Study Of Chaotic Synchronization Control Theory And Its' Application In The Field Of Information Encryption

In order to control chaos, chaotic synchronization control methods and its application in the field of information encryption are studied by merging the latest achievements from chaotic dynamics, advanced control theory, modern cryptology and modern communication technologies. Some methods, such as theory analysis, numerical simulation and experiment research, are employed in this research.The developing history of chaos theory and its application, especially the present researches on chaotic security communication, are reviewed. The researches on chaotic synchronization and present popular topics are discussed widely. The features of chaotic security communication and chaotic encryption based on synchronization are concluded. Finally, a clear study direction is given out in chapter 1.Based on the QR decompose of Jacobi matrix, the principle of computing Lyapunov Exponents (LE) algorithm is studied, and a new calculate program is designed using Matlab 6.5, which can compute the LE and fraction dimension of nonlinear dynamics systems, and the Condition Lyapunov Exponents (CLE) of chaotic synchronization system. Some affect indexes to computing results, such as iteration times, step length, solvers and initial value, are analyzed. How to calculate LE is the theoretical and technical base to study chaotic synchronization control in following chapters.In order to promote the study of chaotic synchronization and modify the performance of synchronization chaotic system, seven performance indexes of synchronization system is proposed, and the relations between control parameters and synchronization performance are discussed. A new multi variable driving error feedback controller is designed, which can realize the synchronization of continuous chaotic systems and hyper-chaotic systems. A new method called linear and nonlinear feedback is put forward to implement synchronization of two discrete systems, andthe synchronization conditions are induced. The simulation verified the correct of this control method.Using adaptive synchronization control approach, based on Lyapunov stability theory and Pecora-Carroll synchronization principle, the synchronization method for a unified chaotic system with certain parameters or uncertain parameters is studied. A scheme of CSK digital security communication based on unified chaotic system is put forward, and the coherent demodulation method is used to recover the bits in the receiver. The theory analysis and value simulation proves that it has good security performances and strong capability against interfere.After the relations between chaotic system and tradition encryption algorithm are compared, we gives out the conception of Safe Chaos and the safety conditions for Safe Chaos. The principle of chaotic sequence encryption is analyzed. After discussing the statistics performances of Logistic chaos map, a data encryption module and an encryption algorithm are designed based on Logistic chaotic map. By using modularization method and multi-threading technology, the encryption software is exploited on the platform VS.Net. It can be used for encrypt static files, such as text, data, and picture.A new network synchronization method called equal interval diving is advanced, and a new data stream encryption scheme is designed through combining 3DES with chaotic algorithm. The real-time transfer protocol library based on adaptive communication environment is realized. Speech encryption transfer over network is implemented. It has many characteristics such as fast encryption velocity, small transmission delay, strong anti-attack capability and high secure performance, and it can be applied to some high safe situations, such as military communication.