Physically unclonable functions (PUFs) have emerged as a promising hardware security primitive, and recent years have seen growing interest in realizing PUFs on photonic integrated circuits (PICs). We classify existing PIC-based PUFs into electrically configured and optically encoded designs. Notably, security properties remain insufficiently analyzed, with mathematical unclonability often assumed without supporting argument. To illustrate this issue, we introduce a modeling attack against the subclass of optically encoded PUFs that operate in a linear optical regime. We show that, for a representative simulated PUF construction, observing as few as 200 challenge-response pairs allows learning the challenge-response mapping. Under canonical modeling assumptions, linear optically encoded PUFs are therefore mathematically clonable, calling for a careful assessment of their suitability for authentication protocols that rely on mathematical unclonability.
Physically unclonable functions (PUFs) have emerged as a promising hardware security primitive, and recent years have seen growing interest in realizing PUFs on photonic integrated circuits (PICs). We classify existing PIC-based PUFs into electrically configured and optically encoded designs. Notably, security properties remain insufficiently analyzed, with mathematical unclonability often assumed without supporting argument. To illustrate this issue, we introduce a modeling attack against the subclass of optically encoded PUFs that operate in a linear optical regime. We show that, for a representative simulated PUF construction, observing as few as 200 challenge-response pairs allows learning the challenge-response mapping. Under canonical modeling assumptions, linear optically encoded PUFs are therefore mathematically clonable, calling for a careful assessment of their suitability for authentication protocols that rely on mathematical unclonability.
With the accelerating expansion of connectivity, the need for advanced cyber-physical security technologies that bridge the digital and physical worlds is becoming more crucial than ever. Physically unclonable functions (PUFs) leveraging nanotechnologies and photonic technologies are emerging as practical and deployable hardware security solutions that go beyond software-based hardware security. Optics- and photonics-based PUFs (often referred to as optical PUFs) offer a range of characteristics beneficial to multiplex strategies that incorporate multilevel and multimodal approaches, based on their fundamental optical and photonic properties. PUFs are categorized as multilevel when multiple responses are generated from a single type of challenge, such as a light source or optical tool. In contrast, they are classified as multimodal when multiple responses are created from various types of challenges involving a combination of different light sources and optical tools. This review highlights recent advances and progress in integrating emerging materials, detection tools, authentication methods, imaging techniques, reconfigurability, and unclonability, which are essential for advancing next-generation multiplex PUFs. To facilitate real-world applications and to support deployment in real-world senarios, we also discuss existing limitations in multiplex optical PUFs and explore potential strategies to overcome such challenges, supporting our increasingly hyperconnected society.
Physically Unclonable Function (PUF) optical circuits are described and implemented within a Photonic Integrated Circuit (PIC) to enhance certain security properties such as device authentication, anti-tamper properties, or for use as a root-of-trust value. Optical processing is advantageous for security applications such as these since they are less susceptible to eavesdropping and side channel monitoring via the difficulty of observing electromagnetic radiation emissions during PIC operation. We employ the use of State of Output Polarization (SOP) variability arising from inherent stresses, strains and manufacturing tolerances present within a fabricated PIC. A customized optical signal processing element is used in our PUF circuit that contains a very narrow "trench" structure with tiny structural variations induced during fabrication that enhances SOP variability. The tiny structural changes in fabricated PICs are fixed resulting in repeatable SOP variation of the optical signals. To avoid a need for PUF calibration, to increase robustness with respect to input power level variation, measurement device resolution and sensitivity; we show that PUF functionality can be conveniently modeled as a discrete MultipleValued Logic (MVL) function. The proposed MVL PUF formulation avoids the need to characterize and measure exact polarization states as well as enabling the use of PUF output measurement devices that have a wide range of resolution and sensitivity specifications. Several different PUF circuits are implemented within a single fabricated PIC and are experimentally evaluated to demonstrate its efficacy.
Physical Unclonable Functions (PUFs) are hardware security primitives whose inherent physical complexity can be exploited for secure authentication and cryptographic key generation. Silicon photonic devices, owing to their suitability for quantum and artificial intelligence applications alongside standard CMOS fabrication processes, constitute a highly promising substrate for integrated multifunctional PUFs. Despite the advanced security guarantees offered by quantum cryptographic protocols and the central role of silicon photonics in quantum technologies, quantum readout strategies based on single-photon states for photonic PUFs remain largely unexplored. In this work, we experimentally demonstrate a silicon nitride (SiN) programmable photonic Mach Zehnder interferometer mesh that implements a unitary transformation and operates as a PUF, whose secret physical signature arises from uncontrollable waveguide variations during fabrication. Using experimentally derived parameters from the SiN integrated mesh, we further introduce and numerically evaluate a quantum readout protocol that combines single-photon states with PUFs. Maximally mixed quantum states are employed to conceal the underlying unitary transformation from passive eavesdropping. Security against adversaries possessing devices fabricated under similar conditions is assessed, with authentication performance quantified through Monte Carlo analysis of the false acceptance and false rejection rates as a function of the number of detected events and corrected errors. The results indicate exceptional performance with equal error rates as low as 10 to the minus 14, highlighting the potential of quantum secure PUFs for high security authentication applications.
With the increase of digital devices, the need for robust authentication mechanisms has become crucial. Traditional methods relying on cryptographic key management are susceptible to various risks, particularly the exposure of keys to interception or theft. As cyber threats evolve, the short-comings of these methods are accentuated, necessitating more secure solutions. Physically Unclonable Functions (PUFs) have emerged as a potential alternative, utilizing inherent hardware variations for device authentication without stored secrets. However, recent studies reveal vulnerabilities in conventional PUF implementations. Simultaneously, there's a growing recognition for authentication mechanisms tailored for quantum devices. This recognition has prompted the exploration of Quantum PUFs (QPUFs), which represent a promising solution to enhance security and reliability, leveraging the unique properties of quantum mechanics. In this paper, we propose a novel approach using QPUFs for device authentication that does not require any quantum communication channel or even quantum memory. We design a quantum circuit to serve as a QPUF, evaluating metrics such as instability, randomness, and uniqueness. Additionally, we devise an authentication scheme that exploits the challenge-response paradigm, taking advantage of the distinctive properties of quantum PUFs. Furthermore, we delineate a threat model to identify and mitigate potential risks associated with the authentication process. By assessing the proposed QPUFs efficacy on real real quantum hardware provided by IBM, this research contributes to the advancement of secure authentication protocols in quantum era.
As quantum technologies advance, ensuring secure authentication of quantum devices has become increasingly important. Existing methods, often relying on stored cryptographic keys, are vulnerable to physical and side-channel attacks. Quantum Physical Unclonable Functions (QPUFs) offer a promising alternative by leveraging quantum phenomena such as superposition, entanglement, and quantum noise to produce unique, unclonable responses. However, many existing QPUF designs are based on simulations or report only idealized, best-case results. This work presents and evaluates a set of QPUF circuits on IBM’s real quantum hardware, assessing their performance in terms of instability, randomness, and uniqueness to identify the most effective configurations. Our results show that specific configurations can achieve a positive balance between stability and device distinguishability, reaching 0.05 instability, 0.48 uniqueness, and 0.75 randomness. These findings provide a solid foundation for implementing robust authentication protocols tailored for quantum devices in real-world settings.
Physical Unclonable Functions (PUFs) provide hardware-level security by exploiting intrinsic randomness to produce device-unique responses. However, machine learning and side-channel attacks increasingly undermine their classical assumptions, calling for new approaches to ensure unforgeability. Quantum mechanics naturally supports this goal through intrinsic randomness and the no-cloning theorem, motivating the study of Quantum Physical Unclonable Functions (QPUFs). Yet, existing QPUF models often assume ideal unitary dynamics, neglecting non-unitary effects such as decoherence and dissipation that arise in real quantum devices. This work introduces a new class of non-unitary QPUFs that leverage open quantum system dynamics as a foundation for security. Three architectures are proposed: the Dissipative QPUF (D-QPUF), which uses amplitude damping as an entropy source; the Measurement-Feedback QPUF (MF-QPUF), which employs mid-circuit measurements and conditional unitaries; and the Lindbladian QPUF (L-QPUF), which models Markovian noise via the Lindblad master equation and Trotter-Suzuki decomposition. Simulation results show that these non-unitary designs achieve strong uniqueness, uniformity, and unforgeability, with controllable reliability trade-offs from stochastic noise. The L-QPUF, in particular, exhibits exponential modeling resistance under limited challenge-response access. By reframing environmental noise as a constructive resource, this work establishes a framework for noise-aware quantum hardware authentication and highlights non-unitary evolution as a viable foundation for post-quantum security.