Blockchain-Enabled SDN for Securing Fog-Based Resource-Constrained IoT

Software-Defined Network (SDN) is vital in simplifying the dynamic network characteristics and device management. However, the centralized architecture of SDN opens the scope for malicious attacks on the controllers. To mitigate such attacks in real-time, we propose an SDN architecture for resource-constrained devices in a fog-enabled IoT environment using a private blockchain (pBC) network. We exploit the decentralized nature of pBC for enabling resource-constrained SDN controllers towards transparently setting flow rules for fog nodes and other devices in the network. In case the miners identify faulty flow rules, pBC allows the SDN devices/fog nodes to retract back to an earlier flow rule while raising a flag against the alleged controller. Additionally, since data in pBC are accessible by all the candidates having the same genesis file, they are readily available to malicious users. Towards this, we further propose encrypting the data before inserting them into the blocks, which helps in securing the data from undesired users. Through the extensive deployment of our proposed fusion, we observe CPU usage of 30% among the devices and latencies in the range of milliseconds, which presents the feasibility of our system with minimum delay. We also observe a reduction in energy consumption by more than 90%, compared to traditional SDN.