Research On Attribute-based Encryption Algorithms For Cloud Data Based On Lattice Problem

With the rapid development of cloud computing,data in the cloud computing environment is facing many security issues,such as the inability to guarantee the confidentiality of user's data and the control of data access rights.Attribute-Based Encryption(ABE)is the most commonly used encryption scheme in cloud computing environments.It can provide safe and reliable user finegrained encryption and flexible data access control.However,most of the existing attribute-based encryption schemes are based on the Prime Factorization problem or the Discrete Logarithm Problem.With the development of quantum computing technology,both the Prime Factorization Problem and the Discrete Logarithm Problem will be solved.Therefore,cloud data security sharing and access control schemes based on traditional attribute-based encryption will be cracked by quantum computing.Similarly,although the encryption algorithm based on lattice can resist quantum computing attacks,most of the current lattice encryption schemes are dedicated to studying how to improve the efficiency of the algorithm and how to improve the accuracy of encryption and decryption,and can not solve the problems of fine-grained encryption and access control,and the problem of user attribute security revocation.Therefore,the current lattice-based encryption algorithm cannot be directly applied to the cloud computing environment.In order to ensure the confidentiality of cloud data,achieve secure fine-grained access control,and resist quantum computing attacks,in this thesis,we mainly study cloud data security sharing and access control algorithms based on lattice problem.The main contributions of this thesis are as follows.Firstly,in this thesis,we propose a revocable multi-authority attribute-based encryption scheme based on an ideal lattice in cloud storage environment(RMABE-IL).This scheme is suitable for cloud storage environments with multiple security domains,and can resist quantum computing attacks,achieve fine-grained access control and user attribute security revocation,and can resist collusion attacks.This scheme combines the multi-authority attribute-based encryption(MA-ABE)structure with the ideal lattice encryption algorithm,and uses the trapdoor function to construct the R-LWE problem in the ideal lattice,so the scheme can realize user fine-grained access control in a multi-authority environment and resist quantum computing attacks.The scheme can realize secure and efficient user attribute revocation by updating some components of ciphertext and key.In addition,by using key randomization technology,the scheme can prevent collusion attacks among legal users,revoked users,and external attackers in the system.Based on the R-LWE problem,it is formally proved that the scheme can resist quantum algorithm attacks and collusion attacks.Secondly,in this thesis,we propose a multi-authority encryption scheme with fine-grained access control based on the R-LWE problem(RMA-LBE).This scheme is suitable for cloud computing environments with multiple security domains.This scheme can resist quantum computing attacks,realize fine-grained access control with user attribute revocation,and support flexible access policy,and resist collusion attacks.This scheme is based on the R-LWE problem,combined with the threshold multi-authority CP-ABE encryption structure,so as to resist quantum computing attacks and realize fine-grained access control.This scheme achieves secure and efficient user attribute revocation by updating part of the ciphertext and secret key components.This scheme applies the extended Shamir key sharing technology to construct the access structure,so as to increases the flexibility of the scheme.The scheme is based on the R-LWE problem,it has been rigorously proven mathematically to resist quantum computing attacks.In addition,the RMA-LBE scheme can resist collusion attacks among revoked users and legal users,collusion attacks.Finally,in this thesis,we propose a revocable R-LWE-based cloud data sharing ABE algorithm(RABE-RLWE).This scheme can realize data sharing with fine-grained access control and secure user attributes revocation,and can resist quantum computing attacks and collusion attacks.This scheme designs a data sharing access control framework in cloud computing environment,and proposes an encryption algorithm based on R-LWE problem to achieve finegrained access control and resist quantum computing attacks.This thesis proves that the RABERLWE scheme can resist quantum computing attacks through rigorous formal proof.Meanwhile,it is also proved that this scheme can resist collusion attacks between revoked users and legal users,collusion attacks between external attackers and legal users,and collusion attacks between revoked users.