Revisiting silk: a lens-free optical physical unclonable function

• Published in: Nature communications Vol. 13; no. 1; p. 247
• Main Authors: Kim, Min Seok, Lee, Gil Ju, Leem, Jung Woo, Choi, Seungho, Kim, Young L., Song, Young Min
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-01-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1075/401; 639/624/399; Coherent light; Cryptography; Data encryption; Humanities and Social Sciences; Lenses; Light sources; Low cost; Microfibers; multidisciplinary; Optical properties; Science; Science (multidisciplinary); Security; Silk; Stochasticity; Textiles
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-27278-5

For modern security, devices, individuals, and communications require unprecedentedly unique identifiers and cryptographic keys. One emerging method for guaranteeing digital security is to take advantage of a physical unclonable function. Surprisingly, native silk, which has been commonly utilized in everyday life as textiles, can be applied as a unique tag material, thereby removing the necessary apparatus for optical physical unclonable functions, such as an objective lens or a coherent light source. Randomly distributed fibers in silk generate spatially chaotic diffractions, forming self-focused spots on the millimeter scale. The silk-based physical unclonable function has a self-focusing, low-cost, and eco-friendly feature without relying on pre-/post-process for security tag creation. Using these properties, we implement a lens-free, optical, and portable physical unclonable function with silk identification cards and study its characteristics and reliability in a systemic manner. We further demonstrate the feasibility of the physical unclonable functions in two modes: authentication and data encryption.
Although conventional optical physical unclonable functions (PUFs) are attractive for security applications, existing optical PUFs have inherent complexity. Here, the authors report a low-cost, lens-free and compact optical PUF that uses silk microfiber-based stochastic diffraction.