kb-fediverse-openwebauth

Federated authentication in the Fediverse uses the OpenWebAuth protocol to enable single sign-on across different servers. It uses a 5-step handshake and WebFinger discovery to let users log into target instances using their home instance identity without creating new accounts.

OpenWebAuth is used in ActivityPub implementations to verify cross-server identity and enable private content access. It allows a server to recognize remote users and grant them access to private posts based on their home instance permissions.

To implement single sign-on for Fediverse users, you follow the FEP-61cf specification and OpenWebAuth 5-step handshake. This involves using WebFinger discovery mechanisms to securely verify a user's home instance identity and grant cross-server access control.

OpenWebAuth differs from OAuth 2.0 and OIDC by focusing specifically on Fediverse cross-server authentication. Unlike traditional OAuth, it uses WebFinger discovery and a dedicated 5-step handshake to seamlessly verify remote identities for private content access without requiring user re-registration.

Security considerations for OpenWebAuth remote authentication include validating the 5-step handshake process and WebFinger discovery mechanisms. Proper implementation ensures that cross-server permissions and private content access are securely granted only to verified users from trusted home instances.

Yes, you can use OpenWebAuth to let users view private content on remote ActivityPub servers. It facilitates cross-server permissions, allowing a remote server to recognize a visiting user's home instance identity and grant private content access based on their existing permissions.