Rewards and penalties are inherent incentives in [[Consensus Mechanism|consensus mechanisms]], and slashing is a type of penalty commonly levied in [[Proof of Stake]] blockchains against one or more [[Validators|validator(s)]]. These penalties are triggered on malicious activity during block attestation, where "slashed" validators can ultimately be removed from the network and lose some/all of its staked funds. Slashing is designed to deter collusion around block proposals and to maintain integrity by preventing block [[Reorgs|reorgs]] or [[Forks|forks]], while bolstering [[Finality|finality]] on the chain. As such, slashing is generally part of the core protocol. >[!tip] In [Ethereum's implementation of slashing](https://ethereum.org/developers/docs/consensus-mechanisms/pos/rewards-and-penalties#slashing), staked funds are slashed using a sliding scale which correlates to the number of flagged validators; the more collusion detected among these validators, the greater the penalty's magnitude. Slashing can occur as a result of various types of misconduct by validators: - Proposing/signing blocks later deemed invalid - [[Double-proposing]], or proposing more than one block for the same slot or time period - [[Surround Voting]], or a validator who is proposing multiple (conflicting) versions of history Implementations will vary across blockchain protocols but generally the protocol will follow these steps: 1. A validator proposes or attests to a block. 2. Other nodes in the network monitor the actions of all validators. 3. If a validator acts maliciously (e.g., signing multiple blocks at the same height), this behavior is detected by other nodes. 4. Evidence of this misbehavior (a [[Fraud Proof|fraud proof]]) is included in a future block. 5. Once this evidence has been added to the blockchain, it's irrefutable and triggers an automatic slashing condition within the protocol. >[!tip] Slashing can sometimes be triggered in situations where *honest* validators go offline, failing to perform their duties from non-participation or some other network consensus failure. If enough nodes fall into such a state, it could result in a global [[Inactivity Leak|inactivity leak]] on the blockchain, where a majority of validator nodes lose some portion of staked funds.