Research On The Multi-proxy Signature Based On Self-certified Cryptosystem

In1996, Mambo, Usuda and Okamoto proposed the concept ofproxy signature. In this signature, a designated proxy signer can generatea valid signature on behalf of the original signer., Mambo et al alsoproposed that a proxy signature scheme should have the quality ofnon-repudiation, verifiability, unforgeability distinguishability.With different needs, the proxy signature has produced a variety ofextended form, Hwang and Shi proposed the multiple proxy signaturetype and designed a scheme.This thesis investigates various multi-proxy scheme based ondiffierent cryptosystem. It focuses on the following issues:1.Cao-Cao scheme is newest and typical multi-proxy signaturescheme which based on the IBC cryptosystem.According to the basicscheme it uses,we proof that Cao-Cao scheme is not secure.Then weimprove the scheme and propose a new scheme which can resist theattack we proposed previous.Then we analysis the security of the newscheme.2.Jin-Wen scheme is the only multi-proxy signature scheme whichbased on the certificateless cryptosystem.We prrof that the scheme cannot resist the forge attack we proprosed.Then we improve thescheme,adding a hash function,and proprose a new scheme based onthe certificateless cryptosystem.Finally,we give a secure analysis andproof of the new scheme.3.Self-certified cryptosystem has been very popular in mobilenetwork and none multi-proxy signature scheme based on thecryptosystem is proposed.Now most of scheme is based on the discretelogarithm and bilinear. Elliptic curve cryptosystem has the advantage ofshort key which can reduce the communication cost.We propose a newmulti-proxy signature scheme based on Self-certified cryptosystem andElliptic curve cryptosystem,analysis its security and finally compare theefficiency and communication cost of several schemes.