Measurement-device-independent quantum dialogue based on entanglement swapping and phase encoding

Quantum dialogue (QD) can implement the bidirectional quantum secure direct communication through quantum channels. In this paper, we propose a measurement-device-independent (MDI) QD protocol based on the entanglement swapping and phase-encoding technology. Our protocol can resist all possible attacks from imperfect measurement devices and is theoretically secure. In our protocol, a round of communication consumes six entangled photon pairs and the two communication parties can exchange two bits of messages. Compared with existing MDI-QD protocols, our protocol does not require the communication parties to share keys in advance. Meanwhile, it adopts the partial Bell state measurement in linear optics, which is feasible under current condition. Based on above features, our MDI-QD protocol has application potential in the field of quantum communication.