Research On Proxy Signature Scheme

The network of computers is gradually changing our life with its development and popularity. Accordingly, information security becomes a crucial factor affecting the developing of network. Digital Signature can meet the demand of E-commerce and E-government affairs by offering the integrity and discrimination of the data. Playing a very important role in the present information society, it is the basis and guarantee of the theory of information security.More often than not, people think it is a must to entrust some of their rights, including the right of signature, to some reliable agents, then, the agents can exercise the rights by standing for them. In information society, people often meet the problem of entrusting the right of signature, so, proxy signature, as a very important branch of digital signature, comes into being.In 1996, Mambo, Usuda, and Okamoto first put forward the concept of proxy signature and drew the original scheme, which blazed a new way for the development of digital signature. Proxy signature is defined that the primitive signer who has the right of signature empowers the proxy signer under the premise of not letting out his own private keys; then, the proxy signer can have a valid proxy signature by representing the primitive signer and the receiver of the proxy signature can test and verify if it is valid or not.As a new breed of digital signature technology, Proxy Signature has drawn people's attention by its high quality. Many scholars have carried out deep explorations and researches and scored great successes in this field. With many basic proxy signature schemes raised, a slew of new proxy signature are springing up such as proxy multi-signature, threshold proxy signatures, ID-based proxy signature, blind proxy signature, proxy signatures with warrant recovery, one-time proxy signatures, ect. Proxy signature will have a bright future with wider use in electronic banks, E- commerce and mobile agent.This paper mainly focuses its research on the following respects:(1) This paper briefly reviews the research background and present situation of proxy signature and makes clear the significance of the proxy signature scheme. After expounding in detail the basic concepts and theories of digital signature and proxy signature, the author introduces some typical proxy signature schemes, analyzes their security and then point out their defects respectively.(2) This paper analyses a typical Proxy Signature Scheme Based on Elliptic Curve Crypto -systems and points out its limitations and makes some proposals of improvements. This paper also puts forward a Certificate- of- Authority Delegate Proxy Scheme based on Elliptic Curve Cryptosystems. This new scheme has the basic characteristics of delegate proxy. Besides, it features much higher security, less amount of counting, faster speed of disposal, much less key-length, much less demand of bandwidth, ect.(3) In viewing of the existing situation that the agent is supposed to conceal their identity, this paper attaches great importance to the Anonymous Proxy Signature Scheme, among which the paper mainly expounds a Proxy Signature Scheme Based on the Discrete Logarithmics by Gu Lize and ID-based Anonymous Proxy Signature Scheme. To begin with, the paper points out the existing security problems of the Anonymous Proxy Signature Scheme as well as makes proposals for improvements. In addition, the paper offers a concrete scheme for ID-based Anonymous Proxy Signature Scheme and analyses it. Finally, based on the two demands for privacy protection and anonymity of delegate agent, the author gives a Proxy Signature Scheme with Privacy Protection and analyses its basic qualities as well as special demands for satisfying delegate proxy signature.