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arXiv · 2610.32634

From Link Availability to Deadline-Constrained Key Service: A Feasibility Framework for Mobile Free-Space Quantum Key Distribution

Hasan Abbas Al-Mohammed
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Abstract

Mobile free-space quantum key distribution (QKD) links can provide secret bits intermittently, whereas applications may need cryptographic key material at specified times. Optical feasibility, positive finite-key output, and deadline-compliant key service are consequently different claims. This technical note formalizes their separation through a time-indexed, security-qualified arrival process and a key-inventory model. Under explicitly stated assumptions, an elementary prefix-feasibility condition characterizes whether all demands can be served without borrowing keys from future contact windows. A stylized finite block model then illustrates why positive long-run optical availability does not ensure positive finite-key output when observations are fragmented into short contacts. Two transparent numerical examples distinguish total key yield from key delivery time and show the conditional benefit of pooling data across acquisition windows. The analysis is intended as a systems-level accounting and benchmarking framework, not a new QKD security proof or a demonstration of hardware performance. It identifies measurements and security assumptions needed to evaluate train, UAV, high-altitude-platform, and satellite-assisted optical QKD against application-level service requirements.

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Hasan Abbas Al-Mohammed. 2026-10-23. From Link Availability to Deadline-Constrained Key Service: A Feasibility Framework for Mobile Free-Space Quantum Key Distribution. https://arxiv.org/abs/2610.32634

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