An adaptive geo-indistinguishability mechanism for continuous LBS queries

Abstract

The popularity of mobile devices with positioning capability and Internet accessibility in recent years has led to a revolution in the Location-based services (LBSs) market. Unfortunately, without preserving the user’s location privacy, LBS providers can collect and log the accurate location data of the service users and provide them to third parties. Many mechanisms have been proposed to preserve the LBS user’s location privacy. These mechanisms provide a partial disclosure of the user’s location. While said mechanisms have had demonstrable effectiveness with snapshot queries, the shortcoming of supporting continuous queries is their main drawback. Geo-indistinguishability represents a formal notion of obfuscation-based location privacy which protects the user’s accurate location while allowing an adequate amount of information to be released to get the service with an accepted utility level. Despite its effectiveness and simplicity, geo-indistinguishability does not address the potential correlation of the subsequent locations reported within the continuous queries. In this paper, we investigate the effect of exploiting the correlation of the user’s obfuscated locations on the location privacy level. We propose an adaptive location preserving privacy mechanism that adjusts the amount of noise required to obfuscate the user’s location based on the correlation level with its previous obfuscated locations. The experiments show that adapting the noise based on the correlation level leads to a better performance by applying more noise to increase the location privacy level when required or by reducing the noise to improve the utility level.