The rapid advances in quantum computing pressure the existing essential cryptographic algorithms. In this context, Quantum Key Distribution (QKD) has been proposed as a quantum safe solution for key distribution. However, current QKD systems require an authenticated classical channel which relies on pre-shared symmetric keys that are manually distributed and do not guarantee the identity of the hardware that hosts them. This paper proposes a novel scheme, the Physically Unclonable Quantum Key Distribution (PU-QKD) system, to intrinsically authenticate the communicating endpoints in QKD. The PU-QKD scheme leverages classical Physical Unclonable Functions (PUFs) to encode the data transmission in discrete variable QKD protocols (e.g., BB84). Our scheme maintains the information-theoretic security of QKD protocols by integrating the PUF as an additional layer. Authentication is bound to hardware, providing a robust fingerprint, while lower post-processing overhead increases key rates. Additionally, the proposed scheme is resilient against state-of-the-art PUF vulnerabilities, such as modeling attacks.
The rapid advances in quantum computing pressure the existing essential cryptographic algorithms. In this context, Quantum Key Distribution (QKD) has been proposed as a quantum safe solution for key distribution. However, current QKD systems require an authenticated classical channel which relies on pre-shared symmetric keys that are manually distributed and do not guarantee the identity of the hardware that hosts them. This paper proposes a novel scheme, the Physically Unclonable Quantum Key Distribution (PU-QKD) system, to intrinsically authenticate the communicating endpoints in QKD. The PU-QKD scheme leverages classical Physical Unclonable Functions (PUFs) to encode the data transmission in discrete variable QKD protocols (e.g., BB84). Our scheme maintains the information-theoretic security of QKD protocols by integrating the PUF as an additional layer. Authentication is bound to hardware, providing a robust fingerprint, while lower post-processing overhead increases key rates. Additionally, the proposed scheme is resilient against state-of-the-art PUF vulnerabilities, such as modeling attacks.
Quantum Key Distribution (QKD) enables Information-Theoretically Secure (ITS) key exchange, robust even against future quantum computing threats. However, a fundamental limitation of QKD is the requirement for an authenticated classical channel, which necessitates a pre-shared secret key. In this work, we address this challenge by adopting a Hybrid Entangled Physical Unclonable Function (PUF) protocol for authentication. We demonstrate that this PUF-based method generates an ITS initial key under minimal explicit hardware assumptions. This approach allows us to experimentally perform a fully ITS-authenticated entanglement-based QKD protocol that relies solely on such assumptions, effectively eliminating the need for pre-shared secrets. This represents a significant step towards the practical realization of quantum network protocols using lightweight, readily available hardware assumptions, without weakening security guarantees.
The Quantum Key Distribution (QKD) protocol utilizes quantum mechanics principles for cryptographic key exchange, ensuring absolute secrecy. Current QKD techniques are susceptible to man-in-the-middle (MITM) attacks due to the absence of an inherent mechanism for identity verification within the quantum channel. For authentication, these systems rely on classical or post-quantum cryptography, which diminishes the perfect security advantage provided by QKD. We present a Physical Unclonable Function (PUF)-based authenticated QKD protocol (PUF-AQKD), which avoids the necessity for authenticated classical channels and is useful in mitigating MITM attacks. The fundamental concept of PUF-AQKD is to implement a phase shift in the basis used for polarizing the transmitted qubits. The phase shift is dictated by PUFs, which are anticipated to result in analogous (correlated) responses for devices manufactured under similar conditions but dissimilar responses in different conditions. An adversary lacking a correlated PUF response shared by Alice and Bob would inadvertently increase the Quantum Bit Error Rates (QBER) observed at Bob’s end. We present a mathematical model to assess the efficacy of the proposed PUF-AQKD method and perform simulations utilizing the NetSquid simulator. The mathematical analysis and simulation findings indicate that PUF-AQKD can efficiently identify eavesdroppers, even during incomplete measurements, without the necessity of an authorized classical channel.
Quantum Key Distribution (QKD) represents a groundbreaking advancement in the field of cryptography, leveraging the principles of quantum mechanics to establish secure communication channels. Unlike classical cryptographic methods, QKD promises theoretically unbreakable security by ensuring that any attempt at eavesdropping can be detected. This thesis explores the practical implementation, challenges, and comparative security of various QKD scenarios within modern network infrastructures. We specifically analyze the security implications of integrating QKD with Software-Defined Networking (SDN) and compare it against Quantum Random Number Generators (QRNG), Post-Quantum Cryptography (PQC), and Physical Unclonable Functions under different conditions, with the aim of providing a comprehensive evaluation of the strengths and vulnerabilities of each approach, guiding future developments in secure communication systems. After the analysis performed in this Master Thesis, we can safely conclude that the Quantum Key Distribution scenario is the ideal use case, having the highest overall security score. Meanwhile, the scenarios of QRNG and PQC are the closest to the ideal security when compared to QKD. Finally, while the PUF scenario has the lowest overall security score, it still presents better authentication features that can prove beneficial if combined with other scenarios.
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.
Quantum key distribution protocols allow two honest distant parties to establish a common truly random secret key in the presence of powerful adversaries, provided that the two users share a short secret key beforehand. This pre-shared secret key is used mainly for authentication purposes in the post-processing of classical data that have been obtained during the quantum communication stage, and it prevents a man-in-the-middle attack. The necessity of a pre-shared key is usually considered to be the main drawback of quantum key distribution protocols, and it becomes even stronger for large networks involving more than two users. Here, we discuss the conditions under which physical unclonable functions can be integrated in currently available quantum key distribution systems in order to facilitate the generation and the distribution of the necessary pre-shared key with the smallest possible cost in the security of the systems. Moreover, the integration of physical unclonable functions in quantum key distribution networks allows for real-time authentication of the devices that are connected to the network.
Quantum key distribution protocols allow two honest distant parties to establish a common truly random secret key in the presence of powerful adversaries, provided that the two users share a short secret key beforehand. This pre-shared secret key is used mainly for authentication purposes in the post-processing of classical data that have been obtained during the quantum communication stage, and it prevents a man-in-the-middle attack. The necessity of a pre-shared key is usually considered to be the main drawback of quantum key distribution protocols, and it becomes even stronger for large networks involving more than two users. Here, we discuss the conditions under which physical unclonable functions can be integrated in currently available quantum key distribution systems in order to facilitate the generation and the distribution of the necessary pre-shared key with the smallest possible cost in the security of the systems. Moreover, the integration of physical unclonable functions in quantum key distribution networks allows for real-time authentication of the devices that are connected to the network.