If i want to encrypt a message that i send to Java Card applet like DES

Question

What are the steps that i have to do ?? is there something missing??
//set the private key
private byte[] KeyData = {0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29,
           0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,0x39, 0x40};
deskey = (DESKey)KeyBuilder.buildKey(KeyBuilder.TYPE_DES_TRANSIENT_DESELECT, 
KeyBuilder.LENGTH_DES, false);
deskey.setKey(KeyData, (short)0);
//InData and OutData are two byte variables for the input message and the //Output message
Cipher cipher;
cipher = Cipher.getInstance(Cipher.ALG_DES_CBC_NOPAD ,false);
cipher.init(deskey, Cipher.MODE_ENCRYPT);
cipher.doFinal((byte[])InData,(short) 0 , (short) InData.length,(byte[]) OutData,(short) 0);
is that correct? or needs something else?
if i set fixed size for Outdata byte i have to do Padding since i choose (ALG_DES_CBC_NOPAD) method??? in order to send the cipher back to host application Thru APDU command??
How big can the cipher become with the key i used if InData are byte[10]
Thanks in advance

Answer 1

I tried too many corrections and i still get unknown error
i tried this code this time
package gr.teiath.netlab.applets;
import javacard.framework.*;
import javacard.security.DESKey;
import javacard.security.KeyBuilder;
import javacardx.crypto.Cipher;
public class MedBooklet extends Applet {
     final static byte MedBooklet_CLA = (byte) 0xB0;
     // PIN relatives
     final static byte PIN_TRY_LIMIT = (byte) 0x03;
     final static byte MAX_PIN_SIZE = (byte) 0x04;
     OwnerPIN pin;
     //DES
     byte keyArray[] = {(byte)0x09,(byte)0x0e,(byte)0x0d,(byte)0x0c,(byte)0x0b,(byte)0x0a,(byte)0x09,(byte)0x08,
               (byte)0x09,(byte)0x0e,(byte)0x0d,(byte)0x0c,(byte)0x0b,(byte)0x0a,(byte)0x09,(byte)0x08,
               (byte)0x09,(byte)0x0e,(byte)0x0d,(byte)0x0c,(byte)0x0b,(byte)0x0a,(byte)0x09,(byte)0x08};
     private byte[] outBuff;
     private short Lc;
     // allocate key object
     DESKey desKey;
     Cipher cipher;
     // Return codes
     final static short SW_VERIFICATION_FAILED = 0x6300;
     // INS commands
     final static byte VERIFY = (byte)0x20;
     final static byte ADDRECENTRY = (byte)0x30;
     final static byte READRECENTRY = (byte)0x40;
     //private RecipeFile recipeFile;
     //private ReferFile referFile;
     private MedBooklet(byte[] bArray, short bOffset, byte bLength) {
          pin = new OwnerPIN(PIN_TRY_LIMIT,MAX_PIN_SIZE);
          pin.update(bArray, bOffset, bLength);
          desKey = (DESKey)KeyBuilder.buildKey(KeyBuilder.TYPE_DES,KeyBuilder.LENGTH_DES,false);
          // set key value
          desKey.setKey(keyArray,(short)0x00);                    
          //recipeFile = new RecipeFile();
          //referFile = new ReferFile();
          register();
     public static void install(byte[] bArray, short bOffset, byte bLength) {
          new MedBooklet(bArray,bOffset,bLength);
     public boolean select() {
          if(pin.getTriesRemaining()==0) return false;
          return true;
     public void deselect() {
          pin.reset();
     public void process(APDU apdu) {
          byte[] buffer = apdu.getBuffer();
          if ((buffer[ISO7816.OFFSET_CLA]==0) && (buffer[ISO7816.OFFSET_INS])== (byte) 0xa4) return;
          if (buffer[ISO7816.OFFSET_CLA]!=MedBooklet_CLA)
               ISOException.throwIt(ISO7816.SW_CLA_NOT_SUPPORTED);
          switch (buffer[ISO7816.OFFSET_INS]) {
          case ADDRECENTRY: addrec(apdu);
               return;
          case READRECENTRY: readrec(apdu);
               return;
          case VERIFY: verify(apdu);
               return;
     public void addrec(APDU apdu){
          //byte[] buffer = apdu.getBuffer();
          //byte byteRead = (byte) (apdu.setIncomingAndReceive());
          //if (byteRead==0x1f)
               //recipeFile.newRecord(buffer, ISO7816.OFFSET_CDATA, (short) byteRead);
//           create cipher instance
          cipher = Cipher.getInstance(Cipher.ALG_DES_ECB_NOPAD,false);
          byte[] buf = apdu.getBuffer();
          Lc = (short) (buf[ISO7816.OFFSET_LC] & 0x00FF);
          //     array storing output buffer
          outBuff = new byte[Lc];
          // initialize cipher
          cipher.init(desKey,Cipher.MODE_ENCRYPT);               
          Lc = cipher.doFinal(buf,(short)ISO7816.OFFSET_CDATA,Lc,outBuff,(short)0x00);
          // set output to be returned with same size of the input
          apdu.setOutgoing();
          apdu.setOutgoingLength(Lc);
          apdu.sendBytesLong(outBuff,(short)0x00,Lc);     
     public void readrec(APDU apdu) {
          byte[] buffer = apdu.getBuffer();
          short le = apdu.setOutgoing();
        apdu.setOutgoingLength( (short) (35) );
        // echo header
        //apdu.sendBytes( (short)0, (short) 5);
        // echo data
       // apdu.sendBytesLong( recipeFile.getRecord() , (short) 0, (short) 35 );
     private void verify(APDU apdu) {
          byte[] buffer = apdu.getBuffer();
          byte byteRead = (byte) (apdu.setIncomingAndReceive());
          if (pin.check(buffer, ISO7816.OFFSET_CDATA, byteRead)== false)
               ISOException.throwIt(SW_VERIFICATION_FAILED);
}I have another Problem When in constructor i try to
cipher = Cipher.getInstance(Cipher.ALG_DES_ECB_NOPAD,false);I cant veriry the PIN so i always get exit command are there conflicts when are in the same constructor between
pin.update(bArray, bOffset, bLength);
VS
cipher = Cipher.getInstance(Cipher.ALG_DES_ECB_NOPAD,false);
VS
register();Are there Limitations about "Cref" do i have to send the data to be encrypted no more than byte of 8 hex ?