Browsing by Subject "Location privacy"

Now showing 1 - 5 of 5

Open Access
The cloaked-centroid protocol: location privacy protection for a group of users of location-based services
(Springer U K, 2012-08-17) Ashouri-Talouki, M.; Baraani-Dastjerdi, A.; Selçuk, A. A.
Several techniques have been recently proposed to protect user location privacy while accessing location-based services (LBSs). However, applying these techniques to protect location privacy for a group of users would lead to user privacy leakage and query inefficiency. In this paper, we propose a two-phase protocol, we name Cloaked-Centroid, which is designed specifically to protect location privacy for a group of users. We identify location privacy issues for a group of users who may ask an LBS for a meeting place that is closest to the group centroid. Our protocol relies on spatial cloaking, an anonymous veto network and a conference key establishment protocol. In the first phase, member locations are cloaked into a single region based on their privacy profiles, and then, a single query is submitted to an LBS. In the second phase, a special secure multiparty computation extracts the meeting point result from the received answer set. Our protocol is resource aware, taking into account the LBS overhead and the communication cost, i.e., the number of nearest neighbor queries sent to a service provider and the number of returned points of interests. Regarding privacy, Cloaked-Centroid protects the location privacy of each group member from those in the group and from anyone outside the group, including the LBS. Moreover, our protocol provides result-set anonymity, which prevents LBS providers and other possible attackers from learning the meeting place location. Extensive experiments show that the proposed protocol is efficient in terms of computation and communication costs. A security analysis shows the resistance of the protocol against collusion, disruption and background knowledge attacks in a malicious model.
Open Access
GLP: a cryptographic approach for group location privacy
(Elsevier BV, 2012-07-01) Ashouri-Talouki, M.; Baraani-Dastjerdi, A.; Selçuk, A. A.
Recently, location privacy during the use of location-based services (LBSs) has raised considerable concerns. There is a wide literature on location privacy from the individual point of view; however, there exist only a few works to support location privacy for a group of users. In this paper, we consider location privacy issues for a group of users who may ask an LBS for a meeting place that minimizes their aggregate distance. The proposed solution, which we call the Group Location Privacy (GLP) protocol, is based on the Anonymous Veto network (AV-net) and homomorphic encryption. It preserves the location privacy of all users even in the case of collusion. Our solution also tries to minimize the LBS overhead for nearest neighbor (NN) queries and communication, i.e., to decrease the number of NN queries sent to an LBS and the number of points of interest (POIs) it returns. Furthermore, GLP greatly decreases the bandwidth usage to a high extent and protects the LBS provider from excessive disclosure of POIs. We discuss the performance and security analysis of the GLP protocol and show that the proposed protocol is secure against partial collusion in a malicious model. (c) 2012 Elsevier B.V. All rights reserved.
Open Access
Preserving location privacy for a group of users
(Scientific and Technical Research Council of Turkey - TUBITAK, 2013) Ashouri-Talouki, Maede; Baraani-Dastjerdi, Ahmad; Selçuk, Ali Aydın
Location privacy is an interesting problem that has been receiving considerable attention. This problem has been widely discussed from the individual point of view; however, there exist only a few works that support location privacy for a group of users. In this paper we consider the problem of supporting location privacy for a group of users during the use of location-based services (LBSs). We assume a group of users who want to benefit from a LBS and find the nearest meeting place that minimizes their aggregate distance. Each user in this scenario wants to protect his or her location from the LBS, outside attackers, and other group members. We show that individual solutions for location privacy cannot be directly applied to the group location privacy problem and a special solution must be developed. We identify the privacy issues for this group scenario and propose a resource-aware solution in order to satisfy these group privacy issues. Our solution is based on secure multiparty computation and the anonymous veto network protocol. The proposed protocol decreases the number of group queries to a large extent, as it only sends a single query to the LBS. Consequently, the LBS overhead to evaluate the query and the size of the LBS result are significantly decreased. The proposed protocol also protects the LBS from the excessive disclosure of points of interest and the LBS provider only needs to apply an existing private nearest neighbor (NN) query algorithm instead of an aggregate NN query algorithm. The performance and security analysis show that the protocol is secure against a partial collusion attack and a denialof-service attack in a malicious model.
Open Access
Privacy-preserving protocols for aggregate location queries via homomorphic encryption and multiparty computation
(2019-07) Eryonucu, Cihan
Two main goals of the businesses are to serve their customers better and in the meantime, increase their pro t. One of the ways that businesses can improve their services is using location information of their customers (e.g., positioning their facilities with an objective to minimize the average distance of their customers to their closest facilities). However, without the customer's location data, it is impossible for businesses to achieve such goals. Luckily, in today's world, large amounts of location data is collected by service providers such as telecommunication operators or mobile apps such as Swarm. Service providers are willing to share their data with businesses, doing this will violate the privacy of their customers. Here, we propose two new privacy-preserving schemes for businesses to utilize location data of their customers that is collected by location-based service providers (LBSPs). We utilize lattice based homomorphic encryption and multiparty computation for our new schemes and then we compare them with our existing scheme which is based on partial homomorphic encryption. In our protocols, we hide customer lists of businesses from LBSPs, locations of the customers from the businesses, and query result from LBSPs. In such a setting, we let the businesses send location-based queries to the LBSPs. In addition, we make the query result only available to the businesses and hide them from the LBSPs. We evaluate our proposed schemes to show that they are practical. We then compare our three protocols, discussing each one's advantages and disadvantages and give use cases for all protocols. Our proposed schemes allow data sharing in a private manner and create the foundation for the future complex queries.
Open Access
Random delay techniques for location privacy in VANETs
(2013) Albakır Çatal, Satiye
Vehicular ad hoc network (VANET) is an emerging new communication technology which has attracted a lot of research attention from academic community and industry. It is promising technology to provide safer and efficient traffic conditions. This is realized by letting vehicles to exchange safety messages. This messaging increases the awareness of vehicles about their neighboring vehicles positions and warns drivers about dangerous situations. However, availability of such information facilitates the tracking of vehicles. So, this information must be protected against the potential misuse. In this thesis, we address the problem of achieving location privacy in VANETs with randomly changing identifiers (i.e. pseudonyms) in the presence of a global passive adversary. We suggest adding a random delay to message broadcast period after the vehicle update its pseudonym in mix zones. By this way, we want to mitigate the linkability between pseudonyms. This could help to make tracking more difficult and increase safety and confidence of drivers using VANET. Instead of adding delay to safety messages completely random, one step taken further and delay is added according to the silent vehicle number in mix zone. We also investigated the effects of different number of mix-zone placements in the network to the location privacy of users. Several simulations have been performed to evaluate the performance of the systems. The results of experiments show that adding delay to message broadcast period improves location privacy of drivers in VANET and also provide information about the relationship between the strength of the adversary and the level of privacy achieved by changing pseudonyms.