Quantum secure direct communication without a pre-established secure quantum channel

摘要

Most of the quantum secure direct communication protocols need a pre-established secure quantum channel. Only after ensuring the security of quantum channel can the sender encode the secret message and send it to the receiver through the secure channel. In this paper, we present a quantum secure direct communication protocol using Einstein-Podolsky-Rosen pairs and teleportation. It is unnecessary for the present protocol to ensure the security of the quantum channel before transmitting the secret message. In the present protocol, all Einstein-Podolsky-Rosen pairs are used to transmit the secret message except those chosen for eavesdropping check. We also discuss the security of our protocol under several eavesdropping attacks.