On August 18th, a joint research team led by Professor Yoo Ho-cheon from the Department of Electronic Engineering at Hanyang University and Professor Park Byul-lee from Sungkyunkwan University has announced the development of PA-PUF(Photoacoustic Physically Unclonable Function)—a device that generates unique cryptographic keys by converting light into sound.

A PUF(physically unclonable function) is a hardware security technology that creates a unique cryptographic key by utilizing the microscopic irregularities naturally formed during the material, structural, and manufacturing processes as a digital fingerprint. Even with identical manufacturing processes, exactly replicating the structure is impossible, making physical duplication infeasible. Thus, PUFs are gaining attention as core technology for anti-counterfeiting and authentication systems. However, existing electronic PUFs have limitations—including complexity in manufacturing processes due to electrode-based signal extraction, scalability challenges, and vulnerability to AI-based machine-learning attacks.

Here, the PA-PUF which the research team developed overcomes these challenges using the photoacoustic effect. The device works by converting the ultrasonic signals generated within a random nanocomposite—composed of visible-light-absorbing CuO nanoparticles and SnO₂ nanoparticles serving as a dispersive matrix—into cryptographic keys. Unique signals can be extracted without electrodes or circuit patterns, allowing for attachment to curved, flexible substrates and even skin.

The team stimulated the composite with nanosecond laser pulses to generate random photoacoustic signals, which were then converted into a 250×250 bit cryptographic matrix. Security performance essential for secured key generation—including bit uniformity, device-to-device Hamming distance, and entropy—reached ideal values across measurements of 10 devices. Furthermore, the device demonstrated strong resistance to AI-based inference attacks such as logistic regression, support vector machines(SVMs), and CNN. Moreover, it continued to operate reliably, maintaining over 95% similarity even when attached to the back of a hand under temperature changes, movement, bending, and environmental noise.

Professor Yoo said,“This study is the first case of implementing a flexible and wearable next-generation security platform using a physical path that converts light into sound, and holds great potential to be extended to various fields such as wearable authentication and Internet of Things (IoT) security.”

This 유탑 토토사이트 was supported by the Ministry of Science and ICT and ICT Broadcasting Innovation Talent Cultivation Project (AI Semiconductor Advanced Talent Training) of the IITP(Institute of Information & Communications Technology Planning & Evaluation). The results were published online in August 2025 in the international journal Nature Communications(IF=15.7) under the title 'Light in, sound keys out: photoacoustic PUFs from stochastic nanocomposites.' Dr. Park Tae-hyun of Hanyang University is the first author, with Professor Yoo Ho-cheon (Hanyang University) and Professor Park Byul-ri (Sungkyunkwan University) as corresponding authors.