Abstract Physically Unclonable Functions (PUFs) offer a promising solution for Internet of Things (IoT) security, yet most optical PUFs are limited to rigid binary authentication. To address this, a novel optical PUF based on chaotic polarization patterns from self‐assembled Diethyl 2,5‐dihydroxoterephthalate (DDT) crystals grown on flexible, large‐area MoS 2 films is introduced. By harnessing the unique polarized photoluminescence (PL) from the random crystal domains, a tri‐modal authentication scheme is demonstrated that provides enhanced security resolution. From the polarized PL images, a 1024‐bit key is extracted and analyzed. The system yields three statistically distinct and clearly separable Hamming distance distributions: intra‐HD (0.0157 ± 0.0061), mutual‐HD (0.2540 ± 0.0229), and inter‐HD (0.4986 ± 0.0149). This tri‐modal verification goes beyond a simple accept/reject decision, offering a more nuanced and robust authentication framework. The PUF exhibits excellent randomness, passing NIST statistical test. The practicality of this approach is further showcased through a proof‐of‐concept smartphone application. This work establishes a new paradigm for flexible, high‐security optical PUFs, holding significant promise for next‐generation IoT and authentication applications.
Abstract Physically Unclonable Functions (PUFs) offer a promising solution for Internet of Things (IoT) security, yet most optical PUFs are limited to rigid binary authentication. To address this, a novel optical PUF based on chaotic polarization patterns from self‐assembled Diethyl 2,5‐dihydroxoterephthalate (DDT) crystals grown on flexible, large‐area MoS 2 films is introduced. By harnessing the unique polarized photoluminescence (PL) from the random crystal domains, a tri‐modal authentication scheme is demonstrated that provides enhanced security resolution. From the polarized PL images, a 1024‐bit key is extracted and analyzed. The system yields three statistically distinct and clearly separable Hamming distance distributions: intra‐HD (0.0157 ± 0.0061), mutual‐HD (0.2540 ± 0.0229), and inter‐HD (0.4986 ± 0.0149). This tri‐modal verification goes beyond a simple accept/reject decision, offering a more nuanced and robust authentication framework. The PUF exhibits excellent randomness, passing NIST statistical test. The practicality of this approach is further showcased through a proof‐of‐concept smartphone application. This work establishes a new paradigm for flexible, high‐security optical PUFs, holding significant promise for next‐generation IoT and authentication applications.
Physical unclonable functions (PUFs) have attracted interest in demonstrating authentication and cryptographic processes for Internet of Things (IoT) devices. We demonstrated four-dimensional PUFs (4D PUFs) to realize time-varying chaotic phosphorescent randomness on MoS 2 atomic seeds. By forming hybrid states involving more than one emitter with distinct lifetimes in 4D PUFs, irregular lifetime distribution throughout patterns functions as a time-varying disorder that is impossible to replicate. Moreover, we established a bit extraction process incorporating multiple 64 bit-stream challenges and experimentally obtained physical features of 4D PUFs, producing countless random 896 bit-stream responses. Furthermore, the weak and strong PUF models were conceptualized and demonstrated based on 4D PUFs, exhibiting superior cryptological performances, including randomness, uniqueness, degree of freedom, and independent bit ratio. Finally, the data encryption and decryption in pictures were performed by a single 4D PUF. Therefore, 4D PUFs could enhance the counterfeiting deterrent of existing optical PUFs and be used as an anticounterfeiting security strategy for advanced authentication and cryptographic processes of IoT devices.
Optical physical unclonable functions (PUFs) have emerged as a promising cryptographic primitive for next-generation security. However, to harmonize with various modern networks, conventional optical PUF is inadequate due to a rigid key space with a fixed specification. This study implements hierarchically controllable randomness sources for multi-level key generation, exploiting speckle characteristics. By adjusting illumination diameter, the speckle size can be modulated, allowing the extraction of three-level keys with various lengths: 64, 256, and 1,024 bits. Performance evaluation reveals that all levels are superb in uniformity, uniqueness, reproducibility, and randomness. Moreover, it is proposed two feasible applications. The first is a hierarchical authentication architecture that spans from Internet of Things (IoT) devices to sensitive information, balancing security and resources. The second is a multi-stage image encryption algorithm, exhibiting holocryptic performance superior to conventional XOR-based encryption. This versatile platform sets a new paradigm for optical PUF, establishing a foundation for robust and expandable next-generation security.
The rapid expansion of the Internet of Things (IoT) has significantly raised concerns over secure identification and authentication of IoT devices. While physical unclonable function (PUF)-based anticounterfeiting cryptography shows promise, implementing multi-factor authentication (MFA) system with resource-constrained PUF device remains a significant challenge. Here, we demonstrate a multidimensional-encoded optical PUF fabricated with multi-color quantum dots (mQDs), resilient to machine learning attacks, for use in anticounterfeiting MFA. Randomly distributed mQDs in a periodic nanostructure fabricated via nanoimprint lithography generate spatially chaotic, unpredictable multiple security keys when ultraviolet (UV) light is only illuminated. Photoluminescence measurements revealed irregular mQD emission, where disordered distribution-induced Förster resonant energy transfer produces unpredictable color patterns. Our PUF-induced multiple keys were validated through advanced PUF metrics like uniformity, uniqueness, correlation factor, entropy, and even resilience to machine learning attack. We further demonstrate efficient implementation of a cryptography protocol with MFA system for IoT applications using mQDs-based optical PUFs. Material systems with physical unclonable functions (PUF) are needed for secure authentication. Here, a multidimensional-encoded optical PUF fabricated with multi-color quantum dots is demonstrated, for multi-factor authentication.
The increasing security threat is a serious challenge to the internet of things (IoT). Hardware‐based security primitive is an essential and powerful way to protect IoT devices from various attacks. But most of the current security hardwares are based on macrophysical features, which are usually produced by reproducible deterministic processes and can be copied by counterfeiters. Herein, a physical unclonable function (PUF) with high robustness based on the intrinsic random micro‐/nanostructures of the electronic packages is proposed thereby demonstrating a low‐cost and label‐free hardware security solution for IoT. Using the unique surface micropattern and the spatially coded laser scattering, the proposed PUFs can be used as anticounterfeiting labels, authentication tokens and cryptographic key generators. With the help of the proposed PUFs, the safety protection is still effective even when the attacker is able to get access to the database because the secret keys are inherently hidden in the complex microscopic stochastic physical features of the PUFs but not the database. The proposed package‐enabled PUFs provide a promising and practical physical protection solution for IoT security.
The increased prevalence of the Internet of Things (IoT) and the integration of digital technology into our daily lives have given rise to heightened security risks and the need for more robust security measures. In response to these challenges, physical unclonable functions (PUFs) have emerged as promising solution, offering a highly secure method to generate unpredictable and unique random digital values by leveraging inherent physical characteristics. However, traditional PUFs implementations often require complex hardware and circuitry, which can add to the cost and complexity of the system. We present a novel approach using a random wrinkles PUF (rw-PUF) based on an optically anisotropic, facile, simple, and cost-effective material. These wrinkles contain randomly oriented liquid crystal molecules, resulting in a two-dimensional retardation map corresponding to a complex birefringence pattern. Additionally, our proposed technique allows for customization based on specific requirements using a spatial light modulator, enabling fast fabrication. The random wrinkles PUF has the capability to store multiple data sets within a single PUF without the need for physical alterations. Furthermore, we introduce a concept called 'polyhedron authentication,' which utilizes three-dimensional information storage in a voxelated random wrinkles PUF. This approach demonstrates the feasibility of implementing high-level security technology by leveraging the unique properties of the rw-PUF.
With the rapid expansion of digital communication and the Internet of Things (IoT), hardware-level security and anti-counterfeiting technologies have become increasingly important. Traditional cryptographic systems depend on mathematically generated keys, which are vulnerable to duplication and physical attacks. In contrast, Physical Unclonable Functions (PUFs) utilize inherent physical randomness to produce unique, unpredictable responses, offering a hardware root of trust for secure authentication. Among various PUF implementations, optical PUFs (O-PUFs) have attracted attention due to their high entropy density, non-contact readout, and immunity to electromagnetic interference. These systems exploit light–matter interactions, such as scattering, reflection, and emission to generate random optical fingerprints. In recent years, photoluminescent (PL) materials have emerged as promising candidates for constructing material-based optical PUFs. Their intrinsic emission randomness, strong optical signals, and tunable luminescence enable secure encoding without complex nanofabrication. Materials such as perovskite quantum dots and lanthanide-based metal–organic frameworks (MOFs) combine high photoluminescence efficiency, environmental stability, and low-cost processability, making them ideal for scalable optical authentication applications. This thesis explores the development and performance evaluation of photoluminescent based PUFs for optical security and anti-counterfeiting. Three types of luminescent materials, namely perovskite quantum dots, lanthanide-based MOFs, and intermolecular charge-transfer (CT) complexes are qualitatively analyzed as potential optical PUF platforms. A particular focus is placed on the statistical evaluation of Terbium-based MOFs (Tb-MOFs) and CT complexes. For Tb-MOFs, two entropy sources are examined: the spatial distribution of MOF microstructures and the randomness in PL intensity. Similarly, CT complexes are evaluated based on their disordered geometric topology. Standardized image processing, including optical imaging, grayscale conversion, and binarization, is employed to extract PUF features. Quantitative metrics such as uniqueness, reliability, and encoding capacity are analyzed. The results demonstrate that both Tb-MOF and CT-based systems achieve high encoding capacity and stable reproducibility within a sub-millimeter scale. This study validates the feasibility of luminescent materials as robust optical PUFs and provides a foundation for scalable, photostable, and intelligent optical authentication systems