Slashing

Slashing is an economic penalty mechanism in Proof of Stake blockchains that automatically confiscates a portion of a validator's staked tokens when they violate protocol rules, providing cryptoeconomic security through the threat of financial loss. The slashable offenses target behaviors that could compromise network integrity: double-signing (proposing or attesting to conflicting blocks at the same height), surround voting (making attestations that contradict previous ones in ways that could enable long-range attacks), and extended downtime in some protocols. When a validator commits a slashable offense, their stake is partially or fully destroyed, and they may be forcibly ejected from the validator set. Ethereum's slashing penalties are substantial: initial penalties of at least 1 ETH plus a correlation penalty that increases if many validators are slashed simultaneously (indicating coordinated attacks). The correlation penalty can reach the entire stake if enough validators misbehave together, this makes large-scale attacks economically ruinous. Slashing conditions are carefully designed to be provable and attributable: you can only be slashed for actions cryptographically signed by your validator key, preventing false accusations. Accidental slashing can occur through operational errors like running redundant validator instances that double-sign, making proper validator setup critical. Slashing represents the 'stick' in Proof of Stake's incentive structure, the counterpart to staking rewards. It makes attacking the network costly even for well-resourced adversaries.