Quantum Secure Direct Communication With Quantum Identification

A one-way quantum secure direct communication protocol with quantum identification utilizing two-photon three-qubit linear cluster states is proposed. The protocol can be used to transmit a secret message and identify user's identification simultaneously. The transmission of information is instantaneous, i.e. the information can be decoded during the transmission and no final transmission of additional information is needed. We prove its robustness against attacks: Any attempt of an adversary to obtain information (and even a bit of information) necessarily induces some errors that the legitimate parties could notice, even in noisy environments. Moreover, this protocol achieves a high efficiency and source capacity since more qubits can be encoded on the same photon.