| dc.description.abstract | The popularity of the Internet promotes the growth of electronic commerce. More and more business transactions are accomplished over the network due to its convenience. The Internet provides the great convenient environment for the business deals, but it does not guarantee the fairness between the transactors. Therefore,
the research on the mechanism to ensure fairness between the transactors in the transaction is important.
Early work on solving the problem of fair exchange relies on the assumption that both transactors have the same or almost the same computing power, but this assumption is impractical. The other category of fair exchange protocols involves a trusted third party to ensure fairness, but an appropriate third party with such functions may not be available.
The concept of concurrent signature scheme was first introduced by Chen, Kudla, and Paterson. It is a scheme which attempts to provide functions closing to fair exchange without relying on a trusted third party and the assumption of the same computing power between two transactors.
We propose a new concurrent signature scheme which performs more efficient than all the previous concurrent signature schemes. The proposed scheme achieves all the properties except anonymity in Nguyen’’s scheme and we will show that this property is in fact minor in most applications to achieve the purpose of a concurrent signature.
There is another important research topic, i.e., micropayment system. It is considered to have a variety of practical applications such as access to charged World Wide Web pages, on-line magazine subscription, on-line database query, Internet pop-up advertisement, multimedia in stream manner over Internet, and so on.
We propose a new micropayment scheme with varying denomination which extensively improves the computational performance of both the customer and the merchant. The varying denomination approach presses close to the usual spending habit of the customer and might be more reasonable for most micropayment applications. | en_US |