Unidimensional continuous-variable quantum key distribution with noisy source

Abstract

We investigate the security of unidimensional continuous-variable quantum key distribution with source noise at the sender. The source noise is ascribed to the legitimate sides rather than the eavesdropper and modeled as a thermal noise coupled with the signal mode through a beam splitter. The physicality bound and expressions of secret key rate are derived against collective entangling cloner attacks. Simulation results show that with source noise, the security bound of unidimensional protocol can be tightened. Moreover, proper source noise enlarges the security region to a wider range of parameters, thus eliminates potential eavesdropping threats and enhances the feasibility of unidimensional protocol.