数字电视广播条件接收系统的原理和实现

【作者】 杨邦文；

【导师】 姚庆栋；

【作者基本信息】 浙江大学 ， 通信与信息系统， 2002， 硕士

【摘要】 随着信息技术的飞速发展，广播电视的数字化已经提上议事日程。数字化给了电视前所未有的灵活性和扩展性。新的数字电视广播平台可以开展更多更诱人的服务，比如高清晰度电视、交互电视、Internet介入等。然而如果没有另外一项重要的技术—有条件接收系统技术的保障，新的业务不会变成现实，因为电视运营商不愿意做没有回报的投资。 电视广播的条件接收系统就是这样一种技术，它保证只有被授权的用户才可以接收广播服务。数字电视的条件接收总的思路是在前端对节目流进行数字加扰，同时把加扰控制字加密后广播出去，条件接收系统采用一定的策略使得只有授权用户可以解密控制字，然后用控制字解扰收看节目。数字电视标准组织DVB并没有对条件接收制定标准，因此开发安全高效的条件接收系统成为数字电视领域最重要最有挑战的工作。 国内电视广播的数字化已经启动，研究数字电视条件接收系统显得特别有意义。本文就这个课题展开论述并提出一种先进的多层加密解决方案。具体内容安排如下： 第一章论述了的条件接收系统的原理和作用、历史和现状，包括数字条件接收系统和模拟条件接收系统。 第二章在DVB规范下论述了数字电视条件接收系统的结构和原理、加密算法、DVB同密规范和通用接口规范。论述了条件接收系统的安全性。 第三章介绍了一种多层加密条件接收系统的详细设计方案，包括加解扰系统、加解密系统。 第四章介绍了与条件接收系统密切相关的管理系统。更多还原

【Abstract】 With the rapid development of information technology, digital television services now begin to be realized. Digital television broadcast platform gives the possibility of much more attractive services,such as HDTV,interactive television and interner access. But this will not become reality without the surport of another technology-conditional access system.Conditional Access System guarantee that only those entitled costomer can access services. CAS scrambles service streams with control word at head-end and broadcast the encrypted control word together with services streams. It is CAS’s responsibility to make sure only entitled terminal can decrypt the control word and descramble service streams.This paper mainly focuses on the design and implement of conditional access systen.Chapter 1 gives a brief description of digital television broadcase and conditional access system.Chapter 2 describes all aspects of conditional access systen in DVB architecture including struct, principium, encrypt arithmetic, DVB simulcrypt and common interface. Then discusses the security and protection of CAS.Chapter 3 describes detailedly an advanced solution of conditional access system, including the details of scramble/descramble and encrypt/decrypt.Chapter 4 describes the implement of manage system which is closely related to CAS.更多还原