Announcements Editorial Letters on Privacy in Location - based Services Privacy - Preserving Techniques

This article presents an overview of privacy problems and solutions to date in location basedservices, with the emphasis on understanding location privacy issues, alternative models, andarchitectures. It concludes with an outlook in location privacy research and its impact on mobileInternet, pervasive computing, and geo-spatial data management. Privacy Risks in Location Based Services With the rapid advances in positioning technologies such as GPS, GSM, RFID, and WiFi(802.11) and the wide deployment of wireless local area networks (WLAN), many devices todayare equipped with wireless communication capabilities and location-awareness. These newtechnologies have enabled a new class of applications, known as Location-Based Services(LBSs). Public disclosure of location information, on one hand, enables many useful locationbased information services, new business opportunities, and a wide array of new quality of lifeenhancing services. But on the other hand, the ability to locate users and mobile objectsaccurately also opens door to new threats intrusion of location privacy [1,5,6].In real world, the location of a mobile user, especially the location trace (time series oflocations) of a mobile, is considered private information, even when such location informationcontains no individually identifiable values. This is because the association of private locationinformation with any identifiable entity can lead to unauthorized disclosure of information aboutthe entity. Inference and computing over a sequence of location updates may lead to exposure ofindividual privacy or organizational privacy, even when the identity information is removedfrom all LBSs. For instance, successive position updates can be linked together, even ifidentifiers are removed from location updates. A known location owned by location-identityrelationship can link a location update to an identity. External observation, if available, can beused to link a location update to an identity.Location privacy can be broadly defined as the ability to prevent other unauthorized partiesfrom learning one's current or past location. From the privacy policy perspective, locationprivacy refers to the claim (right) of individuals, groups, and institutions to determine forthemselves, when, how and to what extent location information about them can becommunicated to others. From the software system perspective, location privacy refers to thecapability of a mobile node or a trusted location server to conceal the relation between thelocation information of a mobile and its personal (or organizational) identifiable information