Cai ZHANG received his Ph.D. degree in Computer Science from Sun Yat-sen University, Guangzhou, in 2015. In the same year, he joined the College of Mathematics and Informatics, South China Agricultural University. From Aug. 2018 to Aug. 2019, he was a visiting researcher with the School of Electronic and Electrical Engineering, University of Leeds, UK.  His research interests include quantum cryptography and information security.