A data encryption scheme and GPU-based query processing algorithm for spatial data outsourcing

With the development of cloud computing, the interest on spatial database outsourcing has been increasing. Therefore, researches for protecting location data privacy in spatial outsourced databases have been actively performed. However, FDH (Flexible Distance-Based Hashing) is easy to access original data because they do not consider data distribution. In addition, since they perform the nearest neighbor query processing by using tree-based indexes, query processing time can be increased depending on tree depth. To solve these problems, we propose a bitmap encryption scheme and a query processing algorithm for spatial database outsourcing. We propose an anchor selection algorithm using a split and merge policy based on data distribution to protect privacy of users from attackers. In addition, we reduce the communication cost for query processing by using GPU processors. Finally, we show from performance analysis that the proposed scheme shows better query processing performance than the existing scheme, while the proposed scheme guarantees users´ privacy.