title: (Android) hacking server by a simple socket
body: <p>I have written an Android game. Now, I want to connect the marks of the players.</p>
  
  <p>The code below is the client side program, which send their names, countries and marks to the server. Basically, I use ':' to separate the information.</p>
  
  <p>However, hackers can know my server ip and port by decompiling .apk file. Then, they can create a basic java application to access my server. They could send me "hacker:badserver:123456789". Finally, the top mark becomes "123456789".</p>
  
  <p>Is it more secure method to connect user's data?</p>
  
  <pre><code>Socket client = new Socket(ip, port);
  OutputStream outToServer = client.getOutputStream();
  DataOutputStream out = new DataOutputStream(outToServer);
  out.writeUTF("Hacker:HK:3910");
  </code></pre>