The point at which a transaction is considered irreversible and economically infeasible to revert.
Finality reflects confidence that a transaction won’t be reversed. In PoW chains, finality is probabilistic and increases with confirmations; in BFT-style consensus, finality can be explicit once validators sign a checkpoint.
An exchange might require 6 confirmations for BTC deposits but fewer for BCH due to differences in block times and reorg risk tolerance.
Factors include network hashrate, reorg depth history, fee market pressure, and attacker costs. Economic finality is reached when reorg cost exceeds potential gain.
For low-value payments, merchants may accept zero-conf on BCH with risk mitigations like double-spend proofs and fraud checks.
All terms and definitions may update as the Cryptionary improves.