Byzantine Generals Problem

We have a problem. This is called a consensus failure. The people in the network did not come to consensus on what the state of reality is. Having no better system, they went with majority rule, which led to dishonest people controlling the network and spending money they didn’t have. If we want to make a permissionless system where anyone can participate without asking, then it must also be resilient to dishonest actors. Now we get to solve one of the hardest problems in computer science: distributed consensus between parties where some are dishonest or unreliable. This problem is known as the Byzantine Generals Problem and is the key that Satoshi Nakamoto used to unlock the invention of Bitcoin.

Inventing Bitcoin: The Technology Behind The First Truly Scarce and Decentralized Money Explained