A security authentication technology that cannot be replicated, similar to butterfly wing structures, has been developed. It is expected to be applicable to QR codes or ID cards for consumer goods, pharmaceuticals, and electronics.
The Gwangju Institute of Science and Technology (GIST) announced on the 22nd that a joint research team led by Professor Jeong Hyun-ho from the Department of Electrical, Electronic and Computer Engineering and Professor Song Young-min from the Korea Advanced Institute of Science and Technology (KAIST) has developed a "nano-optical technology inspired by nature."
Existing QR codes and barcodes are easy to replicate and assign unique information to each product. To address this, a "physically unreplicable function" is used. This involves attaching a unique authentication key to a product by utilizing randomness that occurs during the manufacturing process. However, there are limitations in that adjusting the surface color is difficult and it is easily noticeable.
The research team focused on structural colors seen in butterfly wings, bird feathers, and seaweed leaves. Structural color is that which is displayed by the microstructure of an object rather than pigments. Structural color exists in a state between order and disorder. While it appears uniform on the surface, a close inspection reveals a random internal structure that cannot be replicated.
The research team thinly deposited a dielectric on a metal mirror. They assembled gold particles on top to create a plasmonic metasurface with a quasi-ordered structure. The plasmonic metasurface is an ultra-thin optical structure designed to precisely arrange metal structures on the nanoscale onto a flat surface, allowing for free manipulation of light. To the naked eye, the reflective color appears consistent, but under a high-magnification optical microscope, different random scattering patterns, or optical fingerprints, are revealed in different areas.
These random patterns created with nanostructures can be used for devices. The research team noted, "Even if a hacker attempts to manufacture the device, the time it takes to hack is longer than the age of the Earth, making replication virtually impossible." Professor Jeong Hyun-ho stated, "We have reproduced an optical information that cannot be replicated by recreating the natural structure where order and disorder coexist using nanotechnology." The research findings were published in the international journal Nature Communications on the 8th.
References
Nature Communications (2025) : https://www.nature.com/articles/s41467-025-61570-y