Query authentication and data confidentiality in wireless sensor networks

Abstract: In this thesis we consider different aspects of security in sensor networks, in particular query authentication and confidential data aggregation. Authenticating the queries is important so attackers cannot modify existing queries because this would lead to wrong readings; or insert new queries into the network because this would lead to waste of energy. When answering to queries, in-network aggregation in sensor networks is an efficient way to save energy. Nevertheless, node capture in hostile environments require protocols for data aggregation where the intermediate nodes contribute with their own values to the aggregated data without getting access to it.Our contributions are two protocols for query authentication and confidential data aggregation together with a common layered key distribution scheme. Both static and mobile base stations are supported. The proposed protocols use symmetric cryptography, which is preferred in sensor networks because of the sensor’s limited computational power, energy supply and memory storage. The results from our simulations show that, if an attacker captures a small number of nodes, the attacker can only introduce unauthorized queries into a limited part of the network and can only get access to a small part of the data that is aggregated into the network.