Blockchain consensus mechanisms or algorithms are protocols that ensure all of the nodes on a blockchain agree with each other. This allows for the determination of which transactions get added to the blockchain because they are legitimate. Consensus mechanisms are key since they ensure that everyone utilizes the identical blockchain. They also reduce the risk of attacks.
Proof of Work (PoW)
The first consensus mechanism for the blockchain was Proof of Work (PoW), which Bitcoin uses. PoW is also known as “mining.” With Proof of Work, miners solve a series of mathematical puzzles that rely on computational power. The miner who solves the puzzle first creates a block and earns a reward. All of the puzzles are asymmetric and can only be solved by guessing. In other words, to find the answer faster, you need additional computational power.
It is also noteworthy that the puzzle difficulty depends on the speed at which blocks are mined. This allows for block creation within a given timeframe since puzzles can get easier or harder.
Proof of Work has the major disadvantage of using a vast amount of resources. Many feel that it may be unsustainable due to the sheer number of resources used.
Proof of Stake (PoS)
Proof of Stake (PoS) is an environmentally friendly alternative to Proof of Work that uses fewer resources. PoS works off the idea that those who own more coins within a network have a reason to ensure the network is maintained; after all, this ensures their coins retain a high value.
Proof of Stake relies on randomization to decide who will produce each block. Users have the option of staking tokens and become validators who produce blocks. Doing so will lock up the tokens for a set period of time. To determine who will produce the following block, the process will consider things like the person with the largest stake and the amount of time for which the coins have been staked.
In return for their work, validators receive a reward. This is sometimes part or all of the transaction fees for the given block. Or it may be a set amount of coins. Overall, PoS is significantly more energy-efficient. It also ensures that all validators actually care about the network since they own tokens.
Delegated Proof of Stake (DPOS)
Delegated Proof of Stake is known for being quick. Users stake their coins as a way to vote for delegates, with the vote’s weight depending on the stake. The delegate is an organization or person that wishes to produce blocks. Delegates with the most votes get to produce blocks, earning rewards.
Other Methods
Proof of Capacity relies on plotting. Solutions get pre-stored in hard disks or other digital storage.
Proof of Elapsed Time (POET) fairly and randomly determines who produces the block depending on how long they waited.
There are also other consensus mechanisms, with blockchain projects producing more. These are just among the most common.