WCF has a huge security component to it and encrypts and signs messages by default. It could be an overkill especially if you are debugging or transporting data using a secured channel and are trying to squeeze out every bit of performance.
To avoid this, you can just implement integrity when confidentiality is not a requirement. In such cases, WCF provides the facility to set the protection level on the message. Also note that protection levels can only be set for messages. WCF does not allow the disabling of protection levels for transport security. The following application file snippet illustrates how to achieve this using configuration files; the messages are required to be signed only before they are sent:
<bindings> <wsHttpBinding> <binding name=”test”> <security mode=”Message”> <message defaultProtectionLevel=”Sign”/> </security> </binding> </wsHttpBinding> </bindings>
You can also specify the protectionLevel property through code at ServiceContract and OperationContract as well. Message exchange patterns (MEPs) determine how the messages are sent from the sender to the receiver. WCF does implement security support for both one-way and request-reply MEPs. However, duplex MEPs are available only in WsDuaHttpBinding, NetTcpBinding, and NetNamedPipeBinding.