Consensus Mechanism

A consensus mechanism is the method a blockchain uses to let its distributed participants agree on a single valid version of the ledger without a central authority. It decides who can add the next block and how the network resolves disagreements.

How it works

A good mechanism makes honest participation cheaper or more profitable than cheating. Proof of work ties the right to add blocks to expended computing power; proof of stake ties it to locked-up capital that can be penalised. Other designs delegate block production to elected validators or use variations tuned for speed. In each case the rules ensure that altering confirmed history is economically irrational.

Why it matters

The consensus mechanism shapes a network’s security, energy use, decentralization and transaction speed, so it is one of the most important things to understand about any blockchain. Different chains make different trade-offs among those properties.

Example

Bitcoin uses proof of work, while Ethereum, Cardano and Solana secure themselves with proof-of-stake-based designs.