HTTP Security of ServiceBus

I try to use HTTP ConnectivityMode working with NetTcpRelayBinding for ServiceBus to solve TCP firewall issue.

Can anyone can tell me:

Is HTTP ConnectivityMode secure enough for ServiceBus, I just do not want our app to be easily captured by software like fiddler and get our servicebus issue name and key.  

Furthermore, is message secure enough although at present message security is not too important for us.