Challenge‐Routed Reconfiguration in Multidimensional Black Phosphorus Physical Unclonable Functions for Replay‐Resistant Hardware Authentication

ABSTRACT

Physical unclonable functions (PUFs) provide hardware‐level authentication by converting uncontrollable physical variations into device‐specific challenge‐response pairs. However, conventional PUFs often rely on fixed responses, making exposed responses vulnerable to reuse and replay, while expansion of the challenge space may require additional devices or increased readout complexity. Here, roll‐printed black phosphorus (BP) is introduced as a self‐active multimodal entropy source that intrinsically combines infrared emission, electrical conduction, and strong in‐plane anisotropy. Random variations in layered position, thickness, orientation, overlap, and connectivity generate spatial, spectral, orientation, and percolation disorder. Four polarization‐resolved photoluminescence (PL) intensities and the PL full width at half maximum (FWHM) form a 125‐bit optical authentication response pool, while the electrical PUF provides conductance‐rank‐based routing rules for challenge‐dependent response assembly. Across the optical response channels, the mean inter‐Hamming distance (HD) reaches 0.500 for FWHM, the mean intra‐HD reaches 0 for PL‐YY, the mean bit uniformity reaches 0.500 for PL‐XX, and the mean Shannon entropy reaches 0.985 for PL‐YX. Challenge‐routed responses exhibit a mean inter‐challenge Hamming distance of 0.472, which has been unattainable in conventional PUFs with fixed responses. Server‐issued electrical challenges generate session‐specific response arrangements, enabling replayed responses from previous sessions to be rejected and establishing replay‐resistant, multi‐session hardware authentication.