Privacy-Preserving Location-Proximity for Mobile Apps

Location Based Services (LBS) have seen alarming privacy breaches in recent years. While there has been much recent progress by the research community on developing privacy-enhancing mechanisms for LBS, their evaluation has been often focused on the privacy guarantees, while the question of whether these mechanisms can be adopted by practical LBS applications has received limited attention. This paper studies the applicability of Privacy-Preserving Location Proximity (PPLP) protocols in the setting of mobile apps. We categorize popular location social apps and analyze the trade-offs of privacy and functionality with respect to PPLP enhancements. To investigate the practical performance trade-offs, we present an in-depth case study of an Android application that implements InnerCircle, a state-of-the-art protocol for privacy-preserving location proximity. This study indicates that the performance of the privacy-preserving application for coarse-grained precision is comparable to real applications with the same feature set.