A Secure and Efficient Off line Electronic Payment System for Wireless Networks
An electronic cash system allows the exchange of digital coins with value assured by the bank's signature and with concealed user identity. In an electronic cash system, a user can withdraw coins from the bank and then spends each coin anonymously and unlinkably. In this paper we propose a secure and efficient off line electronic payment system based on bilinear pairings and group signature schemes. The anonymity of the customer is revocable by a trustee in case of a dispute. Because the amount of communication in the payment protocol is about 480 bits, the proposed off line electronic payment system can be used in wireless networks with limited bandwidth.