Multilevel and Flexible Physical Unclonable Functions for High‐End Leather Products or Packaging

Abstract Counterfeit and substandard high‐end leather products have inflicted substantial economic damage worldwide and have tarnished the reputation of the leather industry as a whole. Due to the limited security level, current anti‐counterfeiting measures are often vulnerable to attacks. Physically unclonable function (PUF) is regarded as the pinnacle of protection against counterfeiting. Leather, with a distinctive micro‐nano porous structure and random creasing patterns, serves as an ideal substrate for optical PUF. Here, a flexible and durable leather‐based optical PUF device is introduced that incorporates leather and fluorescent perovskite quantum dots. The fluorescence intensity distributed along the texture of leather offers parametric support for challenge‐response pairs. Combined with a self‐defined fluorescence pattern, the hierarchical authentication of optical PUF is realized. In conclusion, this innovation offers a desired opportunity for achieving high‐security anti‐counterfeiting and information traceability.