Sybil Attack

A Sybil attack is a security threat where a single entity creates multiple fake identities or nodes to gain disproportionate influence over a peer-to-peer network. Named after the book "Sybil" about a person with multiple personalities, these attacks can be used to manipulate voting, disrupt network operations, or undermine consensus. Blockchain networks resist Sybil attacks through mechanisms that make creating identities costly, such as Proof of Work or Proof of Stake.