A new Top-k query processing algorithm to guarantee confidentiality of data and user queries on outsourced databases

With the growth of cloud computing, database outsourcing has attracted a lot of interest. Due to the serious privacy threats in cloud computing, databases need to be encrypted before being outsourced to the cloud. Therefore, various Top-k query processing algorithms have been studied for encrypted databases. However, existing algorithms are either insecure or inefficient. Therefore, in this paper we propose a new Top-k query processing algorithm that guarantees confidentiality of both data and user queries while hiding data access patterns. Our algorithm also allows the query issuer to not participate in the query processing. To achieve a high query processing efficiency, we implement new secure protocols using Yao’s garbled circuit and a data packing technique. A performance analysis shows that the proposed algorithm outperforms the existing work in terms of query processing costs.