| Chaos is a very common phenomenon in the nature world. Chaos is a very complexphenomenon, which is the unity of randomness and certainty, the combination of order anddisorder. The research on chaos will help us to know and learn more from the objectiveworld. The chaos has various potential application in science and technology.In this thesis, we study the certain methods of chaotic secure communication. As thechaotic secure communication scheme is based on control and synchronization of thechaotic system. We will first introduce some common chaotic systems and the methods tocontrol and synchronize them. Following that we will introduce a new chaotic system andsome chaotic characteristics of the new chaotic system will be analyzed, such as the chaoticattractor, the Largest Lyapunov Exponent and the waveform in the time domain. The newchaotic system is successfully applied to secure communication.In order to improve the transmission and safety performance of the single-stagechaotic system, such as chaotic masking, chaotic shift keying, and chaotic modulation, wepresent a new three-stage chaotic communication system. The chaotic systems in both thetransmitter and the receiver end are consisting of the unified chaotic system, which has onlyone parameter for us to set. By adjusting the parameters in the linear module and theinterference system, we can produce tens of different kinds of transmission signals, whichmake it is more difficult for the illegal receiver to decode the encrypt signal. The simulationresults show that the system will realize synchronization quickly, and the information signalcan be recovered successfully under different parameters of the unified chaotic system. |
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