<?

public function uniqid()
    {
        $is_not_found_in_db = 0;

        while ($is_not_found_in_db==0)
        {
            if (function_exists("random_bytes")) {
                $bytes = random_bytes(ceil($lenght / 2));
            } elseif (function_exists("openssl_random_pseudo_bytes")) {
                $bytes = openssl_random_pseudo_bytes(ceil($lenght / 2));
            } else {
                throw new Exception("Utils.php:uniqid() - no cryptographically secure random function available");
            }
            $uniqueid = substr(bin2hex($bytes), 0, $lenght);

            $count = Submission::where('unique_id', $uniqueid)->count();
            if ($count===0)
            {
                $is_not_found_in_db=1;
            }
        }
        return $uniqueid;
    }