This is a question that we receive a lot of tickets on and the answer is there is no perfect way to secure streams 100%. Wowza suggests that you use several of the security options we offer together as your best means of protection. For example, you can block certain IP addresses in addition to using secure tokens so that only the IP addresses of the people you want to have access to the stream will benefit from the secure token exchange. You can use authentication requirements, geoblocking, encryption, IP addresses and secure token all together as your best defense.
These are the security options we offer:
https://www.wowza.com/docs/security-options-in-wowza-streaming-engine