Give briefly description about Message security

https://msdn.microsoft.com/en-us/library/ms733137(v=vs.110).aspx

When using message security, the user credentials and claims are encapsulated in every message using the WS-Security specification to secure messages. This option gives the most flexibility from an authentication perspective. You can use any type of security credentials you want, largely independent of transport, as long as both the client and the service agree.