Study Of Chaotic Sequence And Its Secure Communication System

The traditional spread spectrum sequence has m sequence and Gold sequence, which have good correlation properties and simple formation, but the sequence has few number, low complexity, poor security, and is easily broken. Therefore, we use the characteristics of chaotic signal, chaotic spread spectrum sequence generated replace the traditional spread spectrum sequence. With the development of computer technology, the chaotic spread spectrum sequence generated by single map is easy to be estimated the system parameters by inversion method, and this sequence has low complexity. In this paper, based on a single map, Logistic mapping and Tent mapping constitute compound chaotic mapping, then, put improvement of Logistic mapping together in series, the results of the analysis on the correlation characteristic and the sequence of pseudo randomness show that chaotic spread spectrum sequence is suitable for use in spread spectrum communication and chaotic secure communication system.In the chaotic secure communication system, chaotic synchronization is the key to realize secure communications, such as chaotic masking, chaotic modulation and chaotic spread spectrum communication. To do this, this article introduces several common methods of chaotic synchronization, and The simulation and comparison analysis. Drive-response chaotic secure communication scheme has simple structure, easy to implement, but secrecy is bad. So In order to improve the system of secrecy, the article uses the variant chua’s circuit to produce super chaotic signal, Variant chua’s chaotic synchronization secure communication circuit is designed and simulated by Multisim. The analysis results show that as long as choosing appropriate parameters, it can recover the useful information signal very well. This system has good synchronization feature, implementation is simple.Using traditional digital secure communication ideas, this article studies a secure communication scheme. The fourth-order chua’s chaotic system produces the chaotic spread spectrum sequence, which is considered as an encrypted. Drive-response synchronization method is used to realize the synchronization of chaotic secure communication system, and use it to image encryption system, the simulation results show that the scheme is robust, good secrecy and has a practical value.