Block Finality
Block Finality is the point at which a transaction is considered permanently confirmed and irreversible on the blockchain. In some systems, finality is probabilistic, meaning that as more blocks are added on top, the probability of a reversal decreases but never hits zero.
In other systems, particularly those with advanced finality gadgets, finality is deterministic, meaning once a block is confirmed, it cannot be changed without a hard fork. Achieving fast and deterministic finality is a major goal for protocols, as it allows for safer and more efficient financial transactions.
It is essential for bridges and cross-chain operations, where the certainty of state is paramount. The consensus mechanism determines how quickly and reliably this finality is reached.
It represents the ultimate settlement of a transaction. Without finality, the ledger remains in a state of flux.