Study On The Theory Of Group Signature And Their Applications In Online-Bidding System

This paper presents a brief study on the theory of group signature and their applications in online-bidding systemSince the concept of group signature was advanced by D. Chaum and E. Heyst in 1991, group signature, with its notable speciality, has gained much attention and interest. This paper sums up the research development of group signature, and offers an efficiency analysis of two typical group signature schemes. To make up the defects of ACJT scheme in exculpability, this paper put forward a new reformative project for ACJT, which can fulfill its role in satisfying exculpability.First put forward by D. Chaum in 1982, blind signature is identified as "signing without knowing the content of the files", and it can keep customers' privacy in many cases, such as the usage of electronic cash. As an important part of digital signature technology, blind signature is notable in its application value and promising future. Apart from electronic cash, blind signature is also widely used in system design and exploitation such as electronic vote, on-line bidding, ect.The concept of group blind signature was first brought forward by Lysyanskaya and Ramzan. It can be regarded as a variation of group signature, for it is a combination of "blindness" and group signature schemes. Based on CS97, the first group blind signature LR98 loses its ability of coalition-resistance. Therefore, this paper, with ACJT as its basic group signature scheme, redesigns LR98 scheme and develops into a new group blind signature.Through a special electronic bid-inviting agent, online bidding brings all the bidders into supervision of modern technology, reducing the costs while increasing the efficiency. Therefore, online bidding is very efficient and beneficial. However, in solving the key problems in online bidding, the introduction of cryptography is a must. This paper gives an analysis of security requirements in online bidding system, and offers a way of solution through the use of cryptography. Finally, using group blind signature, we offer an online bidding project, in which a violating bidder can be detected and dismissed. This project not only meets the requirement of bidding flow, but also exerts positive effects on standardizing.