Proof of Personhood
What Entros actually proves, and what it does not.
Proof of personhood is a temporal identity claim: this wallet is operated by a returning human, and the protocol provides a privacy-preserving way to prove that on-chain.
The claim is narrow on purpose. It is not a real-name identity claim, and it is not a one-shot check. The protocol's distinguishing property is consistency across many verifications, captured behaviorally rather than by any document or stored secret.
The bounded question
Entros answers exactly one question on-chain:
Is the same human, returning, over time, operating this wallet?
The protocol does not record who the human is by name, document, or face. It records that a human, behaviorally consistent across a sequence of verifications, is the operator of a particular wallet.
What is recorded
A non-transferable Token-2022 identity Anchor on Solana, plus an IdentityState PDA holding:
- A 256-bit commitment to the user's most recent behavioral fingerprint
- A monotonically increasing verification count
- A timestamp of the last verification
- A computed Trust Score in
[0, 65535]
What is not recorded: raw biometric samples, sensor recordings, or any signal that could re-identify the human outside the protocol's own derivation pipeline.
What gets verified
Each verification captures roughly twelve seconds of three involuntary behavioral signals on the user's device—voice prosody, hand tremor, and touch dynamics. Those signals are reduced on-device to a 134-number statistical summary, hashed into a 256-bit fingerprint, and proven against the previous fingerprint via a zero-knowledge circuit. The proof, the new commitment, and a small protocol fee land on Solana. Nothing else.
A single verification establishes presence. A sequence of verifications, spaced over days and weeks, is what makes the score compound.
Why behavioral, why temporal
A snapshot biometric—face scan, fingerprint, iris—answers the question "is this a person right now?" Generative AI can answer that question deceptively. Behavioral signals captured at a single point in time can also be synthesized.
Behavioral consistency across weeks is a different surface. The drift envelope of a real human's voice, hand, and touch is bounded but unique; reproducing the same envelope, on the same wallet, repeatedly, over months, is a fundamentally harder problem than synthesizing one realistic capture. The harder problem is the one Entros makes operators solve.
What this is not
- Not KYC. No legal-name binding, no document upload, no face scan.
- Not a one-shot check. A single verification establishes presence; the protocol's distinguishing claim is the consistency of the behavioral signature across many verifications.
Where to look next
- Trust Score—the formula, decay, and what each range means
- Anchor PDA—on-chain layout and access patterns
- SAS Attestations—how proof of personhood composes across the rest of Solana