Blockchain Consensus

Blockchain is a distributed peer-to-peer technology. All nodes in the network have to agree on the state of chain and what are its valid blocks. Since there's no centralized control, and nodes cannot be trusted, reaching this agreement is not trivial. Every blockchain implementation must therefore define what's called a?consensus algorithm?to arrive at an agreement.?This is also called?consensus protocol.

Consensus is not exclusive to blockchain. It's a classical problem in distributed computer systems. In fact,

Any algorithm that relies on multiple processes maintaining common state relies on solving the consensus problem.

• TYPES OF BLOCKCHAINS
• Proof of Work (PoW): An expensive computation is required and this can be verified by other nodes. Nodes can remain anonymous and anyone can join.?PoW?is synonymous with mining. Systems that don't use?PoW?can be said to be doing?virtual mining.
• Proof of Stake (PoS): Stakeholders are those having coins or smart contracts on the blockchain. Only they can participate. Those with high stakes are chosen to validate new blocks. They are rewarded with coins. While coins are "mined" in?PoW, they are "minted" in?PoS.?Blocks may still need to be signed off by other nodes before added to the chain.
• Delegated Proof of Stake (DPoS): In?PoS, those with large stakes can take control. In?DPoS, delegated nodes represent the interests of smaller nodes.