$state = getRandomBytes();          
   $state = substr($state,2,16); 
   session_set('state', $state); 
   
    $url = "http://oa.dnc.global/authorize?response_type=code&client_id=chemin_openid&scope=openid profile&redirect_uri=http://chemindeleau.com/callback_openid.php&state=$state";
    
    redirige_par_entete($url);