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.
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.
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.
A Physical Unclonable Function (PUF) is a device with unique behaviour that is hard to clone hence providing a secure fingerprint. A variety of PUF structures and PUF-based applications have been explored theoretically as well as being implemented in practical settings. Recently, the inherent unclonability of quantum states has been exploited to derive the quantum analogue of PUF as well as new proposals for the implementation of PUF. We present the first comprehensive study of quantum Physical Unclonable Functions (qPUFs) with quantum cryptographic tools. We formally define qPUFs, encapsulating all requirements of classical PUFs as well as introducing a new testability feature inherent to the quantum setting only. We use a quantum game-based framework to define different levels of security for qPUFs: quantum exponential unforgeability, quantum existential unforgeability and quantum selective unforgeability. We introduce a new quantum attack technique based on the universal quantum emulator algorithm of Marvin and Lloyd to prove no qPUF can provide quantum existential unforgeability. On the other hand, we prove that a large family of qPUFs (called unitary PUFs) can provide quantum selective unforgeability which is the desired level of security for most PUF-based 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.
Physical unclonable functions (PUFs) leverage inherent, nonclonable physical randomness to generate unique input-output pairs, serving as secure fingerprints for cryptographic protocols like authentication. Quantum PUFs (QPUFs) extend this concept by using quantum states as input-output pairs, offering advantages over classical PUFs, such as challenge reusability via public channels and eliminating the need for trusted parties due to the no-cloning theorem. Recent work introduced a generalized mathematical framework for QPUFs. It was shown that random unitary QPUFs cannot achieve existential unforgeability against quantum polynomial time (QPT) adversaries. Security was possible only with additional uniform randomness. To avoid the cost of external randomness, we propose a novel measurement-based scheme. Here, the randomness naturally arises from quantum measurements. Additionally, we introduce a second model where the QPUF functions as a nonunitary quantum channel, which guarantees existential unforgeability. These are the first models in the literature to demonstrate a high level of provable security. Finally, we show that the quantum phase estimation (QPE) protocol, applied to a Haar random unitary, serves as an approximate implementation of the second type of QPUF by approximating a von Neumann measurement on the unitary's eigenbasis. Published by the American Physical Society 2024
Quantum Physical Unclonable Functions (QPUFs) are hardware-based cryptographic primitives with strong theoretical security. This security stems from their modeling as Haar-random unitaries. However, implementing such unitaries on Intermediate-Scale Quantum devices is challenging due to exponential simulation complexity. Previous work tackled this using pseudo-random unitary designs but only under limited adversarial models with only black-box query access. In this paper, we propose a new QPUF construction based on chaotic quantum dynamics. We modeled the QPUF as a unitary time evolution under a chaotic Hamiltonian and proved that this approach offers security comparable to Haar-random unitaries. Intuitively, we show that while chaotic dynamics generate less randomness than ideal Haar unitaries, the randomness is still sufficient to make the QPUF unclonable in polynomial time. Moreover, we show that the evolution time required to achieve security scales linearly with number of qudits used in the scheme and can be kept public. We identified the Sachdev-Ye-Kitaev (SYK) model as a candidate for the QPUF Hamiltonian. Recent experiments using nuclear spins and cold atoms have shown progress toward achieving this goal. Inspired by recent experimental advances, we present a schematic architecture for realizing our proposed QPUF device based on optical Kagome Lattice with disorder. For adversaries with only query access, we also introduce an efficiently simulable pseudo-chaotic QPUF. Our results lay the preliminary groundwork for bridging the gap between theoretical security and the practical implementation of QPUFs for the first time.
Physical Unclonable Functions (PUFs) are hardware devices with the assumption of possessing inherent, non-clonable physical randomness which leads to unique pairs of inputs and outputs that provide a secure fingerprint for cryptographic protocols like Authentication. In the case of quantum PUFs (QPUFs), the input-output pairs consists of quantum states instead of classical bitstrings, offering advantages over classical PUFs (CPUFs) such as challenge reusability via public channels and non-reliance over any trusted party due to the no-cloning theorem. In recent literature, a generalized mathematical frame-work for studying QPUFs was developed, which paved the way for having QPUF models with provable security. It was proved that existential unforgeability against Quantum Polynomial Time (QPT) adversaries cannot be achieved by any random unitary QPUF. Since measurements are non-unitary quantum processes, we define a QPUF based on random von Neumann measurements. We prove that such a QPUF is existentially unforgeable. Thus, we introduce the first model in existing literature that depicts such a high level of provable security. We also prove that the Quantum Phase Estimation (QPE) protocol applied on a Haar random unitary serves as an approximate implementation for this kind of QPUF as it approximates a von Neumann measurement on the eigenbasis of the unitary.