The Research Of Secure System Of Electronic Commerce Based On Chaos

With the development of Internet and digital communication, more and more people and companies do businesses through electronic commerce. A lot of important information is transmitted on Internet, so how to build safe electronic commerce environments and protect information have become very important for the electronic commerce development.Chaos is complicated dynamic behaviors, and some features of chaos, such as pseudo-random, non-period, sensitive to the initial conditions and parameters and broadband power spectra, are expected to be applicable for hiding message and message authentication. Many chaos-based cryptographic schemes have been designed in recently years. Most of them are self-synchronizing stream ciphers, which are based on chaos synchronization theory. My work is mainly to design and analyze chaos-based hash functions and block cipher.The first chapter is an introduction to electronic commerce, including its some basic concepts, structure, developing stages, modes and status.In the second chapter, according to the previous security theory of electronic commerce, we research and summarize the security systems of electronic commerce from the point of view of technology.In the third chapter, we briefly introduce chaos theory; review the history and current progress on studies of chaos-based encryption.A chaos-based block cipher is designed and analyzed in chapter 4. We utilize coupled logistic maps, incorporating a two-dimensional Cat map to design a block cipher. And based on this block cipher, an image encryption model is analyzed. A large class of attacks is relied on the analysis of statistical properties of the system. We investigate key sensitivity analysis, plaintext sensitivity analysis, and statistical analysis of ciphertext, and statistical analysis of sub-keys.Since Wang Xiaoyun's group found collision problems of MD5 and SHA-1 in 2004 and 2005, the research of Hash functions have became a hot issue. In the fifth chapter we briefly introduce hash functions, analyze a chaos-based hash function, and find its collisions through statistical methods. We revise this algorithm, and set up a safe hash function to overcome this weakness, and based on it and Chen's chaotic system, design one-time digital signature scheme. At last, we introduce the production and problem of the applying chaos theory to the Electronic commerce security.