Study On Evolutionary Computation In Information Security

Cryptology is the core technology of information security, the cipher function design and the security analyzes are one of the hotspot in the current studies. The crypto-algorithm may divide into the stream cipher and the block cipher according to its encryption way. Their security has close relationship with Boolean function which is the core design part of them. Essentially, these system's securities may all sum up as the cipher characteristic problem of Boolean function . The construction of Boolean function satisfied the good cryptology characteristic is an important topic in cryptology research area.Many problems in the cryptology can be represented as optimization problems in mathematics. And the evolutionary computation is a kind of computation model. It simulates the evolutionary process in the nature by computer, especially the biological evolutionary process to solve the difficult optimization problem. This dissertation applies evolutionary computation in the cryptology area, and uses the evolutionary computation method to design cipher function. Compared with the traditional mathematics design method, It can automatically design cipher function with the high cryptology characteristic.First, This dissertation studies the related cryptology characteristics of the Boolean function and establishes the mathematical model of evolution cipher function. It studies the key problem of the evolution cipher function, and designs the high cryptology characteristic Boolean function with the evolutionary computation. The design of Boolean function problem belongs to the discrete optimization problem, but some new algorithms such as the particle swarm algorithm is established in the continues space. Therefore we introduce space transformation concept, establishment continual space to discrete space mapping , and use the local search method and the dissipative mechanism to reduce the continual space to the discrete space mapping in loss, thus make the PSO apply to in the Boolean function design successfully. In addition, according to the original thought of the PSO algorithm, this dissertation introduces swap operator and swap sequence concept, designs the PSO algorithm which can search directly on the discrete domain to avoid the loss of space swappingThen, the dissertation completes the Boolean function automatic design using the Simulated Annealing, and makes the improvement of SA, obtains the good experimental result. Considering that the convergence time of SA is relatively long and the PSO algorithm can converge quickly, therefore, we combine the two algorithms and present the PSOSA algorithm., solves the automatic design problem of Boolean function , obtains the satisfying result.It may use software or hardware to implement the encryption algorithms. The software realization quite is easy, the hardware realization has the formidable superiority in the speed. Now more and more cryptology algorithms can be realized by hardware. FPGA is the more population implementation in the hardware realization. Finally, the dissertation discusses the relationship of the Bool function and...