Cloud Sea:Research On Architecture Of Inter-Cloud And Privacy-Preserving Dynamic Multi-Keyword Ranked Search Technology Over Encrypted Data

With the further development of cloud computing technology,more and more enterprises and individuals upload data to the cloud storage.This can not only save money,but also can reveal the user from the complicated local data management.When we enjoy the convenient,at the same time,the security and reliability of the cloud storage is more and more get the attention of the user.The traditional way is to encrypt the clear data before their private data being uploaded to the clouds by the data owner.But the single cloud platform inherent defects are still unable to be avoided.With the constant improvement of the awareness of data security,this method hasn't been able to meet the requirements of the most of the enterprises.In addition,the outages of the cloud providers are continuing without end,which confused user to whether to store their datas in the clouds.Under the circumstances,the development of cloud computing has been retarded.In this thesis,aiming at the shortcomings of the single cloud platform,we design a multi-cloud structure under the Intercloud-Cloud Sea,which is designed to solve the single cloud security flaws.The structure is based on a semi-trusted third-party.The owner of the data uploads the encrypted data to the CSPs,so that they can be provided with better reliability and security.The semi-trusted third-party is responsible to maintain and manage the index of the user,and manage the allocation of the partition of the encrypted data for users to search,audit,etc.The CSP in the Intercloud only store the fragment of the encrypted data.In order to get the completing encrypted data,CSPs must depend on the index of the semi-trusted third-party.In this thesis,the structure is designed to facilitate the practical application,which needn't to change any code on the CSP and easy to promote.In addition,based on the structure of Cloud Sea,a privacy-preserving and dynamic multi-keyword ranked retrieval algorithm over encrypted data was also designed.The retrieval algorithm accesses the corresponding data among the CSPs based on the keywords provided by the user.It can obtain the result of top-k without using the merge algorithm,which reduces the time complexity of the algorithm.The simulation experimental results were compared with those of the existing multi-cloud structures.The results show that the structure has a more comprehensive security.Comparing with the modified MRSE algorithm in the aspect of the retrieval algorithm,the results show that the proposed retrieval algorithm has obvious advantage in comparison to the modified MRSE algorithm under the structure.