Figure 3.
The network map of keywords. (A) the clustered network map of keywords in the field of TLS. (B) Network visualization of keyword co-occurrence which appeared at least 5 times (67 author keywords).
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.