Based On Chaos Logistic System Sequence Encryption Algorithm Improvement And Applied Research

With the rapid development and wide application of communication technology and network technology, more and more information has been transmitted through the network. Therefore, the security of information is getting more and more important. The cryptography, which aims at the security of information, has become of the important research fields in information science and technology. Several new branches in this field such as chaotic cryptography and quanta cryptography have also attracted many research's interests.Chaotic systems are sensitive to initial conditions and chaotic parameters, and can produce massive high security sequence with analogous randomness, correlation, broadband and continuous spectrum. The main purpose of this dissertation is to investigate the theory and application of Logistic chaotic cryptography, especially the design and implementation of stream ciphers.The preliminaries including the theory and principle of modern cryptography, sequences and chaos are presented at first. Especially importantly introduced some main factors that regarded with the security of the sequence cryptography. And then, I analysis the Logistic system with carefully and comprehensive. With the theory analysis and experiment way. In the next, I gave the traditional sole Logistic chaos sequence encryption algorithm design method, and then aims at its existence shortcoming, especially to "the dynamic characteristic degeneration question" and proposed improvement algorithm: Combined the m-sequence perturbation compound chaos sequence encryption algorithm. And to improved the key sequence in the this article last part which the algorithm produced from sequence randomness, the sequence linear order of complexity as well as the sequence secure aspect has made the comprehensive analysis, and the sequence which produced with the traditional algorithm and the m- sequence carries on the contrast to analyze. Through the theory analysis and experiments method, With the theory analysis and experiment way. I prove the improvement algorithm had distinct improvement in sequence randomness and the periodic aspect compared with the traditional algorithm. Achieves anticipated effect. Finally I improve the algorithm to apply in the digital image encryption. Designed take improved the algorithm as the foundation, the union digital image sets at chaotic technical digital image encryption algorithm. Through 24bit 512×512 digital images carry on the experiment, had proven this digital image encryption algorithm can satisfy the application demandIn this paper, I have widely used method which the combination of the theoretical analysis and mathematics experiment. In the theory analysis, statistical analysis, algorithm design, I used the Matlab 6.0 to made the analysis results graphic.