Quantum steganography with a large payload based on dense coding and entanglement swapping of Greenberger-Horne-Zeilinger states

Zhiguo Qu, Xiu‐Bo Chen, Ming‐Xing Luo +2 more

Tian-Yu Ye, Li-zhen Jiang

A quantum steganography protocol with a large payload is proposed based on the dense coding and the entanglement swapping of the Greenberger—Horne—Zeilinger (GHZ) states. Its super quantum channel is formed by building up a hidden channel within the original quantum secure direct communication (QSDC) scheme. Based on the original QSDC, secret messages are transmitted by integrating the dense coding and the entanglement swapping of the GHZ states. The capacity of the super quantum channel achieves six bits per round covert communication, much higher than the previous quantum steganography protocols. Its imperceptibility is good, since the information and the secret messages can be regarded to be random or pseudo-random. Moreover, its security is proved to be reliable.

Zhiguo Qu, Xiu‐Bo Chen, Xinjie Zhou +2 more

Jian-Wei Pan, Anton Zeilinger

Using just polarizing beam splitters and half-wave plates, we present a practical experimental scheme, by which one can conveniently identify two of the three-particle Greenberger-Horne-Zeilinger (GHZ) states. The scheme can easily be generalized to the $N$-particle case. The GHZ-state analyzer is essential for multiparticle generalizations of quantum dense coding, quantum teleportation, and entanglement swapping.

Takashi Mihara

Yan Feng-Li

A controlled quantum dense coding scheme is proposed with a three-particle non-maximally entangled Greenberger-Horne-Zeilinger(GHZ) state.The third party controlls the quantum channel via the local measurement.By introducing an auxiliary particle and performing an unitary transformation,quantum dense coding will be succeeded with certain probability.