OpenID
An older decentralized authentication standard that lets users sign in with an existing OpenID account.
What is OpenID?
OpenID is a decentralized authentication standard that allows users to sign in to multiple websites using a single OpenID account (typically a URL).
OpenID versions:
- OpenID 1.0: Original version (2005) - URL-based identifiers
- OpenID 2.0: Added extensions, attribute exchange (2007)
- OpenID Connect (OIDC): Modern successor (2014) - JSON-based, OAuth 2.0-based
OpenID was the predecessor to modern standards like OpenID Connect and OAuth. While largely replaced by OIDC, some services still support legacy OpenID 2.0.
Note: When people say "OpenID" today, they usually mean OpenID Connect (OIDC), not the legacy OpenID 1.0/2.0.
Analogy
Think of OpenID like an older version of 'Sign in with Google'. It was the first attempt at decentralized login - users could create an OpenID account (typically URL-based) and use it to log into multiple sites. It's largely been replaced by OpenID Connect (OIDC).
Types and Use Cases
- "Legacy Systems: Some older websites still support OpenID 2.0"
- "Understanding history: OpenID paved the way for OIDC and modern SSO"
- "Migration: Most organizations have migrated from OpenID to OIDC"
- "Education: Some universities still use OpenID for inter-institutional SSO"
How it Works
<!-- OpenID 2.0 Authentication Request (Simplified) -->
<openid:checkid_setup>
<openid:mode>checkid_setup</openid:mode>
<openid:identity>https://user.openidprovider.com</openid:identity>
<openid:return_to>https://sp.example.com/callback</openid:return_to>
</openid:checkid_setup>
<!-- Response -->
<openid:response>
<openid:mode>id_res</openid:mode>
<openid:identity>https://user.openidprovider.com</openid:identity>
<openid:sig>signature_here</openid:sig>
</openid:response>OpenID vs OpenID Connect (OIDC)
OpenID
OpenID Connect (OIDC)
OpenID (legacy) is XML/URL-based (older, 2005)
OIDC is JSON/JWT-based (modern, 2014)
OpenID uses checkid_setup
OIDC uses authorization code flow (OAuth 2.0)
OpenID is largely deprecated
OIDC is widely adopted (Google, Microsoft, Apple)
Best Practices for OpenID
- "Migrate to OIDC: If you're using legacy OpenID, migrate to OpenID Connect"
- "Don't build new systems with OpenID: Use OIDC or SAML 2.0 for new implementations"
- "Understand the difference: When people say 'OpenID', they usually mean OIDC (modern)"
How LoginRadius Powers OpenID
LoginRadius CIAM platform does not support legacy OpenID (1.0/2.0) - we fully support OpenID Connect (OIDC) for modern authentication. Our platform acts as both OIDC Provider (issue ID tokens for your apps) and OIDC Client (connect to Google, Microsoft, Apple). LoginRadius provides OIDC migration guides, legacy OpenID sunset planning, and modern SSO implementation support.
FAQs
OpenID (1.0/2.0) is the older standard (2005/2007) using XML/URL-based authentication. OpenID Connect (OIDC) is the modern standard (2014) using JSON/JWT, built on OAuth 2.0. When people say 'OpenID' today, they usually mean OIDC. OpenID legacy is largely deprecated; OIDC is widely adopted.
No - implement OpenID Connect (OIDC) instead. OpenID (legacy) is deprecated and has security issues. OIDC is modern, more secure, and widely supported by Google, Microsoft, Apple. If you need SSO, choose OIDC or SAML 2.0 - not legacy OpenID.
LoginRadius does not support legacy OpenID (1.0/2.0). We fully support OpenID Connect (OIDC) for modern authentication. LoginRadius acts as both OIDC Provider (for your customer apps) and OIDC Client (connecting to Google, Microsoft, Apple). If you're migrating from legacy OpenID, we can help you transition to OIDC.