Research On Multi-Keyword Dynamic Public Key Searchable Encryption Scheme

Most of the existing dynamic searchable encryption schemes are based on symmetric key,and the multi-keywords public key searchable encryption scheme supporting dynamic update of ciphertext is rarely mentioned,the ciphertext can only be added but not deleted,which will inevitably lead to the waste of cloud storage space and the increase of cost.Therefore,this paper improves the existing public key searchable encryption scheme and studies the dynamic public key searchable encryption scheme with multi-keywords,completes the following main tasks:(1)Based on El Gamal public key encryption algorithm,a dynamic public key searchable encryption scheme(DNBP-PEKS)is proposed.The server verifies the trapdoor generated by the user,and only the user with the private key can search and delete the ciphertext correctly.Different from the existing PEKS scheme "file-keywords" index construction method,this scheme refers to the index construction idea of symmetric searchable encryption scheme to realize the dynamic update of ciphertext,for the keywords that have been searched,it does not need to carry out the mathematical operation on the group,and has high search efficiency.Finally,in the random oracle model,this scheme is proved that this scheme has the security under the adaptive dynamic keywords selection attack,and can resist the adversary's keywords guessing attack.(2)DNBP-PEKS scheme enables users to update the ciphertext in the cloud dynamically and search efficiently,but it only supports single keyword retrieval,resulting in inaccurate search results,at the same time,considering that information may be lost and tampered by adversaries in the process of returning ciphertext file,a verifiable multi-keywords dynamic public key searchable encryption scheme(DVMK-PEKS)is proposed.This scheme uses signature algorithm to sign the ciphertext file,the user can implenment multi-keywords retrieve and delete the ciphertext in the cloud,and verify the correctness of the received ciphertext through the returned signature.(3)An efficient dynamic public key searchable encryption scheme(DMUMK-PEKS)supporting multi-keywords retrieval and multi-users sharing is proposed.The scheme allows the ciphertext generated by the data owner to be shared with multiple users for searching,and can add and delete the user's permissions flexibly.This scheme has not the defect of the most existing multi-users public key searchable encryption scheme,which uses a fixed symmetric key to encrypt multiple files,when the user is revoked,he still has the key,which will bring some security risks.In order to solve this problem,this scheme allocates different random encryption keys to each file,users can only obtain the decryption key of the retrieved ciphertext,which will not affect the security of the ciphertext users have no access to.This scheme refers to the idea of structured encryption to construct index,that not only realizes the dynamic update function of ciphertext,but also makes the scheme have higher search efficiency.