Quantum Key Distribution with Enhanced PQC Validation

Quantum Key Distribution (QKD) provides information-theoretic security based on quantum mechanics, but its practical deployment is limited by its reliance on classical infrastructure and inability to operate as a standalone solution. Recent research emphasizes hybrid approaches that combine QKD with post-quantum cryptography (PQC) to achieve practical and robust security. This paper presents a hybrid key distribution model integrating QKD with the post-quantum key encapsulation mechanism. The two independently generated keys are combined to derive a unified shared secret, enhancing resilience against both classical and quantum adversaries. The system is implemented using a simulated quantum environment, enabling the emulation of quantum communication over classical networks. The proposed approach is validated through a secure image transmission use case, demonstrating the correctness of the hybrid key exchange. The results highlight the feasibility of hybrid classical–quantum cryptographic systems as a practical step toward secure communication in emerging quantum network infrastructures.