Abstract: A controlled quantum secure direct communication scheme based on GHZ-like state is proposed. In the proposed scheme, combining with the quantum CNOT operation, three participants of the communication use the entangled particles in their respective hands which satisfy the nature of the classical XOR relationship to encrypt, control and decrypt the quantum state carrying classical information. Meanwhile, decoying photons is used to prevent eavesdropping and ensure the security of communications. Security analysis shows that the proposed scheme can effectively detect the eavesdropping behavior of internal and external eavesdroppers. At the same time, the message particles transmitted in the communication process are not distributed entangled particles, so the entangled resources in this scheme can be reused.

Key words: quantum information, controlled quantum secure direct communication, GHZ-like state, XOR, CNOT operation