Abstract: Quantum key distribution (QKD) has unconditional security in the information theory. The phase-matching quantum key distribution (PM-QKD) is one of the variants of twin-field quantum key distribution (TF-QKD), which has been proposed recently to overcome the rate-distance limits of point-topoint protocol without quantum repeaters. In view of the fact that the infinite decoy states are not available in practice, four-intensity decoy-state PM-QKD protocol is more practical. Therefore, a novel PM-QKD protocol with four-intensity decoy states, namely four-intensity decoy-state PM-QKD protocol, is propsed in this work. The secure key rate formula of the proposed protocol is presented and its performances are analyzed through numerical simulations to prove its validity.

Key words: quantum optics, quantum key distribution, phase-matching quantum key distribution, decoy state, secret key rate