Hilbert-curve based cryptographic transformation scheme for protecting data privacy on outsourced private spatial data

The study on spatial database outsourcing has been spotlighted with the development of cloud computing. Therefore, researches for protecting location data privacy in outsourced database have been studied. However, the existing spatial transformation schemes are vulnerable to naïve attack models. The existing cryptographic transformation scheme provides high data privacy, but it causes the high query processing cost. To solve these problems, in this paper we propose a Hilbert-curve based cryptographic transformation scheme to protect data privacy and to improve the efficiency of the query processing in outsourced databases. The proposed scheme reduces the communication cost for query processing since we perform a local clustering based on the order of Hilbert-curve. Finally, we show from performance analysis that the proposed scheme outperforms the existing scheme.