protected function generateIdentifier($prefix, $maxLength)
    {
        $hash = null;
        $dictionary = 'abcdefghijklmnopqrstuvwxyz0123456789';

        for ($i = 0; $i < ($maxLength - strlen($prefix)); $i++) {
            $hash .= $dictionary[mt_rand(0, strlen($dictionary) - 1)];
        }

        return $prefix.$hash;
    }