Resilient Collaborative Privacy for Location-Based Services

Abstract

Location-based Services (LBSs) provide valuable services, with convenient features for users. However, the information disclosed through each request harms user privacy. This is a concern particularly with honest-but-curious LBS servers, which could, by collecting requests, track users and infer additional sensitive user data. This is the motivation of both centralized and decentralized location privacy protection schemes for LBSs: anonymizing and obfuscating LBS queries to not disclose exact information, while still getting useful responses. Decentralized schemes overcome the disadvantages of centralized schemes, eliminating anonymizers and enhancing users' control over sensitive information. However, an insecure decentralized system could pose even more serious security threats than privacy leakage. We address exactly this problem, by proposing security enhancements for mobile data sharing systems. We protect user privacy while preserving accountability of user activities, leveraging pseudonymous authentication with mainstream cryptography. Our design leverages architectures proposed for large scale mobile systems, while it incurs minimal changes to LBS servers as it can be deployed in parallel to the LBS servers. This further motivates the adoption of our design, in order to cater to the needs of privacy-sensitive users. We provide an analysis of security and privacy concerns and countermeasures, as well as a performance evaluation of basic protocol operations showing the practicality of our design.

Security and Privacy in Vehicular Social Networks

“…Decentralization of a system could be due to various reasons, among which privacy is one of the main concerns that motivates the decentralization. It has been considered in many works that the central servers in OSNs or LBSs are tend to collect sensitive information of users and even inferring extra information from the collected data [48], [24], [31]. Such central servers fall into honest-but-curious model.…”

“…Pseudonymous can be integrated with different services (and their SPs) to provide secure and privacy preserving VSNs. For example, in [31], a secure and privacy-enhancing LBS is proposed leveraging information sharing and the pseudonymous authentication. Users authenticate their queries and responses under the pseudonyms obtained from the PCA.…”

Resilient privacy protection for location-based services through decentralization

“…An alternative collaborative privacy protection approach is to pass/share LBS-obtained information among users, to decrease exposure to the LBS server [31,55]. The sharing approach requires 1 arXiv:2001.07583v2 [cs.CR] 22 Jan 2020 nodes to cache information received from the LBS and pass it to neighbors when requested.…”

“…However, if such k users are too close, e.g., in a church, a shopping mall, or a cinema, such symbolic "addresses" can still be disclosed. Thus, it is hard to define how large k should be to ensure an appropriate level of protection.An alternative collaborative privacy protection approach is to pass/share LBS-obtained information among users, to decrease exposure to the LBS server [31,55]. The sharing approach requires 1 arXiv:2001.07583v2 [cs.CR] 22 Jan 2020 nodes to cache information received from the LBS and pass it to neighbors when requested.…”

“…Responses signed by the LBS server [55] can be self-verifiable allowing detection of manipulation by a node. However, a misbehaving node passing on tampered responses would remain "invisible" and continue attacking the system, wasting computational power [31]. Moreover, decentralizing functionality could provide an easy way for passive adversaries to learn information from neighbors.…”