Funding for this research was provided by:
National Natural Science Foundation of China (61501080, 61871064, 61572095, 61877007)
National Nature Science Foundation of China (61771090)
Fundamental Research Funds for the Central Universities (DUT19JC08)
Guangxi Key Laboratory of Trusted Software (kx201903)
Article History
Received: 13 October 2018
Revised: 11 May 2019
Accepted: 4 July 2019
First Online: 11 July 2019