https://soadev.nih.gov/sp             urn:oasis:names:tc:SAML:2.0:ac:classes:Kerberos         http://id.incommon.org/assurance/silver         http://id.incommon.org/assurance/bronze         urn:oasis:names:tc:SAML:2.0:ac:classes:Password         urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport