The Research On E-Cash Scheme By Identity-Based Group Blind Signature

The popularity of e-commerce enabled more and more people are interested in online trading, which also makes higher demands on payment systems. Compared with the credit card and electronic check payments or other electronic payment methods, there are obvious advantages for e-cash, such as anonymity, off-line affordability and transferable. But now there are many problems in the research of electronic cash system to be solved, such as membership revocation, transferability, divisibility, multiple-banks and so on. As a branch of cryptography, the group signature offers the ability to hide interior structure of the organizing. So the scheme can be widely used in many domains. At present, the security of the electronic cash systems are all based on group signature technologies.This paper presents a blind signature scheme from current Identity-based signatures, and then converts it to a group blind signature scheme. This scheme is proper for large group that have many group members because the length of the signature and the group public key is not decided by the number of members.This paper presents a new e-cash scheme from the group blind signature scheme. The new electronic cash scheme has the following advantages: (1) It's suitable for the environment of multiple banks; (2)It doesn't require e-Cert issued center; (3) It offers anonymous payment, which means merchants and banks have no way of knowing the true identity of the consumers. However, repeat spend can be traced by the bank with the assist of the trusty institution; (4) It has higher security and shorter key length. These advantages make our e-cash scheme have good practical value.