一种加入有效期的离线电子现金方案

电子现金作为物理货币的电子等价物，已经成为一种安全方便的电子支付手段。由于电子货币容易被复制，所以防止电子现金的重复花费是设计电子现金方案必须考虑的安全问题。现有的电子现金方案中，一般的做法是银行保留所有已经花费的电子货币，然后与新花费的电子货币比较，以发现重复花费。这样就带来了一个问题，即银行的存储花费会无限增大，对其的查询和管理效率也会降低。基于RSA盲签名和Schnorr一次性知识证明设计了一个新的离线电子现金方案，在电子现金中加入了使用有效期，减少了银行历史花费数据库的存储规模，加快了重复花费检测速度。

Off-line electronic cash scheme embedded expiry

E-cash, as the electronic equivalent, is one of secure electronic payments. The double-spending is the kernel problem in the E-cash scheme, since the copying of E-cash is very easy. As the conventional method of avoiding the double-spending, the bank needed to store all the spend E-cash that were used to compare the new deposited ones to find the double-spending. The shortcoming of the method is that the cost of storage and management would be increased infinitely as the number of spending E-cash. A new off-line E-cash scheme based on RSA blind signature and Schnorr one-time knowledge proof was presented. With the E-cash expiry embedded, the storage of bank database for spending E-cash was reduced greatly. At the same time, the efficiency of detecting double-spending was improved.