Privacy Preserving Location based Services Through K-Anonymized Vehicular Social Network

Abstract

Location-based services (LBS) are the services that are used through users’ mobile devices and provide them the information regarding nearby restaurants, hospitals, gas stations, shopping malls, cinema (to name a few). While using LBS, a user needs to provide his/her location coordinates (geo-coordinates) to the LBS server. The revelation of a user’s location may seriously jeopardize his/her privacy. A common solution to this problem is the use of an intermediate anonymizer server that obfuscate the real location of a user among k other users. However, in this scenario, the anonymizer server must be a trusted and therefore, inherits the trust related issue and may also become a single point of failure. Moreover, if anonymizer compromises then the privacy of all the users is compromised. A vehicular adhoc network (VSN) is a subset of a mobile adhoc network (MANET) with some unique characteristics such as rapid speed of nodes (vehicles) that quickly change topologies. A vehicular social network is a combination of VANET and online social network. A VSN is formed by likeminded drivers/passengers or by common location. Like mobile nodes, the vehicles also utilize LBS services. However, an anonymizer cannot be used in this scenario because it needs to be updated with current locations of vehicles and therefore, jeopardizes the privacy of vehicles. A VSN can significantly help in this scenario. This research proposes a distributed k-anonymity based scheme that considers the social ties between the users of VSN and enable vehicles to use LBS in a privacy preserving manner. The proposed scheme uses a trusted authority (TA) such as a government law enforcement agency, that registers vehicles. However, the TA does not know what services are requested by a vehicle. On the other hand, the LBS server does not know which vehicle is requesting the service. In the end, the computational and communication overhead of the scheme is presented. The low computational overhead of TA, LBS server and vehicles shows that LBS can serve several vehicles in a very short time. Similarly, the TA can register and provide pseudo-identities to a number of vehicles without any significant delays.