Research Of Public Key Searchable Encryption Scheme Based On Cloud Environment

Searchable Encryption(SE)is an important technical means and theoretical basis for solving the problem of retrieving data in the form of ciphertext.This paper mainly studies the searchable encryption scheme under asymmetric keys,and analyzes the security,computational and storage efficiency and functionality of the searchable encryption scheme under asymmetric keys.The main security threat of public key searchable encryption scheme is keyword guessing attack,especially internal offline keyword guessing attack,external offline/online keyword guessing attack and so on.Most of the existing schemes use bilinear mapping with high computational cost,and the computational cost is linear with the increase of the number of keywords.Considering the accuracy of retrieval and fine-grained access control for data users,we focus on these issues.The innovation points and main research contents of this paper are as follows:(1)Research on public key searchable encryption scheme based on dual server.For internal offline keyword guessing attacks,most of the existing schemes mainly solve such security threats by introducing the authentication of the public and private key pair of the data sender and the public and private key pair of the receiver.The authentication method has the problem that the data receiver will appoint the data sender in advance.In this paper,the receiver splits the private key into two parts in the trapdoor generation stage,and uses dual servers to perform their respective functions.In order to save costs in the communication process,by introducing the public and private key pair of dual servers,two specific servers are designated to execute the matching test algorithm,which eliminates the use of secure channel and can resist external off-line keyword guessing attacks.Against external online keyword guessing attack,the second encryption method of ciphertext was used to blind the ciphertext,so that external attackers could not identify their forged ciphertext.We ensure the correctness and consistency of the search results,and prove the security of the scheme in the standard model.Compared with other schemes,the scheme has better performance in computational efficiency.(2)Research on an attribute-based searchable encryption scheme supporting dynamic sharing.Ciphertext-Policy Attribute-based Encryption(CP-ABE)can solve the problem of data sharing and privacy security.However,there are still some problems in the existing schemes,such as how to efficiently retrieve the required data and how to efficiently realize dynamic sharing when retrieving massive data.Aiming at the above problems,this paper proposes a CP-ABE scheme supporting dynamic data sharing,and introduces the Searchable Encryption(SE)protocol.This paper proposed an attribute-based searchable encryption scheme supporting dynamic update by combining SE protocol with CP-ABE.In order to solve the problem that it is difficult to search massive data,a searchable encryption protocol is constructed by introducing confusion Bloom filter.Compared with other schemes,the proposed scheme has obvious advantages in computational efficiency and storage efficiency.Finally,in order to realize data dynamic sharing more efficiently,the blockchain technology was introduced to build a policy block,and the access policy was stored in the policy block to complete data dynamic sharing,which ensured data privacy and security.The performance of the scheme is compared,and it has great advantages in computing overhead and storage overhead.