Quantum-resistant pairing evaluation for resource-constrained bluetooth classic

Abstract

The security of state-of-the-art Bluetooth pairing relies on Elliptic Curve Diffie-Hellman (ECDH), which is vulnerable to quantum attacks. However, the feasibility of integrating standardized Post-Quantum Cryptographic (PQC) primitives into the controller-level Bluetooth Classic (BC) protocol stack remains an open question. This paper presents the first comprehensive evaluation of integrating a post-quantum secure key exchange for BC pairing. We analyze the impact of replacing the existing ECDH-based key establishment with NIST-standardized PQC Key Encapsulation Mechanisms (KEMs), focusing on protocol-level packetization, over-the-air transmission overhead, and execution performance in constrained hardware. Using BC’s Link Manager Protocol (LMP) and DM1 packet structure, we quantify Public Parameter Transmission (PPT) latency for classical and post-quantum schemes. We further benchmark ECDH and ML-KEM implementations on an ARM Cortex-M4 microcontroller with characteristics comparable to those of constrained Bluetooth controllers. Our results show that ML-KEM is computationally feasible on such hardware, often matching or outperforming classical ECDH in execution time. However, PQC significantly increases over-the-air overhead. Under ML-KEM, PPT accounts for 60-75% of total key exchange latency, compared to less than 10% for ECDH. Code-based schemes such as HQC are shown to be impractical due to excessive memory and transmission requirements under provided hardware constraints. These findings indicate that the primary obstacle to post-quantum Bluetooth pairing is not computation but wireless packetization, reliability, and energy consumption; facilitating a safe and efficient quantum-secure migration of resource-constrained wireless communication settings.