Passive Decoy-State Reference-Frame-Independent Quantum Key Distribution with Heralded Single-Photon Source

Reference-frame-independent (RFI) quantum key distribution (QKD) is a protocol which can share unconditional secret keys between two remote users without the alignment of slowly varying reference frames. We propose a passive decoy-state RFI-QKD protocol with heralded single-photon source (HSPS) and present its security analysis. Compared with RFI QKD using a weak coherent pulse source (WCPS), numerical simulations show that the passive decoy-state RFI QKD with HSPS performs better not only in secret key rate but also in secure transmission distance. Moreover, our protocol is robust against the relative motion of the reference frames as well as RFI QKD with the WCPS. In addition, we also exploit Hoeffding's inequality to investigate the finite-key effect on the security of the protocol.