Survey of electronic payment methods and systems

In this paper an overview of electronic payment methods and systems is given. This survey is done as part of the Moby Dick project. Electronic payment systems can be grouped into three broad classes: traditional money transactions, digital currency and creditdebit payments. Such payment systems have a number of requirements: e.g. security, acceptability, convenience, cost, anonymity, control, traceability and control of encryption methods. Some requirements appear contradictory and tradeoffs have to be made: - traceability versus anonymity, - on-line versus off-line, - use of dedicated tamper-resistance hardware versus software only. We further present an introduction to the basics of electronic money: encryption, digital signatures, anonymity, and solutions to the double spending problem for digital cash. We give a survey of payment mechanisms, that are either commercially or in a pilot version available today or have been published recently.