Comparison and optimization of different routing methods for meshed QKD networks using trusted nodes

Quantum key distribution (QKD) appears as a promising technique for encrypted communication, preserving security even in the presence of a future powerful quantum computer. At the same time, communication infrastructure becomes increasingly complex, and the exponentially increasing traffic volume makes the application of QKD a challenging task. In addition, current hardware for QKD modules is still subject to research to gain maturity, to guarantee secret key rates, and to mitigate key rate fluctuations and instabilities. Our study analyzes and optimizes five routing algorithms to efficiently use the secret keys as a resource in meshed national-wide networks. By fulfilling distinct security and performance levels, the algorithms are compared with respect to key performance indicators and optimized for blocking probabilities, load balancing, or the management traffic amount. Depending on the application, our study allows operators to choose a well-suited algorithm and gives performance estimates, including an assessment of the performance gap to globally optimized algorithms.