Secure Top-k Query Processing on Encrypted Databases

Privacy concerns in outsourced cloud databases have become more and more important recentlyand many efficient and scalable query processing methods over encrypted data have been proposed.However, there is very limited work on how to securely process top-k ranking queries over encrypteddatabases in the cloud. In this paper, we focus exactly on this problem: secure and efficient processingof top-k queries over outsourced databases. In particular, we propose the first efficient and provablesecure top-k query processing construction that achieves adaptively IND-CQA security. We developan encrypted data structure called EHL and describe several secure sub-protocols under our securitymodel to answer top-k queries. Furthermore, we optimize our query algorithms for both space and timeefficiency. Finally, in the experiments, we empirically analyze our protocol using real world datasetsand demonstrate that our construction is efficient and practical.