What is Byzantine Generals' Problem?

The Byzantine Generals' Problem is a term used in computing to describe a situation in which all parties or components within a system must agree on a single consensus-based strategy in order to avoid complete network failure. Failure can be caused when one of the nodes or other architectural components within the network are unreliable. A network that is able to solve the Byzantine Generals' Problem is considered Byzantine Fault Tolerant (BFT). Most actively used blockchain consensus mechanisms are Byzantine Fault Tolerant.