Integrating Dibs Payment Gateway in Android

Question

I am working on Dibs Payment integration but unable to achieve success. All things are working good in demo mode but when merchant id is supplied to it then before opening card details form it gives an error "Data has been tampered. Checksome is not valid". I dont know what is it. After my googling i found it is something related to MAC calculated but how to calculate MAC in my code. My whole class for payment is as follows with all comments.

public class CheckOut extends Activity {

private static final String TAG = "DIBS." + CheckOut.class.getSimpleName();

private DibsPayment paymentWindow;
public static String total, resname, resid, userid, menunames, itemnames,
        itemquantity, ordertype, address, city, contactno, pincode,
        deliverttime, orderid;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.checkout);
    RandomStringGenerator randomorderid = new RandomStringGenerator();
    Intent i = getIntent();
    // total=String.valueOf(1);
    total = i.getStringExtra("grandTotal");
    resname = i.getStringExtra("res_name");
    resid = i.getStringExtra("res_id");
    userid = i.getStringExtra("user_id");
    menunames = i.getStringExtra("menu_names");
    itemnames = i.getStringExtra("item_prices");
    itemquantity = i.getStringExtra("item_quantity");
    ordertype = i.getStringExtra("ordertype");
    address = i.getStringExtra("address");
    city = i.getStringExtra("city");
    contactno = i.getStringExtra("phone");
    pincode = i.getStringExtra("pin");
    deliverttime = i.getStringExtra("delivery_time");
    orderid = randomorderid.getAlphaNumeric(5);
    Toast.makeText(
            getApplicationContext(),
            orderid + "\n" + resname + "\n" + resid + "\n" + userid + "\n"
                    + ordertype + "\n" + address + "\n" + city + "\n"
                    + pincode + "\n" + contactno + "\n" + deliverttime
                    + "\n" + menunames + "\n" + itemnames + "\n"
                    + itemquantity + "\n" + total, Toast.LENGTH_SHORT)
            .show();
    /*
     * Intent intent=getIntent(); String []
     * arrayList=intent.getStringArrayExtra("payment_item"); // int l_itr =
     * arrayList.length; // while(l_itr.hasNext()) { for(int
     * i=0;i<=arrayList.length-1;i++){
     * 
     * @SuppressWarnings("rawtypes") //HashMap l_map = (HashMap)
     * l_itr.next(); String item=arrayList[i]; Log.v(item, "item"); String
     * item =(String)i.get(DatabaseHandler.KEY_ITEM); Log.v(item, "item");
     * String unicost= (String)l_map.get(DatabaseHandler.KEY_UNITCOST);
     * Log.v(unicost, "unicost"); String l_res_name = (String)
     * l_map.get(DatabaseHandler.KEY_QUANTITY); Log.v(l_res_name,
     * "quantity"); String l_street = (String)
     * l_map.get(DatabaseHandler.KEY_TOTAL); Log.v(l_street, "total"); }
     */

    paymentWindow = (DibsPayment) findViewById(R.id.DibsPayment);

    // Set your listener implementation, to get callbacks in the life-cycle
    // of a payment processing
    paymentWindow
            .setPaymentResultListener(new MyPaymentResultListener(this));

    // Load the payment window with the payment data that suits the payment
    // flow you need
    // Please be patient, when loading on the emulator
    paymentWindow.loadPaymentWindow(constructPaymentData());
}

/**
 * Shows a "cancel" action in the options menu on the phone, which shows how
 * to call cancel functionality into the payment window to cancel ongoing
 * payment processing.
 */
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater menuInflater = getMenuInflater();
    menuInflater.inflate(R.menu.payment_window_menu, menu);
    return true;
}

/**
 * If user chose "cancel" in options menu, we call "cancel" into payment
 * window.
 */
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.menuitem_payment_window_cancel:
        //
        // Calling cancel into payment window cancels the ongoing payment
        // processing.
        // Because cancelling is an asynchronous process, you will need to
        // wait for a callback
        // to paymentCancelled on your PaymentResultListener listener,
        // before being positive that
        // payment window is done cancelling.
        //
        paymentWindow.cancelPayment();
        return true;
    default:
        return super.onOptionsItemSelected(item);
    }
}

/**
 * @return the payment data instance that is needed as input to
 *         {@link DibsPayment#loadPaymentWindow(dk.dibs.android.library.PaymentData)}
 */
private PaymentData constructPaymentData() {
    // IMPORTANT: This needs to be set to YOUR merchant number, that you
    // have obtained through an
    // agreement with DIBS.
    // you can use the merchant "demo" for a demorun through the payment
    // window // read information about demo mode in the documentation

     String merchantId = "******";
    //String merchantId = "demo";

    // The currency the payment is to be processed in
    String currencyCode = "DKK";

    // You set this to your own orderId value
    String yourOrderId = orderid;

    // The amount to be paid, given in "least possible unit" (aka: "oerer")
    long amount = (new Double(total)).longValue();
    // The cards that is allowed to be used in payment window
    List<String> payTypes = new ArrayList<String>();
    payTypes.add("MC");
    payTypes.add("MTRO");
    payTypes.add("VISA");

    // this will add fee to the payment window.
    boolean calcfee = true;

    // In this example, we simply use "PurchasePaymentData", which is a
    // simple "buy-with-credit-card" flow,
    // where no pre-authorization is performed.
    //
    // Look to other subclasses of PaymentData for the other supported
    // flows.
    //
    PurchasePaymentData paymentData = new PurchasePaymentData(merchantId,
            currencyCode, yourOrderId, amount, payTypes);

    paymentData.setCalcfee(calcfee);

    // Set this flag to "true", if you want to be able to use test cards.
    // REMEMBER to reset this to false, in production !!!
    paymentData.setTest(true);

    // If you want checks (and payment failure) if the orderId you gave
    // already have been payed.
    paymentData.setUseUniqueOrderIdCheck(false);

    // If you want MAC security calculations, you will need to pre-calculate
    // a MAC value on your server,
    // based on the values you give to this payment window, and set this
    // pre-calculated MAC value like this.
    //
     paymentData.setCalculatedMAC("");

    // Payment window supports loading cancel or callback URLs based on
    // payment outcome.
    // Another, and maybe better, way to do this in an app, is to listen for
    // the proper callbacks
    // on the listener you set on the payment window, and then do your own
    // cancel or payment success
    // handling against your own servers.
    //

    try {
        paymentData.setCallbackUrl(new URL(
                "http://****.demoprojects.in/accept.php"));
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    try {
        paymentData.setCancelUrl(new URL("http://****.demoprojects.in/accept.php"));
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    paymentData.setLanguage("en_UK");
    paymentData.setTheme(Theme.ANDROID_DIBS);

    // If you need to, you can pass custom options to the payment window,
    // which will be posted back again.
    //
    // Map<String, String> yourCustomOptions = new HashMap<String,
    // String>();
    // yourCustomOptions.put("foo", "bar");
    // paymentData.setCustomOptions(yourCustomOptions);

    return paymentData;
}

/*
 * public void delete() { DatabaseHandler readDatabase = new
 * DatabaseHandler( getApplicationContext()); readDatabase.deleteAll(); }
 */
}

This is the first time i am working on payment. Please help me out as security is the main concern here. Thanks in advance :)

Answer 1

Dibs allow MAC to be calculated by two algorithms The choice of algorithm is up to you. It currently handles MD5 and SHA-1. SHA-1 is recommended by Dibs as it provides better security.

SHA-1(data&currency&method&SecretKey&)

or

MD5(data&currency&method&SecretKey&)

data here is the string containing information regarding the amount and quantity of purchase.

Security > DebiTech DefenderTM > MAC Configuration, here you will find the secret key in dibs dashboard.

Click here for further reference: