The Internet of Things (IoT) is a breakthrough that empowers our everyday life. It allows real-time data analytics, improves industrial production, or provides tailored services. IoT networks deploy many small devices that are energy-constrained. Furthermore, IoT networks and applications lack efficient security. Several attacks occurred against IoT networks due to insufficient security in the past years. However, when security solutions are integrated into IoT networks, they drastically increase the energy consumption of those networks, thus, reducing their lifetime. A major question arises: is it possible to find trade-offs between ensuring security and the energy consumption of security? In this paper, we present a summary of the work done during the thesis, which is the guideline for the corresponding presentation.