Research On Divisible E-cash

With the development of Internet and economy,electronic cash gets more attention of experts and scholars.In the last two years,there have been some more secure,more practical e cash scheme.Divisible e cash,as a special e cash,with general requirements for electronic cash,including ensuring user privacy(anonymity),detecting malicious users(traceability),hard to be forged(unforgeability),can not be repeated use(non reusable)and other requirements.Now,some individual schemes can be proved secure in the standard model and the random oracle model,but still can not meet the efficiency requirements of practical use.Aiming at these problems,on the basis of previous research,this paper proposes a more efficient divisible system based on trusted third party,as an improved version of Canard' scheme,and reduce the number of public parameters and the computation of zero knowledge proof.This paper carried out the following research work: 1)Try to introduce a trusted third party.The bank,users,merchants and a trusted third party form the divisible e cash system.And it is feasible and necessary for introducing the trusted third party.2)Modify the traditional model of divisible e cash.During using(including spending and depositing)divisible e cash,bank can increases a mark on it,in order to find quickly and easily divisible electronic which may be reusedinrepetitive detection of spending or depositing.Through the introduction of a third party,the third party help users and merchants share computing power and calculation pressure,especially in the relevant validation.By marking the index,the duplicate detection method become uncertain,but under the large amount,it reduces the computational complexity and improves efficiency.Moreover,under a large amount,the method brings uncertainty is negligible.By the way,it provides a new way of thinking to solve the problem of large divisible e cash.