An e-cash Scheme with Multiple Denominations and Transferability

An e-cash Scheme with Multiple Denominations and Transferability

E-commerce has developed rapidly in recent years and online transactions and digital services have become popular. However, existing trading systems such as ATMs, credit cards, Paypal, and prepaid systems are potentially unsecure and users’ privacy is not sufficiently protected. Because user information can be easily associated with consumption history in the aforementioned trading systems, consumers’ spending habits and interests are retrieved and analyzed by individuals or businesses or people whose intentions may be suspect and without the consent of the consumers themselves. Therefore, the development of e-cash is critical for future e-commerce. In an e-cash system, blind signatures ensure consumer anonymity and prevent e-cash from being linked to its user. However, the anonymous nature of e-cash makes tracing criminal behavior difficult, so e-cash systems with anonymity revocability have been proposed. To thus expand the applicability of e-cash systems, alternatives have become the goal of subsequent studies (e.g., offline transactions, transferability, and divisible e-cash). This study proposed an e-cash system with multiple denominations that enables e-merchants to give customers change when in an offline environment. The proposed system results in convenient transactions regardless of transaction amount and reduces the amount of e-cash users need to deposit in advance.