Identity-based Signature

The Internet is booming at an amazing speed and has gradually penetrated into people's lives.It has brought great convenience in many aspects,but it has also introduced many security risks,such as information being illegally forged in the network.In this case,digital signatures came into being,and it was mainly used to ensure the authentication of Internet information transmission.However,the traditional digital signature system involves the management of certificates,resulting in high a overhead,and identity?ID?-based signatures solve this problem well.In the identity-based signature scheme?IBS?,the public key is derived from the identity of the user,and the corresponding private key is generated,thereby avoiding the need for the certificate and simplifying the key management process.Therefore,the IBS scheme is preferred in many practical applications.For the IBS scheme,tight security reduction is a very desirable feature that allows for shorter security parameters and better efficiency.However,as far as we know,when designing identity-based signature schemes,there are few research results on tight security reduction.Most IBS schemes have been proved to be safe in random models,and if they are fully instantiated,security is uncertain,which is a problem that cannot be ignored.Therefore,we conducted a series of in-depth studies on this aspect and proposed four IBS schemes with tight security reduction in the standard model.Key leakage problems caused by malicious intrusions and unintentional exposures can lead to serious consequences and even compromise the security of the entire scheme.To solve this problem,the concept of forward security has been proposed to prevent signatures from being tampered with and forged in the event of a key compromise.In addition,blind signatures can provide anonymity protection.Lattice-based cryptography has strong security guarantees and considerable efficiency and is an attractive alternative in the post-quantum era.Therefore,this paper constructs an identity-based blind signature scheme with forward security from lattice:Forward-Secure Identity-Based Blind Signature?FSIBBS?scheme.Specifically,the main work of this paper is as follows:Firstly,an IBS scheme?SSSTR-IBS?against existential forgery under an adaptively chosen message and identity attack in the standard model is proposed.We first propose a signature scheme SSSTR that is unforgeable under the adaptively chosen message attack.Its security is closely related to the-SDH assumption in the standard model.Then,based on the SSSTR scheme,we present the SSSTR-IBS scheme.SSSTR-IBS has tight security reduction and is existentially unforgeable under an adaptively chosen message and identity attack;Secondly,based on the existing three signature schemes,-SDH assumption and the bilinear group defined by Galbraith et al.^[1],three existentially unforgeable IBS schemes under an adaptively chosen message and identity attack of the standard model are proposed.The first scheme is based on the BB signature,the second scheme is based on the S_CMB,SDH signature proposed by Sch?ge^[2]and the third scheme is based on the S_CH,SDHH,SDH signature proposed by Sch?ge^[2].Thirdly,an efficient forward-secure identity-based blind signature scheme is constructed by combining lattice theory.In some existing signature schemes with forward security attributes,the Update algorithm can only obtain the private key of the4)+1 time period from the private key of the4)time period,that is,the time difference is?=1.We have improved the Update algorithm to make it suitable for??1,which is undoubtedly more convenient and flexible.This scheme can effectively solve the threat of quantum computing,guarantee forward security,and satisfy the requirements of blindness.The security proof of the scheme is based on a difficult problem in the lattice—the SIS problem and the scheme is unforgeable under the adaptively chosen message and identity attack in the random oracle model.