一种基于混沌的序列密码生成方法

由于混沌系统对实始条件和混沌参数非常敏感以及生成的混沌序列具有非周期性和伪随机性的特性，近年来混沌系统在密码学领域中得到了较多研究，该文提出一种基于混沌的序列密码生成方法，该方法通过随改变混沌映射的参数来提高混沌的复杂性，同时在有限精度实现时，通过引入扰动序列使输出的混沌序列具有良好的自相关性、均匀分布特性和随机统计特性，而且其周期可用混沌参数改变的周期与扰动序列的周期的乘积来度量，理论研究和模拟结果表明，该混沌序列加密方法具有较好的保密性并且便于软硬件实现。

A Chaotic Sequence Encryption Method

Chaotic systems are sensitive to initial conditions and chaotic parameters, and the chaotic sequences are non periodic and pseudo random. These properties of chaotic systems are suitable for the sequence encryption. But under the finite precision in practical application, the period and the complexity of the chaotic sequence are hard to determine, depending on different initial conditions and parameters. In this paper, a sequence encryption method based on chaos is proposed. The method makes full use of the chaotic properties. By randomly changing the parameters of discrete chaotic map, the method can improve the complexity of chaos and the anti broken strength for chosen plain texts, and enlarge the sequence period. With the introducing of appropriate perturbation aimed to change the initial conditions, the chaotic sequence has the good self correlation property, uniform distribution property and random statistical property under the finite precision in practical applications. In order to facilitate the realization of the method mentioned above, we use m sequences as the parameter sequence and the perturbation sequence. The theoretical study shows that the period of the chaotic sequence generated by this method can be measured with the product of the period of the parameter sequence and the period of the perturbation sequence. In practical applications, users can choose the appropriate m sequences as parameter sequences and perturbation sequences, according to their different requirements for security. In this paper, the software pseudo code implemented in programming and the hardware structures implemented in hardware are included, and how each part of the hardware works and cooperates is explained in details. The computer simulation results also show that the chaotic sequence has good cryptography properties. Therefore, this method is fairly good in security and can be implemented easily in both software and hardware.