Checkpoint
Also known as: Blockchain Snapshot, Finality Marker, State Reference Point
A periodically created state summary in blockchains that optimizes synchronization and enhances finality.
A checkpoint in blockchain refers to a snapshot or summary of the blockchain state at a specific block height, used to aid in synchronization and ensure finality. Checkpoints help new nodes sync faster by allowing them to start from a recent trusted state rather than validating every historical block. They also serve as fixed points in consensus, used in Proof of Stake systems to finalize blocks and prevent long-range attacks. In Ethereum, finality checkpoints occur every epoch, anchoring progress and improving chain security. Checkpoints can be hardcoded, dynamically generated, or voted on by validators.