The Research On Off-Line E-Cash Protocol Based On Smart Card

With the rapid development of electronic commerce, the security of the electronic trade is getting more and more important. Public Key Infrastructure is an important tool to guarantee the EC's security, and the safe EC protocol is the basic to carry through the electronic trade. The electronic cash technology is one of the main technologies. The target of this dissertation is the research on how to design multi-bank and divisible off-line electronic cash protocols using smart card technology according to currently circumstances, it will provide the theoretic support for the developent of the EC payment protocol.Firstly, the relevant math knowledge of the elliptic curve and the elliptic curve cryptography are described, and two digital signatures used in the e-cash protocol are summarized. Then the structure model, the function of Public Key Infrastructure and the relevant knowledge of the smart card are introduced in detail.Secondly, a multi-bank and off-line e-cash protocol based on smart card is presented according to the multi-bank situation exists in the electronic trade. The purpose of the smart card is to prevent double-spending in advance and make the user's trade conveniently. A shared signature based on elliptic curve cryptography is presented at first, and its application in the e-cash protocol is given. Then a multi-bank and off-line e-cash model based on smart card is set up and analysed, the basic premise and the basic module of the protocol are described. Based on the above content, the multi-bank and off-line e-cash protocol based on smart card is fully described, they are the set up of the system parameters, the opening account protocol, the withdraw protocol, the payment protocol and the deposit protocol. Then the security and efficiency of the protocol are analyzed.Finally, an off-line divisible e-cash protocol based on smart card is presented according to the divisibility problem of the e-cash. The prior restraint and the afterward check are used to solve the double-spending problem in the protocol. The basic description, the characteristic, the basic premise and the basic module of the protocol are described, and each part of the protocol is fully described. In addition, the correctness, security, divisibility, unlinkablility, fair anonymity, unforgeability, undouble-spending and efficiency of the protocol are analysed.