Funding for this research was provided by:
NSFC (61572028)
National Cryptography Development Fund (MMJJ20180206)
the Project of Science and Technology of Guangdong (2016B010125002)
the Project of Science and Technology of Guangzhou (201802010044)
Article History
First Online: 5 September 2018
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.