OpenId ConnectAuthentication Provider and Registration Handler, and SAML SSO and just-in-time provisioning are two requirements that the Salesforce Community Cloud can support for self-registration and SSO. OpenId Connect is a protocol that allows users to authenticatewith an external identity provider and access Salesforce resources. A registration handler is a class that implements the Auth.RegistrationHandler interface and defines the logic for creating or updating a user in Salesforce after authentication. SAML SSOis a protocol that allows users to log in to Salesforce with a single click, using an assertion from an identity provider that confirms the user's identity. Just-in-time provisioning is a feature that allows Salesforce to create or update a user account based on the information in the SAML assertion. References: Certification - Integration Architect - Trailhead, [OpenID Connect Authentication Providers], [SAML Single Sign-On (SSO) Service for Salesforce]