AMAKA: A Blockchain-Fortified Framework for Anonymous Mutual Authentication and Key Agreement in IoT

Abstract

The proliferation of resource-constrained Internet of Things (IoT) devices poses formidable security challenges, rendering traditional centralized authentication mechanisms impractical. To address this issue, this paper proposes AMAKA (Anonymous Mutual Authentication and Key Agreement), a novel blockchain-fortified protocol specifically designed for IoT environments. AMAKA utilizes smart contracts to establish a robust framework for device lifecycle management, including registration, updates, and revocation, enabling fine-grained access control under the authority of the equipment manufacturer. The protocol's core synergizes Schnorr signatures with noninteractive zero-knowledge proofs to deliver strong guarantees of mutual authentication, user anonymity, unlinkability, perfect forward secrecy, and conditional traceability. We formally verify AMAKA's security against a wide range of attacks by employing the ProVerif tool under an active adversary model. Furthermore, a prototype deployed on a private Ethereum network demonstrates its practical viability, confirming low on-chain overhead, minimal storage demands, and high computational efficiency. Therefore, AMAKA provides a balanced, secure, and scalable authentication solution for large-scale IoT ecosystems.