Research On Key Technologies Of Ciphertext Retrieval For Cloud Computing

In the era of rapid data growth,cloud computing technology has become one of the research hotspots.With its near-endless storage space and computing power,cloud storage platforms provide users with more convenient data access.Cloud computing can provide big data platforms in a variety of application scenarios such as smart cities,smart healthcare,intelligent transportation,and scientific research.For data management and ease of use,more data owners will upload local data to the cloud server.But these datasets usually contain sensitive information such as health records,ID numbers,and home addresses.If this data is published or shared with some untrusted third parties in the cloud,it will lead to the disclosure of private information.In order to protect the privacy of data,encrypting data before it is outsourced to the cloud server is currently the most widely used method.However,data encryption also increases the difficulty of data usage.Some plaintext-based technologies such as top-k retrieval based on keywords cannot be directly applied to the scene.Therefore,it is of great significance to conduct in-depth research on ciphertext-based retrieval technology.The thesis mainly studies the multi-keyword sortable search technology based on ciphertext.By improving and optimizing the existing scheme,a ciphertext retrieval scheme with high search rate and low storage rate is proposed.Aiming at the privacy problem of data retrieval,this thesis proposes a method based on divide and conquer method to construct index and keyword query method,and build an index tree group with B+ tree structure for data set.In the process of retrieval,the query vectors are grouped in the same way,each group of query vectors is searched on the corresponding index tree group,and finally the results are sorted and returned to the top-k documents with the highest relevance of the query user.A large number of experiments on real data sets show that the proposed method not only has a safe privacy protection effect,but also can significantly improve retrieval performance and reduce index storage space.At the same time,the retrieval scheme has been extended,intelligent error correction and semantic analysis functions have been added to further enhance the user's retrieval experience.Finally,based on the retrieval scheme proposed in this thesis,a multi-keyword sortable ciphertext retrieval system is designed.It realizes the complete process from data import processing to retrieval keyword encryption,to ciphertext retrieval and returning retrieval results,and realizes the transformation from theoretical research to practical application.