PQ-ABS: Post-Quantum Aggregate Blind Signature-Based Anonymous Authentication for Blockchain-Enabled IoMT

Blockchain-enabled Internet of Medical Things (BIoMT) systems require secure and anonymous authentication. However, existing mechanisms rely on classical cryptography, which becomes vulnerable to quantum attacks. This creates a critical need for post-quantum secure authentication that can preserve anonymity while remaining lightweight for largescale deployments. To address this gap, we propose a module-lattice based Post-Quantum Aggregate Blind Signature (PQABS) scheme that combines message blindness, signature aggregation, and Module-LWE hardness to achieve anonymous and quantum-resistant authentication. The scheme integrates with a lightweight blockchain architecture in which multiple signatures from distributed medical entities are aggregated into a single compact proof, significantly reducing verification overhead as the number of nodes increases. Formal analysis demonstrates resistance against correctness, unforgeability, blindness, unlinkability, and its resilience against quantum polynomial-time (QPT) adversaries under Module-SIS and Module-LWE assumptions. A full implementation on Hyperledger Fabric shows that, under growing network size, proposed PQ-ABS framework reduces verification latency by up to 71%, improves throughput by 62%, and maintains stable performance as the blockchain scales, confirming both its security and efficiency for real-time BIoMT environments.