Laser‐Induced Graphene‐Based Dual‐Functional Optical PUFs for Hierarchical Authentication

ABSTRACT As manufacturing precision continues to advance, the demand for reliable anticounterfeiting technology grows, highlighting the importance of hardware keys based on physically unclonable functions (PUFs). However, the commercial deployment of many existing PUFs remains limited by process complexity and high cost. In this study, we propose an optical PUF based on laser‐induced graphene (LIG), fabricated solely through a simple and cost‐effective direct laser patterning process. We demonstrate that the binary key extracted from scattered light through LIG's random micro‐nanostructures can be utilized as a PUF. Additionally, we propose a dual‐functional PUF device capable of simultaneously performing identification and encryption functions by patterning the LIG with a QR code via direct laser writing. This device utilizes identifier metadata to provide a hierarchical authentication process, enabling faster authentication. Finally, we show that PDMS encapsulation preserves the optical PUF response under harsh environmental conditions, providing robustness against external contamination and even water‐jetting.