The hyperentanglement-based quantum secure direct communication protocol with single-photon measurement

Quantum secure direct communication (QSDC) can directly transmit secret messages through quantum channel without keys. The typical entanglement-based QSDC protocol encodes in one degree of freedom and requires the Bell state measurement (BSM). In the paper, we propose a hyperentanglement-based QSDC protocol with the single-photon measurement. Comparing with the BSM, the single-photon measurement is easier to implement and has higher success probability. The adoption of hyperentanglement can increase the capacity of each photon pair, and thus increase the secret message capacity. The message sender can transmit 2 bits of messages with a hyperentangled photon pair in theory. We make the numerical simulations to study the secret message capacity against the collective attack and photon number splitting attack. Our QSDC protocol has potential applications in the future quantum communication field.