Quantum-Secured Hybrid Communication System for Tactical Military Networks: Implementation and Performance Analysis of BB84 Protocol Based on Penny Lane

This paper proposes a quantum key distribution (QKD) based hybrid communication system for enhancing security in tactical military networks. Modern military communication networks face complex threats including jamming, eavesdropping, and potential cryptanalysis by quantum computers, necessitating a new security framework that combines quantum and classical cryptography. This study implements the BB84 protocol using the PennyLane quantum computing framework and quantitatively evaluates the effects of interception probability and channel noise on both the estimated Quantum Bit Error Rate (QBER) and the resulting secure key length after privacy amplification. Experimental results confirm that the session abort rate increases sharply as QBER approaches/exceeds the 11% threshold, and the secure key budget degrades to near-zero in high-threat conditions, which directly limits application-layer encryption continuity. By applying the generated quantum keys to AES-256-GCM encryption, we validate end-to-end hybrid operation and report system-level metrics such as the number of usable 256-bit keys per session and the corresponding rekeying capacity under varying threat and noise conditions.