The security of internet of things (IoT) devices remains a major concern. These devices are very vulnerable because of some of their particularities (limited in both their memory and computing power, and available energy) that make it impossible to implement traditional security mechanisms. Consequently, researchers are looking for new security mechanisms adapted to these devices and the networks of which they are part. One of the most promising new approaches is fingerprinting, which aims to identify a given device by associating it with a unique signature built from its unique intrinsic characteristics, i.e., inherent imperfections, introduced by the manufacturing processes of its hardware. However, according to state-of-the-art studies, the main challenge that fingerprinting faces is the nonrelevance of the fingerprinting features extracted from hardware imperfections. Since these hardware imperfections can reflect on the RF signal for a wireless communicating device, in this study, we aim to investigate whether or not the power spectral density (PSD) of a device’s RF signal could be a relevant feature for its fingerprinting, knowing that a relevant fingerprinting feature should remain stable regardless of the environmental conditions, over time and under influence of any other parameters. Through experiments, we were able to identify limits and possibilities of power spectral density (PSD) as a fingerprinting feature.

This paper addresses the design and the characterization of a battery-free Bluetooth Low Energy (BLE) wireless sensor node powered by radiative wireless power transfer. The battery-free sensors node, as part of a wireless meshed network, is optimized and is able to perform physical measurements (temperature and humidity) and share these measured data over the Internet through the wireless network. It operates by using a standard capacitor of 220 µF as a storage element and is remotely powered by a dedicated RF source using a radiative wireless power transfer. The main task initialization, sensing and broadcasting the measured data by using a BLE protocol requires only 1.2 mJ of energy per task. More the periodicity of physical measurements can be roughly controlled by controlling the radiated power of the RF source.