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Due to the recent developments of wireless positioning capabilities, such as GPS-equipped smart phones and PDA, location-based services (LBSs) are popular (Taniar, 2011; Safar, 2009; Xuan, 2011). In LBSs, mobile users are usually getting location information combined with traffic information, friend finder, and adjacent neighbor. However, the users can make use of these kinds of services by revealing their exact location to a location-based service provider. So, the users may meet a privacy violation problem (Xiong, 2007). Recently, database outsourcing (Singh, 2008; Singh, 2009) has been one of the most popular trends in cloud computing. Due to the rapid advancements in LBSs, the speed of transmitting a terabyte of data over long distance has significantly increased and the amount of information generated in our daily lives has grown rapidly over the past decade. This large amount of information requires sophisticated management systems that are beyond the capabilities of individuals or small business. Thus, database outsourcing boosts up its popularity. Because database is separated from a data owner (DO) in database outsourcing, a service provider (SP) is responsible for data storage and performs query processing for the authorized query issuer. However, because the data owner does not want to disclose the original data to the service provider, privacy issues for the database outsourcing have been actively studied (Xiong, 2007; Qiu, 2008; Yi, 2009; Haber, 2009; Yang, 2009; Sachridis, 2010; Jiang, 2010; Ciriani, 2011; Zhou, 2012; Anil, 2013).