The research content of network security has many aspects: password encryption, transmission security mechanism, virus prevention and so on. ..
The questions you ask are all about network security. ..
I think if you take the level test and the level is level 3 or below, the problems involved in network security are not so difficult, because that's not what you usually ask. I passed level three, but it was only a few years ago. I wonder if there is any reform now. Let's go ....