【作者】 纪美霞；

【导师】 贾小珠；

【作者基本信息】 青岛大学 ， 计算机应用技术， 2007， 硕士

【摘要】 随着计算机网络技术的迅速普及，电子商务得到了飞速发展。对安全、高效、可分的公平离线电子现金系统的研究不仅具有重要的科研学术价值，而且对国家电子商务、金融机构的信息化建设和国民经济的发展具有重大的意义。但电子现金到目前为止还处于研究发展阶段，如何进一步提高效率，提高安全性，实现公平性和可分性等技术问题还没有完全解决。论文主要对可分电子现金系统方案进行研究，提出两种新的可分电子现金方案，设计实现一个无可信第三方的可分电子现金系统，为电子现金支付进入大规模的应用进行有益的探索。首先，介绍了电子现金的基本知识，包括国内外研究现状，主要系统模型、关键技术等，并分析了电子现金的可分性问题。其次，提出了两种新的可分电子现金方案。其一，针对可分电子现金系统中存在的第三方集权的问题，采用分布式可信方将追踪的权力分散给n个可信机构，至少k个可信方联合起来才可以实现追踪。该方案消除了只有一个可信方的集权，在一定程度上控制了可信方任意追踪的权力。其二，针对第三方追踪不确定的问题，提出了一种无可信第三方的可控匿名性的可分电子现金方案。方案中银行根据司法机构提供的线索或凭证，要求同一时间戳的用户打开消息，实现对电子现金和取款人的追踪。最后，设计实现了一个无可信第三方的可分电子现金支付系统。采用C／S设计结构，应用Visual C++ 6.0开发工具，利用ODBC访问SQL Server数据库，实现该系统的基本功能。更多还原

【Abstract】 With the rapid popularization of the computer network technology, electroniccommerce begins to develop quickly. Fair off-line e-cash system with security, efficiencyand divisibility has an important scientific and academic value. Moreover it has animportant significance to our electronic commerce, the information construction offinancial organizations and the development of our national economy. However,electronic cash is still on the stage of research and development so far. Many technicalproblems such as how to enhance efficiency and security and how to realize fairness anddivisibility haven’t been solved completely.This paper devotes to the research of divisible e-cash systems, proposes two newdivisible e-cash schemes, and designs and realizes a divisible e-cash system without TTP(trusted third party), which carries on a beneficial exploration for a large-scale applicationof e-cash payment.Firstly, this paper introduces the basic knowledge of e-cash, including researchactuality abroad and at home, main system models and key technologies, and thenanalyzes the divisibility of e-cash systems.Secondly, two new divisible e-cash schemes are proposed. On the one hand, aimingat the problem that TTP has power centralization in a divisible e-cash system, distributedTTP can disperse the tracing power to n credible organizations, at least k of which canunite to realize tracing. The decentralization of TTP has avoided power centralization andcontrolled arbitrary tracing in a certain degree. On the other hand, aiming at the problemthat TTP causes uncertain tracing, an anonymity-revocable and divisible e-cash scheme isproposed without TTP. In this scheme, according to the clue and certificate provided bythe judicial organization, the bank requires the user to open the message with the sametime stamp, which can realize the trace to e-cash and withdrawer.Finally, a divisible e-cash payment system without TTP is designed and realized.According to client/server design structure and Visual C++ 6.0 development kits,adopting ODBC to visit SQL Server database, this system can realize the necessaryfunctions.更多还原