Embedding Security Keys in Memory... Professor Jong-Ho Lee's Team at SNU ECE Develops World’s First NAND Flash-Based “Concealable PUF” Technology - Introduces a next-generation hardware security solution with both high security and spatial efficiency - Expected to be applied to electronic device security in smartphones, vehicles, IoT, and more - Research published in Nature Communications, a leading international journal ▲ Professor Jongho Lee (left) and researcher Seongho Park (right) from the Department of ECE, SNU The College of Engineering at Seoul National University announced that Professor Jong-Ho Lee's team from the Department of Electrical and Computer Engineering has developed a novel hardware security technology based on commercial 3D NAND flash memory (V-NAND flash memory). The technology, named “Concealable Physical Unclonable Function (Concealable PUF)”, preserves the core strengths of traditional PUFs—namely unclonability and randomness—while introducing a groundbreaking feature: the ability to conceal the security key and reveal it only when needed. This is the first-ever implementation of such functionality using V-NAND flash memory. The results of this research were published on June 3 in Nature Communications, one of the world’s leading scientific journals. ■ Research Background With the rapid advancement of artificial intelligence and big data, the use of data is growing exponentially, bringing data security into sharp focus. As a result, stronger security technologies are required beyond traditional password-based methods. One such emerging solution is the Physically Unclonable Function (PUF). PUFs generate unique values based on minute physical variations that naturally occur during semiconductor manufacturing processes, making them virtually impossible to replicate or predict. However, conventional PUFs have primarily been implemented in laboratory-scale devices, making mass production difficult, and they have faced limitations in safely concealing security keys. ■ Research Achievements To overcome the limitations of conventional PUFs, the research team developed the Concealable PUF by leveraging a unique property of V-NAND flash memory: the Gate-Induced Drain Leakage (GIDL) mechanism used in the erase operation. By weakly applying GIDL, they intentionally amplified the variations in erase behavior across memory cells, thereby generating PUF data. This innovation is particularly significant because it allows PUF functionality to be implemented directly within widely used V-NAND flash memory—without requiring any changes to its circuits or structure. One of the most compelling advantages is the ability to expose the security key only when needed, while concealing it under user data during normal operation. This dual-mode capability maximizes both security and spatial efficiency. Notably, the memory space used for the concealed key can also serve as regular storage when the key is not in use, enabling efficient system design without wasted capacity. The team conducted experiments using commercial V-NAND flash memory, demonstrating that the generated PUF data maintained 100% accuracy and randomness under a wide range of conditions—including temperature changes from 25°C to 85°C and over 10 million repeated read cycles. They also verified the technology’s stability through more than 100 iterations of the conceal-and-restore process, with the original key restored without error each time. In simulated attacks using machine learning-based methods, the PUF data proved highly secure: prediction accuracy remained at the level of random guessing, confirming the strong security resilience of the Concealable PUF. ■ Expected Impact This breakthrough enables the creation of a highly reliable security system that can generate, store, and conceal security keys using existing commercial memory devices, without requiring any hardware modifications. As such, the technology is expected to be widely applicable across a broad range of security-critical electronic devices, including smartphones, vehicles, and Internet of Things (IoT) devices. Looking ahead, the research team plans to expand the application of Concealable PUF technology to a variety of hardware security solutions, further advancing the field of secure system design. ■ Researchers' Remarks Professor Jongho Lee, who led the study, stated, “The Concealable PUF stands out for its creativity and practicality, as it can be implemented using currently mass-produced vertical NAND flash memory technology without modification. We expect it to see widespread use in the field of information security.” Lead author Seongho Park added, “This research is particularly meaningful because it demonstrates that PUFs can be constructed using the erase operation of standard V-NAND flash memory—without altering circuit designs or structures. In particular, the concealment feature, which ensures that the security key is exposed only when needed, opens up new possibilities for PUF technology in terms of both security and space efficiency.” ■ Researcher Career Path Researcher Seongho Park is currently enrolled in the combined Master’s-Ph.D. program in the Department of Electrical and Computer Engineering at Seoul National University. In addition to improving the characteristics of V-NAND flash memory, he is actively conducting research in a range of applied areas, including neuromorphic computing and data security. ▲ Figure 1. Concealable PUF Based on V-NAND Flash Memory Using GIDL Erase. (a) Schematic illustration of the concealable PUF using V-NAND flash memory. (b) Circuit diagram of the V-NAND flash memory. (c) The GIDL erase method. ▲ Figure 2. PUF Key Generation Using GIDL Erase and Operational Mechanism of the V-NAND Flash Memory-Based PUF. (a) Threshold voltage (V_th) distribution of V-NAND flash cells after weak GIDL erase. (b) Comparison between conventional NAND flash-based PUF and the proposed method. (c) Operational mechanism of the V-NAND flash memory-based PUF. (d) Autocorrelation test results of the generated PUF key. [References] Paper Title / Journal: “Concealable physical unclonable functions using vertical NAND flash memory”, Nature Communications DOI: https://doi.org/10.1038/s41467-025-60415-y [Contact] Seongho Park, Advised by Professor Jongho Lee, Department of Electrical and Computer Engineering, Seoul National University: thomasung@snu.ac.kr Source: https://ece.snu.ac.kr/ece/news?md=v&bbsidx=56596 Translated by: Dohyung Kim, English Editor of the Department of Electrical and Computer Engineering, kimdohyung@snu.ac.kr...

On Monday, April 14, Seoul National University signed a Memorandum of Understanding (MoU) with Hyundai Engineering & Construction for collaboration on the development and commercialization of superconductor-based fusion reactor technology. The signing ceremony was held at Seoul National University’s Gwanak campus, with key figures in attendance, including SNU President Honglim Yoo and Hyundai E&C CEO Hanwoo Lee. Fusion power technology—often referred to as the “energy of dreams”—is gaining attention as a game-changer in the future energy sector. It has abundant fuel, poses low risk of explosion, and produces minimal emissions and radioactive waste, making it a safe and clean energy source capable of addressing both the explosive power demand driven by the Fourth Industrial Revolution and the goal of carbon neutrality. One of the core technologies of nuclear fusion is maintaining ultra-high-temperature plasma in a stable state for extended periods. To achieve this, a strong magnetic field generated by superconducting magnets is used to effectively confine the plasma. With recent advances in high-temperature superconducting magnet technology, the magnetic field strength inside fusion devices has more than doubled compared to previous technologies. As a result, the massive superconducting magnets used in fusion reactors—once spanning several tens of meters—are now being scaled down to just a few meters, making compact fusion reactors a reality. This breakthrough is fueling rapid growth in the field, with global private sector investments surpassing 10 trillion KRW, aiming for commercialization by the 2030s. Seoul National University is a global leader in high-temperature superconducting magnet and application research, centered around the Applied Superconductor Research Center (Director: Prof. Seungyong Han, Department of Electrical and Computer Engineering). Additionally, the university leads fusion research through the Fusion Reactor Engineering Research Center (Director: Prof. Yongseok Hwang, Department of Nuclear Engineering), which operates the VEST (Versatile Experiment Spherical Torus) device for education and research purposes. Supported by the Ministry of Science and ICT (MSIT), the High-Temperature Superconducting Magnet Technology Development Project (2022–2026, Project Director: Visiting Professor Sangjin Lee, Department of Electrical and Computer Engineering) is led by the Applied Superconductor Research Center. This large-scale national initiative involves over 200 researchers across 27 institutions in Korea and focuses on developing a wide range of core source technologies related to high-temperature superconducting magnets. The outcomes of this project are having a broad impact, including technological collaboration with Hyundai E&C in the field of fusion energy, and extending to both domestic and international superconducting applications. In July 2024, the Ministry of Science and ICT (MSIT) announced a 1.2 trillion KRW initiative titled the “Accelerated Realization Strategy for Fusion Energy”, highlighting the importance of technological innovations—such as high-temperature superconducting magnet technology—and public-private collaboration in advancing the commercialization of fusion energy. As a follow-up to this strategy, the government established the Fusion Innovation Alliance (Director: Boseon Kang, Director of KFE Center), an independent, industry-led organization aimed at laying the groundwork for private-sector growth and promoting the industrialization of fusion. Through this alliance, MSIT is also emphasizing the importance of university-industry collaboration in fusion-related research. Through this agreement, Seoul National University and Hyundai Engineering & Construction plan to closely collaborate on superconducting fusion reactor technologies, both domestically and internationally. Their cooperation will include: △ Joint research and technology development △ Business development and participation △ Human resource support and operation of mutual consultative bodies. Seoul National University will accelerate its research into core technologies in the fields of fusion and superconductivity, while Hyundai E&C, drawing on its extensive experience with various large-scale nuclear power plants including SMRs,aims to take a leading role in the construction and commercialization of fusion power plants. Together, the two institutions intend to generate strong synergy based on their unique strengths and drive innovation in future energy. Furthermore, Seoul National University recently launched the SNU Energy Initiative (SNU Energy Initiative, Chair: Professor Sungjae Kim, Department of Electrical and Computer Engineering) to comprehensively address issues across the full energy lifecycle. This new agreement with Hyundai E&C is expected to serve as a foundation for exploring new alternative solutions for future energy production together with SNU Energy Initiative. President Honglim Yoo of Seoul National University stated, “This agreement marks an important milestone in the history of superconductivity and fusion research in Korea. Through the collaboration between our two institutions, I hope our country will secure world-leading technological capabilities and contribute to strengthening national competitiveness.” Hanwoo Lee, CEO of Hyundai Engineering & Construction, remarked, “This partnership between leading academic and industrial institutions in Korea is expected to drive a new momentum for the transition to future energy. Today’s agreement is a meaningful step toward moving fusion power development from the laboratory to the construction of commercial reactors, ultimately creating real-world value.” This MoU between Seoul National University and Hyundai Engineering & Construction represents the first instance of a major Korean conglomerate formally entering the fields of fusion energy and high-temperature superconductivity, marking a significant milestone in the history of domestic research in these areas. Moreover, the agreement is especially meaningful as it lays the groundwork for rapidly securing a foothold in the global market, leveraging Korea’s world-class superconducting fusion technology at a time when international competition in this domain is intensifying. Source: https://ece.snu.ac.kr/ece/news?md=v&bbsidx=56588 Translated by: Dohyung Kim, English Editor of the Department of Electrical and Computer Engineering, kimdohyung@snu.ac.kr...

The research team of Suyeon Kim and Jongho Park from the Advanced Flexible Electronics Laboratory (AXEL), led by Professor Yongtaek Hong, was awarded the 'Distinguished Student Oral Paper' at Display Week 2025, organized by the Society for Information Display (SID). The team gave an oral presentation on the topic "Mesh-patterned silver electrode via electrohydrodynamic printing for transparent and flexible quantum-dot light-emitting diodes" at the Young Leadership Conference and the Flexible Display session. Out of the 650 papers presented at SID Display Week 2025, only 36 were selected as ‘Distinguished Papers’, and among them, just 10 papers were honored as ‘Distinguished Student Oral Papers’ and received awards. Celebrating its 63rd anniversary this year, SID (Society for Information Display) is the oldest and most prestigious international conference in the field of displays. Each year, it attracts around 8,000 participants and serves as a central platform where academia and industry come together to share and collaborate on the latest display technologies. Source: https://ece.snu.ac.kr/ece/news?md=v&bbsidx=56558 Translated by: Dohyung Kim, English Editor of the Department of Electrical and Computer Engineering, kimdohyung@snu.ac.kr...

Acting President and Deputy Prime Minister cum Minister of Education Lee Joo-ho is presenting the Geunjeong Medal to Professor Saewoong Bahk during the 44th Teacher's Day Commemoration Ceremony held at the FKI Tower in Yeouido, Seoul, on May 15, 2025. [Presidential Office Press] Source: https://n.news.naver.com/article/001/0015391097?sid=102 Translated by: Dohyung Kim, English Editor of the Department of Electrical and Computer Engineering, kimdohyung@snu.ac.kr...

Professor Jaejoon Kim, Department of Electrical and Computer Engineering, Seoul National University [Provided by the Ministry of Science and ICT. Redistribution and database storage prohibited.] (Seoul = Yonhap News) Reporter Cho Seung-han – The Ministry of Science and ICT and the National Research Foundation of Korea announced that Professor Jaejoon Kim of the Department of Electrical and Computer Engineering at Seoul National University has been selected as the May recipient of the Scientist of the Month Award. Professor Kim was recognized for his contributions in developing lightweight AI models and designing semiconductor accelerators that efficiently compute these models, thereby proposing AI-based technologies that can operate with low power consumption across various environments. Efficiency optimization of AI models—gaining attention recently due to power consumption concerns—can be divided into two approaches: software-centric model compression and hardware-centric semiconductor accelerator technologies. However, since these approaches have typically been developed independently, applying compressed models in practice has often resulted in reduced computational speed. Professor Kim conducted integrated research to develop lightweight AI techniques that take hardware characteristics into account, while simultaneously designing a dedicated semiconductor chip to efficiently support them. This technology supports AI lightweight models with “variable bit precision,” which adjusts the number of bits used in computation according to the required accuracy level or hardware resource constraints. The system uses a single accelerator circuit to handle these models, enabling efficient support for variable precision with a simpler computational unit structure than before. In addition, Professor Kim challenged the conventional belief that achieving high computational accuracy requires floating-point units—which are large in chip area and consume significant power—and demonstrated that integer arithmetic units can achieve the same level of accuracy. These research results were published in the IEEE Journal of Solid-State Circuits in June 2022 and presented at the International Conference on Learning Representations (ICLR) in May 2023. Professor Kim stated, “I will continue to focus on designing low-power integrated circuits that minimize energy consumption to contribute to the sustainable development of AI,” and added, “I expect this research to serve as a core foundational technology enabling AI computation in mobile environments where power efficiency is critical.” Professor Jaejoon Kim’s research team [Provided by the Ministry of Science and ICT. Redistribution and database storage prohibited.] Source: https://www.yna.co.kr/view/AKR20250430062200017?input=1195m Translated by: Dohyung Kim, English Editor of the Department of Electrical and Computer Engineering, kimdohyung@snu.ac.kr...

Seoul National University's (SNU’s) College of Engineering, Department of Electrical and Computer Engineering (ECE, President Yongtaek Hong) achieved great honor by winning numerous awards, including the Special Award in the university division, at the 30th Samsung Humantech Paper Award. The event was hosted by Samsung Electronics and co-sponsored by the Ministry of Science & ICT, and Joongang Ilbo. ECE laboratories of professors Kyunghan Lee, Wooyoung Choi, Jongseon Roh, Jaejoon Kim, Wooseok Choi, Jinho Lee, and Jaehyouk Choi, received a total of 10 awards, including two gold awards. This achievement led them to be honored with the "Special Award for Most Awards in the University Division" and Professor Kyunghan Lee of SNU ECE also received the Special Award for Most Supervised Paper Submissions. Unlike individual awards that are presented individual recipients for their outstanding achievements, special awards are given to universities, high schools, and supervising professors who have demonstrated excellence in their performance. In the university division, Seoul National University received gold awards (with a prize of 20 million won each) in three out of the ten individual award categories. Among these three gold awards, two were awarded to students from the ECE department. In the field of Communication and Networks, student Jongyun Lee (Advisor: Professor Kyunghan Lee, Co Authors: Dr. Jeongmin Bae, Student Jaeyoon Hwang) was honored with the gold award for his paper on a learning-based congestion control technique designed to adapt in real-time to previously unseen network environments. In the area of Devices and Processes, student Jiseong Im (Advisor: Professor Wooyoung Choi, Co Authors: Students Jangseng Kim, Jonghyun Ko, Jeonghyun Kim) was honored with the gold award for his paper on the implementation of a high-density and highly efficient three-dimensional AND-type fully parallel convolutional block. Additionally, ECE students Seongjun Park (Advisor: Professor Jongseon Roh) and Jonghyun Go (Advisor: Professor Jaejoon Kim) were awarded silver medals, while Jihee Kim, Wooseung Nam, Shinik Park, Jongseok Park, Jungwook Hong, and Hongsun Jang received honorable mentions. The Humantech Paper Award was established in the year 1994 with the aim of identifying scientists and researchers who are to lead science and technology of the 21st century, among domestic and international university/graduate students and high school students. This year marks the 30th edition of the award, with a total of 1,189 papers submitted and 115 selected as award-winning papers. Seoul National University's ECE department has consistently produced numerous award winners at the Samsung Humantech Paper Award over the past years. The following table shows the detailed information of the awards received. Author Type Field of Research Advisor Department Jongyun Lee Gold Communication & Networks Kyunghan Lee ECE Department Jiseong Im Gold Physical Devices & Processes Wooyoung Choi ECE Department Seongjun Park Silver Communication & Networks Jongseon Roh ECE Department Jonghyun Go Silver Physical Devices & Processes Jaejoon Kim ECE Department Jihee Kim Honorable Mentions Circuit Design Wooseok Choi ECE Department Wooseung Nam Honorable Mentions Communication & Networks Kyunghan Lee ECE Department Shinik Park Honorable Mentions Communication & Networks Kyunghan Lee ECE Department Jongseok Park Honorable Mentions Computer Science & Engineering Kyunghan Lee ECE Department Jungwook Hong Honorable Mentions Computer Science & Engineering Jinho Lee ECE Department Hongsun Jang Honorable Mentions Computer Science & Engineering Jinho Lee ECE Department *Yoohwan Shin Silver Circuit Design Jaehyouk Choi ECE Department *Seheon Jang Bronze Circuit Design Jaehyouk Choi ECE Department *Students from universities other than SNU. Image from the Awarding Event (Video Link : https://www.youtube.com/watch?v=DkmYzcMfoP4&t=25s ) Source: https://ece.snu.ac.kr/ece/news?md=v&bbsidx=55423 Translated by: Jiyong Yoo, English Editor of the Department of Electrical and Computer Engineering, cyoo7@snu.ac.kr ...

Seoul National University (SNU) held the 2023 spring (78th) Electrical and Computer Engineering (ECE) department graduation ceremony on the 26th of February, year 2024, conferring degrees upon 107 bachelor's, 23 master's, and 62 doctoral students. At the event, degrees were awarded to representatives and awards for outstanding graduate theses were presented, along with certificates of excellence to the top graduates. Professor Jinyoung Choi delivered a message of congratulations and encouragement for the bright future of the graduates. As part of this event, a video was created using photos from the graduates' school lives, allowing them to cherish memories of their university lives. Source: https://ece.snu.ac.kr/ece/news?md=v&bbsidx=55372 Translated by: Jiyong Yoo, English Editor of the Department of Electrical and Computer Engineering, cyoo7@snu.ac.kr...

Development of RIS Technology Compatible with Commercial Satellite Frequencies Installable on Skyscrapers without the Assistance of Additional Equipment Based on Transparent Materials, Performance has been Verified by Attaching to a Moving Vehicle [Edaily Reporter Hyunah Kim] We still have to wait at least 5 years for the commercialization of 6G where satellites become base transceiver stations, but technology that enables 5G operation at satellite frequencies has been recently developed and gaining attention. This technology is expected to maintain connectivity in various environments, including skyscrapers above 60-stories high, KTX trains cruising over the speed of 300km/h, and Urban Air Mobility (UAM, Small aircrafts used in urban areas, anticipated to become a new revolution in transportation). KT(CEO: Youngshub Kim), along with the Seoul National University (SNU) Department of Electrical and Computer Engineering (ECE) research team announced last 27th that they have developed Reconfigurable Intelligent Surface (RIS) technology that operates at 5G wireless communication frequency bands (3.5GHz) and KT Skylife satellite frequency bands (12GHz). This technology was unveiled by KT at the MWC 2024. Usage on Outer Walls of Skyscrapers RIS technology induces the reflection and transmission of electromagnetic waves in desired directions. For example, if we attach RIS to the outer walls of skyscrapers, it enables the transmission of high frequency waves into the building, making it possible for receiving & transmitting such signals without exposing wireless communication equipment outside of the building. Such technology can help the construction of network infrastructures more efficiently. The RIS technology developed by KT and the research team of SNU ECE Department’s professor Jungsuek Oh, transmits not only 6G candidate frequencies, but also 5G wireless communication frequencies and KT Skylife satellite frequencies, through a small surface area. Until now, KT has been developing RIS materials and technologies that operate in the mmWave frequency bands (28GHz) and 6G candidate frequency bands (8GHz, 15GHz). On the other hand, the commercialization of RIS technology for 5G communication seemed to be more challenging, since it required samples with larger surface area, due to the relatively lower frequencies of the 5G frequency bands. However, the newly developed RIS simultaneously obtained a wide transmission angle of over 90 degrees (negative refraction angle) and a high transmission rate by utilizing novel structures and surface engineering technologies. The wide transmission angle helps in improving the quality of indoor wireless transmission. Also, due to the transparency of the RIS material, it can be easily installed by attaching it to a vehicle’s window or manufacturing it as an all-in-one structure. Performance Testing on Car Windows In order to verify the versatility of their RIS technology, the KT and SNU research team attached the RIS to a vehicle window moving on a freeway. They observed that signals directed perpendicular to the vehicle’s moving direction, such as 5G waves from communication towers of the outskirts of the freeway or KT Skylife satellite signals, were refracted into the vehicle. KT will continue to collaborate with equipment manufacturers, material & component companies to apply this RIS technology to building & vehicle windows. In addition, it plans to continuously explore key technologies applicable to various wireless network environments such as RIS to secure technological leadership in the field of 6G wireless communication. Professor Jungsuek Oh from the ECE department of SNU stated, "While most research and demonstrations on conventional transparent RIS have focused mainly on improving penetration loss, our RIS technology and validation have demonstrated for the first time that even under constraints of transparent materials and processing conditions, radio waves can be refracted in arbitrary directions, significantly improving communication coverage." Executive Director Jongsik Lee of KT Network Research Institute stated, "We anticipate that this RIS technology will enhance wireless service quality within moving vehicles. We aim to strengthen our leadership in new wireless communication technologies and contribute to the establishment of 6G networks." Researchers from KT R&D center(Seoul, Seocho-gu) and SNU are testing the performance of their RIS technology (Picture from KT) Source: https://www.edaily.co.kr/news/read?newsId=02020486638794784&mediaCodeNo=257&OutLnkChk=Y Translated by: Jiyong Yoo, English Editor of the Department of Electrical and Computer Engineering, cyoo7@snu.ac.kr...