Since, WCF's support various protocols, such as TCP, HTTP, and MSMQ, the user must ENSURE that the necessary steps are taken to safeguard messages, and also establish security policies for authenticating and authorizing CALLS. WCF provides an easy and rich CONFIGURATION environment for secure messaging. WCF supports the following security models:  

• Message Security: This application uses the WS-Security specification to encrypt messages. Messages are now securely encrypted using certificates and can be sent over any port using PLAIN HTTP.  
• Transport Security: This is a protocol that implements security, so it only works point to point. Since security is protocol-dependent, security support is limited and confined to the standard protocol security limitations.
• TransportWithMessageCredential: It can be referred to as a mixture of both Message and Transport security implementation. Credentials are sent with the message, and the transport layer provides message protection and server authentication.