Design And Analysis Of Cryptosystems Based On Chaos

The development and progress of science and technology and the popularity of network applications bring convenience to the community, at the same time, security issues are also caught people’s attention. Cryptographic techniques are effective means to ensure information security. With the increasingly study of chaos and its applications, cryptographic technique based on chaos, which is an interdisciplinary subject that applies chaos theory into information sciences has been widely studied. This paper designs and research several symmetric encryption algorithm and asymmetric cryptosystems. The main contents are as follows:(1) Design of a novel symmetric cryptosystems based on chaos. A image encryption scheme based on chaos is proposed, in which the key is related to the plaintext. In this way, security has been improved. The degradation when chaos implemented in limit-precise computer is avoided when disturbing its trajectory by incorporating the linear feedback shift register.(2) Cryptanalysis of a symmetric cryptosystems based on chaos. A symmetric cryptosystem is analyzed and found its loopholes. Then chosen plaintext attack is carried out successfully. In the end, some remedial measures are proposed to improve the security.(3) Design of a cryptosystems combining chaos with chaos. An image encryption system based on combination of intertwining logistic maps and cellular automata are proposed after the characteristic study of a few types of cellular automata. The image is encrypted by confusion implemented by pseudo-random number generated by chaos and diffusion by chaos and cellular automata.(4) Analysis and improvement of a key agreement protocol. First analyze a proposed key agreement protocol and find some security problems in it. Then proposed a new key agreement protocol to ensure security based on Chebyshev chaotic map. Analysis proves its security and efficiency.