One more thing related to Tor. So it can be recognized if a traffic is Tor's traffic? For example Wireshark can tell if it is, or just take a look at the captured piece and tell if there's some Tor stuff?

 >>/19642/
You're right it's a large topic but we are discussing large topics all the time. I don't have any specific in mind just the general idea of security. 
> from who
Well from everyone? If one party knows something all the others know it as well.