title: Force re-authentication using onelogin as SP and IDP
body: <p>I'm trying to force a re-authentication using SAML and Onelogin as the IDP, and the onelogin java lib for the SP.
  For certain functions I would like to trigger a re-authentication, before the user can proceed.</p>
  
  <p>First time user logs in to my application he must enter his credentials. After that he is logged in. But when I try to send an AuthnRequest, the user is immediately redirected back to my application without having to enter his credentials again.</p>
  
  <pre><code>&lt;samlp:AuthnRequest
      xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
      xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" ID="ONELOGIN_xxx" Version="2.0" IssueInstant="2019-11-07T12:31:09Z" ForceAuthn="true" Destination="https://myapp.onelogin.com/client/apps/select/xxx" ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" AssertionConsumerServiceURL="https://local.my.app:8443"&gt;
      &lt;saml:Issuer&gt;local.my.app&lt;/saml:Issuer&gt;
      &lt;samlp:NameIDPolicy Format="urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified" AllowCreate="true" /&gt;
      &lt;samlp:RequestedAuthnContext Comparison="exact"&gt;
          &lt;saml:AuthnContextClassRef&gt;urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport&lt;/saml:AuthnContextClassRef&gt;
      &lt;/samlp:RequestedAuthnContext&gt;
  &lt;/samlp:AuthnRequest&gt;
  </code></pre>
  
  <p>How can I force the user to re-enter his credentials again?</p>