A Blockchain-based security model for SDNs

The basic idea of Software Defined Networks (SDNs) is to centralize the control plane and make it programmable using generic APIs. In SDNs, the network intelligence resides within the controller which is considered as the heart of the entire network. The network principles are programmed as controller applications by the administrator using the generic APIs at the North Bound. Though SDNs improve the programmability of the network, the centralized control and flexibility are offered at the cost of security vulnerabilities at various surfaces in the SDN stack. Fortunately, the programmable control plane allows enforcing a sophisticated security policy that can be easily customized for securing the network. Many research studies reveal that the major threat in SDNs is the single point of failure. Any failure in the controller will impact the overall functionality of the network due to which compromising the controller has become the primary target of attackers. Hence, the security of the controller plays a crucial role in the success of SDNs. Besides securing the controller, the overall security of the network is equally important. In this paper, the authors proposed a security model based on Blockchain technology for ensuring consistency among instances of the SDN controller with enhanced security. The said security model is proposed considering the operational flow of the OpenDaylight (ODL) controller as a case study, but can be implemented with any SDN controller.