get rid of exceptions

Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

now i hav used this function

result

javax.crypto.BadPaddingException: Given final block not properly padded

at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)

at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)

at com.sun.crypto.provider.DESCipher.engineDoFinal(DashoA13*..)

at javax.crypto.Cipher.doFinal(DashoA13*..)

at fileviewerframe$DesTest.<init>(Main.java:154)

at fileviewerframe$fileopen.actionPerformed(Main.java:69)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)

at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)

at javax.swing.AbstractButton.doClick(AbstractButton.java:357)

at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1216)

at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1257)

at java.awt.Component.processMouseEvent(Component.java:6038)

at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)

at java.awt.Component.processEvent(Component.java:5803)

at java.awt.Container.processEvent(Container.java:2058)

at java.awt.Component.dispatchEventImpl(Component.java:4410)

at java.awt.Container.dispatchEventImpl(Container.java:2116)

at java.awt.Component.dispatchEvent(Component.java:4240)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)

at java.awt.Container.dispatchEventImpl(Container.java:2102)

at java.awt.Window.dispatchEventImpl(Window.java:2429)

at java.awt.Component.dispatchEvent(Component.java:4240)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)

at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)

at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

that means same exceptions

noobs_will_rulea at 2007-7-29 11:33:18 >

final class CryptoTest {

private static final String PLAINTEXT =

"This is a test of encrypting and decrypting using padding and CBC.";

static {

Security.addProvider(new com.sun.crypto.provider.SunJCE());

}

private CryptoTest() {

super();

}

public static final void main(final String[] args)

throws Exception {

KeyGenerator kg = KeyGenerator.getInstance("DES");

Key key = kg.generateKey();

InputStream plaintextIn = new ByteArrayInputStream(PLAINTEXT.getBytes());

ByteArrayOutputStream ciphertextOut = new ByteArrayOutputStream();

encryptOrDecrypt(Cipher.ENCRYPT_MODE, key, plaintextIn, ciphertextOut);

System.out.println("Ciphertext: " + new String(ciphertextOut.toByteArray()));

InputStream ciphertextIn = new ByteArrayInputStream(ciphertextOut.toByteArray());

ByteArrayOutputStream plaintextOut = new ByteArrayOutputStream();

encryptOrDecrypt(Cipher.DECRYPT_MODE, key, ciphertextIn, plaintextOut);

System.out.println("Plaintext: " + new String(plaintextOut.toByteArray()));

assert(PLAINTEXT.equals(new String(plaintextOut.toByteArray())));

}

private static void encryptOrDecrypt(final int mode, final Key key,

final InputStream in, final OutputStream out)

throws Exception {

Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

cipher.init(mode, key);

byte[] buffer = new byte[cipher.getBlockSize()];

int bytesRead = in.read(buffer);

while (bytesRead >= 0) {

byte[] updated = cipher.update(buffer, 0, bytesRead);

if (updated.length > 0) {

out.write(updated);

}

bytesRead = in.read(buffer);

}

byte[] doFinal = cipher.doFinal();

if (doFinal.length > 0) {

out.write(doFinal);

}

out.flush();

}

}

Note: You should really use a CipherInputStream or CipherOutputStream here (a lot less code). There are a number of optimizations that can be made.

Warning: I only wrapped the ciphertext in a string to print as a demonstration. You always want to leave the ciphertext as a byte array.

- Saish

Saisha at 2007-7-29 11:33:18 >

> wasnt helpful :(

Ditto

hunter9000a at 2007-7-29 11:33:18 >

i am now sending my whole source code may be this is helpful for someone to suggest me a solutionpublic static class DesTest

{

public DesTest(InputStream in,OutputStream out)throws IOException,GeneralSecurityException, ClassNotFoundException

{

Security.addProvider(new com.sun.crypto.provider.SunJCE());

try {

KeyGenerator kg = KeyGenerator.getInstance("DES");

Key generatekey = kg.generateKey();

System.out.println(generatekey);

File keyfile = new File("C:\\Documents and Settings\\ayush\\Desktop\\key.txt");

ObjectOutputStream out3=new ObjectOutputStream(new FileOutputStream(keyfile));

out3.writeObject(generatekey);

out3.close();

ObjectInputStream keyIn = new ObjectInputStream(

new FileInputStream("C:\\Documents and Settings\\ayush\\Desktop\\key.txt"));

Key key = (Key) keyIn.readObject();

keyIn.close();

Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

cipher.init(Cipher.ENCRYPT_MODE, key);

int blockSize = cipher.getBlockSize();

int outputSize = cipher.getOutputSize(blockSize);

byte[] inBytes = new byte[blockSize];

byte[] outBytes = new byte[outputSize];

int inLength = 0;;

boolean more = true;

while (more)

{

inLength = in.read(inBytes);

if (inLength == blockSize)

{

int outLength

= cipher.update(inBytes, 0, blockSize, outBytes);

out.write(outBytes, 0, outLength);

//System.out.println(outLength);

}

else more = false;

}

if (inLength > 0)

outBytes = cipher.doFinal(inBytes, 0, inLength);

else

{outBytes = cipher.doFinal();

//System.out.println(outBytes.length);

out.write(outBytes);

}

InputStream in2=new FileInputStream("C:\\Documents and Settings\\ayush\\Desktop\\output.txt");

File decryptionfile = new File("C:\\Documents and Settings\\ayush\\Desktop\\decryptedoutput.txt");

OutputStream out2=new FileOutputStream(decryptionfile);

decrypt(in2,out2,key);

}

catch (NoSuchAlgorithmException e) {

e.printStackTrace();

}

catch (NoSuchPaddingException e) {

e.printStackTrace();

}

catch (InvalidKeyException e) {

e.printStackTrace();

}

catch (IllegalStateException e) {

e.printStackTrace();

}

catch (IllegalBlockSizeException e) {

e.printStackTrace();

}

catch (BadPaddingException e) {

e.printStackTrace();

}

}

public static void decrypt(InputStream in2,OutputStream out2,Key key) throws IOException, ShortBufferException

{

Security.addProvider(new com.sun.crypto.provider.SunJCE());

try {

Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

cipher.init(Cipher.DECRYPT_MODE, key);

int blockSize2 = cipher.getBlockSize();

int outputSize2 = cipher.getOutputSize(blockSize2);

byte[] inBytes2 = new byte[blockSize2];

byte[] outBytes2 = new byte[outputSize2];

int inLength2 = 0;;

boolean more2 = true;

while (more2)

{

inLength2 = in2.read(inBytes2);

if (inLength2 == blockSize2)

{

int outLength2

= cipher.update(inBytes2, 0, blockSize2, outBytes2);

out2.write(outBytes2, 0, outLength2);

//System.out.println(outLength2);

}

else more2 = false;

}

if (inLength2 > 0)

outBytes2 = cipher.doFinal(inBytes2, 0, inLength2);

else

{outBytes2 = cipher.doFinal();

//System.out.println(outBytes2.length);

out2.write(outBytes2);

}

in2.close();

out2.close();

}

catch (NoSuchAlgorithmException e) {

e.printStackTrace();

}

catch (NoSuchPaddingException e) {

e.printStackTrace();

}

catch (InvalidKeyException e) {

e.printStackTrace();

}

catch (IllegalStateException e) {

e.printStackTrace();

}

catch (IllegalBlockSizeException e) {

e.printStackTrace();

}

catch (BadPaddingException e) {

e.printStackTrace();

}

}

actually i note that on decrypting i loose some last characters of the file

but iam just not able to catch wat is going wrong in the code

Message was edited by:

noobs_will_rule

noobs_will_rulea at 2007-7-29 11:33:18 >

this is the exception i get now

javax.crypto.IllegalBlockSizeException:Input length must be multiple of 8 when decrypting with padded cipher

and exception only pop up when i read the encrypted data from a file

if i just encrypt data and put it to decryption there is no exception

and i am checkin padding here

if (inLength2 > 0)

outBytes2 = cipher.doFinal(inBytes2, 0, inLength2);

else

{outBytes2 = cipher.doFinal();

//System.out.println(outBytes2.length);

out2.write(outBytes2);

}

can somebody help out

noobs_will_rulea at 2007-7-29 11:33:18 >

Thanks. I'm just confused too. But hope it works for you. My guess is your original problem was in how you were reading and writing from byte arrays of different sizes, but that's only a guess.

- Saish

Saisha at 2007-7-29 11:33:18 >

int read(byte[] b)

Reads some number of bytes from the input stream and stores them into the buffer array b.

ok

thanks for clearing my misconception

noobs_will_rulea at 2007-7-29 11:33:18 >