I assert that an "unrecognizable encrypted message" will be a
random sequence of bits. Is my assertion correct?
It's neither correct or incorrect because the specific notion of randomness hasn't been specified.
I don't understand what you mean by "specific notion of randomness hasn't been specified". How many different "notions of randomness" are there?
Your statement is falsifiable, however, since sometimes a non-random string of bits is what you want to get out, if what you would expect to get out normally was also non-random. And you want them to be non-random in the same way.
I agree. The output of the reverse stego process should produce similar results, regardless of the presence of a hidden message. That's the point I've been trying to make. I've been attempting to make that point by describing a hypothetical stego system that, when run in reverse, produces a random sequence of bits. I suppose there could be other hypothetical stego systems that produce non-random output, but then you would need a decryption system that could understand and decrypted that non-random output. I prefer random bit sequences. Or perhaps I should say - bit sequences with no apparent structure.
Of course, this assumes there is no other way to detect a hidden message besides reversing the stego process and testing the result.
Don't count on it. Statistical tests can find correlations you hadn't suspected were there. In fact, for some message types, _not_ finding the correlations may indicate dithering, or maybe a steganographic message.
I agree completely. This is a large part of what makes effective steganography so difficult to achieve. Jim_Miller@suite.com