private boolean creationAccount(String login, String password) {
        //cut off the new prefix 'new'
        
        System.out.println("login : " +login);
        System.out.println("login.substring(3) : " +login.substring(3));
        login = login.substring(3);

        try {

            BufferedReader br = new BufferedReader(
                    new InputStreamReader(
                    new FileInputStream(this.file)));
            String ligne;
            while ((ligne = br.readLine()) != null) {
                String[] resultSplit = ligne.split(":");
                if (login.equals(resultSplit[0])) {
                    br.close();
                    return false;
                }
            }
            br.close();

            String concatenateLigne = login + ":" + password;
            System.out.println(login + ":" + password);
            FileWriter bw = new FileWriter(file, true);
            bw.append(concatenateLigne + "\n").flush();
            bw.close();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
        return true;
    }