Last updated on June 21st, 2023 at 04:36 pm
Proof of Work (PoW) and Proof of Stake (PoS) are two of the most used consensus mechanisms by blockchains in the crypto space. While PoW is the consensus mechanism that is considered to be the original idea of how distributed nodes in a blockchain can come to an agreement on a single state of the network and is used by two of the largest cryptocurrency networks by market cap, Bitcoin and Ethereum, it’s PoS that has been attracting a lot of attention recently. The shift towards Proof of Stake (PoS) is highlighted by Ethereum’s plans to transition to the PoS algorithm as part of its Ethereum 2.0 update.
Wondering how the two consensus mechanisms are different from each other? Then, you’re at the right place. This article will talk about Proof of Work (PoW) Vs Proof Stake (PoS), the difference between the two most commonly used consensus mechanisms. Moreover, we’ll also take a look at why Ethereum is shifting from PoW to PoS.
Let’s dive in!
Why Do Blockchains Need A Consensus Mechanism?
Unlike a centralized system, there is no central authority in blockchain networks responsible for maintaining records or updating the blockchain. This is because all the cryptocurrency blockchains are public, which means that they operate independently from any single authority and are decentralized, self-regulating systems used by network users worldwide. Thus, maintaining a public blockchain requires contributions from all network participants who work as miners and validators to verify and authenticate transactions on the blockchain.
To ensure that all the transactions on the blockchain are genuine, all participants need to reach a consensus on the status of the ledger, and this is where the need for a consensus mechanism like PoW and PoS arises. With the help of a consensus mechanism that is fair, efficient, secure, transparent, and reliable, all the participants can agree on the state of the blockchain as it provides a set of rules which enables participants to decide on the legitimacy of each transaction and the contribution of all network participants.
For instance, a node doesn’t abide by the rules of the consensus mechanism and creates a new block. In such a case, the blockchain continues to operate the same way as long as all the other nodes choose to ignore it. However, if the disobedient node continues to create blocks that disregard the rules of the consensus mechanism, and a few other nodes decide to create blocks on top of these non-standard blocks, there will be a dispute in the blockchain network, which can also result in a hard fork. Therefore, a consensus mechanism like PoW or PoS is needed to prevent frequent hard forks of a blockchain as they can impact the stability of the community.
What Is Proof of Work (PoW)
The idea of Proof of Work (PoW) was initially explained by Cynthia Dwork and Moni Naor in a paper called ‘Pricing via Processing or Combatting Junk Mail‘ in 1993. They proposed PoW to deter spam rather than a consensus mechanism as it’s being used today in the world of blockchain and cryptocurrency. While the idea was proposed in 1993, in 1999, Markus Jakobsson and Ari Juels termed this process as Proof of Work as we know it today. While the idea of PoW has been around for decades, it was only with the arrival of Bitcoin in 2009 that the consensus mechanism truly gained recognition. Thus, the Bitcoin blockchain launch is considered the first notable implementation of PoW as a consensus mechanism.
The consensus algorithm used by Proof of Work (PoW) requires participant nodes of a blockchain to prove that their work successfully verifies the transaction, and as a result, they now have the right to add the transaction to the blockchain. In the Bitcoin blockchain, transactions are grouped in a memory pool known as ‘mempool,’ and the miners need to verify every transaction in this pool. Moreover, a new block is created in the Bitcoin blockchain every 10 minutes.
To validate the transaction in a PoW consensus mechanism, miners solve a cryptographic puzzle that requires high power computational resources. This process of solving the puzzle is known as mining, and the nodes that solve the puzzle get block rewards and transaction fees. In the PoW consensus mechanism, miners compete to become the first miner that solves the puzzle to generate the new block. This puzzle is revised every 2 weeks or 14 days, and based on the miners competing, the puzzle’s difficulty is adjusted. If the difficulty increases, more computational power is required to solve the puzzle.
Let’s take a look at the pros and cons of Proof of Work (PoW) consensus mechanism:
| Pros | Cons |
| PoW reduces the risk of 51% attack, making the blockchain network more difficult and costly to attack. | To solve the complicated puzzles, miners need access to significant computational power, which can be extremely expensive. This acts as a barrier to entry and restricts many from becoming a miner. |
| Miners are rewarded with block rewards and transaction fees as compensation for their ‘work’ using computational power. | The computational power needed consumes a lot of energy and electricity, which has many environmental impacts. |
| PoW enables the development of more decentralized networks. For example, Bitcoin is considered one of the most decentralized blockchain networks in the crypto space. | When a cryptocurrency nears its fixed cap, the PoW model becomes less attractive for miners as the incentives reduce. For example, As Bitcoin nears its supply cap of 21 million BTC, the number of BTC miners receive rewards reduce. |
What Is Proof of Stake (PoS)
Similar to PoW, Proof of Stake is another consensus mechanism used by many networks to maintain their blockchain. It was created as an alternative to Proof of Work as the skeptics of PoW argued the consensus mechanism requires too much energy and computational power, making it a less efficient method.
In PoS, miners can mine or validate transactions in a block depending on the number of coins they hold. Thus, the mining power of each miner reflects how many coins they own and are willing to stake. For instance, a miner that owns 10% of the supply can mine 10% of the blocks in the network. However, this also hinders the cryptocurrency from being used for spending purposes as it incentivizes HODLing.
Let’s take a look at the pros and cons of Proof of Stake (PoS) consensus mechanism:
| Pros | Cons |
| PoS models are more energy-efficient as they don’t require the high computational power needed in PoW. | PoS models can result in less decentralized networks. For example, If a single miner owns a large proportion of the supply, they can control the network. |
| Since the mining power depends on the % of coins owned by the miner, investing in expensive hardware and continuously upgrading them is also eliminated in PoS. | PoS models are deemed to be less secure as they are less decentralized. |
| PoS models are more scalable as the transaction verification process does not need the active involvement of the entire network. | PoS models are seen to be more susceptible to low-cost attacks. |
Why Is Ethereum Shifting To Proof of Stake (PoS)
Ethereum, the second-biggest cryptocurrency by market capitalization, plans to shift to Proof of Stake (PoS) from Proof of Work (PoW). The Ethereum team announced their plans to migrate the Ethereum blockchain to PoS in 2020 and began their shift with the launch of Beacon Chain on 1 December 2020. The Beacon Chain is the first step and introduces Proof of Stake to the Ethereum ecosystem.
At the StartmeupHK virtual festival in Hong Kong, Vitalik Buterin, one of the founders of Ethereum, said, ‘Proof-of-stake is a solution to the [environmental issues] of Bitcoin—which needs far fewer resources to maintain.’ With Ethereum’s move to PoS, it is believed that the blockchain network will become more scalable, more secure, and energy-efficient. Moreover, it will also help the network on-chain as it will result in increased throughput along with less costly and fast transactions.
In Conclusion…
- Both consensus mechanisms have their place in the crypto ecosystem, and their use depends on the primary use case of the project. While Proof of Stake offers many benefits compared to Proof of Work, there is still a long way to go before saying that PoS will replace PoW. Most cryptocurrencies are not in a hurry to shift to PoS as developers and community members currently don’t see the rewards of doing so compared to the efforts involved, and Bitcoin is the prime example of this.
So, which consensus mechanism is better in your opinion, PoW or PoS?
Comment below and let us know more!
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