Research On Chaotic Encryption System Based On Searching

With the development of network technology and increasing frequency of information exchange, the research on information security engineering is becoming more and more important. As a novel technology in cryptography-chaotic cipher system has been attracted dense interest of researchers and widely studied. Chaos, as a kind of nonlinear phenomenon, has many remarkable characteristics: such as pseudo-random, unpredictability of evolution of its orbits, properties of mixing and sensitivity to initial conditions and system parameters. These characteristics are in accordance with the requirements of traditonal cipher. Research also shows that there is some relation between security commnications and chaos. Chaotic encryption has been an active research of nonlinear subject. The relative problems of chaos encryption systems are studied in this thesis using the methods of theoretical deduction and numerical simulation. The main achievements contained in the research are as follows:Synchronization and control for Chen system subject to uncertainties and Lüsystem have been analyzed. In Chen system, based on Lyaponuv theory, two adaptive controllers and the corresponding parameter update law are designed. It is theoretically proved that these two controllers can make two uncertain Chen systems asymptotically synchronized and identify the unknown parameters. Numerical simulations show the effectiveness of the proposed methods further. The comparisons of these two methods show: The method of theorem 3.1 is easier and more feasible than that of theorem 3.2, and the synchronization results are better.E. Alvarez system is a classical chaotic encryption system. The paper introduces a method, which can figure out the secret key accurately. Aim at a good many shortcomings of the system, the authors bring up a new chaotic cryptography scheme based on searching, we also optimize the ciphertext founded on the characteristics of the ciphertext, this technique can make the size of cipher file almost half of the primary size. Both theory and experimentations indicate some character of the cryptography.Based on some study of researches, the authors scheme out a new chaotic map, and testify some cryptography properties of the new chaotic map. Using the new map has speciality of preferable distributing, it can be used in chaotic encryption system. The paper also gives out an example. Numerical simulations indicate that the new method is effective.