Securing NATted IoT Devices Using Ethereum Blockchain and Distributed TURN Servers

Peer-to-Peer (P2P) networking is a decentralized network topology that enables parties to communicate directly without central servers. The main obstacle preventing the heavy deployment of the P2P topology is the Network Address Translation (NAT) which serves as a solution for the exhaustion of IPv4 addresses. Methods proposed by the Internet Engineering Task Force (IETF) to solve the NAT traversal issues include Simple Traversal of UDP through NATs (STUN) and Traversal Using Relay NAT (TURN). STUN is limited by the type of deployed NAT, and TURN is limited by the peers' discovery mechanism which is application dependent. In this paper we propose a Blockchain-based platform that enables TURN servers to act as relays for Internet of Things (IoT) devices behind NAT. It also provides End-to-End (e2e) security for Constrained and Non-Constrained IoT devices. Results showed that the system has minimal impact on the existing network and can be a potential solution for advancing IoT deployment.