Blockchain validators

Blockchain validators are used by PoS systems. A PoS system works by requiring computers that wish to participate in the network to have stake—a large number of tokens—to assist in the blockchain. Unlike PoW algorithms, computers cannot join the network and expect to have any say in consensus. Rather, they must buy in through token ownership. Depending on the network, the naming convention for validators might be different. Tendermint has validators, Steemit and Bitshares have witnesses, Cardano has stakeholders, and so on. A validator is a computer with a positive stake (number of tokens) that is allowed to participate in the network and does so. Each chain has its own rules for how this works, and these will be covered more in-depth in Chapter 7, Achieving Consensus.