SHARP: Private Proximity Test and Secure Handshake with Cheat-Proof Location Tags

Abstract

Abstract.A location proximity test service allows mobile users to determine whether they are in close proximity to each other, and has found numerous applications in mobile social networks. Unfortunately, existing solutions usually reveal much of users' private location information during proximity test. They are also vulnerable to location cheating where an attacker reports false locations to gain advantage. Moreover, the initial trust establishment among unfamiliar users in large scale mobile social networks has been a challenging task. In this paper, we propose a novel scheme that enables a user to perform (1) privacy-preserving proximity test without revealing her actual location to the server or other users not within the proximity, and (2) secure handshake that establishes secure communications among stranger users within the proximity who do not have pre-shared secret. The proposed scheme is based on a novel concept, i.e. location tags, and we put forward a location tag construction method using environmental signals that provides location unforgeability. Bloom filters are used to represent the location tags efficiently and a fuzzy extractor is exploited to extract shared secrets between matching location tags. Our solution also allows users to tune their desired location privacy level and range of proximity. We conduct extensive analysis and real experiments to demonstrate the feasibility, security, and efficiency of our scheme.

Proximity-Based Security Techniques for Mobile Users in Wireless Networks

“…(2) Unlike the work [16] whose location tag incorporates the contents of the ambient packets, this strategy depends on the physical-layer features, including the packet arrival time and RSSI. Without checking the packet contents, this system provides better privacy protection and is more robust against spoofing, eavesdropping, replay attacks and man-in-the-middle attacks.…”

“…Consequently, privacy-preserving proximity tests have recently drawn considerable research attention [10]- [16]. Based Part of this work has been presented in IEEE International Conference on Communications (ICC '13).…”

“…Moreover, a recent study has shown that the RSSbased strategies are vulnerable to man-in-the-middle attacks [17]. To address this problem, Zheng et al have proposed a location tag-based proximity test, which exploits the contents of ambient radio signals to improve the authentication accuracy and provides flexible range control [16]. However, the extraction of the packet contents in the proximity test not only engenders privacy leakage, but also increases the overall system overhead.…”

“…Unlike the content-based location tag [16], the tag in this work consists of the physical-layer features of ambient signals, and thus avoids decoding the ambient signals. Therefore, this work is applicable to the case that the ambient packet decoding is not available or desirable, significantly reduces the computational overhead, and prevents privacy leakages.…”

Location privacy without mutual trust: The spatial Bloom filter

“…His protocol was later improved in efficiency by Saldamli et al [36]. Location tags and proximity tests are also used in [19], as a way of providing local authentication, while [47] presents a secure handshake for communication between the two actors in proximity. The security of the basic proximity testing protocol has been further improved in [31].…”