Electronic cash: cryptography & distributed systems

Electronic Payment Systems that deal with daily shopping and payment over the Internet are one of the most important concerns of today's electronic commerce. There is a large body of research in this field, and in particular, on electronic cash (e-cash) systems. In e-cash systems, protecting customer's privacy has received much attention and many challenging problems relating to the trade-off between multi-party security and system efficiency are proposed. This thesis gives a brief survey of e-cash systems. We investigate various problems raised in building secure and efficient e-cash systems. This includes efficient off-line e-cash, perfect anonymity, revocable anonymity, combining the advantages of on-line and off-line approaches and wallet loss recovery.