Ever heard of blockchain consensus mechanisms? Every crypto user, be it a rookie or expert, has at least heard the term consensus mechanism. Consensus mechanisms are systems set in blockchains to secure the network by ensuring that only responsible parties add new transactions.

The <a href="https://www.allerin.com/blog/8-blockchain-consensus-mechanisms-you-should-know-about">two most popular</a> consensus mechanisms are <a href="https://www.investopedia.com/terms/p/proof-work.asp">Proof of Work</a> and <a href="https://ethereum.org/en/developers/docs/consensus-mechanisms/pos/">Proof of stake</a>. PoW came about by the launch of Bitcoin, but experts discovered that it consumes massive amounts of resources. Hence, PoW was deemed inefficient for new chains. Now came the rise of PoS. 

In PoS, the network allows participants to hold some stakes in the native currency and participate in authenticating and validating transactions. PoS is considered an energy and cost-efficient consensus mechanism. 

After the first introduction of PoS, other <a href="https://www.cryptoknowmics.com/news/everything-you-should-know-about-zcash">projects</a> followed with their versions. Today, the guide discusses three of the most prominent blockchains using PoS, answering the question of who will win the race.     
<h2>Understanding Ouroboros Cardano's PoS</h2>
Cardano is one of the largest blockchain networks today. This network was founded in 2018 to provide solutions that the Ethereum network was never able to. 

At launch, Cardano desired to use PoS as its primary system to strengthen and sustain the network. However, Cardano first did thorough research, creating a new PoS system called Ouroboros. Ouroboros is the first consensus algorithm developed after thorough peer-reviewed research. Ouroboros combines the strengths of PoW with those of PoS systems. 

Ouroboros uses mathematical algorithms for verification, reducing the power consumption vastly. Accordingly, Cardano's Ouroboros breaks the entire blockchain into slots, assigning a leader for each. The chosen slot leaders have to add new blocks to the chain. Accordingly, the slot leaders often consider the last blocks as transient in a system called settlement delay.  

Since its launch, Ouroboros has <a href="https://iohk.io/en/blog/posts/2020/03/23/from-classic-to-hydra-the-implementations-of-ouroboros-explained/">undergone multiple implementations</a> starting with the Ouroboros classic, BFT, Genesis, Praos, and Hydra. The main issue the Hydra version solves is scale, improving the throughput to a range of 1000tps to 1 million TPS. Ouroboros' continuous upgrades set Cardano on a leading path in the PoS race. 
<h2>Ethereum, Ethereum 2 </h2>
Ethereum is the second-largest blockchain network, with the second-highest market capitalization. Today, the main version of the Ethereum network uses a PoW system. However, Ethereum is already planning a merger with Ethereum 2, which uses PoS. 

Ethereum PoS is a significant improvement of PoW in that it reduces the power consumed for computations. The validators have two jobs; creating blocks when chosen or validating proposed blocks. Ethereum calls this validation system attesting. Every validator must be very careful since certifying a malicious block will lose rewards. 

The <a href="https://beaconcha.in/">beacon chain</a> has 64 shards. Shards are small parts of the blockchain. Usually, sharding would complicate the entire Ethereum PoS since Blockchain validators would have to attest from each chain. But, Ethereum's shards are interconnected, and they intercommunicate. Hence, a validation in one shard is synced with all other 63 shards. In the long run, the shards remain in sync.  

Each shard block must have 128 validators every moment, who handle the validation for 32 slots, forming an Epoch. Once they complete the slots, the 128 validator committee is disbanded, and a new one is created. Two-thirds of the network validators must agree for a block to reach finality. 
<h2>Understanding Solana's  PoS</h2>
After discussing the Cardano and Ethereum PoS, it's time to look into Solana. Solana uses a unique <a href="https://academy.binance.com/en/articles/byzantine-fault-tolerance-explained">Byzantine Fault Tolerant</a> system called <a href="https://medium.com/solana-labs/tower-bft-solanas-high-performance-implementation-of-pbft-464725911e79">Tower consensus</a> as the primary way to power the network. Tower consensus uses a <a href="https://medium.com/solana-labs/proof-of-history-a-clock-for-blockchain-cf47a61a9274">Proof of History</a> system, which adds the time factor into the chain.  

PoH uses a delay function to hash events and transactions in the chain, giving each event a unique hash. The unique hashes help the network agree on the order of events without waiting for information from other nodes. Hence, the Solana network achieves high throughput while maintaining top security. So, how does PoS fit into this system?

To participate as a person generating the PoH sequences or transaction validator, you must stake some amount of SOL. According to network reports, the nodes with the highest stakes are allowed to validate and get the reward. Therefore, PoS is used to release PoH sequences and validate transactions.  

Small SOL holders can combine their holdings with larger validators and earn a small portion of the reward. This Proof of stake system combined with PoH protects the network and fosters decentralization. The PoS staking requirements help protect the network from malicious actors.
<h2>Who Wins the POS Race?</h2>
Currently, Cardano is ahead in the PoS race, with Solana following closely. Ethereum is lagging. While all the other chains are already running PoS systems, Ethereum has yet to merge with Ethereum 2 fully. Ethereum had plans to merge the Beacon chain by 2021, later revised to sometime in 2022. The slow full adoption of PoS leaves Ethereum behind in the race. 

Cardano's Ouroboros is probably the most <a href="https://www.cryptoknowmics.com/news/weekly-recap-of-cryptocurrency-world">exciting</a> PoS in the crypto space. Being created after Peer-reviewed research, Cardano solves the minor problems associated with blockchains. Solana is also way ahead when compared to Ethereum. Its PoH and PoS systems seem quite energy-efficient, with long-term sustainability. 

However, as Solana and Cardano grow with Defi and NFTs, they may face issues that will slow their progress. In such a case, Ethereum will already be ahead with solutions, hence likely taking the lead. 

While at the moment, Cardano and Solana are ahead, Ethereum will catch up. But, since Cardano’s Ouroborous is under constant upgrades, it's safe to believe that Cardano will win the race.

Ethereum, Cardano, and Solana, who is winning the race to PoS 

Consensus mechanisms are systems set in blockchains to secure the network by ensuring that only responsible parties add new transactions.

Adam is an outgoing young lad who likes adventures and discovering new things.Despite his boring life, he loves writing about cryptocurrencies and exploring what blockchain technology can do for the coming digital world where all adventures will be virtual.

Ethereum, Cardano, and Solana, who is winning the race to PoS

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