Dynamic Quantum Key Distribution for Microgrids with Distributed Error Correction

TL;DR

The paper tackles secure communication in cyber-physical microgrids by integrating Quantum Key Distribution with a DG-level, observer-based error detection framework. It leverages a dynamic adjacency matrix formulation to reconstruct true signals when quantum keys are corrupted or nodes are manipulated, enabling nominal operation despite adversarial activity. Key contributions include a QKD-integrated system model, real-time error detection metrics, and a signal reconstruction mechanism that adapts the communication topology to isolate threats, validated through case studies. This approach enhances resilience against eavesdropping, malware, and multi-node manipulations, with practical impact for maintaining stability in quantum-secured microgrids.

Abstract

Quantum key distribution (QKD) has often been hailed as a reliable technology for secure communication in cyber-physical microgrids. Even though unauthorized key measurements are not possible in QKD, attempts to read them can disturb quantum states leading to mutations in the transmitted value. Further, inaccurate quantum keys can lead to erroneous decryption producing garbage values, destabilizing microgrid operation. QKD can also be vulnerable to node-level manipulations incorporating attack values into measurements before they are encrypted at the communication layer. To address these issues, this paper proposes a secure QKD protocol that can identify errors in keys and/or nodal measurements by observing violations in control dynamics. Additionally, the protocol uses a dynamic adjacency matrix-based formulation strategy enabling the affected nodes to reconstruct a trustworthy signal and replace it with the attacked signal in a multi-hop manner. This enables microgrids to perform nominal operations in the presence of adversaries who try to eavesdrop on the system causing an increase in the quantum bit error rate (QBER). We provide several case studies to showcase the robustness of the proposed strategy against eavesdroppers and node manipulations. The results demonstrate that it can resist unwanted observation and attack vectors that manipulate signals before encryption.

Figures (10)

• Figure 1: Schematic diagram depicting QKD. CAC is an abbreviation for Classical Authenticated Channel.
• Figure 2: Control architecture of an AC microgrid.
• Figure 3: Stealth attacks targeting system frequency and real power sharing designed by attackers who could eavesdrop on microgrid state information flowing via the communication layer.
• Figure 4: Steps involved in the proposed error detection and mitigation framework.
• Figure 5: Simulink-based implementation of local control at the $x^{th}$ DG in a conventional QKD-enabled microgrid network.