Proof-of-work and proof-of-stake are consensus mechanisms, or algorithms, that allow blockchains to operate securely. These consensus mechanisms keep blockchains secure by allowing only genuine users to add new transactions.

They work by making potential participants prove they have dedicated some resource, like money or energy, to the blockchain. This feature helps filter out those who may not be genuine or committed to the network.

The main difference between proof-of-work and proof-of-stake is how they choose who can add transactions to the chain.