Uses vCenter Server SSO as Identity and Authentication Server. Two types of authentication are supported SIGN and Basic. When Basic authentication is used, the service exchanges username and password for SAML Token from the vCenter Server SSO. When SIGN authentication is used, the service exchanges the SSO SAML token from the SIGN token for another SAML token on behalf of the principal from the vCenter Server SSO. On successful authentication with the SSO, the service returns X-SRS-API-KEY token in the response headers. X-SRS-API-KEY token authorizes access to the service resources.The service associates X-SRS-API-KEY token to the acquired SSO SAML token. The associated SSO SAML token authenticates PowerCLI to the vCenter services.