APDU via USB Connection

Question

I want to create an android app to find my micro-usb (smartcard reader device), so I have a problem with receive data in smartcard (I sent an APDU that is 0x... to smartcard by method usbDeviceConnection.bulkTransfer. But I don’t know how to receive data or something that answer back (It have to answer a data in card back to me after I sent command). And when it answer back how can I encode or translate hex to string?

I guess, (ref from code) I have a 2 endpoint so I have question about endpointIn and endpointOut. What are these params? How can I use it to send and receive data between device and app? I think right, or not? And what is BroadcastReceiver do?

protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
   tv = (TextView) findViewById(R.id.textview);   
   //register the broadcast receiver
   mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
  IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
  registerReceiver(mUsbReceiver, filter);

  registerReceiver(mUsbDeviceReceiver, new IntentFilter(UsbManager.ACTION_USB_DEVICE_ATTACHED));
  registerReceiver(mUsbDeviceReceiver, new IntentFilter(UsbManager.ACTION_USB_DEVICE_DETACHED));

  connectUsb();
}

Here is connectUSB method.

private void connectUsb() {
  Toast.makeText(MainActivity.this,
   "connectUsb()",
  Toast.LENGTH_LONG).show();


  searchEndPoint();

   if (usbInterfaceFound != null) {
  setupUsbComm();

   threadUsbTx = new ThreadUsbTx(usbDeviceConnection, endpointOut);
   threadUsbTx.start();

   //bytes are APDU to send for get data from card.
   threadUsbTx.insertCmd(
   new byte[]{(byte) 0xA0, (byte) 0xA4, 0x00, 0x00, 0x02, 0x3F, 0x00});
   threadUsbTx.insertCmd(
   new byte[]{(byte)0x80, (byte)0xb0, 0x00, 0x04, 0x02, 0x00, 0x0d});
   threadUsbTx.insertCmd(
   new byte[]{0x00, (byte)0xc0, 0x00, 0x00, 0x0d});
   }
  }

Here is class ThreadUsbTx..

class ThreadUsbTx extends Thread {
   boolean running;

  UsbDeviceConnection txConnection;
  UsbEndpoint txEndpoint;
  Queue<byte[]> cmdQueue;
   byte[] cmdToSent;


  ThreadUsbTx(UsbDeviceConnection conn, UsbEndpoint endpoint) {
   txConnection = conn;
   txEndpoint = endpoint;
   cmdQueue = new LinkedList<byte[]>();
   cmdToSent = null;

   running = true;
  }

   public void setRunning(boolean r) {
   running = r;
  }

   public void insertCmd(byte[] cmd) {
   synchronized (cmdQueue) {
   cmdQueue.add(cmd);
  }
  }

   @Override
   public void run() {

   while (running) {

   synchronized (cmdQueue) {
   if (cmdQueue.size() > 0) {
   cmdToSent = cmdQueue.remove();
  }
  }

   if (cmdToSent != null) {

   final int usbResult = usbDeviceConnection.bulkTransfer(
   txEndpoint,
   cmdToSent,
   cmdToSent.length,
   0);

   final String s = new String(cmdToSent);
  String result = null;

   try {
  result = new String(cmdToSent,"TIS620"); // To Thai language
  } catch (UnsupportedEncodingException e) {
  e.printStackTrace();
  }

   final String finalResult = result;
  runOnUiThread(new Runnable() {

   @Override
   public void run() {
  Toast.makeText(MainActivity.this,
   finalResult+" "+String.format("%040x",cmdToSent),
  Toast.LENGTH_LONG).show();
  }
  });
   cmdToSent = null;
   }
  }
  }
  }

Answer 1

The best way to communicate with the USB Card reader is to use the CCID-Compliant one along with an OTG-Capable phone. Take a look at the App "CCID Reader Application Demo" in Playstore. Also useful the library available here. Otherwise you have to implement more or less the CCID-behaviour in your code