Universal Composability Study Of Several Cryptographic Protocols

With the rapid development of computer technology and widespread popularity of mobile devices,computer network has become an indispensable part of work and life.As an important technology,digital signature has been widely used in national security,electronic commerce,electronic finance and other important industries.Security research on digital signature is particularly important.Scholars combine the special properties with signature,and present some signature protocols.Under the complex network environment and distributed environment,a single network environment can not meet the normal secure requirements.This article mainly studies several general universal composable digital signature,and propose several new signature algorithms and verify their universally composable security(UC security)in complex network environment.Universal composability is a kind of technology of studying the security in parallel environment and complex network eviroment.At present,the universal composability research of the digital signature with some special properties is still blank.In this thesis,several kinds of cryptographic protocols with universal composability are studied,such as group signature,group blind signature and broadcast multi-signature.The task lists are as follows:1.The author detailedly introduces the theorems and applications of UC security.2.The author proposes a new group signature protocol,defines the ideal function of group signature in the universally composable framework,and analyzes the UC security of group signature protocol.3.The author designs a group blind signature protocol using the UC framework,constructs the ideal function of group blind signature,then proves that the UC security of group blind signature protocol.4.The author designs a new multiple signature protocol,defines the ideal function of multi-signature in the UC framework,then analyzes its UC security.