Security proof of the two-way quantum secure direct communication with channel loss and noiseJian-Yong Hu, Liu Yang, Shu-Xiao Wu, Rui-Yun Chen, Guo-Feng Zhang, Cheng-Bing Qin, Lian-Tuan Xiao and Suo-Tang JiaEPL, 129 1 (2020) 10004DOI: https://doi.org/10.1209/0295-5075/129/10004