Practical decoy-state method in quantum key distribution with a heralded single-photon source

We propose a practical decoy-state method with heralded single-photon source for quantum key distribution (QKD). In the protocol, three intensities are used and one can estimate the fraction of single-photon counts. The final key rate over transmission distance is simulated under various parameter sets. Due to the lower dark count than that of a coherent state, it is shown that a three-intensity decoy-state QKD with a heralded source can work for a longer distance than that of a coherent state.