Why Consensus Matters

In a decentralized network with no central authority, how do nodes agree on the state of the ledger? Consensus mechanisms solve this problem — they're the rules by which a distributed network reaches agreement. Without consensus, nodes could have conflicting views of which transactions are valid, leading to double-spending and chaos. A good consensus mechanism must be fault-tolerant (works even if some nodes fail), Byzantine fault-tolerant (works even if some nodes are malicious), and live (the system continues to make progress).