Quantum dot physically unclonable functions (QD-PUFs) provide a promising solution to the issue of counterfeiting. When quantum dots are deposited on a surface to create a token, they form a unique pattern that is unlikely to ever be reproduced in another token that is manufactured using the same process. It would also be an extreme engineering challenge to deterministically place quantum dots to create a forgery of a specific device. The degradation of the optical response of quantum dots over time, however, places a limitation on their practical usefulness. Here we report methods to minimise the degradation of photoluminescence (PL) from InP/ZnS quantum dots suspended in a polymer and demonstrate reliable authentication using a fingerprinting technique to extract a signature from PL, even after significant degradation has occurred. Using these techniques, it was found that the addition of a polylauryl methacrylate (PLMA) copolymer improved the longevity of devices. The best performing example of this was the Polystyrene-PLMA based material. From this, it is projected that 1000 bits of information could be extracted and read after a period of years, therefore providing a compelling solution to the issue of counterfeiting.
Quantum dot physically unclonable functions (QD-PUFs) provide a promising solution to the issue of counterfeiting. When quantum dots are deposited on a surface to create a token, they form a unique pattern that is unlikely to ever be reproduced in another token that is manufactured using the same process. It would also be an extreme engineering challenge to deterministically place quantum dots to create a forgery of a specific device. The degradation of the optical response of quantum dots over time, however, places a limitation on their practical usefulness. Here we report methods to minimise the degradation of photoluminescence (PL) from InP/ZnS quantum dots suspended in a polymer and demonstrate reliable authentication using a fingerprinting technique to extract a signature from PL, even after significant degradation has occurred. Using these techniques, it was found that the addition of a polylauryl methacrylate (PLMA) copolymer improved the longevity of devices. The best performing example of this was the Polystyrene-PLMA based material. From this, it is projected that 1000 bits of information could be extracted and read after a period of years, therefore providing a compelling solution to the issue of counterfeiting.
Unique identification of optical devices is important for anti-counterfeiting. Physical unclonable functions (PUFs), which use random physical characteristics for authentication, are advantageous over existing optical solutions, such as holograms, due to the inherent asymmetry in their fabrication and reproduction complexity. However, whilst unique, PUFs are potentially vulnerable to replication and simulation. Here we introduce an additional benefit of a small modification to an established model of nanoparticle PUFs by using a second measurement parameter to verify their authenticity. A randomly deposited array of quantum dots is encapsulated in a transparent polymer, forming a tag. Photoluminescence is measured as a function of excitation power to assess uniqueness as well as the intrinsic nonlinear response of the quantum material. This captures a fingerprint, which is non-trivial to clone or simulate. To demonstrate this concept practically, we show that these tags can be read using an unmodified smartphone, with its built-in flash for excitation. This development over constellation-style optical PUFs paves the way for more secure, facile authentication of devices without requiring complex fabrication or characterisation techniques.
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
Quantum dots (QDs) have garnered significant attention for their unique size-dependent optical and electronic properties, enabling their widespread use in applications ranging from high-efficiency photovoltaics and light-emitting diodes to biomedical imaging and quantum computing. Their tunable emission, high photo-stability, and ease of surface modification make them ideal candidates for precision nanotechnology applications. In this work, we explore a novel and rapidly emerging application of QDs in hardware security through the development of Quantum Dot-based Physical Unclonable Functions (QD-PUFs). Unlike conventional security paradigms, QD-PUFs leverage the intrinsic physical randomness of QD-based nanostructures to generate challenge-response pairs with superior uniqueness, reliability, and robustness. We review the integration of QDs into PUFs, beginning with their material properties and extending to entropy sources arising from synthesis and fabrication, surface and encapsulation effects. A comparative analysis of different readout mechanisms and related applications underscores the unique encoding capacity and security potential of QD-based systems. By demonstrating their feasibility for scalable, high-security applications, this study underscores the transformative impact of QDs in next-generation authentication and anti-counterfeiting technologies.
Ensuring secure authentication is a critical challenge in modern security applications. This study presents a novel approach utilizing the photoluminescence (PL) characteristics of non-toxic quantum dots (QDs) to generate unique optical fingerprints. PL measurements capture emission properties, which are processed through computational algorithms to extract distinct security identifiers. The results demonstrate that this method offers highly distinctive and reproducible optical signatures for authentication and anti-counterfeiting applications. By integrating experimental and computational techniques, this approach enhances precision and security. Future work will focus on optimizing stability and scalability for real-world deployment in secure authentication systems.
Abstract A physical unclonable function (PUF) device leverages manufacturing randomness to generate a unique fingerprint for secure authentication, encryption, and counterfeit prevention. Optical PUFs (OPUFs) have gained prominence due to their strong security, light‐based challenge‐response mechanisms, and potential for quantum‐secure encryption. These devices have promising applications for hardware security, authentication, cryptographic key generation, and anti‐counterfeiting measures across multiple industries. This review enlightens the diverse material platforms used for OPUFs, ranging from fiber optics and liquid crystals to advanced semiconductor nanocrystals and plasmonic metasurfaces, each offering distinct optical characteristics that impact security strength. While no single material system dominates the field, hybrid and multi‐model approaches integrating low‐dimensional materials are being explored to enhance reliability and scalability. Finally, the challenges and future perspectives are outlined, including adaptive OPUFs architectures, utilizing artificial intelligence (AI) for challenge‐response generation, and their integration into quantum communication networks, highlighting how next‐generation semiconductor materials can further advance OPUFs technologies.
The unrelenting advancement of modern technology has inadvertently allowed the production of counterfeit components to become increasingly cheaper and easier, undermining the trust of everyday interactions and communications. An emerging solution to this problem is the use of physically unclonable functions1 (PUFs) - physical devices with random characteristics locked into their structure at the point of fabrication. The application of a stimulus to these constructions results in a hard-to-predict response due to the interaction with the complex microstructure of the device. This response is then used as a 'fingerprint' that can be used for a given application. Among others, these include low-cost device identification and authentication, secure key generation and the binding of software to hardware platforms. However, traditional PUFs have various setbacks: they suffer from not being truly unclonable, are susceptible to sophisticated attacks and bear a risk of emulation and simulation. Here we show that quantum physics lends itself to the provision of unique identities in the form of fluctuations in measurements of resonant tunnelling diodes (RTDs) containing various nanostructures. An example of which is a quantum dot, shown in Fig. 1. This provides an uncomplicated measure of identity, without conventional resource limitations or vulnerabilities. The quantum tunnelling spectrum also shown in Fig. 1 is sensitive to the atomic structure within the RTD, with each device providing extreme uniqueness that is presently impossible to clone or simulate. This new class of authentication device, coined the quantum unclonable function (QUF)2, operate with the fewest resources in simple electronic structures operating above 300 K.