A flexible date-attachment scheme on e-cash

The electronic cash payment system is an important technique that has been utilized for electronic commerce. In this paper, we propose a flexible date attaching method to Chaum's electronic cash scheme, which can also be applied to many other electronic cash schemes. The date attaching method provides an unforgeable and variable scheme to deal with the effective date of e,cash that will allow for many applications. The customer can modify the date slip but it does not become effective until the merchant passes it on to the bank. Also, the usage of this proposed scheme is very flexible, unlike most e-cash schemes that embed an expiration date when e-cash is withdrawn. This scheme still possesses the untraceability property and the computation complexity for customers and merchants is simple when compared to bank operations.