Research On Homomorphic Signature With Controllable Authority

With the rapid development of cyberspace,the cloud computing as a new-style IT Application is now deeply influencing the development of modern Chinese economy society.However,the cloud server E is not entirely true and completely trusted.If E performs harmful actions and the users do not detect it in time,the cumulative consequences may cause serious impact on both the legal users and the country.Storage-cheating attack,computation-cheating attack and privacy-cheating attack are three main kinds of security problems in cloud com-puting at present,and in this paper we mainly focus on studying how to prevent computation-cheating attack.Homomorphic signature is a useful tool and can be used to verify the correctness of the outsourced computation.More concretely,if E honestly carries out computation on user's data?m,it is able to generate a valid signature?_hfor the claimed computation result?m on behalf of the user whose public key is pk.In this paper,in the light of related research,we introduce a new cryptographic primitive called authorized function homomorphic signature.In the new system model,E has to apply to the user for a special key sk_fso that it can evaluate polynomial time computation f on?m.The main contributions of our work are as belows:Firstly,we review the related works in the literature and analyze the insufficiency of most of the state-of-the-art homomorphic signature schemes.In conventional homomorphic signature schemes,E can freely do arbitrary computations.If E chooses an elaborate function f~*and publishes?m~*=f~*(?m)on behalf of the user,it may adversely affect user's right.Aiming at such a problem,we introduce authorized function homomorphic signature as well as the corresponding security models.Secondly,we make innovative and exploring research on functional signature,zero-knowledge proof and signature with perfectly re-randomizable keys,and design three black-box constructions of authorized function homomorphic signature based on them.Security analysis shows that these three black-box constructions can effectively resist forgery attack and provide privacy protection.Finally,we give concrete constructions of functional signature and homomorphic signa-ture as well as two concrete constructions of authorized function homomorphic signature.We also show application scenarios to demonstrate these notions.In conclusion,our work can prevent computation-cheating attack effectively.