Performance Evaluation of Security Solutions for Wireless Sensor Networks

In the recent years, wireless communication is involving not only computers, but a multitude of heterogeneous devices. Wireless Sensor Networks (WSNs) contribute to the new paradigm of pervasive computing, and this translates into new requirements for new applications. WSNs are employed not only on their own, but also in Cooperating Objects Systems (COSs), where mobile physical agents share the same environment to fulfill their tasks, either in group or in isolation. Sensor nodes are typically resource constrained devices deployed in unattended, possibly hostile environments. WSNs and COSs are a tempting target for an adversary, since a security infringement may easily translate into a safety one, with possible consequences in terms of damages to things and injures to people. Main security requirements for WSNs are secure communication, key management and secure bootstrapping. Security usually involves resource greedy operations, while sensors are resource constrained devices. This means that security requirements must be satisfied assuring a lightweight impact in terms of memory occupancy, network performance and energy consumption. In this thesis work, we start from a performance evaluation of the security sublayer of the IEEE 802.15.4 standard in terms of memory occupancy, network performance and energy consumption. Then, present and evaluate a solution to a vulnerability of the IEEE 802.15.4 standard that causes a selective Denial of Service attack. Finally, we present PLASA: a modular and reconfigurable security architecture for WSNs. PLASA extends the STaR architecture. STaR is a secure communication module we designed to provide confidentiality and/or authenticity of communications in a trans- parent and flexible manner. PLASA enhances STaR, introducing modules for key management and secure bootstrapping, so providing a complete system that is suitable not only for the WSN, but for the entire COS.