Wouldn't a man-in-the-middle design make more sense? That would still be detectable but it's far from easy to do. I have to admit I'm not sure how silently Wha

Wouldn't a man-in-the-middle design make more sense? That would still be detectable but it's far from easy to do. I have to admit I'm not sure how silently Whatsapp and the like could essentially force a 'reset' that would allow the man-in-the-middle attack to take place, but generally it's not too unusual for a protocol to get out of sync and require renegotiation.