Efficient Anonymous and Non-Repudiation E-Payment Protocol

Introduction

Internet is designed to allow computers to easily interconnect and to assure that network connections will be maintained even when various links may be damaged, but this versatility also makes it easy to compromise data security and privacy protection for e-commerce application.

E-payment systems allow people to carry out commercial activities in an electronic domain. There are many electronic payment systems that have been proposed in recent years (Liu et al., 2001). A secure e-payment systems protecting privacy can be seen as a protocol involving a customer, a shop and a bank. It is goal to transfer money in a secure way from the customer’s account to the shop’s account. E-payment systems are conventionally divided into those that are on-line and those that are off-line, one can distinguish between on-line payments systems where all parties, the customer, the shop and bank need to be connected on-line, and off-line payments system, where each interaction during the protocol requires two communicating parties only (Camenisch, & Stadler, 1996).

E-payment is a subject of great economic, political and research and Security is an important factor for the wide acceptance of the electronic commerce services. There are many proposals discussed the e-payment protocols which enable anonymity services to protect user’s privacy, Protocols relying on traditional trusted parties easily guarantee exchanges, but are inefficient -because a trusted party must be part of every transaction and expensive because a trusted party wants to be paid for each transaction.

Anonymity of the participant’s is an important requirement for electronic commerce, in particular for payment systems, because anonymity could be in conflict with law enforcement, currently the researches concentrate on accepting of e-payment protocols where the anonymity of the coins is cancellable via a trustee in case of criminal entities. Most of current systems have drawbacks that the anonymity can be misused by fraudulent to perform a perfect crimes like blackmailing or money laundering and do not provide the non-repudiation service which prevent users from repudiate the misusing of the coins like denying, double-spending.

The idea of anonymous payment scheme was introduced in 1982 (Chaum, 1983). In fact this anonymity might be misused by fraudulent to perform a perfect crime (Solms & Naccache, 1992). For instance stealing of the private keys, money laundry, and blackmailing of coins. The uses of blindfolded protocols in the banks are considered as a modern threat (Liu et al., 2001). To avoid these threats the payment schemes must offer anonymity method which accepts the tracing of coins in any of the states mentioned above by an authorized trusted authority. The first scheme that is stopping blackmailing and money laundry was suggested in (Brickell et al., 1995). However, there are some proposals (Camenisch, 1996; M'Raihi, 1996; Jacobson & Youg, 1997) to prevent these threats. Every scheme needs the participation of the trusted authority in the opening of the bank account, and also in the withdrawal of coins. The only scheme that does not need trusted authority participation excepting the anonymity has just suggested in (Binh, 2007). But, it is unable to stop extortion threats and the employ of blindfolding schemes. These threats are just prevented in the scheme of (Hohenberger, 2006), which is also not efficient as it needs the trusted authority interaction in e-payment schemes. In case that one of these threats is needed, they require an on-line e-payment scheme among user, shop, and trusted authority to stop the spending of illegitimate coins.