Integrity for Approximate Joins on Untrusted Computational Servers

In the last few years, many efforts have been devoted to the development of solutions aiming at ensuring the confidentiality and integrity of data and computations in the cloud. In particular, a recent solution for verifying the integrity of equi-join queries is based on the insertion of checks (markers and twins) whose presence provides probabilistic guarantees on the integrity of the computation. In this paper, we propose an approach for verifying the integrity of approximate join queries, which is based on the introduction of a discretized version of the join attribute and on the translation of the approximate join into an equijoin defined over the discrete attribute added to the original relations. The proposed approach guarantees the correctness and completeness of the join result, while causing a limited overhead for the user.