POS4-0174
Multilevel Optical PUF in Color-Programmable Microparticle Monolayers
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
JINMIN LEE (POSTECH)
Co-Author(s)
Abstract
Optical physically unclonable functions (Optical PUFs) generate device-specific challenge–response pairs (CRPs) by converting irreproducible optical patterns into digital keys for authentication. However, many polymer-based Optical PUF platforms rely on highly disordered structures and/or nontrivial readout pipelines, which can obscure systematic, quantitative benchmarking and scalable key design. Here, we present a quantifiable multilevel Optical PUF based on dye-embedded polystyrene (PS) microparticle monolayers. Fluorescent dyes were embedded in PS microparticles using a solvent-swelling/locking approach, which serves as a dye-embedding route. The microparticles were then assembled into near-monolayer patterns via an interface-assisted method, enabling robust confocal readout with reduced depth-related intensity artifacts. The resulting patterns were converted into digital keys using an image-based encoding workflow that leverages three information axes (spatial position, color, and intensity) while accounting for particle–pixel overlap. PUF performance was quantitatively evaluated using entropy and intra/inter Hamming distance metrics, demonstrating that richer structural information in the encoding step increases entropy and improves reproducibility and uniqueness. Overall, this platform provides a modular, engineering-friendly approach to Optical PUFs with mathematically explicit evaluation and an expandable multilevel design space.
