Quantum Secure Direct Communication Achieved by Using Multi-Entanglement.

Aquantum secure direct communication (QSDC) scheme is proposed based on multi-body entangled system in this paper. The mathematical description of the QSDC scheme is given firstly and the process of direct communication is investigated. The communication scheme based on multi-body entangled system and the general method of information coding are further completed. Finally, a communication scheme using four-body systems is introduced as example. [ABSTRACT FROM AUTHOR]