Deterministic Quantum Key Distribution with Untrusted Relay and Finite Sources

Abstract Measurement-device-independent quantum key distribution (MDI-QKD) is proposed to close all loopholes of detection devices in QKD systems, and it holds the potential to double the limit transmission distance of those one-way QKD protocols. However, most MDI-QKD protocols are nondeterministic, which reduces the potential key rate by nearly half. In this paper, we propose a deterministic QKD protocol with an untrusted detection relay and finite sources, and based on the current technology of QKD devices, we derive the performance formula for it. The simulation results show that the performance of this protocol can exceed the MDI-QKD within the long limit transmission distance range, about 445km.