Qian Chen

Authenticating location-based services without compromising location privacy

The popularity of mobile social networking services (mSNSs) is propelling more and more businesses, especially those in retailing and marketing, into mobile and location-based forms. To address the trust issue, the service providers are expected to deliver their location-based services in an authenticatable manner, so that the correctness of the service results can be verified by the client. However, existing works on query authentication cannot preserve the privacy of the data being queried, which are sensitive user locations when it comes to location-based services and mSNSs. In this paper, we address this challenging problem by proposing a comprehensive solution that preserves unconditional location privacy when authenticating range queries. Three authentication schemes for

Authenticating top-k queries in location-based services with confidentiality

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VERDICT: Privacy-preserving authentication of range queries in location-based services

-tree and grid-file index, together with two optimization techniques, are developed. Cost models, security analysis, and experimental results consistently show the effectiveness, reliability and robustness of the proposed schemes under various system settings and query workloads.

Structure-Preserving Subgraph Query Services

State-of-the-art location-based services (LBSs) involve data owners, requesting clients, and service providers. As LBSs become new business opportunities, there is an increasing necessity to verify the genuineness of service results. Unfortunately, while traditional query authentication techniques can address this issue, they fail to protect the confidentiality of data, which is sensitive location information when LBSs are concerned. Recent work has studied how to preserve such location privacy in query authentication. However, the prior work is limited to range queries, where private values only appear on one side of the range comparison. In this paper, we address the more challenging authentication problem on top-k queries, where private values appear on both sides of a comparison. To start with, we propose two novel cryptographic building blocks, followed by a comprehensive design of authentication schemes for top-k queries based on R-tree and Power Diagram indexes. Optimizations, security analysis, and experimental results consistently show the effectiveness and robustness of the proposed schemes under various system settings and query workloads.

Authenticated Online Data Integration Services

We demonstrate VERDICT, a location-based range query service featuring the privacy-preserving authentication capability. VERDICT adopts the common data-as-a-service (DaaS) model, which consists of the data owner (a location registry or a mobile operator) who provides the querying data, the service provider who executes the query, and the querying users. The system features a privacy-preserving query authentication module that enables the user to verify the correctness of results while still protecting the data privacy. This feature is crucial in many location-based services where the querying data are user locations. To achieve this, VERDICT employs an MR-tree based privacy-preserving authentication scheme proposed in our earlier work [3]. The use case study shows that VERDICT provides efficient and smooth user experience for authenticating location-based range queries.

Authenticating Aggregate Queries over Set-Valued Data with Confidentiality

A fundamental problem of graph databases is subgraph isomorphism query (a.k.a subgraph query): given a query graph

Assuring Spatio-Temporal Integrity on Mobile Devices with Minimum Location Disclosure

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Structure-preserving subgraph query services

and a graph database, it retrieves the graphs

Method and apparatus for authenticating location-based services without compromising location privacy

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Authenticating Aggregate Queries over Set-Valued Data with Confidentiality (Extended Abstract)

s from the database that contain