Surely the greatest irony in the blockchain space is that there has never been any agreement on “the best” consensus model. Bitcoin and Ethereum are widely lauded for pioneering the concepts of blockchain and smart contract platforms respectively, but both also come under heavy criticism for their lack of scalability. The scalability challenge is largely due to their use of the proof-of-work (PoW) consensus method.
Therefore, teams of developers have been focusing for years on devising a different method for achieving consensus among network participants. One that removes the bottlenecks caused by PoW, but still achieves the security of decentralization, while maintaining the right balance of incentivizing honest actors and deterring bad ones.
So far, there have been dozens of attempts at solving this quandary. However, only a few have emerged as main contenders, namely proof-of-stake (PoS) and delegated proof-of-stake (dPoS.)
However, a new horse just entered the race. A blockchain project called Solana is developing a secure, scalable blockchain that can handle up to 50,000 transactions per second on its testnet. How does it achieve this? Through a new consensus method, called Proof of History.
Proof of History, Explained
Proof of History (PoH) aims to lighten the load of the network nodes in processing blocks by providing a means of encoding time itself into the blockchain. In a regular blockchain, reaching consensus over the time a particular block was mined is as much a requirement as reaching consensus over the existence of the transactions in that block. Timestamping is critical because it tells the network (and any observer) that transactions took place in a particular sequence.
In a PoW scenario, the successful block miner is the first to find the correct nonce, which requires a certain amount of computing power to perform.