Re: "Ship! Come back!"
"They can update the app, but egress traffic from each participant cannot be avoided without fundamentally changing the protocol."
AFAIK if you were traffic sniffing your phone, all you'd see is encrypted packets going to/from Whatsapp's servers, so there'd be no way to tell there.
As for "ignoring the keys", I mean that currently if someone is added to a group chat, you would normally get a notification along the lines of "J BLoggs has been added to this chat". They could add a client side update such that when GCHQ is added to a group chat, it did not notify the user.
This wouldn't be possible with an open protocol like PGP, but when the only way of using Whatsapp is a closed source program, there's no way of telling what's happening to your conversations other than trusting them.
Biting the hand that feeds IT
