Javax.crypto.BadPaddingException in DES encrypt/decrypt algorithm

Question

I am using DES algorithm, the default provided by J2ME to encrypt and decrypt some text. My problem is that I can encrypt the text but when I decrypt I get javax.crypto.BadPaddingException. I used a sample code from this forum I suppose and modified it to some extend.
Here's the output -
Plain Text :debayandas
Cipher Text :Ɩ2�Ü°*Yð´4}�f¥
Recovered Plain Text :javax.crypto.BadPaddingExceptionAnd here's the J2ME code -
Declaration part:
private boolean midletPaused = false;
        private static String algorithm = "DES";
     private static byte[] secretKey = {(byte) 0x2b, (byte) 0x7e, (byte) 0x15, (byte) 0x16,
                                                  (byte) 0x28, (byte) 0xae, (byte) 0xd2, (byte) 0xa6 };
     private static String secretKeyAlgorithm = "DES";
     private static byte[] iv = "DES".getBytes();
     private static byte[] plainText = null;
     private Key key = null;
     private static Cipher cipher = null;
     private static int ciphertextLength = 512;
        private static byte[] cipherText = new byte[ciphertextLength];
        private static int decryptedtextLength = 1024;
        private static byte[] decryptedText = new byte[decryptedtextLength];commandAction:
public void commandAction(Command command, Displayable displayable) {                                              
        if (displayable == form) {                                          
            if (command == exitCommand) {                                        
                exitMIDlet();                                          
            } else if (command == okCommand) {
                plainText=textField.getString().getBytes();
                encrypt();
                decrypt();                                                        
    } Encrypt:
public void encrypt()
            try
                key = new SecretKeySpec(secretKey,0,secretKey.length,secretKeyAlgorithm);
          cipher = Cipher.getInstance(algorithm);
                cipher.init(Cipher.ENCRYPT_MODE, key);
                cipher.doFinal(plainText, 0, plainText.length, cipherText, 0);
          System.out.println("Plain Text :"+new String(plainText));
          System.out.println("Cipher Text :"+new String(cipherText));
            catch(Exception e)
                System.out.println(""+e);
    }Decrypt:
public void decrypt()
        try
//            cipher = Cipher.getInstance(algorithm);
            cipher.init(Cipher.DECRYPT_MODE,key);
            cipher.doFinal(cipherText,0,cipherText.length,decryptedText,0);
            System.out.println("Recovered Plain Text :"+new String(decryptedText));
        catch(Exception e)
            System.out.println(""+e);
    }Where am I going wrong?

Answer 1

debayandas wrote:
I am using DES algorithm, the default provided by J2ME to encrypt and decrypt some text. My problem is that I can encrypt the text but when I decrypt I get javax.crypto.BadPaddingException. I used a sample code from this forum I suppose and modified it to some extend.How did you get DES in J2ME?
I am asking as there isn't one default implementation in J2ME and as far as I am aware it is not included in any Configurations or Profiles of J2ME.
You might be using [Bouncycastle library|http://www.bouncycastle.org/java.html] or any other third party implementation of DES, in which case please refer to the documentation of it to see in which methods throw BadPaddingException and in what circumstances, in order to pinpoint the problem.
Daniel