I'm busy with an app to emulate normal APDU communication on a Nexus 7 with CM10.1 to an ACR122U102 reader/writer. I found this blog about software card emulation and wrote an app to make my device (the nexus) appear as a card. Now I'm trying to send messages back and forth between this device and the ACR122u. So far, I've only managed to communicate with the nexus 7 by sending D4 40 01 (InDataExchange page 127) APDU's. For the application I'm writing, this should be sufficient.
The problem lays in the answer I send from the device to the reader. Using the transcieve function (android.nfc.tech.IsoPcdA with reflection), I can reply with a byte array of length > 0. This would show up on the reader-end like a normal InDataExchange response (e.g: D5 41 00 01 02 03 with {01 02 03} being the byte array supplied to the transcieve function). But I can't control the status byte nor the SW bytes in the response (D5 41 XX and both SW's). There's no documentation to be found about this IsoPcdA class except the source code itself.
What I want to be able to do is change the XX to a byte of my choice and to send answers of length = 0 (e.g: D5 41 01 without any extra data). Is it possible?
I'm not exactly sure what you are trying to achieve here. Whatever you transceive with IsoPcdA's transceive method are complete APDUs (as defined in ISO/IEC 7816-4, or rather any PDU within the ISO-DEP transport protocol). So the return value of transceive is a full C-APDU (command APDU) and the byte array parameter of transceive is a full R-APDU (response APDU) including the two bytes of the status word (SW1 | SW2). Thus, the last two bytes of that parameter are the status word. In your example SW1 would be 02 and SW2 would be 03.
What you see as status byte in the InDataExchange command of the PN532 NFC controller is not the status word of the APDU but the status of the command execution within the PN532 NFC controller. This status byte gives you information about buffer overflows, communication timeouts, etc and is not something that is returned by the card side.
EDIT : Sample code + test commands:
Sample Code running on Galaxy Nexus (CM 10):
try {
Class isoPcdA = Class.forName("android.nfc.tech.IsoPcdA");
Method isoPcdA_get = isoPcdA.getDeclaredMethod("get", Tag.class);
final IsoPcdA techIsoPcdA = (IsoPcdA)isoPcdA_get.invoke(null, tag);
if (techIsoPcdA != null) {
if (mWorker != null) {
mInterrupt = true;
mWorker.interrupt();
try {
mWorker.join();
} catch (Exception e) {}
}
mInterrupt = false;
mWorker = new Thread(new Runnable() {
public void run () {
try {
techIsoPcdA.connect();
byte[] command = techIsoPcdA.transceive(new byte[]{ (byte)0x90, (byte)0x00 });
Log.d(CardEmulationTest.class.getName(), "Connected.");
while (!mInterrupt) {
Log.d(CardEmulationTest.class.getName(), "C-APDU=" + StringUtils.convertByteArrayToHexString(command));
command = techIsoPcdA.transceive(command);
}
} catch (Exception e) {
Log.e(CardEmulationTest.class.getName(), "Exception while communicating on IsoPcdA object", e);
} finally {
try {
techIsoPcdA.close();
} catch (Exception e) {}
}
}
});
mWorker.start();
}
} catch (Exception e) {
Log.e(CardEmulationTest.class.getName(), "Exception while processing IsoPcdA object", e);
}
Test (using ACR122U):
InListPassivTargets (1 target at 106kbps)
> FF00000004 D44A 0100 00
< D54B 010100046004088821310578338800 9000
InDataExchange with DATA = 0x01
> FF00000004 D440 01 01 00
< D541 00 01 9000
So we get an error code of 0x00 from the card reader (status of InDataExchange command; not part of the actual response APDU), we get 0x01 as the response (this is the IsoDepA response APDU) and we get 0x9000 as the status code for the card reader wrapper APDU (not part of the actual response APDU).
InDataExchange with DATA = 0x01 0x02
> FF00000005 D440 01 0102 00
< D541 00 0102 9000
So we get an error code of 0x00 from the card reader (status of InDataExchange command; not part of the actual response APDU), we get 0x01 0x02 as the response (this is the IsoDepA response APDU) and we get 0x9000 as the status code for the card reader wrapper APDU (not part of the actual response APDU).
InDataExchange with DATA = 0x01 0x02 0x03
> FF00000006 D440 01 010203 00
< D541 00 010203 9000
So we get an error code of 0x00 from the card reader (status of InDataExchange command; not part of the actual response APDU), we get 0x01 0x02 0x03 as the response (this is the IsoDepA response APDU) and we get 0x9000 as the status code for the card reader wrapper APDU (not part of the actual response APDU).
InDataExchange with DATA = 0x01 0x02 0x03 0x04
> FF00000007 D440 01 01020304 00
< D541 00 01020304 9000
So we get an error code of 0x00 from the card reader (status of InDataExchange command; not part of the actual response APDU), we get 0x01 0x02 0x03 0x04 as the response (this is the IsoDepA response APDU) and we get 0x9000 as the status code for the card reader wrapper APDU (not part of the actual response APDU).
Thus, we get exactly the data taht we send as command APDU as response APDU (note that none of these APDUs is formatted according to ISO 7816-4, but that doesnt matter as the IsoPcdA card emulation works with any ISO 14443-4 transport protocol format).
The status code of 0x9000 belongs to the card reader APDU encapsulation (CLA=FF INS=00 P1P2=0000 Lc [PN542 COMMAND] Le=00) that is required as the ACR122U's PN532 is accessed over the CCID (PC/SC) interface. These are pure reader command encapsulation and have nothing to do with the communication over ISO-DEP.
The D440 01 [DATA] is the PN532 command to exchange data (e.g. APDUs) over ISO-DEP and the D541 00 [DATA] is the associated response.
Related
I am trying to get a weight value from a set of weighing scales over USB. It should be quite simple, according to their doc, I need to send two bytes the letter "W" and the carriage return byte. It then responds with 16 bytes of data representing the current weight on the device.
The device has 1 interface, 2 endpoints with a max packet size of 64. I believe I must use the bulkTransfer function as the endpoint types are USB_ENDPOINT_XFER_BULK.
Here is the doc graphic:
How exactly should I send this request and receive the response? My attempt is below, and the response is simply a Start of Heading symbol, then a back quote symbol "`" and a load of zeroes. I have tried to run the code on a polling loop or just a single request but get the same result.
val connection = usbManager.openDevice(scales)
val intf: UsbInterface = scales.getInterface(0)
connection.claimInterface(intf, true)
val endpointReadIn = intf.getEndpoint(0)
val endpointWriteOut = intf.getEndpoint(1)
val bytes = byteArrayOf(0x57.toByte(), 0x0D.toByte())
thread {
val request = connection.bulkTransfer(endpointWriteOut, bytes, bytes.size, 0)
Log.d(TAG, "Was request to write successful? $request")
val buffer = ByteArray(16)
val response = connection.bulkTransfer(endpointReadIn, buffer, buffer.size, 0)
Log.d(TAG, "Was response from read successful? $response")
val responseString = StringBuilder()
for (i in 0..15) {
responseString.append(buffer[i])
}
Log.d(TAG, "Response: $responseString")
val hex = toHexString(buffer)
Log.d(TAG, "Hex: $hex")
connection.close()
}
fun fromHexString(hexString: String): ByteArray {
val len = hexString.length / 2
val bytes = ByteArray(len)
for (i in 0 until len) bytes[i] = hexString.substring(2 * i, 2 * i + 2).toInt(16).toByte()
return bytes
}
Output:
Was request to write successful? 2
Was response from read successful? 2
Response: 19600000000000000
Hex: 01 60 00 00 00 00 00 00 00 00 00 00 00 00 00 00
There was a couple of missing pieces here. I think the big one was not specifying the baud rate, data bit, stop bit and parity which are all achieved via the controlTransfer function.
In the end I couldn't get it to work myself despite getting successful responses while setting these. Then I found this lovely library which is compatible with this RS232 device and it works well. I just need to specify the vid / pid to get a custom driver using the FtdiSerialDriver class.
I'm writing an Android application. I'm trying to send NfcA low-level commands (in my case: HALT and WAKE-UP) to my Mifare Plus S card. The NfcA tech is for "low-level" access to ISO 14443 Type A tags (i.e. the
proprietary protocol as mentioned in ISO 14443-3).
This is part of my code:
protected void onNewIntent(Intent intent) {
if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())) {
tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
UID = Utils.byteArrayToHexString(intent.getByteArrayExtra(NfcAdapter.EXTRA_ID));
}
NfcA nfca = null;
try {
Log.e(TAG, "WakeUpCMD and HaltCMD");
nfca = NfcA.get(tagFromIntent);
nfca.connect();
Short s = nfca.getSak();
byte[] a = nfca.getAtqa();
byte[] HaltCMD = {0x35, 0x30, 0x30,0x30, 0x00};
byte[] WakeUpCMD = {0x35, 0x32, 0x00};
byte[] data = null;
try {
data = nfca.transceive(HaltCMD);
length = data.length;
}
catch (Exception e){
Log.e(TAG, "HALT complete "+Utils.byteArrayToHexString(data));
}
Log.e(TAG, "Tag is connected: "+nfca.isConnected());
//Log.e(TAG, "Response from tag "+Utils.byteArrayToHexString(data));
nfca.setTimeout(100);
data = nfca.transceive(WakeUpCMD);
Log.e(TAG, "Response from tag"+Utils.byteArrayToHexString(data));
nfca.close();
} catch (Exception e) {
Log.e(TAG, "Error when reading tag");
}
}
WAKE-UP Command is sent by the PCD to put PICCs which have entered the HALT State back into the READY
State. They shall then participate in further anticollision and selection procedures.
|b7| |b6| |b5| |b4| |b3| |b2| |b1|
|1 | | 0 | | 1| | 0| | 0| | 1| | 0| {‘52’} = WAKE-UP
HALT Command consists of four bytes and shall be transmitted using the Standard Frame.
First bit transmitted
S | ‘50’ | ‘00’ | CRC_A | E
If the PICC responds with any modulation during a period of 1 ms after the end of the HALT Frame, this response shall be interpreted as 'not acknowledge'.
This is the descriptions of the two commands from ISO 14443-3 which I try to send to my card.
When I start my app, I get a "Tag Lost" Exception. Can you help me? What's wrong? How can I send these commands?
It seems as if you are converting the command codes into null-terminated ASCII character strings before sending them with NfcA.transceive():
byte[] HaltCMD = {0x35, 0x30, 0x30,0x30, 0x00};
byte[] WakeUpCMD = {0x35, 0x32, 0x00};
0x35 0x30 0x30 0x30 gives "5000"
0x35 0x32 gives "52"
This does not make any sense as the commands (50 00 for HLTA, and 52 for WUPA) are hexadecimal representations of the command values already.
For the HLTA command, you would therefore need to send 50 00:
data = nfca.transceive(new byte[] { (byte)0x50, (byte)0x00 });
Note that S (start of communication), E (end of communication), and CRC_A will be automatically added by the NFC controller (or the NFC stack).
For the WUPA command, you could probably try to send 52:
data = nfca.transceive(new byte[] { (byte)0x52 });
However, it is very likely that the NFC stack does not permit you to send 7-bit commands using the transceive method. Instead, the stack may automatically use this command value as one full byte and add a CRC_A.
General note on sending ISO/IEC 14443-3 initialization and anti-collision commands
Sending such commands may or may not work (depending on the NFC stack implementation and the NFC controller). In general I would strongly recommend that you do not send such commands. Particularly the HLTA command will confuse the internal state keeping of the NFC stack on some devices and will lead to unexpected results. Normally, you don't need to exchange such commands, as anti-collision, initialization and activation are handled automatically by the NFC device.
When I try to transceive commands for NFC-V Tag-it HF-I Plus Inlay tag I get a TagLostException for most of the commands.
From the links I have gone through this exception may be caused by incorrect commands.
How can I create correct ISO15693 command byte[] for Nfc V Tag-it HF-I Plus Inlay?
The datasheet shows the supported commands but how can I create correct commands to read NFC-V tags?
The commands in the document are:
The tag that I'm trying to read is:
Code:
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
Log.i(TAG, " tag "+tag );
if (tag != null) {
NfcV tech = NfcV.get(tag);
Log.i(TAG, " tech "+tech );
if (tech != null) {
try {
tech.connect();
Log.i(TAG, " on connect" );
byte[] data = tech.transceive(Nfcv.InventoryRequest());
Log.i(TAG, "resp data " + data);
StringBuilder sb = new StringBuilder();
for (int i = 0; i < data.length; i++) {
byte b = data[i];
System.out.println(b);
sb.append(String.format("%02X ", b));
}
System.out.println("response: " + sb.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
tech.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
I have gone through the following:
NfcV Transceive command throws tag lost exception with TI HF-I plus tag(ISO15693) in android
Transceive Failed on ISO15693 / Tag-it HF-I
Android NfcV Stay Quiet Command
Android NfcV (ISO 15693) tag
Connection error when reading Android NfcV tags
EDIT
Commands that I have tried:
public class Nfcv {
// texas get system info -> tag lost exception
public static byte[] GET_SYSTEM_INFO = ReadNfcActivity.hexStringToByteArray("010A00030418002B0000");
//read multiple blocks -> not working
byte[] read_multiple_blocks= ReadNfcActivity.hexStringToByteArray("010C00030418002301020000");
byte[] readSingleBlock = ReadNfcActivity.hexStringToByteArray("010B000304180020050000");
// readUID generic command -> not working
public static byte[] readUID = ReadNfcActivity.hexStringToByteArray("FFCA000000");
public static byte[] InventoryRequest(){
//working response: 00 00 3A E5 00 04 00 00 07 E0
// R/0 UID is E0 07 00 00 04 00 E5 3A 00 00 (reverse)
return new byte[] { (byte) 0x24, (byte) 0x01, (byte) 0x00};
}
//-> not working
private byte[] ReadSingleBlockUnadressed(byte blocknumber) {
return new byte[] {(byte) 0x00, (byte) 0x20, blocknumber};
}
//-> response 03
public static byte[] get_system_info = {0x00,(byte)0x2B};
}
The Android NFC stack automatically handles polling (searching for tags various tag technologies/protocols), anti-collision (enumeration of multiple tags within one tag technology/protocol) and activation (intitiating communication with one specific tag) for you. You should, therefore, never send commands used for anti-collision and activation yourself. The Inventory command is one such command (that is used to discover tags in range).
With regard to the Inventory command, there is typically no need to send this command. All the information that you would get from this command is already provided by the Android NFC API:
You can get the UID using tag.getId().
You can get the DSFID using tech.getDsfId().
Also, for your app to work reliable across different Android device platforms (= different NFC stacks), you should always use the addressed version of commands (i.e. Address_flag set and UID sent as part of request). See Android NfcV get information command returns only one byte.
If you want to read from/write to the tag, you could use the READ_SINGLE_BLOCK and WRITE_SINGLE_BLOCK commands:
byte[] tagUid = tag.getId(); // store tag UID for use in addressed commands
int blockAddress = 0; // block address that you want to read from/write to
READ_SINGLE_BLOCK:
byte[] cmd = new byte[] {
(byte)0x20, // FLAGS
(byte)0x20, // READ_SINGLE_BLOCK
0, 0, 0, 0, 0, 0, 0, 0,
(byte)(blockAddress & 0x0ff)
};
System.arraycopy(tagUid, 0, cmd, 2, 8);
byte[] response = tech.transceive(cmd);
WRITE_SINGLE_BLOCK:
byte[] cmd = new byte[] {
(byte)0x60, // FLAGS
(byte)0x21, // WRITE_SINGLE_BLOCK
0, 0, 0, 0, 0, 0, 0, 0,
(byte)(blockAddress & 0x0ff),
... // data block that you want to write (same length as the blocks that you read)
};
System.arraycopy(tagUid, 0, cmd, 2, 8);
byte[] response = tech.transceive(cmd);
I'm trying to read a smartcard via my LG P710 Optimus L7 2.
I'm following this tutorial
I can select the "1PAY.SYS.DDF01" directory
I can select the Application
But I can't perform an "GET PROCESSING OPTIONS"
It always result in an 6700 error (Lc or Le wrong)
here is my code
NfcAdapter mNFCAdapter;
Intent intent;
PendingIntent pendingIntent;
private TextView mTextView;
String[][] techList;
IntentFilter[] filters = new IntentFilter[3];
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mTextView = (TextView) findViewById(R.id.title);
mNFCAdapter = NfcAdapter.getDefaultAdapter(this);
intent = new Intent(getApplicationContext(), getClass());
intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
pendingIntent = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0);
techList = new String[][]{
new String[]
{ MifareClassic.class.getName() },
new String[]
{ IsoDep.class.getName() }
};
filters[0] = new IntentFilter();
filters[0].addAction(NfcAdapter.ACTION_NDEF_DISCOVERED);
filters[0].addCategory(Intent.CATEGORY_DEFAULT);
// add type of tag data you want to have - here ndef -> plain text
try {
filters[0].addDataType(MIME_TEXT_PLAIN);
} catch (MalformedMimeTypeException e) {
e.printStackTrace();
}
filters[1] = new IntentFilter();
filters[1].addAction(NfcAdapter.ACTION_TAG_DISCOVERED);
filters[1].addCategory(Intent.CATEGORY_DEFAULT);
filters[2] = new IntentFilter();
filters[2].addAction(NfcAdapter.ACTION_TECH_DISCOVERED);
filters[2].addCategory(Intent.CATEGORY_DEFAULT);
}
#Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
String action = intent.getAction();
mTextView.setText(action);
Toast.makeText(getApplicationContext(), action, Toast.LENGTH_SHORT).show();
Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
IsoDep tagIsoDep;
if((tagIsoDep = IsoDep.get(tagFromIntent)) != null)
if(handleIsoDep(tagIsoDep))
return;
}
private boolean handleIsoDep(IsoDep tag){
try{
tag.connect();
tag.setTimeout(20);
byte[] responseAPDU;
//2PAY.SYS.DDF01
byte[] select_Dir = new byte[]{
(byte)0x00, (byte)0xa4, (byte)0x04, (byte)0x00, (byte)0x0e,
(byte)0x32, (byte)0x50, (byte)0x41, (byte)0x59, (byte)0x2e,
(byte)0x53, (byte)0x59, (byte)0x53, (byte)0x2e, (byte)0x44,
(byte)0x44, (byte)0x46, (byte)0x30, (byte)0x31
};
//Select CC Applet
byte[] select_Applet = new byte[]{
(byte)0x00, (byte)0xa4, (byte)0x04, (byte)0x00, (byte)7,
(byte)0xa0, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x04,
(byte)0x30, (byte)0x60
};
//Send GET PROCESSING OPTIONS command
byte[] Send_Get = new byte[]{
(byte)0x80,(byte)0xA8,(byte)0x00,(byte)0x00,(byte)0x02,
(byte)0x83,(byte)0x00,
(byte)0x00
};
responseAPDU = tag.transceive(select_Dir);
mTextView.setText(mTextView.getText() + handleResponse(responseAPDU));
this returns the APDU-Statusword 9000 -> success
responseAPDU = tag.transceive(select_Applet);
mTextView.setText(mTextView.getText() + handleResponse(responseAPDU));
this returns the APDU-Statusword 9000 -> success
responseAPDU = tag.transceive(Send_Get);
mTextView.setText(mTextView.getText() + handleResponse(responseAPDU));
and this one is making problems: it returns 6700 -> wrong Lc or Le
mTextView.setText(mTextView.getText() + "\n\nDone");
tag.close();
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
The function handleResponse just parses the "responseAPDU" from Binary to Hex an highlights the Statusword
Can anybody tell my what is going wrong?
or just help me out?
PS sry for bad english ;)
As response to my application-select I get:
6f298407a0000000043060a51e50074d41455354524f5f2d046465656e9f38039f5c08bf0c059f4d020b0a9000
6F -> FCI Template 29
84 -> DF Name 07 A0 00 00 00 04 30 60
A5 -> FCI Properietary Template 1E
50 -> Application Lable 07 4D 41 45 53 54 52 4F 5F 2D 04 64 65 6E
9F38 -> PDOL 03 9F 5C 08
BF0C -> FCI Issuer Data 05
9F4D -> Log Entry 02 0B
0A Additional Issuer Data
But I don't know what ive to insert into the Data fild from the GET PROCESSING OPTIONS.
Iv'e red the guidelines in EMV Book 3, section "5.4 Rules for Using a Data Object List (DOL)".
So do I just have to set the data field 83 03 9F 5C 08
and Lc = 5?
In order to help you, the entire ADPU dialog (commands/responses) would be needed.
However, based on your code : hardcoding your select_Dir and select_Applet commands is correct, but you can't hardcode the GET PROCESSING OPTIONS command whose syntax depends on the response of the card (ICC) to your select_Applet command.
EMV 4.3 Book 1, "Table 45: SELECT Response Message Data Field (FCI) of an ADF", explains that a successful card response to the SELECT command contains a "Processing Options Data Object List" (PDOL, tag 9F38). That's the list of fields required by the card to process the transaction (ex : amount, ...). These fields values are to be returned to the card by the terminal (your phone) through the GET PROCESSING OPTIONS command data field (tag 83), as documented in EMV 4.3 book 3, section "6.5.8.3 Data Field Sent in the Command Message" :
The data field of the command message is a data object coded according to the PDOL provided by the ICC, as defined in section 5.4, and is introduced by the tag '83'. When the data object list is not provided by the ICC, the terminal sets the length field of the template to zero. Otherwise, the length field of the template is the total length of the value fields of the data objects transmitted to the ICC.
Knowing that :
Your selected AID (A0 00 00 00 04 30 60) is a Mastercard Maestro one, which is unlikely to have an empty PDOL
But your GET PROCESSING OPTIONS command does not list any value in its data field
You probably have a mismatch between the length of your GET PROCESSING OPTIONS data field and the total length of the fields asked by the card in the PDOL, hence the 6700 checking error returned by the card (EMV Book 1, "Table 33: GET RESPONSE Error Conditions").
You have identified the PDOL requested by the card as : 9F38 -> 03 9F 5C 08.
The 03 tells you the PDOL is 3 bytes long. 9F5C is the tag of the requested field, 08 is the length of the field value that is to be returned by the phone.
Tag 9F5C is defined in EMV Contactless 2.3 Book C2 kernel 2 specification, section "A.1.59 DS Requested Operator ID". The DS Requested Operator ID is defined as
Contains the Terminal determined operator identifier for data
storage. It is sent to the Card in the GET PROCESSING
OPTIONS command.
I'm not familiar with this tag, so I can't tell you what a proper value is.
However, here is what the data field of the GET PROCESSING OPTIONS command should look like, assuming a DS Requested Operator ID has value 01 02 03 04 05 06 07 08, and given the Data Object List formatting guidelines in EMV Book 3, section "5.4 Rules for Using a Data Object List (DOL)" :
83 08 01 02 03 04 05 06 07 08
and Lc = 10
I'm wanting to read MIDI data from an asset stream. The file is a MIDI0 file of length 150 bytes according to Windows. Using this code, I read 150 bytes measured by count, but the output string is only 127.5 bytes.
try {
assetStream = assets.open("MIDI0_7.mid");
int count=0;
do {
byteValue = assetStream.read();
count++;
outputString = outputString + Integer.toHexString(byteValue);
} while (byteValue > -1) ;
Log.d("MUSIC", "Final string " +outputString);
Log.d("MUSIC", "bytes read " +count);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
This read HEX data also doesn't match with the MIDI spec AFAICT. The opening 8 bytes should read
4d 54 68 64 00 00 00 06
but I get
4d 54 68 64 00 06
I can't be sure about the save format of my MIDI file (exported test file with 7 notes from Cakewalk SONAR) so I'm not sure why the MIDI doesn't correspond with the standards, but before I can solve that I need to know where my missing data is! What am I doing wrong to see some bytes getting dropped from my output stream?
Edit:
Okay, found it. Bytes less than 16 are returned as a single character by Integer.toHexString() instead of being a 0x figure. Easily fixed.