Query privacy in wireless sensor networks

Existing mechanisms for querying wireless sensor networks leak client interests to the servers performing the queries. The leaks are not only in terms of specific regions but also of client access patterns. In this paper we introduce the problem of preserving the privacy of clients querying a wireless sensor network owned by untrusted organizations. We investigate two architectures and their corresponding trust models. For the first model, consisting of multiple, mutually distrusting servers governing the network, we devise an efficient protocol, SPYC, and show that it provides full query privacy. For the second model, where all queries are performed through a single server, we introduce two metrics for quantifying the privacy achieved by a client´s query sequence. We propose a suite of practical algorithms, then analyze the privacy and efficiency levels they provide. Our TOSSIM simulations show that the proposed query mechanisms are communication efficient while significantly improving client query privacy levels.