Chaos Theoretical Analysis And Applied Research In Secure Communication

Chaos has been paid wide attention because of its some good intrinsic properties, such as wide-band frequency, similarity to noise and extremely sensitivity to initial condition, and it has been widely and successfully applied to many areas. Analyzing chaotic system and researching chaos control, which is the premise for the application of the chaos, can make us know more special properties of the chaos. Some methods of computing the characteristic parameters of the chaotic system and some methods of controlling the chaos for the secured communication are presented in detail. The main contributions of this dissertation are as follows:1. All kinds of typical methods of computing the characteristic parameters of the chaos are presented at length. Aiming at the default of the Small-Set methods whose results are varied obviously with the variation of the embedding dimension, we computer jointly the embedding dimension and time delay by using the famous C-C methods. The simulation results show that the improving measures are correct and efficient.2. Three typical methods of controlling chaos when the chaotic systems are driven by a common signal are discussed at length firstly, namely adaptive method, sampled data feedback method and moving surface method. We presented the improving measures of the adaptive method and the moving surface method respectively.3. Methods based on the observer and based on the phase-locked loops are discussed comprehensively in this dissertation when the chaotic systems are driven by a chaotic signal. Especially we researched the robustness of the method based on the phase-locked loops deeply, and new theory on computation robustness presented.4. The typical and successful applications in the modern cryptology of the chaos are discussed in this dissertation, and the simulation results substantiate the feasibility and the high reliability of the chaotic key with a concrete instance. Two secured communication designs, one based on phase-locked loops and another based on the unstable periodic trajectory of the chaos, are discussed comprehensively. The simulation results show that applying the chaos in the secured communication is very effective in theory.