SDBlock-IoT: A Blockchain-Enabled Software-Defined Multicontroller Architecture to Safeguard OpenFlow Tables

Integrating Software-Defined Networking (SDN) with the Internet of Things (IoT) simplifies the management of IoT devices; however, it introduces security challenges. Adversaries may manipulate forwarding rules to redirect communication, compromising user security. Additionally, the centralized nature of SDN-enabled IoT networks poses a single point of failure during master controller failure. To address these issues, we present SDBlock-IoT, a distributed SDN architecture based on blockchain technology. This ensures increased resiliency in the event of master controller failure. Our proposed model considers response time and resource utilization of equal controllers, ensuring the most suitable controller assumes the role of master controller. We enhance the integrity of OpenFlow forwarding rules through the Smart Agent and SC, which validate whether a flow is registered on the blockchain or not. The Smart Agent verifies forwarding rules for every new flow request. We conducted experiments on hardware SDN switches using a Ryu OpenFlow controller and a private blockchain, demonstrating the effectiveness of our approach. Evaluation results indicate that SDBlock-IoT outperforms existing solutions in terms of flow verification time, controller recovery time, CPU utilization, and transaction costs.