{"id":201324,"date":"2025-07-25T07:46:14","date_gmt":"2025-07-24T22:46:14","guid":{"rendered":"http:\/\/ee.presscat.kr\/?post_type=research-achieve&p=201324"},"modified":"2026-04-13T03:00:57","modified_gmt":"2026-04-12T18:00:57","slug":"professor-young-min-songs-team-develops-unclonable-optical-fingerprint-security-technology-inspired-by-natures-structural-colors","status":"publish","type":"research-achieve","link":"http:\/\/ee.presscat.kr\/en\/research-achieve\/professor-young-min-songs-team-develops-unclonable-optical-fingerprint-security-technology-inspired-by-natures-structural-colors\/","title":{"rendered":"Professor Young Min Song\u2019s Team Develops Unclonable Optical\u2011Fingerprint Security Technology Inspired by Nature\u2019s Structural Colors"},"content":{"rendered":"
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< (From left) Young Min Song, Professor, KAIST School of Electrical Engineering and Hyeon\u2011Ho Jeong, Professor, GIST School of EECS ><\/span><\/figcaption><\/figure>\n

Our department\u2019s Professor Young\u202fMin\u202fSong, in collaboration with Professor Hyeon\u2011Ho\u202fJeong\u2019s research team at GIST School of EECS, has developed a replication\u2011impossible security authentication technology based on nature\u2011inspired nanophotonic structures.\u00a0<\/span><\/p>\n

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This technology can be easily embedded into physical products such as ID cards or QR codes and, being visually indistinguishable from existing items, provides strong tamper\u2011proof protection without compromising design. It holds broad potential for applications requiring genuine\u2011product authentication, including premium consumer goods, pharmaceuticals, and electronics.<\/span><\/p>\n

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Until now, anti\u2011tampering measures like QR codes and barcodes have been limited by their ease of replication and the difficulty of assigning truly unique identifiers to each item. A recently spotlighted solution is the physically unclonable function (PUF)*, which leverages the natural randomness arising during manufacturing to grant each device a unique physical signature, thereby enhancing security and authentication reliability.<\/span><\/p>\n

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However, existing PUF technologies, while achieving randomness and uniqueness, have struggled with color consistency control and are easily identified (and thus attacked) from the outside.<\/span>\u00a0* Physically Unclonable Function (PUF): A technique that uses physical variations formed during the manufacturing process to generate a unique authentication key. Because these variations are inherently random and unclonable, even if the authentication data is stolen, constructing the exact hardware for authentication is effectively impossible.<\/span><\/span><\/p>\n

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In response, the research team turned its attention to the unique phenomenon of structural color* observed in natural organisms. For example, the wings of butterflies, feathers of birds, and leaves of seaweed all contain nanoscale microstructures arranged in a form of quasiorder*\u2014a pattern that is neither completely ordered nor entirely random. These structures appear to exhibit uniform coloration to the naked eye, but internally contain subtle randomness that enables survival functions such as camouflage, communication, and predator evasion.<\/span><\/p>\n

\u00a0* Quasi\u2011order: A structural arrangement that is neither fully ordered nor fully disordered. In nature, nano\u2011scale elements are arranged in a pattern that blends order with randomness\u2014found, for example, in butterfly wings, seaweed leaves, and bird feathers\u2014producing uniform color at a macroscopic scale while embedding unique optical features.<\/span><\/span><\/p>\n

* Structural Color: Color produced not by pigments but by nano\u2011meter\u2011scale structures that interact with light, commonly seen in living organisms. Classic examples include the iridescent wings of butterflies and the feathers of peacocks.<\/span><\/p>\n

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The researchers drew inspiration from these natural phenomena. They deposited a thin dielectric layer of HfO\u2082 onto a metallic mirror and then used electrostatic self\u2011assembly to arrange gold nanoparticles (tens of nanometers in size) into a quasi\u2011ordered plasmonic metasurface*. Visually, this nanostructure exhibits a uniform reflection color; under a high\u2011magnification optical microscope, however, each region reveals a distinct random scattering pattern\u2014an \u201coptical fingerprint*\u201d\u2014that is impossible to replicate. * Plasmonic Metasurface: An ultrathin optical structure comprising precisely arranged metallic nano\u2011elements that exploit surface plasmon resonance to locally enhance electromagnetic fields, enabling far more compact and precise light\u2013matter interaction than conventional optics.\u00a0<\/span><\/span>* Optical Fingerprint: A unique pattern of reflection, scattering, and interference produced when light interacts with a micro\u2011 or nano\u2011scale structure. Because these patterns arise from random structural variations that cannot be exactly duplicated, they serve as a practically unclonable security feature.<\/span><\/p>\n

The team confirmed that leveraging these nano\u2011scale stochastic patterns enhances PUF performance compared to conventional approaches.<\/span><\/div>\n

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In a hypothetical hacking scenario where an attacker attempts to recreate the device, the time required to decrypt the optical fingerprint would exceed the age of the Earth, rendering replication virtually impossible. Through demonstration experiments on pharmaceuticals, semiconductors, and QR codes, the researchers validated the technology\u2019s practical industrial applicability.<\/span><\/p>\n

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Analysis of over 500 generated PUF keys showed an average bit\u2011value distribution of 0.501, which is remarkably close to the ideal balance of 0.5, and an average inter\u2011key Hamming distance of 0.494, demonstrating high uniqueness and reliability. Additionally, the scattering patterns remained stable under various environmental stresses, including high temperature, high humidity, and friction, confirming excellent durability.<\/span><\/p>\n

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Professor Young\u202fMin\u202fSong emphasized, \u201cWhereas conventional security labels can be deformed by even minor damage, our technology secures both structural stability and unclonability. In particular, by separating visible color information from the invisible unique\u2011key information, it offers a new paradigm in security authentication.\u201d<\/span><\/p>\n

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Professor Hyeon\u2011Ho\u202fJeong added, \u201cBy reproducing structures in which order and disorder coexist in nature through nanotechnology, we have created optical information that appears identical externally yet is fundamentally unclonable. This technology can serve as a powerful anti\u2011counterfeiting measure across diverse fields, from premium consumer goods to pharmaceutical authentication and even national security.\u201d<\/span><\/p>\n

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This work, guided by Professor Young\u202fMin\u202fSong (KAIST School of Electrical Engineering) and Professor Hyeon\u2011Ho\u202fJeong (GIST School of EECS), and carried out by Gyurin\u202fKim, Doeun\u202fKim, JuHyeong\u202fLee, Juhwan\u202fKim, and Se\u2011Yeon\u202fHeo, was supported by the Ministry of Science and ICT and the National Research Foundation\u2019s Early\u2011Career Research Program, the Regional Innovation Mega Project in R&D Special Zones, and the GIST\u2011MIT AI International Collaboration Project.\u00a0<\/span><\/p>\n

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The results were published online on July\u202f8,\u202f2025, in the international journal Nature Communications.<\/span><\/p>\n

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* Paper title: Quasi\u2011ordered plasmonic metasurfaces with unclonable stochastic scattering for secure authentication<\/span><\/p>\n

* DOI:\u00a0<\/span>https:\/\/doi.org\/10.1038\/s41467-025-61570-y<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

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