Design Of Two Partially Blind Signature Schemes

The rapid development of modern Internet technology has promot-ed social progress.It has brought a series of security and protection issues.Cryptography plays an important role in information security,and has made great contributions to solving network security issues.Digital signature is an important research part of cryptography.Because of its unique func-tion and wide application,it has attracted the attention of a large number of scholars.Partial blind signature is a special digital signature improved on the basis of blind signature.In a partial blind signature scheme,the signer can embed a public message in the signing process and cannot be deleted or illegally modified.This public information is confirmed in ad-vance by the signer and the user,and the content can be the validity of the signature or other important information.Compared with blind signature,partially blind signature avoids the problem of signature abuse due to com-plete blindness.It also has the practical functions such as protecting user privacy.The identity-based partial blind signature scheme can avoid the certificate storage problem of traditional public keys and reduce the oper-ation cost.The partial blind signature have attracted great attention from academia and industry.It has been applied in various fields such as elec-tronic cash and electronic voting,so it has become a hot research topic in current digital signature schemes.With the continuous development of science and technology,the safe-ty requirements in various major fields are becoming higher and higher.At present,the most important thing is how to construct a safe and efficient partial blind signature scheme for better application in practice.Based on the previous work,this paper researches and analyzes the identity-based partial blind signature scheme.The main work is as follows:1.This paper analyzes the partial blind signature scheme proposed by Liu Ergen et al.^[50],and finds that the scheme cannot resist tampering with public information attacks.To solve this problem,an improved partial blind signature scheme based on identity is presented.Under the difficult as-sumption of inverse problem based on bilinear mapping,the unforgeability of the scheme is proved under the random prediction model.The efficiency comparison with the same type of scheme shows that the scheme has high-er computational efficiency.2.By analyzing the partially blind signature scheme proposed by Is-lam et al.^[52],it is found that the scheme not only has loopholes in which public information is illegally tampered with,but also does not satisfy par-tial blindness.Through a lot of research and thinking,master the design skills.An identity-based partially blind signature scheme without bilinear pairings is proposed.In this paper,the correctness and partial blindness of the new scheme are proved.Based on the difficult assumption of the discrete logarithm problem on the elliptic curve,the security of the new scheme is proved under the random prediction model.The new scheme does not use bilinear pairs.By comparing with other schemes of the same type,the calculation overhead has obvious advantages.