Controlled Secure Direct Communication by Using GHZ Entangled State

摘要

We present a controlled secure direct communication protocol by usingGreenberger-Horne-Zeilinger (GHZ) entangled state via swapping quantumentanglement and local unitary operations. Since messages transferred only byusing local operations and a public channel after entangled states aresuccessfully distributed, this protocol can protect the communication against adestroying-travel-qubit-type attack. This scheme can also be generalized to amulti-party control system.