QKD Authentication and BB84 Optimization Using QPUFs for the Quantum Internet
Quantum Key Distribution (QKD) enables information-theoretically secure key establishment based on the principles of quantum mechanics. However, practical QKD deployments require an authenticated classical channel to prevent man-in-the-middle attacks. Current implementations typically rely on pre-shared authentication keys that must be securely distributed, stored, and periodically refreshed, creating scalability challenges and potential security risks if compromised. In this work, we investigate the use of Quantum Physical Unclonable Functions (QPUFs) as a hardware-rooted trust mechanism for authentication and protocol optimization in QKD systems. Our framework integrates QPUFs with QKD to dynamically derive authentication material, achieving both information-theoretic and hardware-based security without relying on computational assumptions. We implement and validate the approach by executing tests on real IBM quantum computers. We then compare standard BB84 with a QPUF-assisted variant under realistic communication-channel noise conditions. Results show up to a 30% improvement in Secret Key Rate (SKR) at short distances by eliminating sifting overhead, while maintaining QBER comparable to standard BB84. These findings demonstrate that QPUF-assisted QKD can provide hardware-rooted authentication and IT-secure key establishment, improving performance in practical quantum devices.