A Novel Protocol for Two-Tiered Sensor Networks for Preserving Privacy and Integrity

In many wireless sensor network applications, a Sink needs to collect all the data that are sensed by the sensors which are located at different places. Since, sensors are memory limited readings from sensor nodes are aggregated at intermediate nodes to reduce the communication cost. In this paper we are making use of two-tiered sensor network architecture, where storage nodes serve as an intermediate tier between sensors and a sink for storing data and processing queries. It has been widely adopted because of the benefits of power and storage saving for sensors as well as the efficiency of query processing. In this paper, we propose SafeQ, a protocol that helps to protect the data which is moving between sensor nodes to Data storage or Data storage to Sink or Sink to Data storage and Sink to user. It prevents attackers from gaining information from both sensor collected data and sink issued queries. SafeQ also allows a sink to detect the corrupted file if it is modified. To preserve privacy, SafeQ uses a novel technique to encrypt both data and queries such that a storage node can correctly process encrypted queries over encrypted data without knowing their values. To preserve integrity, a hash message authentication code (HMAC) is generated at the Data storage for verifying the integrity of the query result. So that sink can use this information to verify whether the result of a query contains exactly the data items that satisfy the query.