Passive-state preparation continuous-variable quantum key distribution with an independent source

Abstract

This paper employs an independent source to enhance passive state preparation continuous-variable quantum key distribution. In contrast to the original passive state protocol, the entanglement source is controlled by an untrustworthy third party, Charlie, rather than the sender. Alice and Bob are individually connected to Charlie through insecure channels. Moreover, the asymptotic key and finite-size analysis are used to evaluate the security of the proposed protocol. We also examine this protocol in one and two-dimensional scenarios. The simulation shows that one-dimensional protocol can significantly increase the maximum transmission distance. However, it is crucial to exercise caution when implementing two-dimensional protocol in practical settings, as the performance profile of two-dimensional protocol is intricately linked to the communication pinch angle and the location of the entanglement source.