public function removeAuthContextClassRefWithPrefix(&$state)
    {
        $conf = Configuration::getConfig(self::CONFIG_FILE_NAME);
        $prefix = $conf->getString(self::PROPNAME_PREFIX, null);

        if (is_null($prefix)) {
            return;
        }
        unset($state['saml:RequestedAuthnContext']['AuthnContextClassRef']);
        $array = array();
        foreach ($this->authnContextClassRef as $value) {
            if (!(substr($value, 0, strlen($prefix)) === $prefix)) {
                array_push($array, $value);
            }
        }
        if (!empty($array)) {
            $state['saml:RequestedAuthnContext']['AuthnContextClassRef']
                = $array;
        }
    }