Research On Security Efficient Multi-bank Divisible Electronic Cash Protocol

With the rapid development of information technology and electronic commerce,electronic cash has become the ideal method of payment with the advantages of anonymity,divisibility and so on. The research of security, efficient and practical e-cash paymenttechnology is one of the key issues to be solved in the e-commerce transactions and is thescientific basis of payment systems, which have important scientific value and broadapplication prospects. However, there are still many deficiencies in the existing e-cashprotocols, such as specific algorithms, cryptography, e-cash model, security, and theformal analysis of protocol. To slove these problems, the main researches of this paper areas follows.Firstly, the shortcomings of the classic binary tree model and its cost principle arecomprehensive analysed, a new binary tree model is built and a new cost principle isproposed as the basis of design the protocols in later chapters. The new binary tree modeland its cost principle can achieve all the nodes on the binary tree can be spent, so thesystem can improve the the total spend e-cash, reduce the number of signature in withdrawphase and he amount of computation in deposit phase of the bank, ensure the efficiency ofthe divisible e-cash protocol. On the basis of the new binary tree model and its costprinciple, the divisible e-cash model is presented as the reference standards to designprotocol. CL signature based on bilinear pairings is proposed to sign in the protocol. Nodeoptimization calculation method is proposed, which allows the user to spend the sameamount of computation done by any electronic cash and effectively improve the efficiencyof the protocol. And then the specific process of all node spent efficient divisible e-cashprotocol is descripted in detail, analysis shows that the protocol has achieve a variety ofsecurity and has high efficiency.Secondly, based on the new binary tree model and its cost principle, take full accountof transitivity of the e-cash, a transferable divisible e-cash model is built, and an efficienttransferable off-line divisible e-cash protocol is proposed. Using divisible technology toachieve all nodes on the binary tree can be spent and accurate payment of goods. Transferable realization of e-cash in the amount of information transfer process does notincrease and improve the efficiency of the program. Non-formal analysis shows that thisprotocol meets the fundamental security, and accountability and fairness of the protocolare analyzed by Qing-Zhou logic method, which makes up the lack of formal analysisdefect in existing e-cash protocols.Thirdly, based on the new binary tree model and its cost principle, the single bank isexpanded to multi-bank situation, and a multi-bank divisible e-cash model and a fairnessmulti-bank divisible e-cash protocol based on certificateless group signature are proposed.Using certificateless group signature technology can effectively solve the problem ofgroup members dynamically join and revocation and reduce the communicationcomputation, so it can improve system efficiency and practicality. The protocol not onlyhas good security, but also meets the accountability and fairness by Qing-Zhou logic.Finally, multi-bank divisible e-cash protocol is used in the actual e-commercetransactions, and a Qinhuangdao Port coal electronic transaction system is designed andimplementationed. By the test, the system is very good to realize the basic functions ofelectronic transactions, to meet the security nature of anonymity and unforgeability, andquickly processes in the phases of withdraw, payment and deposit. The prototype systemreflects the security, efficient and useful features, which can promote the practicalapplication of e-cash system.