Design And Analysis Of Proxy Signature Scheme

With the rapid development of computer communication network, it is deeply hoped that people can finish their trading activities quickly in the distance by the means of electronic apparatus. As a result, digital signature came into being which is widely used in society. Digital signature has been playing a very important role in the fields of information security, identity authentication, data integrity, nonrepudiation and anonymity, etc. As a special digital signature scheme, proxy digital signature can settle some proxy problems which other normal digital signature schemes cann't solve. Because of this particularity, proxy digital signature can be widely applied to many fields, such as e-election, mobile communication, mobile agent, e-commerce activities and so on. Since the year of 1996 when Mambo, Usuda and Okamoto firstly advanced the concept of proxy signature, many proxy signature schemes have been raised, such as proxy multi-signature scheme, threshold proxy signature scheme and proxy blind digital signature scheme. And plentiful achievements have been made in the studies of proxy digital signature. However, many proxy signature schemes have some defects in security, efficiency and feasibility. So it is of great significance to design secure, efficient and feasible proxy signature schemes. This paper made some meaningful attempts in the fields mentioned above.Chapterl, introduction of backgrounds in which proxy digital signature emerged, meaning in reality and development.Chapter2, introduction of some relative mathematics and cryptology.The following three chapters, the main part of this paper, in this part, the author analyzed several already-proposed classical proxy signature schemes and raised some new proxy signature schemes.The main contributions of this paper:1. Through the analysis of two threshold proxy signature schemes, we proved that Q-C-X scheme can't resist forgery attack and public key substitute attack, and T-H-Y scheme can't stand up to forgery attack from original signer. And some amendments have been made to both schemes. After the amendments, both schemes can resist attacks mentioned above. Moreover, a new nonrepudiable threshold proxy signature scheme with known signers was advanced which has features of less calculating amount, higher...