Trustee- based Anonymity- revocable Fair Divisible E- cash System

For the first time,this paper proposes a practical divisible off- line e- cash schema based on trustee.The anonymity,which the customer's privacy depend on,can be revoked whenever needed so as to punish crime and gain authorization of go- vernment.Fairness in the trade process prevents traders on both sides from loss.The divisible e- cash,which can be precisely divided like real cash,are paid in precision.By quoting the concept of digital signature transformation,introducing trustee,fairness in trade process and revocation of anonymity are realized.Trustee is only involved in during registration,disputation,revocation of anonymity. In addition,this kind of e- cash acts as a means to curb repetitive- spending,overdrawing,counterfeiting.Computation overhead of our system are 60 times less than the rapidest one at present based on binary- tree divisible e- cash system.