Research On The Method Of Attribute Based Encryption With Keyword Search

With big data era coming,the cloud storage solved the problem of data storage and sharing well,but the data stored in the cloud is frequent hacked,revealing data confidentiality and privacy.Therefore,the concept of searchable encryption was put forward to realize the function that use the keyword cipher for quick retrieval,which ensured the confidentiality of data.However,the traditional searchable symmetric encryption and the searchable public key encryption are both one-to-one communi-cation modes,which obviously cannot satisfy the era of information sharingAttribute-based encryption can satisfy one-to-many data sharing,attribute-based encryption is introduced into searchable encryption to realize one-to-many data sharing and fine-grained search authorization.Although existing searchable schemes based on attribute encryption satisfy the requirement of confidentiality,but there are problems of ciphertext length,the disclose of access structure,key leakage and so on.According to the above requirements,this paper designs three attribute-based searchable encryption schemes,which are of great significance to improve the privacy protection of data in the cloud and increase the security performance of the system.In this paper,the main content is as follows(1)To address the problems of key leakage and large computation amount in current attribute-based searchable encryption schemes,this study proposes a multi-keyword ranked search scheme based on attribute encryption in cloud environment Firstly,the scheme not only supports fine-grained search authorisation,but also has constant ciphertext length.Secondly,users' private keys are blinded before being submitted to the cloud server,which ensures the security and confidentiality of users' keys.Thirdly,to reduce search complexity,this study uses TF-IDF rules to calculate the relevance scores of documents and given keywords,and then ranks the documents.(2)In view of the fact that the data owner loses physical control over the u-ploaded cloud data,the cloud service provider may face the problem of duplicate data occupying the storage space,this paper proposes a novel verifiable attribute-based keyword search over encrypted data supporting data deduplication.In the scheme,attribute-based encryption with hidden structure is introduced to achieve effective access authorization based on its one-to-many advantage,as well data con-fidentiality.A data label of each shared file is generated to finish data deduplication,while the third-party auditor and hash function are adopted to ensure data integri-ty,including ciphertext,plaintext and symmetric key.Moreover,in order to solve the problem of high computational load caused by attribute-based encryption,out-sourced decryption is used to optimize the scheme.(3)In order to meet the requirements of privacy,low user-side computation and integrity verification of searchable encryption schemes,this paper proposes a verifi-able attribute-based keyword search scheme with privacy preservation.The scheme adopts the ordered multi-valued attribute access structure and ordered multi-valued attribute set,and fixes the position of each attribute to reduce the parameters and related computation cost and to improve the efficiency of the scheme,while in key generation,the hash values of specific attributes are calculated to distingnish the different values of multi-valued attributes.At the same time,hash and pair opera-tion are used to hide the access structure and prevent the disclosure of the access structure.The inverted index structure and Merkle tree are used to establish the data authentication tree,which can verify the correctness of the document returned by the cloud server provider and the result of outsourced decryption.In addition,outsourced decryption is used to reduce the computation cost on the user side.