一个新的利用Smart卡的公正的电子现金系统

该文综述了离线电子现金系统的研究成果及其发展现状,改进了Brands及杨波等提出的利用防窜扰的Smart卡的电子现金系统,提出了一个新的利用Snart卡的公正的电子现金系统的设计方案。其主要工作是在Brands文的系统中增添了公正性,在特定的条件下,用户的匿名性可以被撤消。与杨波的文章比较,用户不需要到可信方处注册,并且用户的所有支付都是不可联系的,从而提高了系统的效率与安全性。其性与已有文献一样,都是基于随机Oracle模型与盲数字签名的限制性假设之上的。

A Fair E-Cash System with Smart Card

The key point in the design of off-line e-cash system is how to prevent the double spending. There are three ways to solve this problem as yet: One way is using tamper resistant smart card to achieve prior prevention; The other way is using cryptographic technique to detect double spending afterwards; The third way is to integrate the above two ways, and this kind of e-cash system provides both prior prevention and detection afterwards which is the most secure scheme till now. As we all know, Untraceable off-line electronic cash system, which offers a level of payer anonymity during a purchase, gives an opportunity to criminal, such as laundering, corruption and kidnapping. Frankel Y., Tsiounis Y. and Yung M. first introduced the notion of fair off-line electronic cash (FOLC), which extends this capability to allow a qualified third party to revoke the anonymity of the payer under a warrant or other specified "suspicious" activities. In this paper, we improve the payment system with smart card proposed in and , and present a fair off-line e-cash system with smart card. The main contribution of our solution consists of the "fair" property as opposite to , and the security and efficiency as opposite to . In our system, Payer does not need to register at the third party, and payment is also unlinkable as opposite to . We improved the efficiency of the FOLC in , and by letting the trusted third party publish two public keys f 2=g x T 2 and f * 2=f x -1 T 2 . The efficiency is achieved preserving the same level of integrity for user, shop and bank at the same time. The security of our system is based on random oracle model and restrictive assumption of blind signature, which is the same as , , and .