Message security encrypts each individual message to protect sensitive data. Transport security secures the end-to-end network connection to protect the network traffic.
Use the following transport security criteria to decide whether to use it or not:
Point-to-point. Transport security supports point-to-point communication and does not support intermediary scenarios or protocol transition.
Streaming. Transport security can support streaming data scenarios.
Binding limitations. Transport security does not work with the wsDualHttpBinding.
Authentication limitations. Transport security does not work with negotiation, username or Kerberos direct authentication.
Use the following message security criteria to decide whether to use it or not:
Intermediaries. Message security supports scenarios with intermediaries or protocol transition.
Encryption flexibility. Message security allows you to encrypt part of message while leaving other parts in clear-text.
Binding limitations. Message security does not work with the netNamedPipeBinding. Secure conversations. Secure conversation only works with message security.
Authentication limitations. Message security does not work with basic or digest authentication.