Signal would be the same sort of thing. Perhaps you meant something with no central contral like a XMPP MUC. That way Apple would have no entity to threaten. Of

Signal would be the same sort of thing. Perhaps you meant something with no central contral like a XMPP MUC. That way Apple would have no entity to threaten. Of course then Apple would just nerf all the XMPP clients in the app store and/or the government would block access to all the XMPP servers in use. Dunno how well XMPP over Tor would work here...