<p>The Internet of Things (IoT) has brought tremendous novelties, offering advanced solutions and enhancing modern life through its different services and processing capabilities. However, the increasing number and heterogeneous nature of IoT devices have made network management a complex task, which is further complicated by significant security and trust challenges. In order to tackle these challenges, the intrinsic programmability and centralized management of Software-Defined Networking (SDN) present a compelling basis for simplifying network control, facilitating abstraction, and fostering the advancement of IoT networks. Concurrently, blockchain technology offers decentralized trust, immutability, and transparency, positioning it as an excellent adjunct to SDN in mitigating security issues associated with IoT. This paper provides a new mechanism that integrates SDN, blockchain, and artificial intelligence, to achieve a secure and trusted environment for IoT. The proposed solution allows robust access control, validation of data transactions, trusted device management, and anomaly detection using the strengths of each technology in dealing with growing threats in IoT ecosystems. Unlike existing SDN-Blockchain-IoT models, which often focus on static configurations or partial integrations, our system achieves full automation and real-time enforcement through smart contract–SDN coordination. In this paper, we specifically focus on the integration of SDN and blockchain, evaluating their impact on enhancing the security of IoT environments.</p>