Figure 4.

Illegal information exchangeC${}_{{\mathsf{D}}_{\mathsf{1}}}$⇏P${}_{{\mathsf{F}}_{}}$. D-Link.933L does not want to share any service withApple.LukePhone (i.e., there are no outgoing arrows), butPhilips.HueMotioncan potentially act as a bridge between the two devices. This might lead to critical information leak, therefore it has to be prevented.