Consensus

Consensus is the process of reaching a general agreement among nodes within a blockchain. There are various algorithms available for this especially when it is a distributed network and an agreement on a single value is required.

Mechanisms of consensus: Every blockchain has to have one mechanism that can handle various nodes present in the network. Some of the prime mechanisms for consensus by blockchain are the following:

• Proof of Work (PoW): This is the most commonly used consensus mechanism, also used by the first ever cryptocurrency, Bitcoin. This algorithm has proven most successful against Sybil attacks.
• Proof of Stake (PoS) this makes the mining of new blocks easier for those who have the highest amount of cryptocurrency.
• Delegated Proof of Stake (DPOS) one small change it has over PoS is that each node that has a stake can delegate the validation of a transaction to other nodes by means of voting.
• Proof of Importance (POI) this is designed to be energy efficient and can also run on relatively less powerful machines. It relies on stake as well as the usage and movement of tokens to establish trust and importance.
• Proof of Elapsed Time (PoET) this is a blockchain algorithm created by Intel, using Trusted Execution Environment (TEE) to have randomness and security in the voting process using a guaranteed wait time.
• Proof of burn (PoB) this is mostly used for bootstrapping one cryptocurrency to another. The basic concept is that miners should prove that they have burned coins, that is, they have sent them to a verifiable unspendable address.
• Proof of activity (PoA): A random peer is selected in this from the entire network to sign a new block that has to be tamper-proof.

All the preceding algorithms and a host of already available or currently under research make sure that the perfect consensus state is achieved and no possible security threats are present on the network.