Measurement-device-independent quantum secure direct communication based on quantum cover channel and multiple degrees of freedom of hyperentanglement

Abstract Quantum secure direct communication (QSDC) achieves direct and secure transmission of information which does not need a pre-shared key. To improve the practical reliability of QSDC systems, Measurement-device-independent quantum secure direct communication protocol (MDI-QSDC) have emerged, which provide a more secure communication method by eliminating the dependence on measurement devices. This paper proposes an MDI-QSDC protocol based on polarization-spatial-orbital angular momentum mode hyperentanglement and quantum covert channel (QCC). This protocol can transmit 6-bit information in one round of communication, eliminating security vulnerability and information leakage associated with measurement devices. Compared with the previous MDI-QSDC protocols, this paper further clarifies the enhancement of channel capacity and security through numerical simulation studies. Further, the protocol introduces imperceptible QCC on polarization-spatial mode, which is significantly more secure than direct coding on polarization-spatial mode only. Based on the above features, the potential of the proposed high-capacity MDI-QSDC protocol in quantum communication is highlighted.