Device-Independent Quantum Secure Direct Communication with Single-Photon Sources

Quantum secure direct communication (QSDC) can directly transmit secrete messages through quantum channel. Device-independent (DI) QSDC guarantee the security relying only on observation of Bell inequality violation, but not any detailed description or trust inner workings users' devices. In paper, we propose a DI-QSDC protocol with practical high-efficient single photon sources. The parties construct entanglement channel from photons by adopting heralded architecture, which makes message leakage rate independent transmission loss. distance and efficiency current are about 6 times 600 those in original protocol. Combining purification, nearly perfect completely eliminate leakage. This may have important application future field.