You can also use letsencrypt to encrypt your streams and your manager. I am not sure if i can add my website address where i have a tutorial about it. Otherwise send me a PM.
You should be able to use that also behind your router. As long as you portforward port 80 and 443 to your Wowza server, to be able to create a Letsencrypt certificate.
Then a minor adjustment to your server config and you can run your streams over SSL.