Solana vs Ethereum, Chapter 3: An In-Depth Blockchain Comparison
Consensus Models:
A consensus model is an algorithm or mechanism that allows all nodes and validators in the network to agree that a transaction is valid before it is confirmed. As such, consensus models vary widely. Here we will look at the consensus models that both projects use as a benchmark when comparing Solana and Ethereum.
Ethereum Consensus Model:
As I mentioned, Ethereum has made the transition from PoW consensus to PoS consensus. But what are the differences, and why adjust the main blockchain protocol? There are several reasons. To fully understand the benefits, I will briefly explain how each consensus model works.
Proof-of-work (PoW) consensus was introduced by Satoshi Nakamoto as a solution to the notorious "double-spending" problem in the scientific community. In short, it requires computers (nodes) to compete to solve an extremely complex equation that can mathematically prove the validity of a transaction. The equation is so complex that it requires a lot of computing power for nodes to guess the answer repeatedly. In the end, the first node to guess the answer correctly wins the transaction fee and puts it into the block. The process is repeated until the blocks are full and are cryptographically added to the blockchain. Although PoW is incredibly secure, it consumes a huge amount of energy. In addition, with significant initial costs, the network can easily be monopolized by a few large players.
On the other hand, Proof-of-Stake (PoS) works through validators, each of whom has a significant “stake” at risk (minimum 32 ETH), and are randomly selected to “confirm” the validation of transactions. Accordingly, validators are rewarded for confirming and proposing new blocks. If validators carry out malicious activities, their share will be reduced.
There are many benefits to moving from PoW consensus to PoS consensus. Firstly, overall energy efficiency increases by more than 99%. Thus, the ongoing costs of the validator are reduced. However, the initial cost will constantly increase in accordance with the value of ETH. In addition, validators do not require expensive mining equipment. Also, by providing greater immunity to centralization, PoS helps to better maintain the security of shard chains.
Solana Consensus Model:
Solana takes a completely different approach to network consensus. The company's founder, Anatoly Yakovenko, combined his more than 40 years of experience in distributed systems with the developing blockchain industry. The result was “time to consensus,” proof of history (PoH).
PoH is a revolutionary protocol that allows validators to have verifiable proof of transaction order down to a granular level. As a result, Solana's transaction throughput is 10,000 times faster than other leading chains.
At a fundamental level, proof of history (PoH) is a way to “cryptographically verify the passage of time between two events.” Each transaction or piece of data receives a unique timestamp representing the state, index, and data using cryptographically secure hashes. In this way, the order of events can be guaranteed and the exact time of data creation can be determined. Although PoH is critical to the consensus model, it is not the main consensus protocol. Instead, Solana uses a practical Byzantine Fault Tolerance (PBFT) mechanism called "Tower Consensus" intertwined with the PoS mechanism.
The combined efforts of PoS validators using the PoH protocol and optimizing consensus make Solana one of the fastest, most secure and decentralized blockchains in the world. The Tower Consensus protocol reduces latency by using the PoH protocol as a global time source.
