A Research Based On The Chaos For Pseudo-Random Bit Generator And Encryption Algorithms

With the rapid development of computer, network and other information technology, information as an intangible resource has penetrated into all walks of life, making an important contribution to the development of various fields. As a kind of important information resources, pseudo-random number sequence has been widely used in cryptography, Monte Carlo calculations, image encryption and other areas. Meanwhile, WSN data security attracts more and more attention for the massive use of WSN, and its application value of unfolding. As one of the most effective means to protect data security, encryption technology is constantly being applied for WSN’s data security protection.Chaos that is a complex dynamic system has lots of properties similar to cryptography’s. For example, the inherent characteristics of pseudo randomness of chaos corresponds to pseudo random sequence in cryptography, and extreme sensitivity to initial conditions and control parameters corresponding to of chaos corresponds to the diffusion characteristics of traditional password. Based on these characteristics mentioned above, chaos constantly being used in generating pseudo-random bits and the design of encryption algorithms.In this thesis we design a pseudo random bit generator, and a block encryption algorithm that is suitable for wireless sensor network, using chaos technology combined with other technologies. The specific content of the work as follows:(1) Designing a new, parallel pseudo-random bit generator based on coupled chaotic map, whose main feature is the use of a one-dimensional coupled chaotic mapping system. By selecting a valid parameter, we can not only ensure that the system is complex spatiotemporal chaos but also ensure that sequence has good statistical properties by limited, convenient shift operation, and it is suitable for the hardware platform. Meanwhile, the seudo-random bit generator can be used to output parallel random bit sequences.(2) A block encryption algorithm is proposed for wireless sensor network, which has64-bit block and256-bit key. The algorithm consists of Feistel structure of16rounds and two simple permutation operation. In the round function, we use controlled permutation and Arnold Map as nonlinear transformation. Sub-key expansion algorithm uses the method of RC5’s. The implementation of the algorithm is simple, and all operations can be done by shifting and simple logic operations. The statistical results show that the algorithm has a good diffusion and confusion effect and has a strong ability to resist differential attacks.