Robust Long-Distance Quantum Key Distribution Using Proxy Encryption and Secure Cloud-Based Solutions

The secure communication system called Quantum Key Distribution (QKD) needs improvements in long-distance implementation because energy loss and eavesdropping threats exist. The authors present the Multi-layer Proxy Encryption Scheme (MPES) which combines proxy re-encryption together with entangled quantum particles to achieve security enhancements along with distant QKD transmission capability. Quantum repeaters within the MPES model conduct multiple encryption and decryption operations which guards fiber-optic channel data transfers. The trust-based shortest path algorithm enables more efficient photon transfer which leads to decreased transmission loss and improved efficiency. The experimental data shows that key errors decreased by 62.5% while energy efficiency increased by 90.90% when implementing the MPES against standard BB84 protocol operation. Optimal conditions for photon mean free path required keeping wavelengths at 0.0051 nm and determined the most efficient photon energy span to be between 0.01 MeV. The new modeling system enhances quantum communication protection and simultaneously achieves satisfactory key transmission speeds. The conducted research shows MPES presents itself as an effective solution for quantum-secure communication at extended ranges within cloud environments.