Byzantine generals problem

This is one of the classic problems faced by various computer networks, which until recently had no concrete solution. This problem is called Byzantine Generals' Problem (BGP). The problem at its root is about consensus, due to mistrust in the nodes of a network.

Let's imagine that various generals are leading the Byzantine army and are planning to attack a city, with each general having his own battalion. They have to attack at the same time to win. The problem is that one or more of generals can be disloyal and communicate a duping message. Hence, there has to be a way of finding an efficient solution that helps to have seamless communication, even with deceptive generals.

This problem was solved by Castro and Liskov, who presented the Practical Byzantine Fault Tolerance (PBFT) algorithm. Later, in 2009, the first practical implementation was made with the invention of Bitcoin by the development of PoW as a system to achieve consensus.

We will be discussing in detail the BGP in later chapters.