This demonstration presents iPDA, a system to support privacy-preserving data access in location-based mobile services. The iPDA system consists of three main components: 1) a mobility-aware location cloaker that cloaks the user’s location with a region and transforms a locationbased query to a region-based query, 2) a progressive query processor that efficiently evaluates a result superset for the location-based query and, 3) a result refiner that refines the superset to generate the exact query result for the user. We discuss in detail the architecture and functionalities of our iPDA system. In addition, a tourist information system named iGuide, as an iPDA application, is prototyped for demonstration.