In this paper, a three-party controlled quantum secure direct communication
protocol based on GHZ-like state is proposed. In this scheme, the receiver can
obtain the sender’s two secret bits under the permission of the controller. By using
entanglement swapping, no qubits carrying secret messages are transmitted. Therefore,
if the perfect quantum channel is used, the protocol is completely secure. The
motivation behind utilizing GHZ-like state as a quantum channel is that if a qubit
is lost in the GHZ-like state, the other two qubits are still entangled. The proposed
protocol improves the efficiency of the previous ones.
کلید واژگان :
Quantum cryptography · Controlled quantum secure direct communication · Entanglement swapping · GHZ-like state · Efficiency
