Encryption Algorithm Based On Chaos Theory, Research And Applications

With the development of modern technology and network, the digital information has been applied to many areas worldwide. However, because of its easy replicability, information security is becoming more and more important. The research on the information security and protection has important academic significance and practical value.Cryptography is one of basic methodologies for information security.Researches has been shown that there is a natural relationship between chaos and cryptography, such as the sensitive dependence on initial conditions and control parameters, the density of the set of all periodic points and topological transitivity which are related to some features such as confusion and diffusion in cryptography. And the basic way to design strong cryptosystem implies quasi-chaos, so chaos-based encryption techniques have been a hotspot in recent researches and it plays an increasingly important role in information security.Focusing on the researches and applications of chaotic ciphers, the dissertation contains the following works:1 Chaos theory is introduced in detail from different aspects. Firstly, the ubiquity of chaotic phenomena in natural science and social science are pointed out, and the history of chaos theory is reviewed. Secondly, the definition of chaos is presented, the characteristics of chaotic dynamics are described, and criteria and rules of chaos are given. Finally, various promising applications of chaos are summarized briefly.2 The cryptography and chaos theory are introduced in detail and then a comparative study is performed on the relationship between chaos theory and cryptography. Then, the advantage of chaotic encryption is given.3 The chaos system based on PCA neural network has been analyzed in detail and necessary conditions for a chaos system are pointed out. Then an encryption algorithm based on chaos has been proposed and a file-encryption system is developed. Finally, the security of the algorithm has been proved by tests from the perspectives of statistical analysis, key space analysis and differential cryptanalysis.4 The encryption algorithm based on chaos is applied to the digital image encryption. At first, the meaning of the research on digital image encryption is introduced and several common image encryption algorithms are given in detail. Then, we present a new image encryption algorithm using chaos encryption. Finally, the security and effectiveness of the application are analyzed.5 The encryption algorithm based on chaos is applied to the project - the GuoDun Seal System of Sichuan, including software registration and data encryption. For software registration, a safe and reliable registration algorithm is designed, enabling it to set limits on the uniqueness of registration code for a single machine as well as on the validity duration. As for data encryption, the very important information that can not be shown as plaintext is encrypted into ciphertext by chaotic encryption.6 Finally, all the researches performed in this paper are summarized, and an outlook for the future development of the chaos theory and its applications in information security is provided.