Personhood Credentials (PHCs)

Protocolo Semántico y de Datos

A verifiable credential type specifying claims that attest a credential holder is a real, unique person within an issuing ecosystem (e.g., a government, employer, university, or nonprofit community). PHCs add a credential-type semantic layer on top of the W3C Verifiable Credentials Data Model, defining what data a personhood credential carries and how its claims are structured for cross-ecosystem interpretation. Originally proposed in the August 2024 'Personhood Credentials' paper as a response to generative AI's ability to defeat CAPTCHAs and impersonate humans; being standardized by the Decentralized Trust Graph Working Group (DTGWG), a joint ToIP-DIF working group .

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Licencia N/A — specification document, not source code; reference implementations in OpenVTC (Apache-2.0) and other FPP-ecosystem projects are open source
Estado de Desarrollo 📝 Borrador
Detalle del Estado de Desarrollo Draft / Standardization in progress (specification under development at DTGWG; multiple reference implementations underway including in the First Person Project ecosystem and OpenVTC)
Propietario Specification origin: 27 multi-institutional authors of the August 2024 Personhood Credentials paper led by researchers from MIT, OpenAI, Microsoft, Harvard, UC Berkeley, and other institutions. Standardization: Decentralized Trust Graph Working Group (DTGWG) — joint ToIP-DIF Working Group
Órgano de Gobierno Decentralized Trust Graph Working Group (joint ToIP–DIF working group) | None (originating multi-institutional author group spanning MIT, OpenAI, Microsoft, Harvard and UC Berkeley; not itself a governing body)
País International (multi-institutional academic and industry collaboration)
Año de Inicio 2024
Stack N/A — specification, not implementation
Financiamiento Specification work supported by sponsoring organizations of the DTGWG (ToIP, DIF, Linux Foundation Decentralized Trust, Customer Commons, Ayra Association); original paper produced by academic and industry research collaboration
Última Investigación 1 jul 2026

Dominios de Caso de Uso

Co-creación y Conocimiento

Protocolo Semántico y de Datos Atributos

Orígenes Proof of personhood / Decentralized identity (response to generative AI defeating CAPTCHAs and traditional bot-detection; alternative to centralized biometric solutions like Worldcoin)
Base de Datos N/A — credentials are stored in user-controlled digital wallets; no centralized database is part of the specification
Lenguaje de Consulta N/A — credential exchange uses standard VC presentation/verification protocols rather than a query language
Formatos de Datos W3C Verifiable Credentials Data Model (JSON-LD by default; JWT/SD-JWT serializations also possible per the underlying VC spec); zero-knowledge proof presentations for threshold-based unique-personhood proofs
Edición Colaborativa en Vivo N/A
Edición de Texto Enriquecido N/A
Soporte Móvil N/A — credentials can be presented from any wallet on any platform; the specification is platform-agnostic
Soporte Web N/A — same as above
Aplicaciones Nativas N/A — same as above
Términos Free open standard (no licensing fees for adoption)
Fondos N/A — open standard, no funding round
Basado En W3C Verifiable Credentials Data Model (the underlying credential framework PHCs extend); W3C Decentralized Identifiers (for issuer and holder identity); Personhood Credentials paper, August 2024 (originating specification); zero-knowledge proof cryptography (for threshold-based unique-personhood verification)
Compatibilidad con la Web Semántica Full (built on W3C Verifiable Credentials Data Model, which uses JSON-LD as its primary serialization; PHC claims are expressed as RDF-compatible structured data)
Madurez del Protocolo / Estandarización W3C Draft / DTGWG standardization track (originating paper August 2024; specification work ongoing in the Decentralized Trust Graph Working Group, a joint ToIP-DIF participation Working Group; expected to produce a formal W3C-track specification)
Tipo de Vocabulario / Ontología Identity attestation / Proof of personhood (specifies a credential-type vocabulary for attesting that the holder is a real, unique person within a given issuing ecosystem)
Patrón de Uso Embedded in other protocols (PHCs are exchanged via standard VC issuance and presentation protocols such as OpenID4VC and DIDComm; the specification defines the semantic content of a particular credential type rather than its transport)