What Is a “Rollback” in the Context of a Blockchain and What Are Its Consequences?

A rollback in the context of a blockchain is the process of reverting the blockchain's state to a previous point in time, typically to a checkpoint, in order to undo the effects of a malicious attack or a critical bug. The consequences of a rollback can be significant.

All transactions that occurred after the checkpoint are effectively erased, which can lead to financial losses for users who participated in those transactions. A rollback can also damage the reputation of a blockchain project, as it demonstrates that the blockchain is not truly immutable.