Internet of things security is a multidisciplinary research field dedicated to understanding, identifying, and mitigating security risks and vulnerabilities within the interconnected ecosystem of devices, systems, and data that constitute the Internet of Things. It investigates threats and proposes countermeasures across hardware, software, network, and platform layers, considering the unique challenges posed by device heterogeneity, scale, resource limitations, and distributed architectures, with the critical significance of ensuring the confidentiality, integrity, availability, safety, and privacy of IoT deployments across diverse applications.