  Wireless Sensor Networks (WSNs) provide sensing and monitoring services by
means of many tiny autonomous devices equipped with wireless radio
transceivers. As WSNs are deployed on a large-scale and/or on long-term basis,
not only traditional security but also privacy issues must be taken into
account. Furthermore, when network operators offer on-demand access to sensor
measurements to their clients, query mechanisms should ideally leak neither
client interests nor query patterns. In this paper, we present a
privacy-preserving WSN query mechanism that uses standard cryptographic
techniques. Besides preventing unauthorized entities from accessing sensor
readings, it minimizes leakage of (potentially sensitive) information about
users' query targets and patterns.
