Optimized Blockchain Consensus for Secure and Scalable Routing in 6G Nonterrestrial and Terrestrial IoT Networks

The convergence of nonterrestrial networks (NTNs) and terrestrial networks (TNs) in 6G presents a paradigm shift for the Internet of Things (IoT), enabling ubiquitous connectivity but introducing severe routing challenges across a dynamic, multidomain topology. Traditional blockchain-based routing frameworks often fail to adapt to the mobility, heterogeneity, and energy constraints of IoT deployments. This article proposes a Proof-of-Route (PoR) blockchain consensus protocol, augmented with Proof-of-Authority (PoA), with adaptive validator rotation for secure and scalable routing. The protocol integrates cryptographic route authentication, dynamic validator selection, and wallet-based key management. This ensures its resistance against black holes, Byzantine attacks, and Sybil attacks. Unlike prior work, our framework was evaluated under conditions that mirror real-world operational stress. Modular Docker-based containers were developed to represent devices in a 6G-IoT setting. They simulated intermittent link availability, varying latencies, node churn, and handovers. Results revealed that the proposed protocol achieved up to an average latency of 42.3 ms, a packet delivery ratio (PDR) of 98.7% with scalability verified up to over 500 nodes. This article offers a robust, scalable, and secure solution for the complex routing demands of 6G networks.