Fault tolerant quantum secure direct communication with quantum encryption against collective noise
Huang Wei, Wen Qiao-Yan, Jia Heng-Yue, Qin Su-Juan, Gao Fei
Chin. Phys. B . 2012, (10): 100308 -100308 .  DOI: 10.1088/1674-1056/21/10/100308