Further Reading

Proof of Personhood

Proof of personhood allows someone to digitally prove they are a unique human.

Building a global, scalable and inclusive proof of personhood system is at the core of World ID. Whenever World ID is used, whether through Sign In with Worldcoin or Anonymous Actions, the verifier app can additionally request information from the user related to their proof of personhood. The user can then choose to share that information.

Maximum privacy. Given that proof of personhood is about just proving someone is human, and not who they are, proof of personhood is handled with the highest privacy standard. Users share their proof of personhood anonymously. Each credential is issued in an independent set, with no other information attached (more on The Protocol).

Multiple credentials. Proof of personhood is not a binary yes or no in the digital world, but rather a spectrum. Multiple signals can contribute to determine where a potential user falls on the spectrum. In the World ID Protocol, the strongest credential a user holds will be used to generate the proof of personhood. The choice of credentials is a trade-off that apps and users must decide on. Weaker credentials will generally be easier for users to obtain but more easily spoofed or sybil attacked.

Proof of Personhood Credentials Spectrum

Credential Selection

The choice of which credentials to accept is up to the app (easily configured in IDKit). Sign In with Worldcoin will always accept all credentials.

By default, IDKit is configured to accept only Orb credentials. This is the strongest credential and is the only one that is verifiable on-chain.

For Cloud apps, there is more flexibility for credential selection -- IDKit can be configured to accept any combination of credentials. Accepted credentials should be configured based on how strongly the app needs to verify that a user is a unique human.

We recommend requiring Orb verification in instances where users are given a financial incentive, such as a signup bonus or airdrop. For other situations, such as a social media app, it may be sufficient to only require a phone number. An app can always choose to support multiple credentials and react according to which credential was used.

Available Credentials

This list will continue to grow as more credentials are supported for proof of personhood in the World ID Protocol.

CredentialDescriptionHumanness LevelAvailability
OrbBiometric in-person verification, uniqueness through iris (details).StrongestON-CHAIN CLOUD
PhoneUnique device check and unique phone number verification.WeakCLOUD
FaceUnique and privacy-preserving face match.MediumCOMING SOON