System And Analysis Of The Proxy Signature

The research of digital signature and relative problems is one of the most active field of cryptography and information security. The research of digital signature schemes is of very importance and applied value. In this dissertation, some special signatures are researched. It includes 5 chapters. The chapter 1- 4 mainly research the concept of proxy signature, typical proxy signature schemes, designated confirmer signature, multi-signature etc. and analysis a few typical proxy signature schemes, improve a few typical proxy signature schemes.Our contribution1 survey digital signature and its important significance and discribe background, present situation and progress signature.In the present research of network information security, public-key cryptosystem is regarded as widely approved one. The implement in the public-key cryptosystem depends on the technique of digital signature scheme. It is because that the digital-signature function can achieve a certificate authority in constructing a public key infrastructure (PKI). Along with the change in the general situation, the study correlated to the digital signature changes as well.Proxy signatures have many applications in the mobile agent, the e-commerce, the e-vote and so on .However, most of the existing proxy signature schemes have some problems to solve and perfect. These issues include how to implement nonrepudiation of proxy signature, how to withstand the public key substitution attack forgery attack and collusion attack, how to solve the problem of using secure charnel, how to distribute the right of the proxy signers, how to implement the confidential delivery of proxy signalize, and how to protect the benefit of the receiver in casa of a later dispute.2 introduce conception, requirement and categories of proxy signature, and give some typical proxy signature schemes.In the real world, people often delegate some of their rights, such as signing right, to reliable proxy and let proxy perform these rights on behalf of them Seals are often used to sign on behalf of institutions, because the seal is transferable among people. Digital signature is an electronic simulation of handwritten signature, but it doesn't have the function of delegation. In 1996, Mambo, Usuda and Okamoto firstly introduced the concept of proxy signature, which allows a designated person, caleda proxy signer, tosign on behalf of an original signer. Mambo et al showed proxy signature should have properties of undeniability, verifiability, unforgeability, distinguishability and identifiablity and so on, and proposed three types of delegation: full delegation, partial delegation and delegation with warrant.We survey the achievements in the field of proxy signature;briefly give a description of various types of proxy signature schemes such as Schnorr signature scheme, MUO96, SLH, YBX etc. signature schemes.3 Analysis a few typical proxy signature schemeswe analysis a few typical proxy signature schemes, which have important significance for the development of this study field, show attack scenarios against these schemes. Almost all previous proxy signature schemes are insecure against original signer's forgery.4 improve a few typical proxy signature schemesBased on the analysis of attack scheme, an improved proxy multi-signature scheme was proposed. The new scheme is safe. Moreover, the original signer can set up the time limit of the proxy power holding by the proxy signer and can trace the receiver of the signature. And then a designated-receiver proxy multi-signature scheme is proposed. In this scheme, original signers nominate a person as signature receiver when they delegate his signing capability to a proxy signer, and the proxy signer can generate valid proxy signature on behalf of the original signer which none but the nominated receiver can verify and accept it.5 summaryFinally, some problems in the study of this field are presented, and several main research directions are pointed put as well.Most research of proxy signature in the present is based on the schnorr digital signature scheme. Compared with standardized RSA cryptosystem, the security of the digital signature scheme by Schnorr should be re-discussed over. Even the assumption that the fulfillment of security is equivalent can be held, the current proxy signature schemes still exist lots of blind spot in practice. Therefore, this paper sets the points of design on both security and efficiency, through an overall induction toward the related literature including the basic concepts and the proposed scheme, the security and efficiency in performance can be given, then, based on the induction, a practicable proxy signature scheme can be formed, and further contributed to the research of publickey infrastructure to promote the development of information technology.