Research Of Electronic Cash System Based On Discrete Logarithm

With the widespread use of electronic commerce, more and more businesses are conducted via Internet. So the security and efficiency of electronic payment becomes a serious issue. The jumped-up payment tool--electronic cash is more adaptive than the credit card and electronic check which is widely used at present, because it is characterized by the anonymity, off-line practicability and transferability. The existing electronic cash systems are based on the group signature, which is a digital signature scheme with distinguishing features. The group signature has the high-security and can hide the interior structure of the organization. So the scheme is widely used in many domains.This paper defines an electronic cash system based on the group signature. Aiming at the existing problems of the group signature and electronic cash, we first design a new group signature with member revocation, and then establish two new electronic cash systems with relatively higher security and efficiency.Firstly, a new member revocation scheme of the mature ACJT group signature with higher efficiency is defined. The member revocation is always a hard problem in the research of the group signature. Quantized analysis of the new sheme shows that the length of the signature is shorten by 60%, the number of the operation is reduced by 20%. Furthermore, the new scheme meets all the security requirement of the group signature.Secondly, there are many electronic cash systems based on the ACJT group signature at present. In this paper, we analyze the advantages and deficiencies of two typical schemes and define a new scheme with higher security and efficiency.Thirdly, we design a secure and efficient electronic cash system based on a new group signature scheme. The new system provides revocable anonymity and prevents the double-spending, blackmail and juggling the sum of money, so it is secure. Furthermore, the system's efficiency is much better than others because of the new group signature scheme.Finally,a practical electronic cash system is implemented based on Java and Oracle database. The system achieves the primary function of electronic cash. It is full of meaning to our research.