Blockchain Reorganization Probability

Blockchain reorganization probability is the statistical likelihood that a network will revert a sequence of blocks in favor of a longer chain. This occurs when two validators find a block at the same time, leading to a temporary fork.

In proof-of-work and some proof-of-stake systems, the chain with more work or stake is considered the "truth," causing the shorter chain to be discarded. This risk is highest immediately after a block is mined.

For financial derivatives, a reorganization can cause a trade to be "un-done," leading to significant financial discrepancies. Users must wait for enough "confirmations" to ensure that the probability of a reorg is negligible.

The risk is not uniform across all chains and depends on the consensus mechanism and the number of active nodes. Understanding this probability is vital for setting appropriate confirmation requirements for large trades.

It is a fundamental trade-off between speed and certainty.