Proof of Personhood
A verification mechanism establishing that an on-chain identity or account belongs to a unique human being, without necessarily revealing who that person is.
Proof of personhood refers to systems and protocols designed to verify that a given on-chain identity or account corresponds to one unique, real human being, distinguishing genuine individual participants from bots, duplicate accounts, or automated scripts. Approaches range from biometric verification and government-ID checks to social-graph-based or in-person verification events, and can be designed to preserve privacy by proving uniqueness without necessarily disclosing the underlying person's identity.
Proof of personhood is a specific approach to achieving Sybil resistance (see Kaavon's "Sybil Resistance" glossary definition) — the broader goal of preventing one entity from gaining disproportionate influence by creating many fake identities — and is especially relevant to systems like quadratic funding (see Kaavon's dedicated glossary entries on public-goods funding), one-person-one-vote governance schemes, or airdrop distributions, where simply requiring a crypto wallet or minimum token balance doesn't prevent a single person from creating many wallets to claim a disproportionate share.
Examples
- A quadratic funding round without proof of personhood is vulnerable to a single participant splitting their contribution across many wallets to disproportionately boost the matching funds a project receives.
- Proof of personhood systems aim to verify genuine human uniqueness, which is a stronger and different guarantee than simply verifying that a wallet holds a minimum token balance.