Supermajority (Ethereum)
Web3 / mining staking
In Ethereum's Proof of Stake consensus protocol, a supermajority represents at least two-thirds of the total staked ETH actively validating the network. This threshold is critical for achieving finality on the blockchain, meaning once two-thirds of validators attest to a block, it becomes irreversible under normal network conditions. Supermajority thresholds protect against validator attacks by requiring an attacker to control or compromise significantly more than half the network's stake. The mechanism creates strong economic incentives for honest participation, as attempting to double-sign or create conflicting attestations results in severe penalties called slashing, where validators lose portions of their deposited stake. Example: During normal Ethereum operation, when a block receives attestations from validators representing at least 66.7% of total staked ETH within an epoch, the Casper Finality Gadget marks it as "justified" and subsequently "finalized," making historical reversions computationally and economically impossible. Why it matters for mining and staking: Supermajority requirements ensure validator security and network stability by making attacks economically infeasible. This encourages widespread stake decentralization and rewards honest validators through participation incentives while punishing malicious behavior.
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