1. Information Security Center, Beijing University of Posts and Telecommunications, Beijing, China
2. School of Mathematical Science, Capital Normal University, Beijing, China
3. Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
4. Chern Institute of Mathematics and LPMC, and the Tianjin Key Laboratory of Network and Data Security Technology, Nankai University, Tianjin, China