Privacy in geo-social networks: proximity notification with untrusted service providers and curious buddies

TL;DR

This paper analyzes privacy issues in geo-social proximity notifications, proposing two new protocols that ensure complete privacy from service providers and controllable privacy from friends, with demonstrated efficiency and effectiveness.

Contribution

It introduces two novel privacy-preserving protocols for proximity services that outperform existing solutions in privacy, accuracy, and cost, validated through analysis and implementation.

Findings

Protocols ensure complete privacy from service providers.

Protocols provide controllable privacy with friends.

New protocols outperform existing solutions in privacy and efficiency.

Abstract

A major feature of the emerging geo-social networks is the ability to notify a user when one of his friends (also called buddies) happens to be geographically in proximity with the user. This proximity service is usually offered by the network itself or by a third party service provider (SP) using location data acquired from the users. This paper provides a rigorous theoretical and experimental analysis of the existing solutions for the location privacy problem in proximity services. This is a serious problem for users who do not trust the SP to handle their location data, and would only like to release their location information in a generalized form to participating buddies. The paper presents two new protocols providing complete privacy with respect to the SP, and controllable privacy with respect to the buddies. The analytical and experimental analysis of the protocols takes into account privacy, service precision, and computation and communication costs, showing the superiority of the new protocols compared to those appeared in the literature to date. The proposed protocols have also been tested in a full system implementation of the proximity service.