A Practical Electronic Currency System

The main idea of this paper is indicating and discuessing one off-line electronic cash system.After I introduced the basement of the PKI/CA system,this paper introduce one electronic cash electronic cash system.above this system .This paper introduce three main protocols of this cash system.they are Initialize and Open a account procotol,Pay a bill procotol,Save a bill procotol.In which I used some new ideas and methods.The most important is a new blind signature plan.By this plan,I achieved one effective under control electronic cash mathsmatic model.This paper indicated and proved some signature and other protocols.Then this paper achieved six main idea of electronic cash given by Okmato using new idea and plan.the six idea is (l):independence ; This electronic cash do not relay in the computer system,It can be translate on the net.(2)security, This electronic cash can defend double spending and forgeing.can be stored safely in the memory of computer or in SMART cards.(3)Anonymous. This electronic cash do not leage any information of Its users.(4)The ability on the off-line state. This electronic cash can be use freely even the bank is not on line.(5) Can be transfered; One user of This electronic cash can be transferred to another user.(6)Can be splided. This electronic cash can be dividided into some less amount cash,and the total amount is the same steadly.(7)Micro electronic cash ,very small amount electronic cash can be achieved and how to use this electronic cash among more than two users.(8)mult-payment and security of this electronic cash.At the end of this paper,discuessed some special charactical idea and security idea of this electronic cash system.