Blockchain-Assisted Lightweight Authentication Protocol for Resource-Constrained IoT Devices in 5G Smart Environments
The ubiquity of lightweight resource-constrained Internet-of-Things (IoT) devices in 5G smart environments necessitates authentication protocols with the conflicting goals of being lightweight, highly secure, and having a decentralised credential management structure. Existing schemes use trusted third-party key distributors or heavyweight cryptographic primitives infeasible to IoT embedded hardware; they also fail to anchor device credentials on a permissioned blockchain ledger for tamper-evident credential revocation. In this work, we introduce BLAP-IoT: a Blockchain-Assisted Lightweight Authentication Protocol over live Hyperledger Fabric 2.5.9 that leverages elliptic-curve Diffie–Hellman over P-256 curve, keyed MACs, and a three-message challenge-response protocol to provide injective mutual authentication with device key confirmation. Device credential commitments are stored on-chain to facilitate decentralised and efficient device revocation without revealing secrets on-chain. A formal security verification of the protocol in ProVerif 2.05 shows session-key secrecy, injective mutual authentication, and perfect forward secrecy in the presence of the Dolev-Yao attacker. The empirical evaluation of BLAP-IoT on measured P-256 primitives reports that the scheme achieves a total computation cost of 0.303 ms on constrained devices — up to 52% less than compared schemes, 1920-bit two-way communication overhead, and 0.218 mJ device energy consumption. The underlying blockchain layer sustains up to 277 transactions per second (TPS) in peak throughput, with end-to-end authentication latency less than 13 ms at 1000 concurrent devices.