A Byzantine node can behave arbitrarily: lie, tell different neighbours different things, go silent, or behave correctly until later. The name comes from Lamport, Shostak and Pease’s 1982 paper about generals agreeing on a plan when some of them are traitors.
The classic bound for exact agreement: with nodes you can tolerate at most traitors if .
Relevance to robots
Hacked firmware, spoofed GPS, and a failed sensor that still reports plausible numbers look the same from the outside. A compromised PLC in a water treatment plant is also a Byzantine node (see cyber-physical security).
See also
- resilient consensus for agreement on continuous values.
- Byzantine-robust learning for training models when some workers lie.
References
- L. Lamport, R. Shostak, M. Pease. The Byzantine generals problem. ACM Transactions on Programming Languages and Systems, 1982.