Privacy-Preserving Kth Element Score over Vertically Partitioned Data

Given a large integer data set shared vertically by two parties, we consider the problem of securely computing a score separating the kth and the (k + 1) to compute such a score while revealing little additional information. The proposed protocol is implemented using the Fairplay system and experimental results are reported. We show a real application of this protocol as a component used in the secure processing of top-k queries over vertically partitioned data.