An Efficient and Novel Semi-Quantum Deterministic Secure Quantum Communication Protocol

Based on single photons in both polarization and spatial-mode degrees of freedom, an efficient and novel semi-quantum deterministic secure quantum communication (SQDSQC) protocol is presented. In this protocol, quantum sender only adopts the single photon as initial quantum resource. Under the premise of introducing two unitary operations, the communicants perform eavesdropping check and encoding secret message separately according to the transformation characteristics of the degrees of freedom of single photon, which improves the communication efficiency. Compared with other semi-quantum protocols that only consider the single photon with one degree of freedom, our protocol possesses a higher information transmission capability, because each single photon can carry two bits of secret message in a communication process. In addition, the single-photon measurement involved in the proposed protocol can reduce the complexity of the communication process. Eventually, the security analysis of this protocol shows that it can defend many types of attacks, such as the Trojan horse attack, the intercept-resend attack, the measure-resend attack, the entangle-measure attack, the DoS attack and other attacks.