Quantum Secure Direct Communication Using Entangled Photon Pairs and Local Measurement

We present a scheme for quantum secure direct communication,in which the message is encoded by local unitary operations,transmitted through entangled photons,and deduced from both the sender and receiver's local measurement results.In such a scheme,only one pair of entangled photons is consumed,and there is no need to transmit the sender's qubit carrying the secret message in a public channel,in order to transmit two-bit classical information.