Products · 3 min read
Proof of human
In short Three layers: a real device for everyone, a liveness and one face, one account check for verified humans, and private proofs that let them prove it anywhere without being tracked. No names or ID documents.
Every promise Kin makes depends on one thing: that each Kin identity belongs to one real, unique person. This chapter explains how we check that, and why the checks reveal so little.
What we need to know, and what we don't
To keep the network fair, Kin needs to answer three questions about an account:
- Is it running on a real device, not an emulator or a script?
- Is there a live person behind it, not a photo, a mask or a deepfake?
- Is this person's only account?
Kin does not need anyone's name, address, ID document or social profiles to answer them, so it does not ask for them.
Three layers of checks
1. A real device (every account)
When Kin ID runs, the phone's own security services confirm that the app is genuine and running on a real, untampered device. Combined with one active account per device and a sign in method that cannot be created in bulk, this stops most automated and farmed accounts before they start. Nothing personal is shared in this step.
2. One face, one account (verified humans)
To become a verified human, a person takes a short selfie video. A liveness check confirms that a live person is present, not a photo, video, mask or deepfake.
The face is then turned into a template: a string of numbers that describes it well enough to recognise a second account, but that cannot be turned back into a picture. The template is compared with those of other verified humans to catch duplicates. The selfie itself is deleted within seconds of the check, and the comparison runs in protected hardware so that no one at Kin can browse faces.
Verification is optional for chatting and mining. It is required for the verified human badge, for the airdrop, and for apps that ask for it through Kin OAuth.
3. Proving it elsewhere, without being tracked
Once verified, a person can prove they are human to other apps, and to the blockchain, without becoming traceable:
- In apps. Through Kin OAuth and Kin Pass, each app receives a different anonymous identifier for the same person, together with a simple answer: human, and unique to this app. Two apps cannot compare notes to follow someone around.
- On chain. For the airdrop, each verified person holds a private credential. When claiming $KIN on BNB Smart Chain, they submit a zero knowledge proof: a cryptographic proof that they are one of the verified humans and have not claimed yet, which does not reveal which one. The blockchain can check the claim; neither the public nor Kin can link the wallet to the account.
Inclusion
Not everyone can or wants to take a selfie video. Verified humans will be able to vouch for a small number of friends, giving them a lighter level of trust for most of Kin. Vouching has limits, and vouching for fake accounts costs the voucher their own standing. The airdrop will still require the face check.
Consent and law
Face templates are biometric data in many countries. Verification will only ever happen with explicit consent, templates will be deleted when an account is deleted, and our approach will be reviewed against data protection law, including the GDPR and state biometric laws in the United States, before it launches.
Proposed Templates are kept only while the account exists, and deleted with it. Selfie videos are never stored. The verification provider is named in the Privacy Policy, processes data only on Kin's instructions, and is reviewed every year.
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