How Do “Checkpointing” Mechanisms Enhance Finality in Some Blockchains?

Checkpointing involves periodically and officially confirming the state of the blockchain at a specific block height. This is often done by a trusted entity or a consensus of a secondary network.

Once a block is checkpointed, it is considered absolutely final and irreversible, even in the event of a chain reorganization attempt. This mechanism provides stronger, more immediate finality than the probabilistic finality of native PoW, making 51% attacks on older, checkpointed blocks impossible.