数字电视条件接收系统加解密算法的实现

条件接收系统是数字电视发送和接收技术的保障系统，是数字电视的重要组成部分。数字电视条件接收系统中的核心问题是节目流的加扰及加扰控制字的安全传输问题，针对这一问题，采用3层密钥的密码体系模型对CAS的加密机制进行了描述，详细阐述了RSA，DES，3DES三层加密算法及实现方案，对3种算法分别在Xilinx ISE6．1下采用Verilog硬件描述语言进行了仿真，仿真结果表明算法实现方案在实现速度和占用资源方面都比较理想，论证了该算法实现方案在CAS中的可行性，最后对算法的安全性进行了简要地讨论。

Realization of Digital TV Conditional Access System of Encryption and Decryption Algorithm

Conditional access system is the supporting system for the transmission and receiving technology of digital TV,and is an important composing part of digital TV.The kernel question in conditional access of digital TV is the scrambling of the program stream and the secure transmission of control word.According to this question,the paper adopts cryptogram model of the three layer key to analyze the key mechanism in CAS, respectively expatiates the algorithm and realization scheme of the RSA,DES,3DES in detail.and the three algorithm is simulated by adopting Verilog language in Xilinx ISE 6.1.The result indicates the realization scheme of algorithm is perfect in the speed and the using of resource, demonstrates the feasibility of the realization scheme of algorithm in CAS,at the end of this paper briefly debates the security of the algorithm.