High-capacity measurement-device-independent deterministic secure quantum communication

Deterministic secure quantum communication (DSQC) is an important branch of quantum cryptography and has attracted continuous attention. However, in practical DSQC, the receiver's detectors can be subjected to detector-side-channel attacks launched by the outside eavesdropper. Moreover, encoding the information in only one degree of freedom (DOF) of photons makes DSQC inefficient. Here, to remove all the detector side channels and increase single-photons' channel capacity, we report the first high-capacity measurement-device-independent DSQC (HC-MDI-DSQC) protocol by using photons' polarization-spatial-mode DOFs. This method is similar to the idea of MDI quantum key distribution. Theoretical analyses show that it is advantageous in terms of security and efficiency compared with the state-of-the-art DSQC protocols.

Automated summary

In practical DSQC, detector-side-channel attacks are common, and encoding information in only one DOF of photons can lead to inefficiency. By utilizing the polarization-spatial-mode DOFs of photons, we propose the HC-MDI-DSQC protocol, which removes detector side channels and increases channel capacity. Theoretical analyses show that this method is advantageous in terms of security and efficiency compared with current DSQC protocols.