Quantum-aware secure blockchain intrusion detection system for industrial IoT networks.

The Industrial Internet of Things (IIoT) integrates sensors, actuators, controllers, and gateways across critical industrial sectors such as manufacturing, energy, oil and gas, and transportation. The convergence of operational technology (OT) and Information Technology (IT) has enabled real-time automation, predictive maintenance, and large-scale process optimization. However, IIoT infrastructures are increasingly exposed to sophisticated cyberattacks, ranging from ransomware and Advanced Persistent Threats (APTs) to false data injection and denial-of-service (DoS) campaigns. Moreover, the emergence of quantum computing introduces an additional dimension of vulnerability, since widely deployed public-key cryptographic schemes such as RSA and elliptic-curve cryptography (ECC) will be rendered insecure under Shor's algorithm, while Grover's algorithm accelerates brute-force search against symmetric ciphers. In anticipation of this threat, the security of IIoT must evolve toward post-quantum resilience. This paper proposes a Quantum-Aware Secure Blockchain Intrusion Detection System (QASB-IDS), a novel hybrid framework that combines intrusion detection with post-quantum blockchain security and quantum key distribution (QKD). The system introduces a hierarchical consortium blockchain tailored to IIoT, ensuring tamper-proof and decentralized storage of intrusion detection alerts and anomaly model updates. The IDS employs a lightweight hybrid signature-anomaly detection approach that extracts features from IIoT traffic and classifies them using a CNN-LSTM model optimized for constrained devices using Edge-IIoTset, SWaT, and XIIoTID datasets. Model updates are securely aggregated with privacy guarantees and anchored on blockchain using lattice-based post-quantum signatures. Critical gateways additionally deploy QKD to protect session key distribution. Evaluation using recent industrial intrusion datasets demonstrates that QASB-IDS provides improved detection accuracy, low false alarms, and strong resilience against both classical and quantum-capable adversaries.