Scheme for Deterministic Secure Quantum Communication with Three-qubit GHZ State

We present a novel scheme for deterministic secure quantum communication by using three-qubit Greenberger-Horne-Zeilinger (GHZ) state as quantum channel. It will be shown that secret messages can be encoded by employing four two-unitary collective operations, and decoded by Bell-basis measurements and some additional classical information. Security of the communication can be ensured by the order rearrangement of photon pairs techniques and the decoy photon checking technique. It has a high capacity as each GHZ state can carry two bits of information, and has a high intrinsic efficiency because almost all the instances except for the decoy checking photons (its number is negligible) are useful. Furthermore, this protocol is feasible with the present-day technique.