Pay attention that relaying node knows nothing about the packet inside,
but just its size and priority. Transition packets are encrypted too:
using well-known @url{https://en.wikipedia.org/wiki/Onion_routing, onion
-routing} technology. @emph{bob} can not read @emph{bob-airgap}'s packets.
+encryption} technology. @emph{bob} can not read @emph{bob-airgap}'s packets.