Joint Server, Source Rate, and Link Allocation Strategy for Semi-QKD in Power Systems

Semi-quantum key distribution (Semi-QKD) can generate unconditionally secure keys between the substations and control center in power systems. These keys can be used to encrypt and decrypt measurements and control commands. This paper studies the problem of allocating a minimal number of quantum servers with optimal source rates and fiber links on a pre-existing cyber layer of power systems to satisfy the minimum required key rate under an attacker’s presence. We formulate the problem as a binary optimization problem to upgrade the cyber layer of power system to supports semi-QKD. We use genetic algorithm to develop an optimal allocation strategy due to the complexity of the allocation problem. We examine the proposed allocation strategy on the cyber layer of the IEEE 14-bus and the IEEE 39-bus test systems. Our results demonstrate that the target key rate can be achieved at different attack levels with a number of quantum servers and fiber links that is 70% and 31%, respectively, less than the results of a benchmark for the IEEE 14-bus system. Also, we obtained a number of quantum servers and fiber links that is 66.67% and 17%, respectively, less than the result of a benchmark for the IEEE 39-bus system. Our results demonstrate that the proposed solution requires 80% and 97% less quantum server upgrades compared with QKD for the IEEE 14-bus and the IEEE 39-bus test systems, respectively.