Proof of Human (PoH)

High assurance biometric credential captured by the Orb and used for uniqueness.

Introduction

The Proof of Human (PoH) Credential is the highest-assurance credential issued under World ID. Enrollment is a two-step process: the user first obtains an Orb credential by completing an Orb capture process, which proves they are a live human. They then exchange that Orb credential at the PoH Issuer Service with a PoH credential which confirms uniqueness.

Use Cases

Use the PoH Credential when you need a strong guarantee that you are interacting with a unique, live human. It is the right choice for:

• Sybil resistance: enforcing one account per human for airdrops, voting, rewards, or rate limiting.
• High-assurance authentication: gating sensitive actions where you need biometric confidence that you’re interacting with the correct, unique human.
• Proof of personhood: distinguishing humans from bots, agents, and synthetic identities.

Credential Structure

This credential implements the following attributes beyond the defaults in the Credential.

Attribute	Description
genesis_issued_at	The Unix timestamp of the user’s first PoH credential. Remains constant across credential renewals.
expires_at	Unix timestamp when the credential expires. This is currently three years after the most recent issuance.
associated_data_hash	The PoH credential has no associated data, so this field is always FieldElement::ZERO.

In addition, the credential implements the following claim:

Claim 0 - Orb Credential Commitment

A commitment that binds the PoH credential to the Orb credential the user presented at issuance. This allows the PoH Issuer to attest that the credential was minted from a valid Orb verification without revealing the underlying Orb credential to relying parties.

Source	Value
Orb credential	H(hashes.json) — the hash signed by the Orb during enrollment.

Credential Renewal

Users can renew their PoH credential to extend its validity as long as the Orb capture is deemed fresh by the issuer. Each renewal updates the credential with expires_at = now + 3 years while genesis_issued_at remains constant.

Technical Reference

For issuer endpoints and implementation-specific details, see the PoH Issuer reference.