Quantum secure direct communication by using GHZ states and entanglement swapping

Abstract

We present a three-party quantum secure direct communication protocol by using Greenberg–Horne–Zeilinger (GHZ) states and entanglement swapping. The proposed scheme realizes authorized parties' secure exchange of their respective secret messages simultaneously and directly in a set of devices. We show that the scheme is secure against eavesdropper's commonly used attacks. We also generalize the protocol to the N-party case by using N-partite GHZ states.