public RedirectResult RequestAuthentication()
{
string handleAuthenticationResponseUrl = Url.Action("HandleAuthenticationResponse", "Account", null, Request.Url.Scheme);
string antiForgeryStateToken = Guid.NewGuid().ToString();
Session["OAuthAntiForgeryStateToken"] = antiForgeryStateToken;
string antiReplayNonceToken = Guid.NewGuid().ToString();
Session["OAuthAntiReplayNonceToken"] = antiReplayNonceToken;
var request = new AuthenticationRequest(
scope: "openid",
responseType: "code",
clientId: Configuration.CLIENT_ID,
redirectUri: handleAuthenticationResponseUrl,
state: antiForgeryStateToken,
nonce: antiReplayNonceToken);
string requestUrl = request.GetRequestUrl(Configuration.AUTHORIZATION_ENDPOINT_URL);
return(Redirect(requestUrl));
}