Consensus rules

When we say consensus, we talk about a group of techniques used in systems with many participants to agree on decisions that benefit the whole underlying system. While voting gives the power to decide to a few selected individuals that fulfill a set of requirements, consensus takes in consideration each and every one of the participants to agree on the global way of thinking.

Each algorithm that implements any form of consensus when it comes to blockchain technology must provide the following features:

• To agree on decisions that benefit the whole system: The idea is to take choices that not only benefit the individual, but the entire network, so that everybody has a better platform.

• To allow open participation: Every person should be completely free to join and make decisions that they believe will be positive.
• To be secure enough so that malicious actors can't prejudice the system: All the consensus agreements have to be toward the betterment of the systems, where malicious users can't have enough power to decide for many others.

The problem with reaching consensus started with what's known as the Byzantine Generals Problem, a problem that consists on the fact that many computers can't easily agree on a predetermined order. Some computers will receive the order late, others will ignore it because they don't benefit from fulfilling it, while others will follow the order as best as they can.

In essence, consensus rules are mandatory to achieve a global state that all agree with, while being rewarded for participating in a beneficial manner in the decision-making process.