详细描述了基于IP网的密钥分发系统的设计方案,其中身份认证子系统利用数字证书技术实现对用户身份的认证,安全通道子系统利用非对称加密、数字签名、数字信封等技术保障通信的完整性和保密性;最后还对IP-CA中客户端(DVB-IP)的结构和功能进行了描述。基于IP网的CA系统利用IP网的双向性,使用软件替代IC卡,不仅节省了系统的成本,提高了系统的安全性,而且对于将来的有线电视网和计算机网的融合有一定的借鉴意义。更多还原

【Abstract】 With the development of the digital television, many new services have been provided to serve people, such as Video-On-Demand, pay-per-view, information-on-demand. Digital television provided a service platform for services and Network Company. The conditional access is the key system of the digital television. It ensures the benefit of consumer, program supply and network company. It guarantees the legal benefit of consumer and supply by encryption technology, good design and strict rule of law.This paper is based on the concise and deep-going survey of CA system and finished the following three parts:1. Introduce the encryption technology involved in the CA system; analyze the principle and the secure framework of the CA system, including the composition, principle, architecture and secure framework of the CA system.2. Introduce the concept of IP-CA, suggest to design the CA system based on IP net, the design not only scrambles the original video stream according to the standard scrambler, but also uses the security authentication system, instead of the IC card, to realize the authentication, authorization and charge management.3. Describe the design of the CA system based on IP net, and the Identity Authentication system uses the digital certificate to realize the Authentication of client’s identity, and Secure Tunnel system uses the Digital Signature, Asymmetrical Encryption and Digital Envelope Technology to ensure the confidentiality and integrality of the communication between the server and client. At last, describe the architecture and function of the client which belongs to the IP-CA system.The IP-CA system takes take advantage of the duplex communication in the IP net, and uses the software to replace the IC card, then not only reduces the cost of the system and enhances the security of the system, but also provides one method for the convergence of cable net and IP net.更多还原