Proof of Personhood evaluated across measured cost to farm an identity, uniqueness checkable without the issuer, biometric data collected and deletable, and verified population you can count.
Ranked here: proof-of-personhood systems, which issue identities meant to be unique to one person, for gating an airdrop, a vote or a faucet against sybils. Not ranked here: identity products whose identities are not meant to be unique to one person.
#1 of 8 · published ranking
Idena
81ChainChoice Score
4199
Why it leads
Idena is 2 points ahead of Self, mainly because it scores higher on its cost to farm an identity and its biometric data and deletion.
Show the arithmetic
Ahead of Self on cost to farm an identity (+2.0 points) and biometric data and deletion (+1.4 points)
Cost
Not priced· No comparable price is published
ReviewedNext review by Published Methodology v2026.11.1
How this page is reviewed
Reviewed means every product ranked on this page was read against its sources on or after that date; every ranked category is re-read at least every 45 days. Models research, extract and parse. A deterministic engine ranks. Every quote passes an adversarial refute pass.
No provider can pay for a position in this table. The code that computes this order cannot read which links carry a referral code, and every build proves it. Every score below rebuilds from the published criteria.Ranking v2026.11.1 · 4 criteria · 8 products · same inputs, same order
How we review · 8 ranked of 8 assessed · 4 criteria · 0 sponsor weight
How we review
8ranked
8assessed
4criteria
0sponsor weight
Recommendation first, comparison only if needed.
Reviewed and rechecked on the current cycle.
Commercial relationships disclosed before clickout.
Personal comparison
Proof of Personhood ranked comparison
No comparable price is published; ranking still uses verified product evidence.
RankProviderBest fitScore
1
IdenaSynchronous global validation ceremony...Top ranked
Biometric data collected and deletable — 10/10Trade-off: The mechanism is intact and the network still validates on schedule, but 158 total id...
81score
Check availability for your country
Idena · idena.io. Provider links appear once we know which country you are browsing from: ChainChoice links to providers only where it serves in full.
Commission: This provider pays ChainChoice nothing for this link. Disclosure
Crypto products are high risk. Check the provider is authorised where you live before you deposit.
2
SESelfZero-knowledge proofs over NFC governme...
Uniqueness checkable without the issuer — 9/10Trade-off: The on-chain registries held 32,223 identity commitments in total on 2026-09-28 (4,36...
79score
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Self · self.xyz. Provider links appear once we know which country you are browsing from: ChainChoice links to providers only where it serves in full.
Commission: This provider pays ChainChoice nothing for this link. Disclosure
Crypto products are high risk. Check the provider is authorised where you live before you deposit.
3
Proof of HumanityKleros-arbitrated registry where a vide...
Uniqueness checkable without the issuer — 10/10Trade-off: Roughly 3,400 live v2 humanities across both chains is too small to populate a consum...
74score
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Proof of Humanity · proofofhumanity.id. Provider links appear once we know which country you are browsing from: ChainChoice links to providers only where it serves in full.
Commission: This provider pays ChainChoice nothing for this link. Disclosure
Crypto products are high risk. Check the provider is authorised where you live before you deposit.
Tied for #3 · ordered by name, A to Z
4
World IDIris-scanned Orb enrolment producing a...
Measured cost to farm an identity — 9/10Trade-off: The five-chain deployment is not one security domain, and it is more fragmented than...
74score
Check availability for your country
World ID · world.org. Provider links appear once we know which country you are browsing from: ChainChoice links to providers only where it serves in full.
Commission: This provider pays ChainChoice nothing for this link. Disclosure
Crypto products are high risk. Check the provider is authorised where you live before you deposit.
Biometric data collected and deletable — 8/10Trade-off: The 20-point threshold is a statistical dividing line, not a uniqueness proof, and it...
64score
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Human Passport · passport.human.tech. Provider links appear once we know which country you are browsing from: ChainChoice links to providers only where it serves in full.
Commission: This provider pays ChainChoice nothing for this link. Disclosure
Crypto products are high risk. Check the provider is authorised where you live before you deposit.
6
BRBrightIDSocial-graph uniqueness derived from ve...
Biometric data collected and deletable — 10/10Trade-off: Applications cannot check uniqueness from public state at all — every verdict arrives...
58score
Check availability for your country
BrightID · brightid.org. Provider links appear once we know which country you are browsing from: ChainChoice links to providers only where it serves in full.
Commission: This provider pays ChainChoice nothing for this link. Disclosure
Crypto products are high risk. Check the provider is authorised where you live before you deposit.
2 more assessed and ranked below — none of them hidden for commercial reasons.
Ranked on 4 published criteria weighted 32/26/22/20, which set goal alignment — 30 of the 86 points. The rest: regional access 20 (constant here), evidence depth 18 (constant here), ease of use 10 (constant here), institutional trust 8 (constant here). Profile match is shown in breakdowns but carries no weight.
How you can lose money here, and what the ranking scores
Information failure: the number is wrong or bought, or your data leaks.
Scored by Measured cost to farm an identity · 32% (Idena 8/10, Self 7/10, Proof of Humanity 9/10)
Scored by Uniqueness checkable without the issuer · 26% (Idena 8/10, Self 9/10, Proof of Humanity 10/10)
Scored by Biometric data collected and deletable · 22% (Idena 10/10, Self 9/10, Proof of Humanity 2/10)
Scored by Verified population you can count · 20% (Idena 8/10, Self 8/10, Proof of Humanity 7/10)
What matters most before choosing in this category
The buyer here is an airdrop, a governance vote or a faucet trying to price out sybils, so the only number that matters is what it costs an attacker to be counted twice — and the second number that matters is how many humans the gate can actually admit. Both are worse than the marketing. Every registry in this category that can be counted is two to three orders of magnitude smaller than what the category advertises: Self's three Celo registries held 4,369 identity commitments on 2026-08-11 against a claim of infrastructure "already accessible to billions of people across 180+ countries", and Proof of Humanity held 3,384 live humanities on Gnosis and 55 on Ethereum. The systems claiming millions are precisely the ones exposing no counter at all, and the one "live" home-page counter in the pool sat at exactly 2,560,606 on two separate read dates. Even the largest operator cannot state its own figure: World's FAQ still serves the unrendered placeholder "Already, [insert verified human ticker] people have verified their World ID at an Orb." while three different World-sourced totals run simultaneously. Choose on the cost of the marginal fake identity and on a population you can read yourself — a small honest number beats a large unverifiable one.
What does it cost an attacker to produce one more accepted identity — and is that cost physically rate-limited or just a software fee?
Can a relying party settle the uniqueness question from public state, without the issuer's cooperation or uptime?
How many humans has this actually verified, and can you read that number without taking the vendor's word for it?
Default starting point
The #1 overall and the scoring weights
IdenaData checked Sep 2026
Synchronous global validation ceremony in which every participant solves the same AI-resistant puzzles at the same moment, on a chain where one identity is one node.
Synchronous global validation ceremony in which every participant solves the same AI-resistant puzzles at the same moment, on a chain where one identity is one node. Strongest on biometric data collected and deletable (10/10): Idena collects no personal or biometric data: validation means solving image-sequence puzzles called flips in a synchronous session lasting under two minutes, with no document, face, palm or iris capture and no template held by anyone. Weakest on measured cost to farm an identity (8/10): Each identity must pass a synchronous validation ceremony, solving flips at the same moment as every other participant, and the ceremony still runs every epoch. Entry is rationed through invitations from validated nodes, which the whitepaper concedes can be sold and double-sold. Published price: Entry is not sold, it is rationed: "New invitations can only be sent out by validated nodes. The number of new invitations per node is limited and decreases as the network grows, while the total amount of generated invitations gets larger.
Best forBiometric data collected and deletable — 10/10
Main tradeoffThe mechanism is intact and the network still validates on schedule, but 158 total identities at epoch 227, the last validation (24 September 2026) — down from 3,468 at epoch 100 and 172 at epoch 218, with 105 of them in a validated state when read on 28 September 2026 — means Idena is a research-grade sybil gate, not a distribution channel, and the buyer must also solve bridging its verdict to whatever chain they actually pay out on.
Verify before signupEntry is not sold, it is rationed: "New invitations can only be sent out by validated nodes. The number of new invitations per node is limited and decreases as the network grows, while the total amount of generated invitations gets larger. The core Idena team is also granted to issue a limited number of invitations per epoch to support the growth of the network." (Idena whitepaper, Technology page, docs.idena.io/docs/wp/technology, re-fetched 28 September 2026, HTTP 200). No fee is charged to obtain an identity. The only posted capital figure is the stake below which a validated identity's votes are not counted, which the same page defines as "Identities having the stake below the threshhold of 0.5% * median_top100 , where median_top100 represents the median stake of top 100 accounts." The Idena indexer (api.idena.io/api/Epoch/228, fetched 28 September 2026, HTTP 200) reports "discriminationStakeThreshold":"115.805645452700191557" iDNA for epoch 228, validation scheduled 2026-09-29T15:00:00Z, down from 162.431920295848299628 iDNA at epoch 219 (api.idena.io/api/Epoch/219, same date) — a fall of about 46.63 iDNA (arithmetic: 162.43 − 115.81).
Weighted criteria
Measured cost to farm an identity32%
Uniqueness checkable without the issuer26%
Biometric data collected and deletable22%
Verified population you can count20%
Methodology
How this category is reviewed
Reviewed on measured cost to farm an identity, uniqueness checkable without the issuer, biometric data collected and deletable, and verified population you can count.
The order on this page is the published ranking for this category. Every criterion, weight and source behind it is on the methodology page.
Frequently asked
Questions people ask before choosing proof of personhood
How much does it actually cost to farm one more identity?
It depends entirely on whether the gate is a physical ceremony or an arithmetic threshold, and the score-based gate is the cheap one. Human Passport publishes both its threshold and its weights: threshold() returned 200000 (20.0000) on all six mainnet decoders on 2026-08-11 and the published weights re-verified digit for digit, which means the cost of clearing it is the cheapest basket of credentials that sums past 20. NFTScore#50 at 16.246 plus ETHScore#50 at 16.021 — two pure on-chain-activity credentials drawn from two separately capped categories — sum to 32.267, and neither requires a human to be identified at any point. Deduplication does not close the gap either, because the documentation binds it to "a given scoring instance", so the same evidence counts again for the next buyer. An exchange-issued account-bound token would not do the same job: it is minted only after the exchange completes KYC, so a human genuinely is identified. The systems at the other end of the range price the marginal identity in physical scarcity — a distinct iris presented in person, a distinct government document chip, or a live synchronous ceremony — which is the only cost a farmer cannot simply pay in software.
Can a relying party check uniqueness without the issuer?
Sometimes, and the failure modes are worth reading before you integrate. Proof of Humanity is the clean case: there is no issuer to ask, because the verdict is a view function on a deployed contract that a third party can call directly. Human Passport puts both the verdict and the threshold on chain, but its decoder does not fail closed — calling isHuman on an address that has never created a passport reverted with data 0x120a2e77 on all six mainnet decoders, and keccak256("AttestationNotFound()") independently produces those same leading four bytes. An integrator who writes the obvious `if (decoder.isHuman(user))` gets a reverted transaction rather than a rejection for the overwhelming majority of addresses. At the other extreme, Humanity Protocol's verification oracle is a single private key: on 2026-08-11 both the mainnet HumanityVerificationOracle and its FeeEscrow returned the same owner(), an address with no bytecode and a transaction count of zero — one externally owned account controlling both the contract that certifies humanity and the contract holding applications' prepaid balances, on a chain whose own documentation is headed "Mainnet temporarily offline" while it was in fact producing blocks one second apart.
What biometric data does each system take, and can you get rid of it?
The range runs from nothing at all to permanent public exposure. Self publishes a retention and deletion policy, BrightID publishes one for its social graph, and Humanity Protocol says where the palm template is stored and for how long; all three pages return HTTP 200 from links on the vendors' own home pages. Self's and BrightID's were favourable enough to raise their scores. Humanity's lowered its own: it reserves the right to "transfer and store your Biometric Data to our or our service providers' servers" and to retain personal information for "a period of five (5) years after the termination of such business relationship". At the bottom of this criterion sits the only system whose enrolment requirement is permanent public exposure of the user's face, which is not deletable by any mechanism the vendor offers.
Reviewed28 September 2026Method4 criteriaCategoryproof_of_personhood
Not financial advice · For informational purposes only · Always do your own research
