title: Is urn:oasis:names:tc:SAML:2.0:nameid-format:emailAddress a valid NameID format?
body: <p>In the OASIS specs I can read the following valid nameid-formats:</p>
  
  <ul>
  <li>urn:oasis:names:tc:SAML:2.0:nameid-format:persistent</li>
  <li>urn:oasis:names:tc:SAML:2.0:nameid-format:transient</li>
  <li>urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress</li>
  <li>urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified</li>
  <li>urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName</li>
  <li>urn:oasis:names:tc:SAML:1.1:nameid-format:WindowsDomainQualifiedName</li>
  <li>urn:oasis:names:tc:SAML:2.0:nameid-format:kerberos</li>
  <li>urn:oasis:names:tc:SAML:2.0:nameid-format:entity</li>
  </ul>
  
  <p>but can't find urn:oasis:names:tc:SAML:2.0:nameid-format:emailAddress.</p>
  
  <p>If I do a fast google search, this format appears several times, including a documentation of <a href="https://support.ciscospark.com/customer/portal/articles/1909112-sso-setup" rel="noreferrer">Cisco Spark</a>. </p>
  
  <p>Can someone clarify to me this issue? It seems that someone invented this nameid-format and now some IdP/SP using it.</p>