I. Introduction
With the development of 5G technology, more and more Internet of things devices access to cyberspace. According to the latest research of Transforma Insights, the number of active IoT devices will reach 7.6 billion by the end of 2019, and it is expected to grow to 24.1 billion by 2030, with a compound annual growth rate (CAGR) of 11%[1]. However, Internet of things devices are vulnerable to hackers because of their low level of self-protection. For example, in 2016, hackers used nearly a million Internet of things devices infected by Mirai virus to launch a DDoS attack on Dyn, a DNS service provider on the east coast of the United States. This attack caused many websites to be inaccessible, including twitter, GitHub, BBC and so on[2].