Ensuring Anonymity for LBSs in Smartphone Environment

Abstract

With the rapid growth of GPS-enable Smartphones, the interest on using Location Based Services (LBSs) has increased significantly. The evolution in the functionalities provided by those smartphones has enabled them to accurately pinpoint the location of a user. Because location information is what all LBSs depend on to process user's request, it should be properly protected from attackers or malicious service providers (SP). Additionally, maintaining user's privacy and confidentiality are imperative challenges to be overcome. A possible solution for these challenges is to provide user anonymity, which means to ensure that a user initiating a request to the SP should be indistinguishable from a group of people by any adversary who had access to the request. Most of the proposals that maintain user's anonymity are based on location obfuscation. It mainly focuses on adjusting the resolution of the user's location information. In this paper, we present a new protocol that is focused on using cryptographic techniques to provide anonymity for LBSs users in the smartphone environment. This protocol makes use of a trusted third party called the Anonymity Server (AS) that ensures anonymous communication between the user and the service provider. Keywords—Location Based Services, Anonymity, Location Information The massive evolution in wireless communications and the dramatic increase in the usage of smartphones have facilitated a greater ability to access mobile networks and their services. Be- cause smartphones are easy to carry and available while the users are moving around, accessing network services has become easier and ubiquitous. At the same time, Location Information (LI) introduced a new and highly personalized class of applications and services. The availability of such functionality along with the ability to uni- quely identify smartphones, enabled service providers to provide services based on their location removing the time and location constrains that are associated with providing services to custom- ers. Information services that make use of the location of users by either utilizing satellites or mo- bile network cells, with the intention of providing services that are customized to their precise geographical area are called Location Based Services (LBSs). LBSs are usually accessible by mobile devices such as Smartphones, Personal Digital Assistants (PDAs) and mobile phones. There are varieties of LBS applications that include emergency services, point of interest search, ※ This research was supported by Ministry of Land, Transport and Maritime Affairs of Korean gorernment (Grant 36- 2007-CAirport)