The maturity and developments of quantum key distribution (QKD) enable its application for encrypting dense wavelength-division multiplexing networks (DWDMNs), ensuring security in the presence of scalable quantum computers. The potential infrastructure reuse and costly deployment of a QKD network (QKDN) require jointly optimized deployment and utilization. We develop and solve a multi-layer problem formulation that fulfills the required keys of the DWDMN demands with the cost-minimized QKDN and maximized reuse of the present infrastructure. Our approach proves the feasibility of currently available QKD devices to encrypt nation-wide DWDMN with multi-period network planning. Furthermore, we compare static and dynamic routing approaches to quantify the advantage of software-defined networking for key management networks (KMNs). Depending on the network load, our multi-layer optimization shows potential savings between 9% and 45% of QKD devices compared to the baseline. Additionally optimizing the operation with dynamic routing increases the performance further, but the gain is negligible for encrypting DWDMNs.    «

The maturity and developments of quantum key distribution (QKD) enable its application for encrypting dense wavelength-division multiplexing networks (DWDMNs), ensuring security in the presence of scalable quantum computers. The potential infrastructure reuse and costly deployment of a QKD network (QKDN) require jointly optimized deployment and utilization. We develop and solve a multi-layer problem formulation that fulfills the required keys of the DWDMN demands with the cost-minimized QKDN and...    »