Secure friend discovery in mobile social networks

Mobile social networks extend social networks in the cyberspace into the real world by allowing mobile users to discover and interact with existing and potential friends who happen to be in their physical vicinity. Despite their promise to enable many exciting applications, serious security and privacy concerns have hindered wide adoption of these networks. To address these concerns, in this paper we develop novel techniques and protocols to compute social proximity between two users to discover potential friends, which is an essential task for mobile social networks.We make three major contributions. First, we identify a range of potential attacks against friend discovery by analyzing real traces. Second, we develop a novel solution for secure proximity estimation, which allows users to identify potential friends by computing social proximity in a privacy-preserving manner. A distinctive feature of our solution is that it provides both privacy and verifiability, which are frequently at odds in secure multiparty computation. Third, we demonstrate the feasibility and effectiveness of our approaches using real implementation on smartphones and show it is efficient in terms of both computation time and power consumption.

I. Introduction

Motivation. Online social networks, such as Facebook and Myspace, have experienced an explosive growth recently. Mobile social networks, which bring social networking to mobile phones, represent a natural next step and have already generated a lot of excitement. For example, cell phone manufacturers and cellular service providers have developed their own social networks (e.g., Nokia, Virgin Mobile) and provided software support for mobile social networks (e.g., Motorola). Compared to (Internet-based) online social networks, mobile social networks offer several distinctive advantages: (i) much larger potential user base, with 4 billion mobile phone subscribers [33] compared to only 300 million broadband subscribers [7], (ii) the built-in localization capability of mobile phones which enables rich and new location-based services, and (iii) applicable to a wider range of application scenarios because unlike online social networks, they do not necessarily require access to a computer or the Internet.