Research And Implementation Of Efficient And Verifiable Searchable Encryption In Cloud Storage

With the rapid development of cloud storage,uploading local data to cloud storage pools becomes the first choice for data users.However,as cloud servers are not always trustworthy,it is often the case that before uploading,users would encrypt their personal data first.To improve the efficiency in retrieving encrypted data,cryptography experts introduced the searchable encryption(SE)technology.Researches have shown that different SE secure index structures lead to different levels of keyword search efficiency – scientific index structures will substantially improve the efficiency in retrieving encrypted data.This paper,in the context of the searchable symmetric encryption technology employed in cloud storage,presents a high-efficiency,verifiable,secure index structure by incorporating a balanced binary keyword search tree,a Bloom filter and message authenticity technology.The detailed research and innovation process is as follows:1.Based on the time and space-efficient balanced binary keyword search tree and Bloom filter,an efficient,secure index structure that had sub-linear search time and low overhead of cloud storage was introduced.The scheme utilized the balanced binary keyword search tree to build a file index tree T that could guarantee the keyword search time O(logn)under the most adverse condition.Yet,if the encrypted information on every node of the tree T was to be stored in the cloud,large storage overhead would ensue.To tackle the problem,the space and search-efficient Bloom filter was adopted to optimize the tree T,hence creating a binary vector secure index I,which guaranteed that there was sub-linear search time,and decreased the storage overhead of the index structure in servers.2.Based on the data structure and self-balancing function of the balanced binary keyword search tree,an efficient index structure that allowed parallel research by multiple processors and dynamic update was presented.The scheme,with the above-mentioned one as the groundwork,used the data structure of the balanced binary keyword search tree to make it possible for multiple processors to retrieve encrypted data simultaneously,which handsomely enhanced encrypted data retrieval efficiency,optimizing user experience.In addition,the self-balancing function of the balanced binary keyword search tree was realized to implement the dynamic update of files.3.A verification algorithm that could examine the credibility of and get curious about the search results of servers was proposed.When authorized users were searching a keyword,servers would return the search results and at the same time return a verification set.By verifying the verification set with the algorithm,users could conclude whether the cloud servers had faithfully executed the search request.