利用电子钱包的有效的公正支付系统

该文提出了一个有效的利用电子钱包的公正支付系统。系统中用户只拥有一个银行账号；提款时用户得到一个关于本人身份字的盲签名并向银行提供构造正确的供跟踪的信息；支付时用户在防窜扰卡的协助下向商家证明所支付电子现金的有效性，并提供可跟踪的正确信息；委托人完全离线，不参与系统中除跟踪协议以外的任何协议的执行，仅需要保存好自己的密钥并在需要跟踪时使用之。系统的安全性基于离散对数困难问题，分析表明该系统是安全有效的。

An Efficient Fair Payment System by Electronic Wallet

Electronic payment systems are well-understood to be an essential step on the road to electronic commerce, and are thus in high demand. There has been a strong effort in developing secure untraceable off-line electronic cash protocols since Chaum proposed the first e-cash system in 1991 and some systems are now in use. However, there are still many open problems in the field of e-payment system research. The basic problems with all electronic payment systems for issuers of e-cash are to prevent double spending and to prevent kidnap and laundering. For the using of credit card in transaction is very popular, it is proper to design e-payment system based on smart card. There are many researchers making great efforts to do this work and gain some useful results. In this paper, an efficient fair payment system by electronic wallet is presented. Users in the system have only one personal account in the bank. In the withdrawal protocol, the user gives a correctly constructed message for possibly coin tracing to the bank and gets a blind signature on his identity from the bank. In the payment protocol, with the help of tamper-resistance card, the user proves to the shop that he spends a valid e-cash and sends a correctly constructed message for possibly owner tracing to the shop. A valid e-cash can be deposited to the bank by the shop. If a user spends an e-cash more than one times, with the help of the Trustee, the bank can find the user easily. Unlike other systems, the Trustee in this system is off-line entirely, it does not need to be involved in any protocols except the owner-tracing and coin-tracing protocols. The security of the system is based on the discrete logarithm problem. Upon the analyses, it indicates that the system is secure and efficient.