Restricted common data in anonymous E-cash system

Discuss the problem of infinite increasing coin list in anonymous E-cash systems, which reduce the efficiency of whole system greatly. Though some methods are suggested, no one can solve the problem with high efficiency and flexibility. Here, we use the technique of adding information in blind signatures to deal with this problem. Through adding timestamp in signatures, we can separate the valid period of all used coins into pieces. Only the coins in the last stage are recorded. So the scale of the coins list is controlled. We also analyze the anonymity of these data, and add some indispensable restrictions to them. These restrictions can ensure that the imported data don’t break the anonymity of the customers. In order to fulfill these qualifications, we lead to the concept of restricted common data (RCD). Furthermore, we propose two schemes to add RCD in the blind signature. The simple one is easy to implement, while the complex one can note the value of the coin. The usage of RCD leads to little additional cost, as well as maintaining the anonymity of customers. This method fits for most kinds of anonymous E-cash systems.