Funding for this research was provided by:
National Natural Science Foundation of China (61772133, 61472081, 61402104, 61370207, 61370208, 61300024, 61320106007, 61272531, 61202449, 61272054)
Jiangsu Provincial Key Laboratory of Network and Information Security (BM2003201)
Ministry of Education of the People's Republic of China (No. 93K-9)
Article History
Received: 15 December 2017
Revised: 10 June 2018
Accepted: 18 June 2018
First Online: 16 July 2018