Sybil Attack
An attack where one actor spins up many fake identities to gain outsized influence over a network.
The name comes from a case study of a patient with multiple personalities. In a network, one person spins up hundreds of nodes or accounts to fake a crowd — enough to stuff a vote or surround a node and feed it false data.
Blockchains fight this by making identity expensive. Proof-of-work ties influence to computing power; proof-of-stake ties it to capital at risk. You can fake a thousand accounts cheaply, but you can't fake a thousand accounts' worth of electricity or staked coins.
Related terms
A consensus method where miners burn computing power to earn the right to add blocks and deter cheating.
Proof of Stake (PoS)A consensus method where validators lock up coins as collateral instead of burning electricity to secure the chain.
NodeA computer running a blockchain's software, keeping a copy of the ledger and relaying transactions to peers.
AirdropA free distribution of tokens to wallets, often to reward early users or bootstrap a new community.