In an IdP initiated sign-on scenario, what is the required element to confirm a SAML assertion?

In an IdP initiated sign-on scenario, the required element to confirm a SAML assertion is a valid SAML response. This response is generated by the Identity Provider (IdP) after the user has successfully authenticated. The SAML response contains the assertion, which is a statement that the IdP makes regarding the user's identity and additional attributes.

The importance of the valid SAML response lies in its role as a secure communication of authentication data between the IdP and the Service Provider (SP). The SP must validate the response to ensure it was issued by a trusted IdP and is free from tampering. This involves checking signatures, validating the response's format, and confirming that the assertions contained within it are authentic and unexpired.

Other aspects such as username and password, user attributes mapping, and session management are related to the broader scope of identity management and user experience but do not directly serve in the confirmation of a SAML assertion in this specific context. The core requirement is the SAML response as it is essential for the authentication process initiated by the IdP.