Quantum Key Distribution at Microwave Frequencies with Cryogenic Components

We perform analytical calculations and numerical modelling to propose a microwave quantum key distribution (QKD) scheme with cryogenic microwave electronic components for superconducting quantum computing. Our results show that a positive secret key rate is achievable in the superconducting quantum processor's frequency range between f= 4 GHz and f= 10 GHz, when the generator and detector operate at cryogenic temperatures. We examine the channel model and secret key rate for different receiver radii at a dilution refrigerator environment, e.g., temperatures between T= 100 mK and T= 10 mK, and find that the safe distance could achieve more than 150 m by using a larger receiver at lower temperatures.