Measurement‐Device‐Independent Quantum Key Distribution With Third‐Party Quantum Sources

ABSTRACT

Traditional quantum key distribution (QKD) protocols secure communications by trusting the source or the measurement device. Among these, measurement‐device‐independent quantum key distribution (MDI‐QKD) protocols remove the need to trust the measurement device by delegating it to an untrusted third party. We categorize the operations of the QKD protocol into three fundamental processes: realizing quantum sources, applying unitary operations, and performing measurements. Furthermore, we have designed an MDI‐QKD protocol utilizing third‐party quantum sources, which establishes connections with the BB84 protocol, the BBM92 protocol, and the first MDI‐QKD protocol. Specifically, the three protocols can be regarded as special cases of the proposed protocol under different equivalent implementations. Under the assumptions of the source's dimension and ideal operation devices, the proposed protocol can guarantee information‐theoretic security even if the quantum sources and measurement devices are controlled by an adversary. Moreover, we demonstrate that its security is equivalent to that of the BBM92 protocol, with a tolerable error rate of approximately . Finally, we give a generalization of the proposed protocol and a corresponding experimental setup framework. This work reveals certain inherent connections between different quantum key distribution protocols, enriching the research results of quantum key distribution.