Digital chaos cipher system

二进制随机变量序列在现代数字通信系统中有着重要的应用。对于这样的序列，已经提出了几种线性反馈移位寄存器序列。然而，众所周知，在概率论中，伯努利移位是独立同分布（i.i.d.）二进制随机变量在回顾了混沌动力学的基本问题，特别是信息源与马尔可夫链的密切关系后，给出了独立同分布序列的产生方法。二进制随机变量使用混沌动力学。这种生成方法是作为一类遍历映射的简单对称性组成的充分条件而给出的。此外，我们还给出了这种序列在以下方面的应用：1）在流密码系统中的密钥序列的应用; 2）在码分多址彩色图像通信系统及其扩展的数字水印系统中的应用。此外，在异步直接序列/码分多址系统中，由马尔可夫链产生的扩频码的性能进行了理论评估。

A sequence of binary random variables has found significant applications in modern digital communication systems. For such sequences, several kinds of linear feedback shift register sequences have been proposed. It is, however, well known in probability theory that the Bernoulli shift is a fundamental theoretic model of a sequences of independent identically distributed (i.i.d.) binary random variables. After reviewing fundamental subjects of chaotic dynamics, in particular, a close relationship between information sources and Markov chains, we gave the generation method of sequences of i.i.d. binary random variables using chaotic dynamics. Such a generation method is given as a sufficient condition composed of simple symmetric properties for some class of ergodic maps. Furthermore, we gave the applications of such sequences: 1) to running key sequences for stream cipher systems and 2) to a color image communication system through code-division multiple access channels and its extended version, a digital watermarking system. In addition, the performance of spread spectrum codes generated by a Markov chain is theoretically evaluated in asynchronous direct-sequence/code division multiple access systems.