Finality
Also known as: Transaction Finality, Consensus Finalization, Blockchain Irreversibility
The assurance that a blockchain transaction is permanently recorded and cannot be reversed or altered.
Finality in blockchain refers to the point at which a transaction becomes irreversible and is considered permanently confirmed. It ensures that once a transaction is finalized, it cannot be changed, double-spent, or removed from the ledger. There are two main types: probabilistic finality, common in Proof of Work systems like Bitcoin, where deeper confirmations reduce reversal chances; and absolute finality, found in BFT-style Proof of Stake systems, where transactions are immediately and irrevocably finalized after consensus. Finality is crucial for financial applications, cross-chain interactions, and user confidence in decentralized systems.