Upgrading the Cyber Layer of Power Systems to Support Semi-Quantum Key Distribution

This paper investigates upgrading the classical cyber layer of power systems to support semi-quantum key distribution. With such an upgrade, only a few cyber nodes are required to have full quantum capabilities (i.e., generation, transmission, and measurement of qubits) while the rest of the cyber nodes are required to have limited quantum capabilities (i.e., transmission and measurement of qubits). As a result, unconditionally secure keys can be shared between the control center and the power substations to encrypt and decrypt critical measurement and control data. We study the problem of allocating the minimum number of quantum servers (i.e., nodes with full quantum capabilities) on the pre-existing cyber layer to satisfy the required key distribution rate in an attacker’s presence. Due to the associated computational complexity, we propose a greedy algorithm to solve the allocation problem. We examine the proposed allocation algorithm on the cyber layer of the IEEE-14 bus test system. Our results demonstrate that the target key rate can be satisfied at different attack levels.