I am new to java and trying to encrypt and decrypt two text messages using Cipher and SecretKey as shown in the code bellow(Line 241, at the very bottom). Whenever I tries to Decrypt this encrypted message, I get an error saying:
javax.crypto.BadPaddingException: Given final block not properly padded
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher
I am using 3 Threads in this code and two buffers/queues called q1 and q2. At first, I put a message in a buffer/queue. Then in the next class, I retrieve that message and encrypt it, and send to the next class. Then that class will put it in a buffer/queue again. Finally, at the last class, it will retrieve from the buffer and decrypt it. This is where the problem happens. There is a Synchronization error going on. I have been trying to figure this error for many days now and no luck. Other online documentations didn't help either. I would greatly appreciate if you could edit this code or show me with an example
import java.security.KeyPairGenerator;
import java.security.KeyPair;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.PrivateKey;
import java.security.Signature;
import java.io.*;
import java.util.*;
import java.util.concurrent.TimeUnit;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
class Q5 { //Queue/Buffer
byte[] shipmentConfirmation;//will include the actual message content been delivered
boolean valueSet = false;
synchronized byte[] get()
{
while(!valueSet)
try
{
wait();
}
catch(InterruptedException e)
{
System.out.println("InterruptedException caught");
}
//System.out.println("Got: " + n);
valueSet = false;
notify();
return shipmentConfirmation;
}
synchronized void put(byte[] shipmentCinfirm)
{
while(valueSet)
try
{
wait();
}
catch(InterruptedException e)
{
System.out.println("InterruptedException caught");
}
this.shipmentConfirmation = shipmentCinfirm;
valueSet = true;
//System.out.println("Put: " + n);
notify();
}
}
class Global5{
public static int sendcouter = 0;
public static SecretKey secret_Key;
public static Cipher desCipher;
}
//<<security pattern>> SymmetricEncryptionEncryptor
class SecurityEncryptor//<<security>> Encryptor
{
static byte[] Encryptor(byte shipmentConfirmation[],Cipher c) throws Exception //Encryptor
{
byte[] ciphertext = SecurityEncryptionAlgorithm.EncryptionAlgorithm(shipmentConfirmation,c,Global5.secret_Key);
return ciphertext;
}
}
class SecurityEncryptionAlgorithm//<<security>> EncryptionAlgorithm
{
static byte[] EncryptionAlgorithm(byte shipmentConfirmation[],Cipher c,SecretKey sk) throws Exception
{
c.init(Cipher.ENCRYPT_MODE, sk);
return c.doFinal(shipmentConfirmation);
}
}
//<<security pattern>> aSecureAsynchronousMCReceiverConnector
class SecurityDecryptor//<<Security>> Decryptor
{
static byte[] Decryptor(byte EncryptedShipmentConfirmation[],Cipher c,SecretKey sk) throws Exception //Decryptor
{
byte[] ct = SecurityDecryptionAlgorithm.DecryptionAlgorithm(EncryptedShipmentConfirmation,c,sk);
return ct;
}
}
class SecurityDecryptionAlgorithm//<<Security>> DecryptionAlgorithm
{
static byte[] DecryptionAlgorithm(byte EncryptedShipmentConfirmation[],Cipher c,SecretKey sk) throws Exception
{
c.init(Cipher.DECRYPT_MODE, sk);
return c.doFinal(EncryptedShipmentConfirmation);
}
}
public class testFigure1 { //Main
public static void main(String args[]) throws Exception {
Q5 q1 = new Q5();//creating buffer/queue
Q5 q2 = new Q5();
System.out.println("How many messages to send: ");
Scanner in = new Scanner(System.in);
int input = in.nextInt();//Get input from the supplier
aSupplierInterface Supplier = new aSupplierInterface(q1, input);
aSecuritySenderCoordinator SenderCoordinator = new aSecuritySenderCoordinator(q1, input, q2);
aSecurityReceiverCoordinator receive = new aSecurityReceiverCoordinator(q2, input);
Supplier.t_pro.join();
SenderCoordinator.t_coordinator5.join();
receive.t_SecurityReceiverCoordinator5.join();
System.out.println("End of Program!");
}
}
class aSupplierInterface implements Runnable //<<application Component>> aSupplierInterface
{
Q5 q;
int supinput;
Thread t_pro;//pro to represent producer or suppler
aSupplierInterface(Q5 qq, int input)
{
supinput = input;
this.q = qq;
t_pro = new Thread(this, "Producer");
t_pro.start();
}
public void run()
{
int i = 0;
String shipment;
byte[] shipmentConfirmation;
while(i<supinput)
{
i++;
shipment = "This is the Delivery Number: "+ i;
shipmentConfirmation = shipment.getBytes();
q.put(shipmentConfirmation);//Putting supplier's goods in a queue/buffer
}
}
}
class aSecuritySenderCoordinator implements Runnable //<<security coordinator>> aSecuritySenderCoordinator
{
Q5 q;
Q5 q2;
Thread t_coordinator5;
int supinput;
public aSecuritySenderCoordinator(Q5 qq, int input, Q5 q2) throws Exception
{
supinput=input;
this.q = qq;
this.q2=q2;
t_coordinator5 = new Thread(this, "coordinator5");
t_coordinator5.start();
}
public void run()
{
byte[] pkShipmentConfirmation;
byte[] shipmentConfirmation;
int i = 0;
while(i<supinput)
{
i++;
//Getting goods that supplier has put in the queue previously
pkShipmentConfirmation=q.get();//This will contain content of the message/delivery you are sending
KeyGenerator keygen;
try {
keygen = KeyGenerator.getInstance("DES");
Global5.sendcouter++;//To Create the key once
if(Global5.sendcouter==1)//Create once
{
Global5.secret_Key = keygen.generateKey();
Global5.desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
}
//String st1 = new String(pkShipmentConfirmation);//just to print a message
//System.out.println("*ORIGINAL MESSAGE:"+st1);
shipmentConfirmation = SecurityEncryptor.Encryptor(pkShipmentConfirmation,Global5.desCipher);//Encrypting
new anAsynchronousMCReceiver(q2, shipmentConfirmation);
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
class anAsynchronousMCReceiver
{ //<<communication pattern>> anAsynchronousMCReceiver
Q5 q;
anAsynchronousMCReceiver( Q5 q2, byte[] shipmentConfirm) throws Exception
{
this.q = q2;
q.put(shipmentConfirm); //Entering received data in to the Queue/Buffer
}
}
class aSecurityReceiverCoordinator implements Runnable//<<security coordinator>> aSecurityReceiverCoordinator
{
Thread t_SecurityReceiverCoordinator5;
Q5 q;
int supinput;
byte[]encryptedShipmentConfirmation;
public aSecurityReceiverCoordinator(Q5 q2, int input) throws Exception
{
this.q = q2;
supinput = input;
t_SecurityReceiverCoordinator5 = new Thread(this, "SecurityReceiverCoordinator5");
t_SecurityReceiverCoordinator5.start();
}
public void run()
{
try {
int i = 0;
while(i<supinput)
{
i++;
encryptedShipmentConfirmation = q.get();
byte[] confirmation = SecurityDecryptor.Decryptor(encryptedShipmentConfirmation,Global5.desCipher,Global5.secret_Key);//ERROR HAPPENS HERE
String shipConfirmation = new String(confirmation);
System.out.println("AT DelivertyOrder: " + shipConfirmation);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
If you copy and past this program, it will run on your computer
