Study On Proxy Signature And Multi-Bank E-Cash System

Substituting Electronic Commerce (E-commerce) for traditional business has become a new trend in commercial development. One of the most important differences between them is electronic payment. As electronic cash (E-cash) is one of the most attractive electronic payment forms, electronic cash system has attracted lots of researchers' attention at home and aboard. In order to satisfy practical requirement, multi-bank E-Cash system has been proposed. In recent years, many related strategies based on group signature have also been provided. Generally, each of them has certain degree flaws although they have some advantages respectively.Proxy signature, which allows the original signer to entrust the signature rights to proxy signer and enables the proxy signer to sign effectively on behalf of him, is a new kind of digital signature. Since the idea of proxy signature just meets the requirements of multi-bank system models, some researchers come up with multi-bank E-cash system based on proxy signature and provide an implement scheme which has remarkable advantage in multi-bank management and computing efficiency. However, there are some hidden dangers in the scheme and thus limit greatly its practical utility.The present paper firstly introduces 3 mathematics-dilemmas commonly used in cryptography and some basic knowledge related to digital signature. It also discusses the development and research current situation as well as the definition, classification and several classic schemes of proxy signature. Then, a self-certified anonymous proxy signature scheme based on the view of self-certified public key policy and the scheme of anonymous proxy signature are proposed. The proposed scheme not only lightens the burden of verifier, but also has characteristics such as anonymousness and trackability. After that, related knowledge and concepts about E-Commerce and electronic payment have been introduced. The development of studies on multi-bank E-Cash system is reflected, and the shortcomings of system schemes are also analyzed. At last, a scheme of multi-bank E-Cash system based on the self-certified anonymous proxy signature proposed above has been designed. A completely trusted third party is not necessary in our scheme. It makes the system model simpler and reinforces undeniability and anonymousness of cash-publishing bank, therefore strengthens security of whole system and anonymousness of E-Cash. The application of self-certified public key policy also can lighten the burden of verifying cash for corporation and depositing bank. In conclusion, the scheme has powerful utility to improve current multi-bank E-cash system based on proxy signature.