Top-k Query Processing over Distributed Sensitive Data.

Distributed systems provide users with powerful capabilities to store and process their data in third-party machines. However, the privacy of the outsourced data is not guaranteed. One solution for protecting the user data against privacy attacks is to encrypt the sensitive data before sending to the nodes of the distributed system. Then, the main problem is to evaluate user queries over the encrypted data. In this paper, we propose a complete solution for processing top-k queries over encrypted databases stored across the nodes of a distributed system. The problem of distributed top-k query processing has been well addressed over plaintext (non encrypted) data. However, the proposed approaches cannot be used in the case of encrypted data.