Certificateless Partially Blind Signature Using Elliptic Curve And Its Application

In a normal blind signature,the signer knows nothing about the signed message.If the feature is illegally used in the electronic cash system,it can lead to serious consequences such as tax evasion,tax evasion and money laundering.In order to solve the potential problem,the partially blind signature was proposed by Abe and Fujisaki in 1996.The partially blind signature not only inherits the feature of blind signature anonymity,but also has another one,that is,the signer can embed the public information agreed with the message user in advance in the signature to prevent the signature from being illegally abused.Various certificateless partially blind signature schemes were proposed.However,there are some drawbacks of some schemes that affect their use in modern electronic cash systems.This paper focuses on certificateless partially blind signature using elliptic curve and its application in the electronic cash system.The main research contents and achievements are as follows:(1)In order to solve the efficiency problem of the certificateless blind signature scheme proposed by Liu et al.in 2017,an improved scheme is proposed.In the key generation phase,the bilinear pairing operation is not used,and the point multiplication operation on the elliptic curve is used.The calculation amount of the improved scheme is about one-seventeenth of that of the original scheme,so the efficiency of the improvement scheme is improved.The public information in the certificateless blind signature scheme proposed by Zhao Zhenguo in 2016 is easily falsified,and another scheme is proposed.The hash function is used to generate the parameters used in the blinding process.The unidirectionality and strong collision of the hash function ensure the uniqueness of the parameters,thus preventing the falsifying of public information.(2)Based on these two improved schemes,a new certificateless partially blind signature scheme using elliptic curve is given.Under the random oracle model,it is proved that the new scheme is partially blind and unforgeable.Compared with the efficiency of similar schemes,the new scheme has a shorter signature length,which improves the computational efficiency.(3)The new scheme is used in the electronic cash system.The characteristics that a popular and practical electronic cash system should have are listed.According to the electronic cash system model,each stage process is embodied,and an offline electronic cash system is designed.The security and practicability of the new scheme are analyzed.The results show that the new scheme satisfies the security features such as anonymity,unforgeability and resistance to man-in-the-middle attacks in the offline electronic cash system.