Secure keyword-based Ranked Semantic Search over Encrypted Cloud Data

With the advent of cloud computing, many organizations and individuals are interested in outsourcing their complex data management to the public cloud for economic savings and ease of access. As sensitive information may have to be encrypted before outsourcing, the data utilization service based on plaintext keyword search is not suitable for the encrypted cloud data. In this paper, we propose a solution for ranked semantic keyword search (RSS) over encrypted cloud data. With the design of semantic extension, the proposed scheme could return not only the exactly matched files, but also the files including the terms semantically related to the query keyword. In the proposed scheme, the data owner generates a piece of file metadata for each file, and uploads the encrypted metadata set and file collection to the cloud server. After receiving a query request, the cloud server first finds out the keywords that are semantically related to the query keyword according to SRL. Then both the query keyword and the extensional words are used to retrieve the files. Eventually, the result files are returned in order according to the total relevance score. Detailed security analysis shows that our solution is privacy-preserving and secure under the previous searchable symmetric encryption (SSE) security definition. Experimental evaluation demonstrates the efficiency and effectives of the scheme.