Energy-efficient and secure implementations for the IoT

The IoT or Internet of Things is defined by, for example, the Internet Engineering Task Force (IETF) as the network of physical objects or “things” embedded with electronics, software, sensors, and connectivity to enable objects to exchange data with the manufacturer, operator and/or other connected devices. Since the creation of the concept in 1999, the IoT has gained a lot of popularity, and, it is still increasingly used in various environments. This is also the reason for the numerous challenges that characterise the IoT. This dissertation focuses on three important challenges to provide IoT security: heterogeneity, performance, and foremost energy-efficiency. The IoT is a heterogeneous environment due to the variety of devices, network architectures and wireless communication technologies that are used. Furthermore, these IoT devices typically have to adhere to performance requirements while they have limited storage and computation capabilities due to the fact that they are battery-powered.

The contribution of this dissertation is four-fold. The first contribution consists of providing end-to-end security in a heterogeneous environment. For this purpose, the use of object security is analysed and applied in a proof-of-concept system. The second contribution is the analysis and optimisation of using coupons in constrained devices. This technique reduces the computation cost of generating digital signatures. The third contribution is the in-depth analysis of the energy consumption of security algorithms in terms of both computation and communication cost. This energy-security analysis is used to define an approach on how to optimise the duration of security sessions to reduce the energy impact of a session-based security protocol. Finally, the fourth contribution is a healthcare use case, providing end-to-end security using a public-key approach on the one hand and a symmetric-key approach on the other hand.

In summary, this dissertation describes the research outcomes of the in-depth and practical study of the aforementioned security techniques to provide energy-efficient, performance-aware end-to-end security in a heterogeneous IoT environment.