A Korean research team has developed a security technology that verifies the authenticity of products by using unique patterns created as nanoparticles arrange themselves at random. It can be checked with only a smartphone flashlight or a laser pointer, without expensive specialized equipment.
Professor Kim Sang-wook's team in the department of materials science and engineering at KAIST said on the 26th that, jointly with Professor Kwon Seok-jun's team at Sungkyunkwan University, it developed a physical unclonable function (PUF) technology that uses a "colloid nano pattern." The results were published online in July in the international journal Nature Communications.
PUF is a security technology that uses the different physical properties that arise by chance in each product or device as a kind of "fingerprint." It takes advantage of the fact that even when using the same materials and processes, it is difficult to reproduce microscopic structures exactly the same.
The researchers caused particles hundreds of nm (nanometers, one-billionth of a meter) in size to self-assemble on water to create a different arrangement each time. When ordinary light was shined on the nano structures formed in this way, different colors and reflection patterns appeared depending on the particle arrangement. When a laser was fired, the light spread in multiple directions, creating another unique pattern.
The researchers implemented a method that verifies authenticity by separately registering the two types of optical patterns and then comparing them with the results observed on actual products. They noted that to counterfeit this, one would have to reproduce not only the nano structures but also the patterns that appear under ordinary light and laser, increasing the difficulty of duplication.
Meanwhile, they also broadened the scope of application. The researchers succeeded in transferring the nano structures onto the surfaces of various materials such as plastic and metal, transparent film, and hydrogel.
Professor Kim Sang-wook said, "The key to this study is that while creating random structures that are hard to replicate, it also makes it easy to verify authenticity with simple tools like a flashlight or a laser pointer," adding, "We expect it to evolve into next-generation security technology that can be readily used in everyday life, such as electronic device authentication and anti-counterfeiting labels."
References
Nature Communications (2026), DOI: https://doi.org/10.1038/s41467-026-75781-4