基于椭圆曲线含有效期的离线电子现金系统

为防止电子现金重复花费和数据库记录无限制的膨胀问题，改进了现有的利用椭圆曲线密码系统构造的离线电子现金系统．改进的系统利用了椭圆曲线良好的密码特性，并采用零知识证明方法．在取款协议中采用基于椭圆曲线的部分盲签名方案，使电子现金包含由银行颁布的有效期，超过有效期的电子现金历史记录将被清除，这样减少了通信量和计算量，提高了执行效率．在支付协议中采用并行的椭圆曲线零知识证明，提高了系统的安全性．

Offline E-cash System with Finite Circulation Period Based on Elliptic Curve

To prevent e-cash from double-spending and unlimited increase in the records of databases, an improved offline e-cash system based on elliptic curve cryptography was proposed. The improved system utilizes good properties of elliptic curve cryptography system and adopts zero knowledge proof. Partial blind signature based on elliptic curve cryptography ensures that the e-cash is valid only in the period issued by the bank according to the withdrawal protocol, and the historical record of the e-cash that exceeds the valid period will be removed, which greatly reduce the amount of traffic and effort of calculation and improve the efficiency. The security of the system was improved by adopting the elliptic curve zero knowledge proof in the payment protocol.