Slashing

Slashing is a punishment mechanism used in Proof of Stake blockchains to penalize validators who behave maliciously or in ways that could threaten the security of the network. When a validator commits certain specific violations — particularly actions that look like deliberate attempts to cheat the consensus process — a portion of their staked cryptocurrency is automatically and irreversibly destroyed. The validator is also forcibly removed from the active validator set.

The most common slashable offense is “double voting” — signing two different blocks at the same height as if both are valid. In Ethereum, slashing initially burns a minimum of 1/32 of the validator’s stake, but if many validators are slashed at the same time — suggesting a coordinated attack — the penalty scales up dramatically and can approach 100% of the stake. This “correlation penalty” punishes large-scale attacks far more severely than isolated accidents. Slashing is distinct from inactivity penalties, which are gentler and applied when a validator is simply offline or unresponsive.

Example: Imagine a bank that employs auditors to verify financial records. Each auditor puts up a personal bond before starting work. If an auditor is just occasionally late submitting reports, they get a small fine. But if they are caught deliberately certifying false records — especially as part of a group scheme — they lose their entire bond and their license is revoked permanently. Slashing works on exactly this principle.