In open systems, there is still no simple way to know whether we are dealing with many real people or with one actor operating many accounts.

Existing blockchain systems price participation using computation (Proof-of-Work) or capital (Proof-of-Stake).

We’ve released a scientific paper on Proof-of-Biometric-Uniqueness (PoBU), which studies a third approach: enforcing one-human-one-account as a rule for participation in a permissionless blockchain and as a basis for Sybil resistance.

The paper defines PoBU as a way to limit who can take part in consensus by requiring each participant to prove they are a unique real human, with clear and measurable error bounds based on biometric performance and system settings.

The paper is backed by live data from an already running chain that uses PoBU at the consensus layer.

It provides:
• a protocol-level definition of PoBU and its eligibility interface
• a threat model covering issuer concentration, eligibility compromise/coercion, availability, and privacy
• and a reproducible empirical evaluation based on public chain-derived data

Using direct Substrate RPC, the paper analyzes validator activity and block production on the live Humanode network.

In a recent 90-day window, the top-10 block authors produced about 4.5% of sampled blocks, with hundreds of different validators active over time.

If you are interested in how one-human-one-account can be expressed as a protocol property, measured on a real network, this paper is the reference.

Read the paper here: https://papers.humanode.io/pobu.pdf