Hyper-chaotic System And Its Applications In Secure Communication

Chaos is a seemingly random and internal non-regular motion. It is the unity of order and disorder, certainty and randomness. The research on chaotic dynamics is a popular topic today. In recent years, computer technology, information technology and communications technology has a rapid development, especially the concept of information infrastructure and construction plans are presented, the massive worldwide information networks which are as the core of the computer are gradually formed. In the21st century, the multimedia communication gradually became an important means of information exchange, information security and secure communication has become increasingly important. From state secrets to people’s lives, such as credit cards, automatic teller machines, secure telephone, confidential fax, Internet and other online information delivery, we need to have adequate security measures to protect their safety. In the nonlinear circuit system, chaotic signals which due to the properties of inherent randomness, non-periodic, continuous broadband spectrum, similar noise, is suitable for using in secure communications. In particular the discovery of chaos synchronization, the confidential communications which is based on chaos theory entered a stage of practical application.In this paper, based on a Qi three-dimensional autonomous chaotic system, by adding a linear feedback controller, a new four-winged single equilibrium point hyper-chaotic system has been constructed; based on the Lorenz chaotic system, by adding a nonlinear controller, a new hyper-chaotic generalized Lorenz system has been constructed.By using the knowledge of chaotic dynamics, the nature of the two new hyper-chaotic systems is analyzed and studied. Separately the dynamics of the two new hyper-chaotic systems have been analyzed, namely, symmetry, dissipation, equilibrium and stability. The Lyapunov spectrum and Poincare mapping sections within the appropriate index parameters has been illustrated Two new hyper-chaotic systems has periodic, chaotic and hyper-chaotic state. By using two conditions of center manifold theorem, calculated the necessary parameters of the new single equilibrium four-wing hyper-chaotic systems in Hopf bifurcation, and verified by numerical simulation and analyze.Based on the theoretical analysis and numerical simulation, according to the actual parameters range of the electronic components, the corresponding analog circuit has been designed for the two new super-chaotic systems respectively. And build the actual circuit in the bread board and printed circuit board. In the analog oscilloscope a real hyper-chaotic attractor phase trajectory waveform has been obtained, which verified the existence of the two new hyper-chaotic systems and the effectiveness of chaotic signal on the physical level.Based on the above work, by using of chaotic modulation method in the chaos synchronization, due to the new four-wing single equilibrium hyper-chaotic system the confidentiality of the circuit is designed. A simple sine wave signal, after adding the hyper-chaotic signal has became superimposed signals which can not be easily deciphered. At the receiver, using the same hyper-chaotic synchronization signal demodulate the signals, so that the signals can be reverted to the former sine wave signal. By using this design of the circuit, the feasibility and effectiveness of the hyper-chaotic signals in the application of communications privacy can be validated.