Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2608.18869

Secure Medical Data Transmission Using Quantum Key Distribution and Post-Quantum Cryptography in Real-World Fiber Networks

Vasile-Laurentiu Dosan, Paul Spooren, Sebastian Moeckel, Alessandro Zannotti, Alek Lagarrigue, Pablo Vazquez, Marc Bodenstein, Jonas Jelonek, Sarika Mishra, Jansen Dwan, Natasa Pavlovic Tucakovic, Fabian Steinlechner, Kevin Füchsel, Thomas Hühn, Oliver de Vries

quant-phSubmitted Aug 19, 2026• Announced Aug 20, 2026• 0 citations• Revised Sep 11, 2026 (v2)
v1 · Aug 19, 2026v2 · Sep 11, 2026
arXivHTMLPDF

Abstract

The threat quantum computers pose to classical public-key cryptography motivates the deployment of quantum-safe communication for critical infrastructure such as healthcare, finance, and energy systems. Quantum key distribution (QKD) and post-quantum cryptography (PQC) offer complementary security guarantees, information-theoretic key exchange and quantum-resistant end-to-end authentication that can be combined in a layered architecture. Here, we demonstrate a field-deployed quantum-secure network integrating entanglement-based QKD with end-to-end PQC over 140 km of installed fiber in Thuringia, Germany, connecting a rural health kiosk to a university hospital via a trusted-node architecture comprising heterogeneous underground and aerial fiber links. Unlike conventional deployments that rely on a dedicated key management system to forward keys to applications, our architecture injects QKD keys directly into standard Linux-based VPN tunnels between adjacent nodes, while PQC secures the communication end-to-end, remaining fully compatible with existing infrastructure and software. Polarization-entangled photon pairs were generated at 810 nm and 1550 nm, with the telecom photon transmitted over deployed fiber. Active polarization stabilization and dispersion compensation preserve the entanglement and enable 22 days of continuous, fully autonomous operation, further underscoring the technological maturity of entanglement-based QKD approaches in a real-world fiber environment. Although the two deployed links were operated during separate rather than concurrent periods, the predominantly aerial link exhibited markedly greater instability, with QBER variations most strongly correlated with wind speed. The generated keys secured a telemedicine proof-of-concept without modifying existing medical systems, demonstrating a practical framework for quantum-safe critical infrastructures.

Related papers

Post-Quantum Cryptography Resilience in Telehealth using Quantum Key Distribution

Don Roosan, Rubayat Islam Khan, Saif Nirzhor +1 more

Objective: The authors propose and evaluate a novel cybersecurity architecture for telehealth that is resilient against future quantum computing cyber threats. By integrating post-quantum cryptography (PQC) with quantum key distribution (QKD) and privacy-preserving mechanisms, data confidentiality and immutability for patient records in a post-quantum era are ensured. Methods: A multi-layered design approach was adopted. The PQC algorithms (e.g. CRYSTALS-Dilithium) were integrated at the blockchain consensus layer to resist quantum attacks. A directed acyclic graph (DAG)-based ledger managed high transaction throughput and latency constraints typical of telehealth. A QKD-enhanced key management protocol leveraged quantum channels for secure exchanges. Zero-knowledge proofs (ZKPs) and secure multiparty computation (MPC) verified transactions without exposing sensitive patient data. A granular access control model used attribute-based encryption and smart contracts to govern which participants could view or modify encrypted medical records. Results: The prototype was developed within a simulated telehealth network comprising hospitals, clinics, and patient devices. The PQC signatures at the consensus layer provided effective resistance to both classical and anticipated quantum attacks. The QKD facilitated secure key distribution, while ZKPs and MPC enabled validation of healthcare transactions without compromising patient privacy. Despite increased computational overhead, the DAG approach efficiently handled parallel transactions, indicating improved scalability compared to traditional linear blockchains. Conclusion: A QKD-enhanced, PQC-driven framework successfully addresses critical security and privacy requirements, safeguarding medical data from emerging quantum threats. Although overhead and infrastructural costs are significant, sustained cryptographic resilience and robust patient confidentiality underscore its suitability for next-generation healthcare systems. Future studies should explore additional optimizations, homomorphic encryption, and larger-scale pilots under regulatory standards.

Blockchain in Healthcare Today•Apr 29, 2025•12 citations

Multi-node quantum key distribution network using existing underground optical fibre infrastructure

Mariella Minder, Andreas Siakolas, Stephanos Yerolatsitis +2 more

Quantum key distribution (QKD) offers unconditional information security by allowing two distant users to establish a common encryption key resilient to hacking. Resultingly, QKD networks interconnecting critical infrastructure and enabling the secure exchange of classified information, can provide a solution to the increasing number of successful cyberattacks. To efficiently deploy quantum networks, the technology must be integrated over existing communication infrastructure, such as optical fibre links. Yet, QKD poses stringent requirements on the conditions of the network over which it is deployed. This work demonstrates the first quantum communication network in Cyprus via the deployment of a multi-node quantum network, exploiting existing commercial underground optical fibre. The network employs bidirectional occupation of fibres and wavelength multiplexing in a ring architecture to achieve, with minimal use of dark fibres, high-rate QKD. Results obtained reveal consistent key generation rates across all nodes, confirming reliable operation in a real-world environment. This deployment highlights the feasibility of leveraging existing telecom infrastructure for quantum-secured communication, marking a significant step toward scalable and cost-effective quantum networks suited for critical applications.

quant-pharXiv:2512.02701•Workshop on Specialty Optical Fibers and Their Applications (WSOF)•Dec 3, 2025•0 citations

Quantum-safe dual-link architecture with PQC-based authentication and CV-QKD

Aida Garcia-Callejo, Andrés Ruiz-Chamorro, José Ignacio Sánchez +6 more

This work presents a dual-link hybrid cryptographic architecture combining post-quantum cryptography (PQC) with Quantum Key Distribution (QKD) for secure classical channel authentication and key establishment. The first link targets resource-constrained aerial or mobile scenarios, using ASCON-80pq for authentication with session keys established via ML-KEM-768. A proof-of-concept free-space implementation demonstrates the feasibility of this lightweight solution. The second link focuses on terrestrial fiber networks, employing ContinuousVariable QKD (CV-QKD) for key distribution, Kyber-based authentication, and AES-256-GCM encryption within a TLS context. Designed under composable security principles, the architecture supports integration into dynamic network environments such as SDN and multi-tenant infrastructures. Experimental results highlight key performance indicators including energy consumption, authentication latency, and resilience to attacks. The work demonstrates the practicality of hybrid PQC–QKD systems for civilian and defense use, advancing readiness of dual-use quantum-safe communications.

SPIE Quantum Technologies for Defence and Security•Oct 29, 2025•0 citations

Secure Quantum Key Distribution Protocol for Hybrid Classical-Quantum Networks

Saiyed Faiayaz Waris, L. Bhagyalakshmi, M. Muni Babu +3 more

The existence of quantum computing presents an existential threat to the traditional cryptographic algorithms, and there is a need to create communication mechanisms that are fundamentally secure. In this regard, the concept of Quantum Key Distribution (QKD) provides information-theoretic security, which is founded on quantum mechanics. Nevertheless, conventional QKD protocols have serious shortcomings such as lack of distance in communication, vulnerability to side-channel attacks, and inability to support the large-scale heterogeneous network. We suggest that HQNet-QKD a Hybrid Quantum Key Distribution framework can help solve these issues by offering a more secure, scalable and future-proof key exchange framework in hybrid classical-quantum networks. To support multi-layered security, the proposed architecture is a network ensuring the smoothness of decoy-state BB84, Measurement-Device-Independent QKD (MDI-QKD), entanglement/twin-field-based QKD with verifiable Secret Sharing (VSS) and Post-Quantum Cryptography (PQC). It provides a complete methodology such as system architecture, mathematical modeling, and end-to-end key synthesis. When used over a distance of 300 km, simulation and testing have shown that HQNet-QKD can achieve up to$2.7 \times$higher secret key rate (SKR) than conventional methods, secret communication at 700 km and resilience to both quantum and classical attacks more than 96%. In addition, the framework guarantees forward secrecy, detector-side immunity, contextbound key derivation, and composability and thus resistant to current and future adversaries. It has a low-computational overhead modular design, making it trivial to deploy in a real world, in applications like quantum-secured 5G backbones, cloud data centers, critical infrastructure, and satellite-based communication systems. The findings make HQNet-QKD a new generation solution to quantum-safe secure communication and the first step towards the implementation of the quantum internet.

IEEE International Conference on ICT in Business Industry & Government (ICTBIG)•Dec 12, 2025•18 citations

PQC-Enhanced QKD Networks: A Layered Approach

Paul Spooren, Andreas Neuhold, Sebastian Ramacher +1 more

We present a layered and modular network architecture that combines Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) to provide scalable end-to-end security across long distance multi-hop, trusted-node quantum networks. To ensure interoperability and efficient practical deployment, hop-wise tunnels between physically secured nodes are protected by WireGuard with periodically rotated pre-shared keys sourced via the ETSI GS QKD 014 interface. On top, Rosenpass performs a PQC key exchange to establish an end-to-end data channel without modifying deployed QKD devices or network protocols. This dual-layer composition yields post-quantum forward secrecy and authenticity under practical assumptions. We implement the design using open-source components and validate and evaluate it in simulated and lab test-beds. Experiments show uninterrupted operation over multi-hop paths, low resource footprint and fail-safe mechanisms. We further discuss the design's compositional security, wherein the security of each individual component is preserved under their combination and outline migration paths for operators integrating QKD-aware overlays in existing infrastructures.

quant-pharXiv:2604.05599•International Conference on Quantum Communications, Networking, and Computing (QCNC)•Apr 8, 2026•1 citation

Benchmarking hybrid quantum-safe cryptography over real-world infrastructures

Jaime S. Buruaga, Juan P. Brito, Vicente Martín

Abstract 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.

EPJ Quantum Technology•May 15, 2026•0 citations
The threat quantum computers pose to classical public-key cryptography motivates the deployment of quantum-safe communication for critical infrastructure such as healthcare, finance, and energy systems. Quantum key distribution (QKD) and post-quantum cryptography (PQC) offer complementary security guarantees, information-theoretic key exchange and quantum-resistant end-to-end authentication that can be combined in a layered architecture. Here, we demonstrate a field-deployed quantum-secure network integrating entanglement-based QKD with end-to-end PQC over 140 km of installed fiber in Thuringia, Germany, connecting a rural health kiosk to a university hospital via a trusted-node architecture comprising heterogeneous underground and aerial fiber links. Unlike conventional deployments that rely on a dedicated key management system to forward keys to applications, our architecture injects QKD keys directly into standard Linux-based VPN tunnels between adjacent nodes, while PQC secures the communication end-to-end, remaining fully compatible with existing infrastructure and software. Polarization-entangled photon pairs were generated at 810 nm and 1550 nm, with the telecom photon transmitted over deployed fiber. Active polarization stabilization and dispersion compensation preserve the entanglement and enable 22 days of continuous, fully autonomous operation, further underscoring the technological maturity of entanglement-based QKD approaches in a real-world fiber environment. Although the two deployed links were operated during separate rather than concurrent periods, the predominantly aerial link exhibited markedly greater instability, with QBER variations most strongly correlated with wind speed. The generated keys secured a telemedicine proof-of-concept without modifying existing medical systems, demonstrating a practical framework for quantum-safe critical infrastructures.
Objective: The authors propose and evaluate a novel cybersecurity architecture for telehealth that is resilient against future quantum computing cyber threats. By integrating post-quantum cryptography (PQC) with quantum key distribution (QKD) and privacy-preserving mechanisms, data confidentiality and immutability for patient records in a post-quantum era are ensured. Methods: A multi-layered design approach was adopted. The PQC algorithms (e.g. CRYSTALS-Dilithium) were integrated at the blockchain consensus layer to resist quantum attacks. A directed acyclic graph (DAG)-based ledger managed high transaction throughput and latency constraints typical of telehealth. A QKD-enhanced key management protocol leveraged quantum channels for secure exchanges. Zero-knowledge proofs (ZKPs) and secure multiparty computation (MPC) verified transactions without exposing sensitive patient data. A granular access control model used attribute-based encryption and smart contracts to govern which participants could view or modify encrypted medical records. Results: The prototype was developed within a simulated telehealth network comprising hospitals, clinics, and patient devices. The PQC signatures at the consensus layer provided effective resistance to both classical and anticipated quantum attacks. The QKD facilitated secure key distribution, while ZKPs and MPC enabled validation of healthcare transactions without compromising patient privacy. Despite increased computational overhead, the DAG approach efficiently handled parallel transactions, indicating improved scalability compared to traditional linear blockchains. Conclusion: A QKD-enhanced, PQC-driven framework successfully addresses critical security and privacy requirements, safeguarding medical data from emerging quantum threats. Although overhead and infrastructural costs are significant, sustained cryptographic resilience and robust patient confidentiality underscore its suitability for next-generation healthcare systems. Future studies should explore additional optimizations, homomorphic encryption, and larger-scale pilots under regulatory standards.
Quantum key distribution (QKD) offers unconditional information security by allowing two distant users to establish a common encryption key resilient to hacking. Resultingly, QKD networks interconnecting critical infrastructure and enabling the secure exchange of classified information, can provide a solution to the increasing number of successful cyberattacks. To efficiently deploy quantum networks, the technology must be integrated over existing communication infrastructure, such as optical fibre links. Yet, QKD poses stringent requirements on the conditions of the network over which it is deployed. This work demonstrates the first quantum communication network in Cyprus via the deployment of a multi-node quantum network, exploiting existing commercial underground optical fibre. The network employs bidirectional occupation of fibres and wavelength multiplexing in a ring architecture to achieve, with minimal use of dark fibres, high-rate QKD. Results obtained reveal consistent key generation rates across all nodes, confirming reliable operation in a real-world environment. This deployment highlights the feasibility of leveraging existing telecom infrastructure for quantum-secured communication, marking a significant step toward scalable and cost-effective quantum networks suited for critical applications.
This work presents a dual-link hybrid cryptographic architecture combining post-quantum cryptography (PQC) with Quantum Key Distribution (QKD) for secure classical channel authentication and key establishment. The first link targets resource-constrained aerial or mobile scenarios, using ASCON-80pq for authentication with session keys established via ML-KEM-768. A proof-of-concept free-space implementation demonstrates the feasibility of this lightweight solution. The second link focuses on terrestrial fiber networks, employing ContinuousVariable QKD (CV-QKD) for key distribution, Kyber-based authentication, and AES-256-GCM encryption within a TLS context. Designed under composable security principles, the architecture supports integration into dynamic network environments such as SDN and multi-tenant infrastructures. Experimental results highlight key performance indicators including energy consumption, authentication latency, and resilience to attacks. The work demonstrates the practicality of hybrid PQC–QKD systems for civilian and defense use, advancing readiness of dual-use quantum-safe communications.
The existence of quantum computing presents an existential threat to the traditional cryptographic algorithms, and there is a need to create communication mechanisms that are fundamentally secure. In this regard, the concept of Quantum Key Distribution (QKD) provides information-theoretic security, which is founded on quantum mechanics. Nevertheless, conventional QKD protocols have serious shortcomings such as lack of distance in communication, vulnerability to side-channel attacks, and inability to support the large-scale heterogeneous network. We suggest that HQNet-QKD a Hybrid Quantum Key Distribution framework can help solve these issues by offering a more secure, scalable and future-proof key exchange framework in hybrid classical-quantum networks. To support multi-layered security, the proposed architecture is a network ensuring the smoothness of decoy-state BB84, Measurement-Device-Independent QKD (MDI-QKD), entanglement/twin-field-based QKD with verifiable Secret Sharing (VSS) and Post-Quantum Cryptography (PQC). It provides a complete methodology such as system architecture, mathematical modeling, and end-to-end key synthesis. When used over a distance of 300 km, simulation and testing have shown that HQNet-QKD can achieve up to2.7×2.7 \times2.7×higher secret key rate (SKR) than conventional methods, secret communication at 700 km and resilience to both quantum and classical attacks more than 96%. In addition, the framework guarantees forward secrecy, detector-side immunity, contextbound key derivation, and composability and thus resistant to current and future adversaries. It has a low-computational overhead modular design, making it trivial to deploy in a real world, in applications like quantum-secured 5G backbones, cloud data centers, critical infrastructure, and satellite-based communication systems. The findings make HQNet-QKD a new generation solution to quantum-safe secure communication and the first step towards the implementation of the quantum internet.
We present a layered and modular network architecture that combines Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) to provide scalable end-to-end security across long distance multi-hop, trusted-node quantum networks. To ensure interoperability and efficient practical deployment, hop-wise tunnels between physically secured nodes are protected by WireGuard with periodically rotated pre-shared keys sourced via the ETSI GS QKD 014 interface. On top, Rosenpass performs a PQC key exchange to establish an end-to-end data channel without modifying deployed QKD devices or network protocols. This dual-layer composition yields post-quantum forward secrecy and authenticity under practical assumptions. We implement the design using open-source components and validate and evaluate it in simulated and lab test-beds. Experiments show uninterrupted operation over multi-hop paths, low resource footprint and fail-safe mechanisms. We further discuss the design's compositional security, wherein the security of each individual component is preserved under their combination and outline migration paths for operators integrating QKD-aware overlays in existing infrastructures.
Abstract 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.