COmmunications and Networking with QUantum Operationally-Secure Technology for Maritime Deployment (CONQUEST)

Saikat Guha

Abstract : Saikat Guha has been in discussions with Kamil Bradler of CipherQ Corp. on extending the proof technique of Lutkenhaus et al., PRA 79, 012307, which proved security and a rate lower bound for a binary-input (BPSK) CV QKD protocol. The main challenge in extending this proof technique to an M-ary is that this requires us to retain the entire relative geometry of the M purifications of the Eve's states (i.e., M choose 2 inner products). We are investigating a way where we could argue that the symmetry of the transmitted ensemble (e.g., a M-ary PSK constellation) is preserved in the symmetry of a particular purification of Eve's conditional states, which lets us proceed with evaluating bounds to conditional entropies using only a few parameters that describe that geometry, and in turn will hopefully lead to a rate lower bound with a simple-to-implement key map that only has a few quantities that Alice and Bob need to estimate during the channel estimation step.

Christopher J. Chunnilall, Timothy P. Spiller

Wenhao Lin

Maritime communication systems face critical challenges in ensuring secure, reliable, and long-range connectivity due to inherent vulnerabilities in traditional encryption, coverage gaps in remote sea areas, and susceptibility to eavesdropping under complex maritime conditions. While Unmanned Aerial Vehicle (UAV)-assisted networks have expanded coverage, security remains a persistent concern. Quantum communication, leveraging quantum key distribution (QKD), offers a paradigm shift by ensuring information-theoretic security. This paper proposes a UAV-based quantum relay maritime communication system that integrates QKD, UAV relays, and satellite networks to establish a hybrid quantum-classical architecture. The innovation lies in deploying UAVs as dynamic relay nodes to enable BB84-protocol-based QKD, while satellites ensure global coverage. Key advancements include: (1) a unidirectional quantum channel design featuring UAV-mounted quantum emitters (Alice) and ship-based receivers (Bob), minimizing technical complexity while ensuring secure key distribution; (2) a multi-layered network integrating ship-UAV-ship, ship-UAV-base station, and ship-satellite communication modes, enhancing resilience against environmental interference; and (3) real-time quantum-classical synergy, where classical data channels (e.g., AES-encrypted) are dynamically secured by QKD-generated keys, achieving compatibility with existing infrastructure while eliminating key leakage risks. Simulations validate the system’s resilience under maritime conditions: optimizing parameters such as detection efficiency (eff > 90%) and dark count (dc < 10⁻⁶/pulse) achieves a stable secure key rate over 100 km, with a Quantum Bit Error Rate (QBER) below 0.5% at 200 km. The proposed architecture offers transformative applications in maritime safety, emergency response, and offshore operations, providing eavesdropping-resistant links for remote vessels and secure data exchange for critical infrastructure. By bridging the gap between quantum security and practical maritime deployment, this work establishes a scalable blueprint for next-generation communication systems in military, commercial, and environmental monitoring domains.

Wenchao Dai, Yuan Lü, Jun Ping Zhu +1 more

Cătălin-Eugen Bucur, Georgiana Crihan, Elena-Gratiela Robe-Voinea +3 more

Abstract The rapid advancement of quantum technologies is reshaping the landscape of cybersecurity, communications, and critical infrastructure protection, including maritime logistics infrastructures, smart ports, vessel traffic management systems, and autonomous maritime platforms, while simultaneously generating both substantial opportunities and emerging security challenges. Emerging paradigms such as Quantum Key Distribution (QKD), quantum networks, and post-quantum cryptography challenge the adequacy of classical security mechanisms. This study aims to examine the dual-use nature of quantum technologies and evaluate their implications for secure communication and navigation systems in maritime logistics, smart port ecosystems, and defence-oriented environments. The research adopts a conceptual and analytical approach, examining current developments in quantum technologies along with their cybersecurity implications. It evaluates the limitations of existing cryptographic systems in the context of quantum computing advancements and explores hybrid security models that integrate post-quantum cryptography with quantum communication techniques. The analysis also considers defence-oriented requirements, including resilience, secure communications, and the protection of critical infrastructure within NATO-aligned environments. The findings highlight that classical cryptographic approaches are increasingly vulnerable to quantum-enabled attacks, necessitating a transition towards quantum-resilient architectures. The study identifies the strategic advantages of quantum technologies, such as enhanced security through QKD, while also highlighting associated risks, including implementation complexity, operational constraints, and policy challenges. The dual-use character of these technologies is shown to have significant implications in both the civilian and military sectors. Finally, the paper proposes a unified conceptual framework that bridges current cybersecurity practices with emerging quantum-enabled paradigms. The framework supports the development of adaptive, sustainable, and future-proof security architectures capable of addressing evolving threat landscapes. The results underscore the importance of coordinated technological, operational, and policy efforts to ensure secure adoption of quantum technologies in critical domains. Special attention is paid to the resilience of maritime communications and navigation infrastructures against quantum-enabled cyber threats, including GNSS spoofing, communication intercept, and supply-chain disruption.

M. Krelina