Consensus Mechanism

A consensus mechanism is a set of rules or principles by which a group of network participants come to an agreement about the state of the network. When two or more nodes are in disagreement about the state of the network, they use the consensus mechanism to reach a common understanding. Once they have reached an agreement, the nodes can then start transacting based on that understanding.

In a distributed ledger system such as Bitcoin, every node maintains a copy of the blockchain. This allows for rapid and secure transactions between parties because everyone can agree on what is happening without needing to go through a central authority. The consensus mechanism is used to reach an agreement about which blocks are added to the blockchain and which are rejected. Nodes use a number of methods to reach consensus, including majority voting, proof-of-work, and proof-of-stake.

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Briefly talk about the Proof of Work (PoW)
Proof of Work is a consensus mechanism used in blockchain networks to ensure that nodes agree on the state of the network. It works by requiring nodes to solve a difficult mathematical problem in order to add a new block to the blockchain. This problem is called a proof-of-work puzzle. Nodes that solve the puzzle first are rewarded with cryptocurrency.

The difficulty of the proof-of-work puzzle is adjusted every few blocks so that it takes an average amount of time for a node to solve it. This makes it difficult for anyone to generate blocks quickly. As a result, it is difficult for someone to control the network. The proof-of-work puzzle is also designed so that it is impossible to generate a block faster than everyone else. This protects the network from attackers who try to generate blocks in order to take advantage of others.

Briefly talk about the Proof of Stake (PoS)
Proof of Stake is another consensus mechanism used in blockchain networks. It works by requiring nodes to hold a certain amount of cryptocurrency in order to add a new block to the blockchain. This ensures that the nodes are more likely to agree on the state of the network.

Nodes that hold more cryptocurrency are more likely to be chosen as validators. Validation is a process by which nodes determine whether or not new blocks should be added to the blockchain. Validators use their own copies of the blockchain and check each block against consensus rules.

Other type of consensus mechanism
In crypto ecosystem the two most used consensus mechanisms are PoW and PoS but other types two types are also used. These are Byzantine Fault Tolerance and Delegated Proof of Stake.

Byzantine Fault Tolerance is a type of consensus mechanism that works when there are multiple nodes that are trying to make a decision. If two of the nodes disagree on what the correct action is, then they will try and reach an agreement by voting with their respective copies of the blockchain.
Delegated Proof of Stake is a type of consensus mechanism that works when there is just one node that needs to make a decision. This node is known as the authority node and it can validate new blocks by simply checking to see if the block has been added to the correct chain.

Thankyou @fredquantum for this great lesson