Research On Applications Of Chaos Theory To Digital Product Security

With the popularization of computer and progress of network,E-commerce is being applied more and more widely in the world. The security of digital product has become the common focus of both academia and enterprises. The research on the security of digital product has important academic meaning and practical value. In order to protect the security of digital product, the effective integrity and comprehensive application of various security techniques, such as cryptography, information steganography, security protocol, and so on, are required. The diversity of digital product, the complexity of security function and the endless evolution of attacks insistently demand the research and development of more information security techniques with security, high efficiency and reliability. Currently, it is one of the hot promising projects on the combination of nonlinear science and information science to apply chaos theory to information security. In this paper, chaos-based information security techniques have been carefully studied and applied to protect the security of digital product. The following tasks have been accomplished in this paper: 1) Chaos theory is introduced in detail at different aspects. First, the ubiquitousness of chaotic phenomena in natural science and social science is pointed out, and the research history of chaos theory is reviewed. Second, the definition of chaos is presented, the characteristics of chaotic dynamics are described, and the criterion and rule of chaos are given. Third, several classical chaos model scattering in the whole paper are collected. Finally, the wide promising application of chaos is summarized briefly. 2) Detailed analysis of the state-of-the-art techniques in chaos-based cryptography is carried out. First, the outline of modern cryptography is presented. Second, the relationship between chaos theory and cryptography is compared in detail. Then, the systemic descriptions of different chaos-based ciphers are given in the order of the typical chaos-based stream cipher, the typical chaos-based block cipher, other ideas for chaos-based cipher, and the chaos-based image encryption. 3) Careful research on the chaos-based Hash function construction for text digital product is done. First, the definition and general structure of Hash function are given. Second, the feasibility of chaos-based Hash function construction is analyzed. Third, the known typical construction schemes are introduced. Finally, a scheme for one-way Hash function construction based on the chaotic map with changeable-parameter is proposed. Theoretical analysis and computer simulation demonstrate that it can satisfy all the performance requirements of Hash function in an efficient and flexible manner. It is practicable and reliable, with high potential to be adopted for practical application. 4) Security analysis of a chaos-based encryption-Hash combined algorithm is carried out in detail. The cause of vulnerability of the original algorithm is found, and the corresponding enhancement measures are proposed. Theoretical analysis and computer simulation illustrate that the modified scheme is more secure than the original one and possesses other good properties at the same time. Especially, it can perform both encryption and hashing simultaneously based on a dynamic look-up table. 5) Chaos is applied to the digital image hiding. By using the latest research achievement in chaos-based cryptography, two novel information-hiding schemes are proposed, namely the image information-hiding scheme based on chaos and iterative blending, and the other one based on chaos and image sharing. Theoretical analysis and computer simulation illustrate that they are both feasible, with good hiding and robust performances. Moreover, the algorithms are simple and practical. 6) It is explained that the traditional way to text digital product authentication is no longer suitable for image digital product, and a new one has to be designed in view of the characteristics of digital image. Through the improvement of Yeung-Mintzer's original scheme, a novel fragile watermarking scheme entirely based on chaos theory is proposed for digital image authentication. Theoretical analysis and computer simulation demonstrate that the whole scheme is secure, efficient, practicable, and with simple structure and strong ability of tamper localization. 7) Three corresponding secure transaction schemes based on chaos for digital product are proposed for the special requirement in different application backgrounds. They are a chaos-based scheme for web fair micro-payment, a chaos-based scheme for deniable authentication, and an efficient chaos-based scheme for anonymous and fair digital goods exchange, respectively. The first one, the web fair micro-payment scheme, is for the low value-pay network information service. It utilizes the one-way property of chaotic iteration to construct Hash function chains, realizes the unit-by-unit release of information service and guarantees the fairness of the exchange. The scheme has simple structure, higher security, less traffic and greater processing efficiency. Moreover, the flexibility of the transaction object is great so that it is easy to extend. The second one, the deniable authentication scheme, is for a special condition in real E-commerce: on the first hand, it enables a receiver to identify the source of a given message just like the traditionalauthentication scheme. On the other hand, a receiver cannot prove the source of the message to a third part. By using the semi-group property of Chebyshev chaotic map and the combined property of a chaos-based encryption-Hash combined algorithm, a secure and efficient scheme is proposed for the deniable authentication. The scheme is efficient, practicable and reliable. The third one, the anonymous and fair digital goods exchange scheme, aims at protecting the customers'privacy, such as purchasing interests and habits, and the anonymity and fairness of the exchange process. By using the combined property of a chaos-based encryption-Hash combined algorithm and the exchange property in RSA, a secure and efficient scheme is proposed for the anonymous and fair digital goods exchange. It is efficient, practicable and reliable. 8) Finally, the research work of this paper is summarized, and the future developing direction is indicated.