Glossary
Proof of Personhood
Any mechanism that verifies an account corresponds to a unique living human — biometrics, social vouching, government ID — used for Sybil resistance and UBI experiments.
Proof-of-personhood schemes try to bind one digital identity to one human. Worldcoin uses iris biometrics; BrightID and Idena use social-graph or proof-of-attendance games; Gitcoin Passport aggregates many lower-strength signals; some governments offer digital IDs that crypto wallets can attest to.
Strong personhood is the missing primitive for fair on-chain voting, airdrops, and UBI. The unsolved trade-off is between biometric strength (concentrates trust in the verifier) and permissionless decentralization (weaker against Sybil farms).