Simulation and analysis of a QKD-PQC protocol for secure communication channel authentication

Quantum computing threatens traditional cryptographic systems based on integer factorization and discrete logarithm problems. This paper proposes a hybrid secure communication framework integrating Quantum Key Distribution (QKD) with Post-Quantum Cryptography (PQC) for authentication. The BB84 protocol is used for quantum key generation, while CRYSTALS-Dilithium signatures secure the classical communication channel. A Python-based simulator models photon transmission, Quantum Bit Error Rate (QBER), intercept-resend attacks, and authentication verification. Results show that QBER increases proportionally with eavesdropping probability, enabling reliable attack detection. The integration of QKD secrecy with PQC authentication ensures both confidentiality and integrity. Performance evaluation demonstrates that the additional latency introduced by PQC authentication remains within acceptable limits. The proposed hybrid framework provides a scalable and quantum-resistant solution suitable for next-generation secure communication systems.