The 777 is fully FBW apparently and many (all?) sensors communicate wirelessly. What are the chances that it was hacked by a passenger or remotely and taken over this way?
I don't have direct experience with the 777, but do with the 787 and other aircraft systems. I am not aware of any wireless sensors. There are a lot of sensors which communicate with the various computers over multiplexed wired data buses.
ARINC 429 is a legacy, but still heavily used, digital data bus.
ARINC 629 is used on the 777.
ARINC 664 is used on the 787 (and Airbus A380).
The military systems and some commercial systems also use MIL-STD-1553 and other digital busses.
All wired.