PU-QKD: Enhancing Authentication of Quantum Key Distribution via Physical Unclonable Function

The rapid advances in quantum computing pressure the existing essential cryptographic algorithms. In this context, Quantum Key Distribution (QKD) has been proposed as a quantum safe solution for key distribution. However, current QKD systems require an authenticated classical channel which relies on pre-shared symmetric keys that are manually distributed and do not guarantee the identity of the hardware that hosts them. This paper proposes a novel scheme, the Physically Unclonable Quantum Key Distribution (PU-QKD) system, to intrinsically authenticate the communicating endpoints in QKD. The PU-QKD scheme leverages classical Physical Unclonable Functions (PUFs) to encode the data transmission in discrete variable QKD protocols (e.g., BB84). Our scheme maintains the information-theoretic security of QKD protocols by integrating the PUF as an additional layer. Authentication is bound to hardware, providing a robust fingerprint, while lower post-processing overhead increases key rates. Additionally, the proposed scheme is resilient against state-of-the-art PUF vulnerabilities, such as modeling attacks.