1. Shaanxi Key Laboratory of Blockchain and Secure Computing, Xidian University, Xi’an, Shaanxi, China
2. Department of Computing and Mathematics, Manchester Metropolitan University, Manchester, U.K.
3. Department of Computer Science, College of Computers and Information Technology, Taif University, Taif, Makkah, Saudi Arabia
4. Computer School, Hubei University of Arts and Science, Xiangyang, Hubei, China
5. Graduate School of Science and Engineering, Hosei University, Chiyoda City, Tokyo, Japan