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Practical K Nearest Neighbor Query Scheme with Two-Party Guarantees in Road Networks

In order to achieve user's privacy preservation and data security of LBS server in road networks, a query scheme for points of interest(PoI) is proposed in this paper based on oblivious transfer and private information retrieval. The scheme can proceed in two phases: Firstly, we take vertexes in road networks as generating elements to construct a new data structure which is employed to store the distribution information and details of PoIs which are encrypted with different symmetric keys for sake of data security of LBS server. And an oblivious transfer protocol is presented based on the data structure, which facilitates a user to privately obtain the unique key materials corresponding to his interested PoIs without revealing any other PoI information in LBS server since the data is its asset. Then, a private information retrieval protocol is presented to obtain the interested PoI details, the user does not need to provide his location or explicit query content in the query, whereas he can derive an accurate result with the previous key materials, so it guarantees the user's privacy as well. Finally, performance analysis and experiments show that our scheme is more efficient and accurate in a real scenario compared with existing solutions.