Research On E-Cash Of E-Commerce

Electronic payment system is the kernel and the key tache of E-commerce system. E~cash is one of the most important payment means in the E-commerce system. It is significative on the theory and the praxis to research the high effective and safe fair electronic cash system, moreover to implement the controllable of the anonymity of e-cash. The research of this dissertation focused on fair electronic cash theory based on group signature, it can prevent blackmail crime. The main works are as follows:Firstly, this paper designed corresponding protocol by analyzing cryptography. Secondly, it summed up basal property model developmental status of the E-commerce and e-cash. Finally, we recommend especially cryptography technique used in the fair electronic cash system: Group signature. Dynamic group signature.Aim at the property of e-cash and blackmail crime, this paper put forward two fair electronic cash schemes by linking with idiographic signature scheme: "A new fair electronic cash based on a group "and "Fair electronic cash based on a dynamic group signature scheme " . In this two, the blackmailed cash were marked by the group manager, so that the bank can distinguish it from the valid cash. Our scheme not only has all the advantages of D. Bugler' s scheme, but also overcomes its some drawbacks such as inefficiency and impractical assumptions. The size of the group public key and the group signatures is independent on the numbers of groupmembers. The algorithms and protocols of the group signatures are efficient. A serious drawback of our scheme is that each signing key can just sign one message; this is a problem waiting to more research and to resolve.