Verification is achieved not through a central authority but rather through solving a puzzle that requires a significant amount of work
Proof of Stake - Ethereum
Verification is achieved through validators who lock up set amounts of cryptocurrency in a smart contract on the blockchain in exchange for the right to validate new transactions
If validators are found improperly validate bad or fraudulent transactions, they may lose some or all of their stake as a penalty.
Proof of History - Solana
Verification is achieved through Verifiable Delay Functions (VDFs).
All Solana transactions are hashed with an preimage resistant algorithm such as SHA256 that runs over itself continuously with the previous output used as input for the next hash. The input hash, the counter and the output hash are public
If one takes a picture with that day’s New York Times, one can be certain that the photo took place after that day’s NYT was published; similarly, if one receives a message with the input hash, we know it was generated after the counter which is linked with that input hash