[jitsi-users] How to secure connection?

I still have the following problem and questions, maybe someone can help? I would really appreciate it :-).

I would like to secure my connection for video chat. I am running Lubuntu 14.4. In the video https://www.youtube.com/watch?v=udBBDHT-_UA there is a little text one has to read in order to check whether the connection is with the right person and then the connection gets secured. However I only see a red unlocked lock-symbol and I don't get any text. What do I have to do? I have seen that there are a lot of security settings in "Settings -> Security -> Chat"* in the main Jitsi-window and in the Chat window under "Secure Chat -> Automatically Secure Chat"* - however all those settings haven't helped to secure the chat and I am more confused than ever.

Also for security reasons I would like to know whether the XMPP-protocol results in a peer-to-peer connection, which is only established by the server (as it was with Skype in the old days) or whether the server handles the connection itself (as it was with ICQ in the old days, I have no idea how it is nowadays).

In summary:
1. What do all those options mean?
2. How do I secure my video calls?
3. Do the calls go via other servers or is it a peer-to-peer connection?

My best, Richard

* Not literally, since I translated the menu items into English.