Efficient Authentication in High Security Wireless Sensor Networks

Chung, Antony and Roedig, Utz (2011) Efficient Authentication in High Security Wireless Sensor Networks. PhD thesis, Lancaster University.

Abstract

Wireless sensor networks (WSNs) promise to greatly enhance and simplify the collection of sensor data in many applications. Individually, nodes are relatively limited, with minimalist computational power, communication bandwidth and energy. Lots of effort continues to be made to manage these limitations whilst providing a powerful overall system. Unfortunately, these limitations and solutions introduce new security challenges that must be solved. This work enhances authentication in WSNs for high security scenarios. A review of available security solutions for wireless sensor networks found an over-emphasis on link-layer security. This is insufficient as attackers can easily imitate any node if a single key in the network is compromised. End-to-end security offers an improvement by allowing the sink to authenticate the source of a message as well as its integrity. The impracticality of using public key cryptography for all communication requires that different symmetric keys are shared between the sink and individual nodes. This can cause significant communication overhead in the network, unbalanced energy use and network lifetime reduction. The first contribution addresses this problem with the concept of Broadcast Key Establishment (BKE). BKE allows the sink to distribute key material using a broadcast that is used to securely generate different keys on each node. The evaluation shows that this method significantly reduces overheads, extends the life of the network and causes less disruption. The combination of wireless communication and exposed resources on nodes has resulted in new attack threats. For example, attackers can inject arbitrary messages and waste computational resources via cryptographic algorithms. The second contribution, Distance-Based Message Authentication, focuses on physical layer security to reject messages, based on distance measurement, as early as possible. Practical experiments evaluate ranging accuracy and optimisations. This work therefore improves WSN authentication by efficiently distributing keys, for end-to-end authentication, and protects resources against depletion attack.