## 3 Proposed Approach: Quantum Key Distribution (QKD)  
Quantum key distribution (QKD) exploits the fundamental principles of quantum mechanics to provide information-theoretic security, making it inherently resistant to attacks--even those executed by advanced quantum computers. This approach starkly contrasts with classical encryption schemes, whose security relies on the presumed computational difficulty of solving certain mathematical problems. Rather than depending on complex calculations, QKD utilizes intrinsic quantum phenomena--such as the Heisenberg uncertainty principle and the No-Cloning Theorem--to guarantee protection against interception and eavesdropping. In practice, any measurement of the quantum states used for key transmission inevitably alters those states, thereby alerting legitimate communicators to the presence of an intruder. The integration of QKD into unmanned aerial vehicles (UAVs) and ground stations necessitates the deployment of compact, power-efficient components, including lasers, polarization modulators, microlenses, polarization filters, and single-photon detectors. Empirical observations indicate that incorporating QKD hardware into UAVs increases energy consumption by roughly 25%, largely due to the operation of single-photon detectors and polarization modulators, which in turn may reduce the UAVs' operational range by 10-15%. This drawback is mitigated by energy-efficient components, such as compact lasers and optimized modulators. Advances in hardware design--exemplified by the adoption of nanoscale single-photon detectors with dark count rates below 10 Hz and compact polarization modulators that achieve a 30% reduction in power consumption compared to conventional designs--enable seamless integration into UAV platforms. Although current hardware, particularly single-photon detectors, is limited by dark count rates exceeding 10 Hz and by the need for the further optimization of polarization modulators to attain stable key generation rates of 10-100 Mbps in field conditions, ongoing developments in quantum technologies (e.g., miniaturized entangled photon sources and improved single-photon detectors with dark count rates below 1 Hz) promise to enhance the scalability and efficiency of QKD, potentially doubling key generation rates under existing field conditions. The efficiency of QKD is critically dependent on atmospheric conditions, geometric losses, and receiver characteristics. For example, the BB84 protocol demonstrates a robust performance across varying environmental scenarios; however, the key generation rates decline by approximately 40% under foggy conditions, and heavy rainfall incurs an additional 15% processing overhead for error correction. To counteract challenges such as Doppler shifts and rapid line-of-sight changes, the QKD system employs real-time beam tracking and dynamic key reconciliation processes, thereby maintaining stable quantum channel communication even at UAV speeds exceeding 100 km/h. This study models the effects of these variables on the link range, stability, and key generation rate. Furthermore, the proposed QKD architecture incorporates secure relay nodes and decentralized synchronization mechanisms to facilitate effective key exchange in multi-UAV operations. Simulations reveal a 15% efficiency loss in high-density UAV environments, indicating the need for advanced coordination protocols. Detailed analyses of these factors enable the optimization of QKD system parameters to ensure reliable operation under authentic low Earth orbit (LEO) conditions. Extending the models to multi-UAV networks--by incorporating node mobility patterns and inter-UAV communication dynamics--suggests an overall network efficiency reduction of 25% due to cumulative attenuation effects in high-density operations. Atmospheric attenuation, resulting from photon scattering and absorption, can diminish both the communication range and key generation rates, while the geometric losses associated with laser beam divergence further limit the effective range.