基于智能卡的含有效期的电子现金系统

为防止银行数据库记录的无限膨胀，提高系统的执行效率，该文将有效期加入基于智能卡的电子现金系统中，提出基于智能卡的含有效期的离线电子现金系统。该系统采用基于椭圆曲线的数字签名技术来实现。智能卡由于容量有限，椭圆曲线需要较小长度的密钥就可以获得较高的安全性，相对离散对数，椭圆曲线更适合应用于基于智能卡的电子现金系统中。因为该系统基于椭圆曲线离散对数表示问题，所以其安全性也是基于椭圆曲线离散对数的安全性。

E-cash System with Validity Duration Based on Smart Card

In order to prevent the database of the bank expanding infinitely and improve the performance efficiency of the system, this paper proposes an off-line e-cash system with validity duration based on the smart card by adding the validity duration into electronic cash system. The system applies the signature based on the elliptic curve to realize. As the capability of the smart card is limited, and the elliptic curve can achieve much better security and only need much shorter keys, the elliptic curve is much more adapt to e-cash system based on smart card than the discrete logarithm. The system is based on expression question of elliptic curve dispersed number, so its security is based on the security of elliptic curve dispersed logarithm.