Proxy Signature Related Theoretical Research And Application

With the rapid development of Internet and E-business, the information security of network has aroused much public concern of people. Under this background, the digital signatures, as the substitutes of the manuscript signatures, are certain to have the wide perspective of application. The proposal and widely acceptance of the concept of PKI/PMI have already made the digital signature the basis and backbone of the network security system. So it has become an important research area. Under the various application backgrounds, the digital signature is rquested to satify various demands. In face of these demands, many special digital signatures are proposed and several research directions come into being. Proxy signature is a typical one. This dissertation mainly studies it, which is a kind of special digital signature.In 1996, Mambo, Usuda and Okamoto firstly proposed the concept of proxy signature. If the original signer and the proxy signer have the protocal with the law efficacity, the proxy signer may substitute the original signer to sign the file. Because the proxy signature has the important function in the actual application, it arouses much public concern as soon as it is proposed. The sort and demand of security are becoming more and more. All kinds of the proxy signature schemes have appeared.This dissertation studies some typical digital signature schemes. Some compare and analyse of the security is given and some schemes which have some weakness are improved. It also studies some typical problems in the research of the proxy signature and proposes several new schemes. Considered the utilities of the schemes, the dissertation compares these new schemes with the typical schemes in existence. The result is that the new schemes have the better utilities.There are some different kinds of methods of researching the proxy signature. We research the number of original signers and proxy signers. Mambo, Usudo, Okamoto firstly proposed the scheme which one original signer authorizes one proxy signer. It's 1 vs. 1. Hwang proposed the muliti-proxy signature scheme by combining the multi-signature with the proxy signature. An original signer can authorize the multi proxy signers. It's 1 vs. n. Afterwards, Yi lijiang proposed a new kind of concept: the proxy multi-signature scheme. The proxy multi-signature scheme is the multi original signers can authorize the proxy signer. It's n vs. 1. We can see that there are 1 vs. 1,1 vs. n, n vs.1. So it will appear n vs. n. Hwang first proposed this kind of proxy signature scheme. It is called the multi-proxy multi-signature scheme. But Hwang's scheme is not...