Architected Nanomaterials Powering Optical Physical Unclonable Functions

Global threats from counterfeiting and hardware security breaches demand advanced anti-counterfeiting technologies. Physical unclonable functions (PUFs) provide a promising hardware-security primitive by leveraging intrinsic randomness for unique identification. Optical PUFs (OPUFs) are especially advantageous due to their non-contact operation and high encoding capacity. Recently, the performance of OPUFs has been transformed by architected nanomaterials, including engineered nanostructures, stochastic textures, and composites, which use unique optical properties to generate complex, unclonable signatures. This review comprehensively surveys the landscape of OPUFs based on these materials, focusing on fabrication strategies, operating principles, performance metrics, and applications from secure labeling to information encryption. We critically analyze how different material architectures enable sophisticated optical encoding and enhance security entropy, environmental robustness, and practical readout. Finally, we discuss key challenges, including scalability, long-term stability, and standardization, and outline future research directions for developing next-generation, high-security authentication solutions based on these advanced materials.