Research On Proxy Digital Signature Based On Certificateless

The development of network communication and the unprecedented prosperity of computer technology make our life more convenient and fast with open network.People have much easier access to shop,pay and store data.But what cannot be ignored is the network and information security.Such factors as malicious extortion virus,unknown hackers,network fraud and information theft,which affect the security of cyberspace,have prevailed in this era.Originated from public key cryptography,the certificateless cryptosystem has been extensively studied since it was proposed.Against the backdrop of limited network environment,it can give full play to its best performance and be applied to all aspects in the field of information security.The system has the advantage of greatly reducing the burden caused by the calculation and communication of public key certificate,and effectively solving the problem of private key escrow,without user's public key certificate.Proxy digital signature means that when the signer(called the original signer)transfers his/her digital signature right to another agent or agents,the agent can sign on behalf of the original signer.This kind of special digital signature can get rid of the shackles of practical problems.This paper studies the proxy digital signature scheme on basis of the certificateless cryptosystem.The main work is summarized as follows:(1)This paper gives an analysis of a certificateless proxy blind signature scheme.It is found that proxy authorization can be forged by two specific algorithms,through simulating adversaries attacking the scheme by using the algorithms.Moreover,improvements are made on the basis of the original scheme,and the security is enhanced on the premise of not increasing the amount of computation.(2)In accordance with the relevant research of certificateless cryptosystem and several special digital signatures,a certificateless proxy multi digital signature scheme with forward security is proposed to solve the problem of key leakage.The analysis of security attribute andcalculation quantity statistical analysis indicates that this scheme cannot forge proxy signature with high computational efficiency.(3)In order to solve the problem of abuse of proxy signer's signature power,this paper takes advantage of time stamp and updating part of proxy key.Firstly,a basic method of certificateless proxy signature whose proxy can be revoked by the original signer and the corresponding security model are defined,and a certificateless proxy signature scheme with revocable proxy is constructed.In the random oracle model,it is proved that based on the ECHLP the scheme features good security,which is not valid to adaptive chosen-ciphertext attack.The result of calculation quantity evaluation shows that the calculation cost is smaller than the original scheme.