我是java新手，尝试使用 Cipher 加密和解密两条短信和SecretKey如下面的代码所示(第241行，最底部)。每当我尝试 Decrypt这条加密消息，我收到一条错误消息:
javax.crypto.BadPaddingException: Given final block not properly padded
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher
我在这段代码中使用了 3 个线程和两个名为 q1 和 q2 的缓冲区/队列。首先，我将一条消息放入缓冲区/队列中。然后在下一个类中，我检索该消息并对其进行加密，然后发送到下一个类。然后该类将再次将其放入缓冲区/队列中。最后，在最后一个类，它将从缓冲区中检索并解密。这就是问题发生的地方。发生同步错误。我已经尝试解决这个错误很多天了，但没有成功。其他在线文档也没有帮助。如果您可以编辑此代码或向我展示示例，我将不胜感激
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();
}
}
}
如果您复制并粘贴此程序，它将在您的计算机上运行
最佳答案
无需过多查看代码，我就可以看到它使用 Cipher 的共享实例。 Cipher 不是线程安全的，它在 SecurityDecryptionAlgorithm 和 SecurityEncryptionAlgorithm 中都使用，所以它会带来麻烦......而问题在于内部缓冲区被损坏并抛出您所显示的异常。
要解决此问题，只需在每个加密/解密上实例化密码(首选解决方案)，为每个线程创建一个实例，或者使 SecurityDecryptionAlgorithm 和 SecurityEncryptionAlgorithm 中的静态方法同步并为每个人提供不同的 Cipher 实例。
我会从 Global5 中删除 Cipher，并在每次调用加密或解密时实例化一个新的密码。
为了使其更加明显，此代码调用
c.init(Cipher.ENCRYPT_MODE, sk);
和
c.init(Cipher.DECRYPT_MODE, sk);
在同一个实例中......我确信这会进一步混淆密码。
关于Java 密码填充错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39276955/