Optically reconfigurable physical unclonable functions based on 2D MoS₂ ring-oscillator arrays for attack-resistant hardware authentication.

Abstract

Hardware-level security is crucial for establishing trust in the rapidly expanding Internet-of-Things (IoT) and edge computing systems. A promising approach employs physical unclonable functions (PUFs) which leverage intrinsic process variations to generate unique and irreproducible identifiers. However, conventional silicon-based PUFs often suffer from limited entropy and lack of reconfigurability, becoming vulnerable to machine learning attacks. Here, we present an optically reconfigurable PUF based on a 64-cell array of five-stage ring oscillators fabricated from wafer-scale monolayer MoS₂. The system exhibits spectrally selective frequency shifts under red, green, and blue (RGB) illumination, establishing a dynamic optical entropy dimension that enables on-demand, reversible rekeying without hardware modification. We develop a robust key-generation pipeline combining within-chip normalization, random-projection q-ary quantization, and the Secure Hash Algorithm 256 (SHA-256) privacy amplification, followed by hash-based message authentication code (HMAC)-based key derivation. The resulting keys demonstrate near-ideal uniformity (~50%) and inter-device Hamming distance (~0.677 at q = 3, 39 ~ 0.761 at q = 4), while remaining resilient to advanced machine learning attacks (≤ 52% accuracy). We further demonstrate image encryption and authentication with noise-like ciphertexts and reliable tamper detection. This work introduces a promising class of material-intrinsic, optically addressable security primitives for trusted edge computing applications.