I. Introduction
The exponential growth of Internet of Things (IoT) presents substantial sustainability challenges, as traditional power solutions like power grids or batteries are not scalable to accommodate the deployment of a vast number of devices over extensive areas. To fulfill these sustainability needs, energy harvesting emerges as a promising solution [1], [2]. It empowers wireless devices by scavenging energy from the environment, such as solar, RF energy, and biothermal energy, allowing nodes to operate semi-perpetually without battery replacements [3], [4]. In this work, we consider the sustainable IoT network where nodes harvest ambient RF energy. Although the energy harvesting feature can greatly enhance the sustainability and scalability of IoT network [5]–[7], it arises a unique security challenge known as malicious energy attack (MEA) [8].