Sybil Attack
Creating thousands of fake identities to manipulate network/airdrop decisions.
Sybil attack: attacker creates hundreds/thousands of addresses pretending to be different users to capture DAO votes, multiply airdrop rewards, manipulate reputation. Classic P2P problem. Defenses: PoW (energy per address), PoS (stake), KYC (off-chain), proof of personhood (Worldcoin, Gitcoin Passport). 2024 airdrops (Arbitrum, LayerZero) had thousands of Sybil farmers.
In plain words
An attacker creates thousands of fake wallets pretending to be different people - and grabs 1000x more in an airdrop or wins a DAO vote.
Example
Arbitrum airdrop March 2023: estimates 30% of 1.2B USD (360M) went to Sybil farmers, not real users.