The Application Of Blind Signature To Electronic Cash

With the rapid development and wide application of the communications networks, e-commerce and e-government technology have quietly rising. The importance of computer network security and business transaction security is increasing. In e-commerce transactions, consumers’ demand for user privacy, anonymity and consuming information is increasingly prominent. Blind signature as a special digital signature, has the property of anonymous and untraceable, and plays an important role in the electronic cash, anonymous voting and electronic auctions and other applications. Therefore, it has become a hot research topic in e-commerce system.In this paper, we mainly focus on how to design a secure electronic cash system. We analyze the certificate-based blind signature scheme applied in electronic cash system, and point out the vulnerability in its program. Besides, we give an improved scheme and analyze the efficiency of the program. The scheme is provably secure in the random oracle. In addition, the study of partially blind signature scheme without certificates and its application used in electronic cash scheme are given. The security and efficiency analysis of the system are proved. The main research results are put forward as follows:1. We analyze an untraceable off-line electronic cash system and propose a new untraceable off-line electronic cash scheme, which based on Schnorr signature. The program can meet the use’s anonymity and untraceable feature. In this scenario, the user’s anonymity will be revoked if a malicious consumption occurs. Analysis found that the length of the signature of the program is short, and the system improves the efficiency of the program and reduces the communication cost. 2. According to the special nature of electronic cash, we improve the provably-secure electronic cash based on certificateless partially-blind signature, and construct a secure and efficient electronic cash system that based on Elliptic Curve Cryptosystem. The system that we improved is based on certificateless partially-blind signature, and provides the user anonymity, the consumer’s double spending, malicious merchant and steal coins that existed in electronic cash system, as well as special scene’s computational efficiency and other issues. In addition, it is provably secure against two types of adversaries in the certificateless cryptography, and it improves the efficiency of e-cash system.