Yeah, but most unencrypted data doesn't look like random noise. If you run a few statistics on a packet/file/whatever and it looks random, you can comfortably assume its probably encrypted.
> ... you can comfortably assume its probably encrypted.
Or compressed, so you'd need to be able to detect every compression format ever created. I imagine that any time somebody serializes a succinct data structure [0], you're going to have to add a signature for that as well. I'm not confident that even an organization with the resources of the NSA would be able to keep up with that, you'd have to make illegal the writing of data structure libraries. Of course, the optimistic bureaucrat would see this as an opportunity for the creation of another federal entity, like the patent office, where code can be submitted for registration and approval. The Department of Circumlocution™.
