Standards
OpenID Connect
Also known as: OIDC
The identity layer built on OAuth 2.0 — the protocol that powers 'Sign in with Google' and most modern federated authentication.
OpenID Connect (OIDC) is the identity layer built on top of OAuth 2.0. OAuth 2.0 is about delegated authorization ("let this app call that API on my behalf"); OIDC adds identity claims ("here's who the authenticated user is"). The result is the "Sign in with Google / Microsoft / Apple" flow that most web apps offer.
OIDC introduces the ID token — a JWT that asserts who the user is, when they authenticated, what scopes they consented to. OIDC also defines discovery metadata (the /.well-known/openid-configuration endpoint) that clients use to bootstrap.
OpenID4VCI and OpenID4VP — the two specifications LearnCoin plans to implement for EUDI Wallet alignment — are extensions to the OIDC flow. Instead of issuing an ID token (which just identifies the user), the issuer returns a verifiable credential. Instead of presenting an ID token to the verifier, the holder presents a VP. Same OAuth-style handshake, different payloads.
Related terms