Problem when decrypt database data with DES. (Input length must be multiple of 8 when decrypting with padded cipher)

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I want to store data (encrypted with DES) and then take the encrypted data from database and present it as a list. But I have a problem. Here is the code.

Java

public void EncryptDemo(){
    try {
        FileInputStream keyfis = new FileInputStream("mainkey.key");
        byte[] encodedKey = new byte[keyfis.available()];
        keyfis.read(encodedKey);
        keyfis.close();
        Key KeyFromFile = new SecretKeySpec(encodedKey, "DES");
        Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        String text=txtToEncryptData.getText(), output;
        cipher.init(Cipher.ENCRYPT_MODE, KeyFromFile);
        DataDemo = cipher.doFinal(text.getBytes());
        InsertIntoDataBase();
        //I store it as varbinary in database
    } catch (FileNotFoundException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IOException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (NoSuchAlgorithmException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (NoSuchPaddingException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (InvalidKeyException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IllegalBlockSizeException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (BadPaddingException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    }
}

    public void DecryptDemo(){
    try {
        FileInputStream keyfis = new FileInputStream("mainkey.key");
        byte[] encodedKey = new byte[keyfis.available()];
        keyfis.read(encodedKey);
        keyfis.close();
        Key KeyFromFile = new SecretKeySpec(encodedKey, "DES");
        Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, KeyFromFile);
        String sql = "{call SelectAll}";
        CallableStatement call = conn.prepareCall(sql);
        call.execute();
        ResultSet result = call.getResultSet();
        DefaultListModel model = new DefaultListModel();
        while(result.next()){
            DataDemo = result.getBytes("TestData");
            byte[] plainText = cipher.doFinal(DataDemo);
            String after = new String(plainText);
            model.addElement(after);
        }
        lstDecryptResult.setModel(model);
    } catch (SQLException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (FileNotFoundException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IOException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (NoSuchAlgorithmException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (NoSuchPaddingException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (InvalidKeyException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IllegalBlockSizeException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    } catch (BadPaddingException ex) {
        Logger.getLogger(MainGUI.class.getName()).log(Level.SEVERE, null, ex);
    }
}

The encrypt and storing is allright. But when I take data from database, I get this error when decrypt at:

Java

byte[] plainText = cipher.doFinal(DataDemo);

The error is:

Jul 19, 2013 11:40:05 AM databaseencryptdecryptdemo.MainGUI DecryptDemo
SEVERE: null
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher

Any solution???

Posted 19-Jul-13 23:45pm

Minh Hikari

Updated 19-Jul-13 23:48pm

v4

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Comments

AlphaDeltaTheta 21-Jul-13 11:25am

Have you verified that the SQL call returns the correct data?

Minh Hikari 21-Jul-13 11:30am

Yes, it has. The only problem is: I do the decrypting and face this error.

AlphaDeltaTheta 21-Jul-13 11:53am

And is the length a multiple of eight

Minh Hikari 21-Jul-13 12:56pm

You mean the definition of data type in database is varbinary(multiple of 8)? I tried it too and still stuck there.

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Minh Hikari · Accepted Answer · 2013-07-21T16:28:00

I found the solution. But I think it's not the best.

I changed the type of table DataDemo from varbinary to image and everything became alright. But my data size store in database is heavier (about 4 times) than the oigin data.

But at least I solved my problem.

Does anyone have a better solution? I willing to hear from you.