In this chapter, we explained some of the most prominent protocols in blockchain and traditional distributed system consensus. We covered several algorithms, including Proof of Work, Proof of Stake, traditional BFT protocols, and the latest protocols, such as HotStuff. Distributed consensus is a very ripe area of research and academics and industry researchers are participating in this exciting subject. It is also a deep and vast area of research, therefore, it is impossible to cover every protocol and all dimensions of this gripping discipline in a single chapter. Nevertheless, the protocols and ideas presented in this chapter provide solid ground for further research and more in-depth exploration.
In the next chapter, we'll introduce Bitcoin, which was the first blockchain and cryptocurrency, invented in 2009.