How to protect Streaming Key from public?

I am sending a live RTMP stream from OBS to Wowza Streaming Engine and playing it back in Flow Player on my website. Members of my website will be able to stream to their own “channels”.

The only issue is that if a viewer on my website views the source, he/she can access the stream key. If a user gets another users stream key, then they would be able to stream to their channel.

What is a good way to protect this stream key?