The Polymer Society of Korea

Abstract

As hacking and counterfeiting advance, the limits of traditional cryptographic methods are becoming evident. Physical Unclonable Functions (PUFs), which use physical randomness to generate unique device responses, offer a promising alternative. Optical PUFs provide high entropy and low replicability, making them suitable for secure applications. However, conventional optical PUFs rely on static structures, producing only one fixed response. This limits encoding capacity and reduces consistency under mechanical deformation.
We present a Si-polymer-based optical PUF that generates varied responses via wrinkle-crack patterns formed under tensile strain. A SiOx layer created by ultraviolet ozone treatment induces random wrinkles due to elastic mismatch. These structures produce direction and strength-dependent patterns and maintain high reproducibility after repeated deformation. This approach offers a flexible and reliable platform for future hardware security systems.