Customer Efficient Electronic Cash Protocols
Chun‐I Fan, Bo‐Wei Lin, Shi‐Ming Huang · Journal of Organizational Computing and Electronic Commerce · 2007
The technology of electronic cash makes it possible to transmit digital money over communication networks during electronic transactions. Owing to the untraceability and unforgeability properties, electronic cash can protect the privacy of customers and guarantee security of payments in the transactions. This paper introduces a customer-efficient electronic cash protocol where each customer only needs to store 1 coin for w dollars and transmit 1 coin for a w-dollar payment. Compared with traditional electronic cash protocols, the proposed method greatly reduces not only the storage required for the customers, but the communication traffic in the payments as well. Furthermore, the computation cost of each customer in the payment stage is greatly reduced by more than 99% as compared with other storage efficient electronic cash protocols. The proposed protocol is quite suitable for situations where storage and computation capabilities are limited, such as smart-card or mobile environments. In addition, both the problem of money laundering and the unlimited-growth problem of the bank's database, which records all spent coins for double-spending checking, are also considered in the proposed protocol. Especially, our basic idea is independent of the underlying cryptographic primitives such that it can be implemented by any public-key encryption, symmetric encryption, digital signature, and partially blind signature scheme.