OID4VCI

OID4VCI

Standards

• OpenID for Verifiable Credential Issuance 1.0 (final)
• OAuth 2.0 Authorization Framework (token and grant semantics)
• SD-JWT VC profile (dc+sd-jwt credential format)
• W3C Verifiable Credentials Data Model 1.1 / 2.0 (jwt_vc_json, jwt_vc_json-ld, ldp_vc formats)
• W3C VC Data Integrity 1.0 (ecdsa-rdfc-2019, eddsa-rdfc-2022 cryptosuites for ldp_vc)

Available Flows

Flow ID	Name	Steps	Description
oid4vci-pre-authorized	Pre-Authorized Code	6	Resolve offer, discover metadata, exchange pre-authorized code, receive token + c_nonce, submit proof, receive issued credential
oid4vci-pre-authorized-tx-code	Pre-Authorized + tx_code	6	Same flow with mandatory tx_code at token exchange
oid4vci-deferred-issuance	Deferred Issuance	8	Full end-to-end flow: offer, metadata, token, credential request, deferred response with transaction_id, polling, credential ready

Demo Scenarios

• Pre-Authorized Issuance — Resolve by-reference offer, exchange token, submit proof, receive issued credential (format per credential configuration)
• Pre-Authorized + tx_code — Enforce out-of-band tx_code before token issuance
• Deferred Issuance Polling — Receive transaction_id, poll until credential is ready

Credential Details

Property	Value
Credential configuration selection	Wallet chooses from credential_configurations_supported (e.g., one configuration describing a university degree VC type)
Credential formats	dc+sd-jwt (SD-JWT VC), jwt_vc_json, jwt_vc_json-ld, ldp_vc (W3C Data Integrity)
Proof container	proof or proofs with proof_type: jwt (e.g., {"proof_type":"jwt","jwt":"<compact-jws>"})
Proof JWT header type	openid4vci-proof+jwt
Proof JWT required claims	iss, sub, aud, nonce, iat, exp, cnf.jwk
Deferred issuance indicator	transaction_id returned by credential endpoint (e.g., an opaque identifier such as "txn_...")

Pre-Authorized Code Issuance Flow (OID4VCI §4, §6.1, §7)

1. Resolve Credential Offer — Wallet receives credential_offer_uri out-of-band and fetches the credential offer object from the Credential Issuer. Offer contains credential_issuer, credential_configuration_ids, and grants.urn:ietf:params:oauth:grant-type:pre-authorized_code.
2. Discover Issuer Metadata — Wallet fetches /.well-known/openid-credential-issuer to discover credential_configurations_supported, credential_endpoint, nonce_endpoint, deferred_credential_endpoint, and token endpoint URL.
3. Token Request — Wallet calls token endpoint with grant_type=urn:ietf:params:oauth:grant-type:pre-authorized_code, pre-authorized_code, and tx_code when required by the offer grant.
4. Token Response — Authorization Server validates the pre-authorized code (and tx_code if required) and returns access_token, token_type, scope (if applicable), c_nonce, and c_nonce_expires_in.
5. Credential Request — Wallet submits credential_configuration_id and proof/proofs (proof_type: jwt) with a proof JWT bound to the active c_nonce and the credential issuer audience.
6. Credential Response — Issuer validates proof key binding, nonce freshness, and audience/subject constraints, then returns:
   • Immediate: format matching the credential configuration (e.g. dc+sd-jwt with disclosures, jwt_vc_json, jwt_vc_json-ld, or ldp_vc with Data Integrity proof), credential, next c_nonce, or
   • Deferred: transaction_id, next c_nonce — wallet then polls deferred_credential endpoint until credential is ready.

Contract Enforcement

• Credential offer envelope enforces XOR: exactly one of credential_offer or credential_offer_uri.
• tx_code is required when the offer grant includes a tx_code object.
• Proofs are required when proof types are declared for the credential configuration.
• Proof JWT header typ must be openid4vci-proof+jwt.
• Proof must include iss, sub, aud, nonce, iat, exp, and cnf.jwk.
• Nonce is freshness-bound and one-time in issuance requests (replay and expiry are rejected).
• Deferred polling requires matching transaction_id and same access token lineage.

Endpoints

Endpoint Role	Discovery Source	Purpose
Credential Issuer Metadata Endpoint	/.well-known/openid-credential-issuer/{issuer-path}	Discover issuer metadata, credential configurations, and endpoint URLs
Credential Offer URI	credential_offer_uri	Retrieve a credential offer by reference
Token Endpoint	Issuer/Authorization Server metadata	Exchange pre-authorized_code (or authorization grant) for access token and nonce
Nonce Endpoint	nonce_endpoint from issuer metadata	Request a fresh c_nonce challenge when needed
Credential Endpoint	credential_endpoint from issuer metadata	Submit proof and request credential issuance
Deferred Credential Endpoint	deferred_credential_endpoint from issuer metadata	Poll a pending issuance transaction with transaction_id

Illustrative Examples (Non-Normative)

• Pre-authorized token request body (form-encoded): grant_type=urn:ietf:params:oauth:grant-type:pre-authorized_code&pre-authorized_code=...
• Proof JWT protected header: {"typ":"openid4vci-proof+jwt","alg":"<wallet-signing-alg>"} and payload includes aud, nonce, cnf.jwk
• Deferred credential response shape: {"transaction_id":"...","c_nonce":"...","c_nonce_expires_in":...}

What To Validate

• Credential offer envelope: exactly one of credential_offer or credential_offer_uri
• Metadata retrieval: well-known endpoint resolves to issuer metadata and endpoint URLs
• Token exchange: pre-authorized_code grant processing and tx_code enforcement when offered
• Proof JWT: typ=openid4vci-proof+jwt, cnf.jwk key binding, aud matches issuer, nonce matches active c_nonce
• Nonce behavior: replayed or expired c_nonce is rejected; next nonce is returned after successful issuance
• Credential response: serialization matches negotiated format (e.g. dc+sd-jwt includes issuer-signed JWT + disclosures, ldp_vc includes Data Integrity proof)
• Deferred flow: issuance_pending before ready time, then final credential on successful poll