Java Card - Applet selection failed - applet

Question

Below is DES encryption code. I am getting error 0x6999: "Applet selection failed".
package JCardDES;
import javacard.framework.*;
import javacard.security.*;
import javacardx.crypto.*;
public class JCard_DES extends Applet
{
// globals
DESKey deskey;
Cipher cipherCBC;
final short dataOffset = (short) ISO7816.OFFSET_CDATA;
static byte[] TrippleDESKey = {(byte) 0x38, (byte) 0x12, (byte) 0xA4,
(byte) 0x19, (byte) 0xC6, (byte) 0x3B, (byte) 0xE7, (byte) 0x71, (byte) 0x00, (byte) 0x12, (byte) 0x00,
(byte) 0x19, (byte) 0x80, (byte) 0x3B, (byte) 0xE7, (byte) 0x71, (byte) 0x01, (byte) 0x12, (byte) 0x01,
(byte) 0x01, (byte) 0x01, (byte) 0x03, (byte) 0xE7, (byte) 0x71};
// constructor,
// initialization
private JCard_DES(byte bArray[], short bOffset, byte bLength)
{
try {
deskey = (DESKey) KeyBuilder.buildKey(KeyBuilder.TYPE_DES, KeyBuilder.LENGTH_DES3_3KEY, false);
cipherCBC = Cipher.getInstance(Cipher.ALG_DES_CBC_NOPAD, false);
}
catch (CryptoException e) {
ISOException.throwIt((short) ((short) 0x9000 + e.getReason()));
}
if (bArray[bOffset] == 0)
{
register();
}
else
{
register(bArray, (short)(bOffset+1), bArray[bOffset]);
}
}
// install
public static void install(byte bArray[], short bOffset, byte bLength)
{
new JCard_DES(bArray, bOffset, bLength);
}
public void process(APDU apdu)
{
byte[] buf = apdu.getBuffer();
if (selectingApplet())
{
return;
}
doTrippeDES(apdu);
}
// DES encryption
private void doTrippeDES(APDU apdu)
{
byte a[] = apdu.getBuffer();
short incomingLength = (short) (apdu.setIncomingAndReceive());
if (incomingLength != 24) ISOException.throwIt(ISO7816.SW_WRONG_LENGTH);
deskey.setKey(TrippleDESKey, (short)0);
cipherCBC.init(deskey, Cipher.MODE_ENCRYPT,new byte[]{0,0,0,0,0,0,0,0},(short)0,(short)8);
cipherCBC.doFinal(a, (short) dataOffset, incomingLength, a, (short) (dataOffset + 24));
cipherCBC.init(deskey, Cipher.MODE_DECRYPT,new byte[]{0,0,0,0,0,0,0,0},(short)0,(short)8);
cipherCBC.doFinal(a, (short) (dataOffset + 24), incomingLength, a, (short) (dataOffset + 48));
// send results
apdu.setOutgoing();
apdu.setOutgoingLength((short) 72);
apdu.sendBytesLong(a, (short) dataOffset, (short) 72);
}
}
That's strange, because without the initialization codes in try/catch block, there is no problem to select the applet.
My script file (APDU script) is
powerup;
// Select JCard_DES
0x00 0xA4 0x04 0x00 0X06 0XFC 0X74 0X41 0XA1 0X9B 0X63 0x7F;
Please guide me where i'm going wrong since i'm new to Java Card Programming
Thanks

Answer 1

Your command length (Lc) is incorrect. It should be 0x07 instead of 0x06.
0x00 0xA4 0x04 0x00 0X07 0XFC 0X74 0X41 0XA1 0X9B 0X63 0x7F

Answer 2

error code 0x6999 means applet selection failed.To determine the correctness of your aid and uniqueness.Pay attention to rules inside sometimes choose aid will appear automatically when the concept of completion.