This is one of the examples of what not to do from "End-to-End Arguments in System Design" (Saltzer, 1984) [1]: The function in question can completely and cor

This is one of the examples of what not to do from "End-to-End Arguments in System Design" (Saltzer, 1984) [1]: The function in question can completely and correctly be implemented only with the knowledge and help of the application standing at the endpoints of the communication system. Therefore, providing that questioned function as a feature of the communication system itself is not possible. Applications vary in what needs encryption and how that encryption is implemented, so it is better to leave this to them to implement; otherwise, all applications may suffer the cost of your protocol's encryption implementation without getting the actual encryption that they need. [1] http://pages.cs.wisc.edu/~bart/739/papers/end-to-end.pdf http://pages.cs.wisc.edu/~bart/739/papers/end-to-end.pdf