一种高安全性的级联型混沌扩频序列

针对传统一维混沌映射产生序列复杂度低、保密性不理想等问题，提出了一种基于Logistic改进型映射和Cubic映射的级联型混沌序列。新序列的混沌映射表达式由原来的低次一阶差分方程扩展为高次二阶差分方程，映射迭代过程由单级迭代变为二级交叉迭代，从而提高了混沌系统的复杂性。对新序列的非线性动力学混沌特性和扩频通信性能进行了仿真对比，结果表明新序列具有混沌吸引子结构更加复杂、初值敏感性更强、序列复杂度更高、安全性更好的特点，最后验证了新混沌序列具有和传统一维混沌序列相当的扩频特性。

A high security serial chaotic spread spectrum sequence

The sequence generated by the traditional single chaotic map has the problem of low complexity and poor secrecy.This paper proposes a serial chaotic sequence based on improved Logistic mapping and Cubic mapping. The expression of chaotic mapping by the original low times first order difference equations expands to high times second order difference equation,and mapping iterative process is changed from single-stage iteration to second-stage cross iteration so that the new sequence produces a more complex mapping expression of chaos. The nonlinear dynamics chaos characteristics and spread spectrum communication performance of the new sequence are simulated and the results show that the attractors of the proposed chaotic sequence are more complex,the initial sensitivity is more stronger. The complexity of this sequence becomes higher. This sequence possesses much better security performance. Finally the feasibility of the chaotic sequence in spread spectrum communication is verified.