A critical analysis of deployed use cases for quantum key distribution and comparison with post-quantum cryptography
Nick Aquina, Bruno Cimoli, Soumya Das, Kathrin Hövelmanns, Fiona Johanna Weber, Chigo M. Okonkwo, Simon Rommel, Boris Škorić, Idelfonso Tafur Monroy, Sebastian R. Verschoor
Quantum Key Distribution (QKD) is currently being discussed as a technology to safeguard communication in a future where quantum computers compromise traditional public-key cryptosystems. In this paper, we conduct a comprehensive security evaluation of QKD-based solutions, focusing on real-world use cases sourced from academic literature and industry reports. We analyze these use cases, assess their security and identify the possible advantages of deploying QKD-based solutions. We further compare QKD-based solutions with Post-Quantum Cryptography (PQC), the alternative approach to achieving security when quantum computers compromise traditional public-key cryptosystems, evaluating their respective suitability for each scenario. Based on this comparative analysis, we critically discuss and comment on which use cases QKD is suited for, considering factors such as implementation complexity, scalability, and long-term security. Our findings contribute to a better understanding of the role QKD could play in future cryptographic infrastructures and offer guidance to decision-makers considering the deployment of QKD.
Quantum Key Distribution (QKD) is currently being discussed as a technology to safeguard communication in a future where quantum computers compromise traditional public-key cryptosystems. In this paper, we conduct a comprehensive security evaluation of QKD-based solutions, focusing on real-world use cases sourced from academic literature and industry reports. We analyze these use cases, assess their security and identify the possible advantages of deploying QKD-based solutions. We further compare QKD-based solutions with Post-Quantum Cryptography (PQC), the alternative approach to achieving security when quantum computers compromise traditional public-key cryptosystems, evaluating their respective suitability for each scenario. Based on this comparative analysis, we critically discuss and comment on which use cases QKD is suited for, considering factors such as implementation complexity, scalability, and long-term security. Our findings contribute to a better understanding of the role QKD could play in future cryptographic infrastructures and offer guidance to decision-makers considering the deployment of QKD.
Quantum computing advances pose a serious threat to conventional public-key cryptographic systems such as RSA and elliptic curve cryptography as quantum algorithms may undermine the computational assumptions that guaranty their security. This challenge has driven the development of quantumsafe security approaches among which Quantum Key Distribution (QKD) represents a fundamentally different paradigm based on quantum mechanical principles rather than mathematical complexity. This paper presents a structured review of recent progress in QKD based on a systematic analysis of literature between 2020 and 2025, we examine core protocols including discrete-variable, continuous-variable, measurement-deviceindependent, and twin-field approaches, while also discussing their relationship with post-quantum cryptography as a complementary strategy for future secure communication systems. We provide a unified comparison framework to support practical design and policy decisions by organizing protocols and implementations along deployment dimensions. The study analyze theoretical foundations, implementation technologies across fiber, free-space, satellite, and integrated photonic platforms, and key performance trade-offs involving scalability, security robustness, and deployment feasibility. Findings indicate substantial progress in transitioning QKD from laboratory research toward practical implementations, supported by advances in network architectures, integrated hardware and hybrid cryptographic designs. The comparative analysis will highlight distinct strengths and limitations among protocol families and emphasize the potential of combining QKD with post-quantum cryptographic methods to enhance resilience. Remaining challenges including scalability constraints, implementation-level vulnerabilities, performance limitations over long distances, and integration with existing communication infrastructures are critically discussed. Finally, emerging research directions such as quantum repeaters, hybrid quantum-classical security models, and exploratory directions such as artificial intelligence-assisted optimizations are identified as key factors in enabling the evolution of QKD toward largescale quantum-secure networking.
This research paper offers an in-depth analysis of the potential benefits of quantum key distribution (QKD) to provide secure communication channels. The limitations of classical cryptography are explored in detail, highlighting the need for alternative approaches to mitigate against the growing sophistication of cyber threats. The advantages of QKD, including its absolute security and ability to detect eavesdropping, are also extensively discussed, along with successful case studies of QKD deployments and critical lessons learned from these initiatives. Despite its potential advantages, the paper also acknowledges the challenges and limitations of practically implementing QKD in its scalability, cost, interoperability, susceptibility to quantum attacks, and the importance of investment in research and development to accelerate progress in this field. Additionally, the paper examines successful implementations of QKD in real-life scenarios. The potential applications of QKD in various sectors, such as government and military, healthcare, and finance, are highlighted. The regulatory and legal challenges surrounding using QKD protocol encryption, including the need for licensing and approval, are also briefly discussed. In conclusion, the paper discusses future opportunities and challenges for quantum cryptography and QKD in achieving sustainable and secure communication and the prospects of practical implementation of QKD. To address the challenges and promote QKD deployment in sustainable communication networks, this paper recommends increasing funding for continuing QKD research and development; international collaboration between academia and industry; stakeholder engagement to ensure QKD's safe, secure, and ethical deployment; and the incentivization of QKD deployment in critical infrastructure. Additionally, governments should prioritize QKD research and education programs to create a skilled workforce in developing and deploying QKD technology. Overall, the findings of this research demonstrate the need for more research, development, and policy recommendations to enable the practical deployment of QKD in sustainable communication networks and ensure their security and resilience.
This study provides a comprehensive review of quantum cryptography and its implications for U.S. national security in the face of emerging quantum technologies. The primary objective is to investigate the potential of quantum cryptographic methods in creating unbreakable encryption and their future role in enhancing digital security. Employing a systematic literature review and content analysis, the study draws on recent peer-reviewed articles, institutional reports, and academic journals from 2013 to 2023. The methodology focuses on evaluating the evolution, current state, and challenges of quantum cryptography, along with its integration into existing security frameworks. Key findings reveal that Quantum Key Distribution (QKD) and post-quantum cryptography (PQC) offer promising solutions against the threats posed by quantum computing to classical encryption methods. However, the practical implementation of these technologies faces significant challenges, including technological limitations and the need for global standardization. The study underscores the urgency for U.S. national security policy to prioritize the development and integration of quantum-resistant cryptographic technologies and to foster international collaboration for standardization. Finally, the study highlights the transformative potential of quantum cryptography in digital security, emphasizing the need for continued research and collaboration to overcome implementation challenges. Future research directions include the development of efficient quantum cryptographic protocols and ethical considerations surrounding the deployment of quantum technologies. This study contributes to the discourse on securing national interests in the face of advancing quantum computing capabilities. Keywords: Quantum Cryptography, Digital Security, Post-Quantum Cryptography, Quantum Key Distribution.
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.
The blockchain technology has become a foundation of decentralized digital infrastructures, allowing secure, transparent, and tamper-resistant transactions in the finance and governance systems as well as supply chains ecosystems. But, existing blockchain systems are critically dependent on classical cryptography including RSA, ECDSA and hash-based primitives, which are becoming more susceptible to new entrant quantum computing. The quantum algorithm, especially Shor and Grover ones are a real challenge to the digital signatures, key exchange systems, and consensus integrity, which makes the sustainability of blockchain systems a serious concern in the long term.The practical approach of achieving quantum-resilient security without the use of quantum hardware-specific devices has seen considerable popularity in the form of Post-Quantum Cryptography (PQC). Although the literature is mostly concentrated on algorithm design, there is little work on the topic of architectural implementation of PQC in the framework of decentralized blockchain solutions. This chapter offers a systematic discussion on quantum threats, review of the most prominent families of PQC algorithms and suggests suitable deployment-related options to deploy quantum-safe cryptographic tools to blockchain systems. The chapter identifies trade-offs between security, scalability, and performance through comparative assessment and real-world case analysis, including PQC testnets in development and enterprise blockchain projects. The most important contribution of this work is the ability to introduce the gap between theory of cryptographic developments and the aspects of practical blockchain implementation challenges, providing an overall framework of the transition towards quantum-resilient distributed systems. The results would assist the researchers, practitioners and policy makers, to develop a future-proof blockchain architecture that would be in place to withstand digital trust in post-quantum age.
Advances in quantum computing pose a significant threat to the widely used Public Key Infrastructure (PKI). The two leading technologies to address this challenge are Post-Quantum Cryptography and Quantum Key Distribution. A promising approach is the hybridization of these technologies - combining their respective strengths while mitigating their limitations - and integrating them with the cryptographic mechanisms used today to enhance crypto-agility and facilitate transitioning to a quantum-safe infrastructure. However, changing current network protocols to quantum-safe alternatives is not just a matter of security: their efficiency and scalability must also be demonstrated within real-world telecommunications infrastructures to ensure their practical adoption. In this work, we present the first long-running test with detailed measurements of a suite of hybrid quantum-safe protocols that integrate classical cryptography, PQC, and QKD within a production environment (MadQCI). Using standardized protocols and interfaces and employing Transport Layer Security (TLS) as the base protocol for real-world comparison, this study demonstrates the efficiency and scalability of the proposed solution in deployed heterogeneous networks. These results mark a significant step towards the widespread adoption of quantum-safe hybrid protocols and contribute to clarifying the path toward their future standardization in next-generation telecommunications networks.