Research On Chaos Theory In Secure Communication System

Communications security technology is of long history and its core content is continuously updated with the times. Over the last decade, communications and computer networking are widely applied in the human social life. The attack and defense of information are more and more intense. How to better protect information security is now the major theoretical and technical problem in the the field of information technology.Because of the strange dynamic features of chaotic orbit, chaos theory was introduced to communications security technology and became a hot topic in related fields. This paper studies the discrete and continuous chaotic motion, building high performance secure communication system. Considering the core role of computer and the Internet in modern communications, this research focused on the combination of discrete digital map and the traditional chaotic secure communication. The work of this paper is mainly in the following areas.(1) The novel chaotic secure communication should have such features like facing to digital technology and Internet, adapting to bad channel transmission characteristics, reflecting outstanding characteristics of chaotic dynamics evolution. In order to sovle the big security risk which exists in low dimensional discrete chaotic secure communication system this paper proposes a multi layer-key secure communication of chaotic mapping program, encrypted with the dynamic parameter map chaotic signal. This method can not only withstand the attacks in the phase space, but also can more effectively overcome the weakness of orbit periodicity caused by digital chaos mapping.(2) An adaptive control measure is proposed to attack some of the early chaotic parameter modulation secure communication system. A multi layer-key secure communication algorithm of chaotic mapping program is designed, which can effectively defense many attacks.(3) The widely applied discrete maps have the weakness of small amount, small range of parameter adjustment, periodic windows. So its application in secure communication is very unfavorable. This paper constructs a novel sub-parabolic map. Its characteristics of the bifurcation diagram and Lyapunov exponent features are quite good, and suitable for the requirements of information encryption. Piecewise parabolic map are used to construct a satisfactory composite sequence in phase space distribution, and a chaotic image encryption scheme is designed based on this compound chaotic sequence.(4) The potential application of unlimited encryption folding maps in the information field is great, but there is few case applied. So how to construct desired infinite folding map is an urgent mathematical problem. This paper proposes universal construction rules of infinite folding map, according to which one can construct free chaos infinite variety of folding map by a known mathematical form. This paper also constructs a number of infinite folded maps with excellent dynamic characteristics. The author analyzed its mathematical properties and designed a chaotic encryption model based on infinite folded map.(5) Chaotic secure communication masking system faces serious security vulnerability, so this paper proposes a two-stage cascade of chaotic secure communication system solutions to effectively prevent attacks from filters. In addition, for the continuous chaotic secure communication system which can not be used in the case of RF channels the author proposed a chaotic secure communication based on asynchronous and orthogonal modulation. The author also took effective attempt on designing chaotic secure communication system based on TS fuzzy model.