Research On Several Chaotic Secure Communication System Based On Observer

The research has studied the relative problems of united chaotic system and chaotic modulation and their application in secure communication using the methods of modeling and numerical simulation. The main work in this paper can be summarized as follows:The three special characters about united chaotic system are analyzed. And a new secure communication method based on the state observer is proposed by chaotic modulation. A model at transmitter and the state observer at receiver are designed according to the special features of united chaotic system. After the information signals are modulated into the parameter of chaotic system, the information embed the chaotic signal carrier. Finally, by the observer designed at receiver the original information signal is recovered successfully. Theoretical analysis and numerical simulations are presented to verify the effectiveness of the proposed scheme.A new chaotic secure communication about digital signal based on the method of chaotic modulation is proposed. In this scheme, a new transformation mechanism about digital signal and analog signal is designed. By this new transformation mechanism and the former secure communication scheme about analog signal, the digital secure communication scheme is designed successfully. Theoretical analysis and numerical simulations are presented to verify the effectiveness and feasibility of the proposed scheme.Based on chaotic masking and chaotic modulation, a multistage secure communication is proposed. A multistate secure communication system is designed and the chaotic signal produced by modulation is taken as level 1 confidential signal. Then level 2 confidential signal is formed after level 1 confidential signal is added to the chaotic carrier. The complicacy and security is enhanced. Theoretical analysis and numerical simulations are presented to verify the effectiveness, security and flexibility of the proposed scheme.The primary quality of united hyperchaotic system is studied and a new secure communication scheme based on a state observer is proposed. A new observer designed based on a secure communication scheme based on state observer proposed by forgoing chapter improves the speed and accuracy of the information signal modulation. Finally, the effectiveness and feasibility of the state observer is verified by theoretical analysis and numerical simulations. A new digital signal secure communication scheme is proposed based on chaotic masking. The model of drive-response system is put to use and the chaotic masking is realized by generalized projective synchronization and poles configuration technology. This type of chaotic masking is of fast masking speed. According to the change of chaotic system's state, the binary signal is transmitted and the information signal is recovered at the receiver by the masking state of chaotic system. Theoretical analysis and numerical simulations are presented to verify the effectiveness of the proposed scheme.