public void StopApduOperations()
{
currentIsoDept?.Close();
currentIsoDept?.Dispose();
currentIsoDept = null;
currentTag = null;
currentIntent = null;
}
public void OnTagDiscovered(Tag tag)
{
IsoDep isoDep = IsoDep.Get(tag);
if (isoDep == null)
{
Console.WriteLine("[CODE] Unsupported Tag");
//navigator.failureNavigation("Unsupported Tag");
}
else
{
Console.WriteLine("[CODE] IsoDep Found");
isoDep.Connect();
byte[] command = BuildSelectApdu(ACCESS_CARD_AID); //Once we find a tag, trancieve the command
try
{
byte[] result = isoDep.Transceive(command);
// If the matching AID is successfully found, 0x9000 is returned from the device as the status word (last 2
// bytes of the result) (0x9000 is the OK Status Word - this is returned if the phone is authorised and the scan was successful). Everything before the status word is
// payload, in this case will be the user ID - this means result will be dynamic
int resultLength = result.Length;
byte[] statusWord = { result[resultLength - 2], result[resultLength - 1] }; //Grab last two bytes for the status word
byte[] payload = new byte[resultLength - 2]; //Initialise empty array payload
Array.Copy(result, payload, resultLength - 2); //We know the lengths, so copy from those indexes into a new array
bool arrayEquals = SELECT_OK_SW.Length == statusWord.Length;
for (int i = 0; i < SELECT_OK_SW.Length && i < statusWord.Length && arrayEquals; i++)
{
arrayEquals = (SELECT_OK_SW[i] == statusWord[i]); //Compare byte by byte, ISO-DEP communcation is in bytes - we're looking for 0x90, 0x00
if (!arrayEquals)
{
break;
}
}
if (arrayEquals) //Only if the status word is OK, unauthenticated devices will not respond with the "OK" status
{
// The NFC device will respond with the userId as a payload
string payloadString = System.Text.Encoding.UTF8.GetString(payload);
Console.WriteLine($"Recieved Payload: {payloadString}");
OnPayloadReceived(payloadString);
}
}
catch (TagLostException e) //If something happens or the tag moves away, this is thrown. Close communication and inform user that an error occurred
{
isoDep.Close();
Console.WriteLine("[CODE] Caught tag loss error");
Device.BeginInvokeOnMainThread(async() => {
await Xamarin.Forms.Application.Current.MainPage.DisplayAlert("Error", $"Tag Lost Error", "OK");
});
}
}
}
public void OnTagRemoved()
{
try
{
isoDep.Close();
OnCardRemovedFromField(new EventArgs());
}
catch (Exception e)
{
throw e;
}
}
protected override void OnNewIntent(Intent intent)
{
base.OnNewIntent(intent);
Tag tag = intent.GetParcelableExtra(NfcAdapter.ExtraTag) as Tag;
SetResult(Result.Canceled, intent);
if (tag != null)
{
IsoDep isoTag = IsoDep.Get(tag);
try
{
isoTag.Connect();
isoTag.Timeout = 30000;
byte[] resp = isoTag.Transceive(selectCommand);
int length = resp.Length;
if (resp[length - 2] == (byte)0x90 && resp[length - 1] == 0x00)
{
DoChallengeYubiKey(isoTag, slot, challenge);
}
else
{
Toast.MakeText(this, Resource.String.yubichallenge_tag_error, ToastLength.Long)
.Show();
}
isoTag.Close();
}
catch (TagLostException e)
{
Toast.MakeText(this, Resource.String.yubichallenge_lost_tag, ToastLength.Long)
.Show();
}
catch (IOException e)
{
Toast.MakeText(this, GetString(Resource.String.yubichallenge_tag_error) + e.Message,
ToastLength.Long).Show();
}
}
else
{
SetResult(Result.Canceled, intent);
}
Finish();
}
/// <summary>
/// Reads the travel card data from HSL Mifare DESFire card.
/// </summary>
/// <param name="card">The card to try to read.</param>
/// <returns>A deserialized Travel Card object if the card was valid, otherwise null.</returns>
public static async Task <TravelCard> ReadTravelCardAsync(IsoDep card)
{
try
{
card.Connect();
byte[] selection = card.Transceive(HslCommands.SelectHslCommand);
if (selection != null &&
selection.Length > 0 &&
selection.SequenceEqual(HslCommands.OkResponse))
{
// Travel card info bytes
byte[] appInfo = null;
byte[] periodPass = null;
byte[] storedValue = null;
byte[] eTicket = null;
byte[] history = null;
// Temporary containers for history chunks
byte[] hist1 = new byte[2];
byte[] hist2 = new byte[2];
appInfo = await card.TransceiveAsync(HslCommands.ReadAppInfoCommand);
periodPass = await card.TransceiveAsync(HslCommands.ReadPeriodPassCommand);
storedValue = await card.TransceiveAsync(HslCommands.ReadStoredValueCommand);
eTicket = await card.TransceiveAsync(HslCommands.ReadETicketCommand);
hist1 = await card.TransceiveAsync(HslCommands.ReadHistoryCommand);
// If we have more history, the last two bytes of the history array will contain the MORE_DATA bytes.
if (hist1.Skip(Math.Max(0, hist1.Length - 2)).ToArray() == HslCommands.MoreData)
{
hist2 = await card.TransceiveAsync(HslCommands.ReadNextCommand);
}
// Combine the two history chunks into a single array, minus their last two MORE_DATA bytes
history = hist1.Take(hist1.Length - 2)
.Concat(hist2.Take(hist2.Length - 2)).ToArray();
var rawCard = new RawTravelCard(appInfo, periodPass, storedValue, eTicket, history);
if (rawCard.Status == CardStatus.HslCardDataFailure)
{
System.Diagnostics.Debug.WriteLine("Failed to construct travel card. Data appears to be invalid.");
return(null);
}
else
{
return(new TravelCard(rawCard));
}
}
else
{
System.Diagnostics.Debug.WriteLine("Failed to construct travel card. This doesn't seem to be an HSL Travel card.");
return(null);
}
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine("Failed to construct travel card. Reason: " + ex.ToString() + ".\nStack trace:" + ex.StackTrace);
return(null);
}
finally
{
card.Close();
}
}
