Sybil Attack

A Sybil attack is an attempt to gain outsized influence over a network by creating many fake identities that look like independent participants. Because anyone can spin up unlimited nodes or wallet addresses at almost no cost, open peer-to-peer systems need a scarce resource to make identity expensive: proof of work ties influence to computation, and proof of stake ties it to capital at risk. Sybil resistance also matters away from consensus — in airdrop farming, governance votes and reputation systems, where one person can pose as thousands of users. A successful Sybil attack can also surround a node with attacker-controlled peers and feed it a false view of the chain, so wallets and validators should connect through several diverse, independent peers rather than one provider.