CipherInputStream 挂起

Question

我正在尝试使用加密通过使用 java 的套接字进行通信。我已经成功地与未加密的套接字通信，但是当我尝试加密时，程序冻结了。

这是父类Connection 工作得很好：

public class Connection implements Runnable
{
    protected Socket socket;
    protected ObjectInputStream objectInputStream;
    protected ObjectOutputStream objectOutputStream;
    protected Thread listeningThread;
    protected Thread dispatchThread;
    protected boolean listen;
    protected ArrayBlockingQueue<Object> readingQueue;
    protected ConnectionListener connectionListener;

    public Connection()
    {
        listen = true;
        readingQueue = new ArrayBlockingQueue<Object>(10);
    }

    public Connection(Socket socket, ConnectionListener listener)
    {
        listen = true;
        connectionListener = listener;
        readingQueue = new ArrayBlockingQueue<Object>(10);

        this.socket = socket;

        try 
        {
            objectOutputStream = new ObjectOutputStream(socket.getOutputStream());
            objectInputStream = new ObjectInputStream(socket.getInputStream()); 
        } 
        catch (IOException e) 
        {
            e.printStackTrace();
        }

        startConnection();
    }

这是使用加密的子类：

public class EncryptedConnection extends Connection
{
    private Key key;
    private Cipher cipherEncryption;
    private Cipher cipherDecryption;

    public EncryptedConnection(Socket socket, ConnectionListener listener, byte[] keydata)
    {
        super();
        super.socket = socket;
        super.connectionListener = listener;

        try
        {
            key = new SecretKeySpec(keydata, "AES");
            cipherEncryption = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipherDecryption = Cipher.getInstance("AES/CBC/PKCS5Padding");

            byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
            IvParameterSpec ivspec = new IvParameterSpec(iv);

            cipherEncryption.init(Cipher.ENCRYPT_MODE, key, ivspec);
            cipherDecryption.init(Cipher.DECRYPT_MODE, key, ivspec);

            objectOutputStream = new ObjectOutputStream(new CipherOutputStream(socket.getOutputStream(),cipherEncryption));
            objectInputStream = new ObjectInputStream(new CipherInputStream(socket.getInputStream(),cipherDecryption));
//The hanging or freezing occurs on the above line of code

        } 
        catch(Exception e)
        {

        }

这是创建套接字的服务器代码：

@Override
    public void run() 
    {
        try 
        {
            while(true)
            {
                Socket s = serverSocket.accept();

                byte[] key = new byte[16];
                for(int i=0;i<key.length;i++)
                    key[i] = 0x01;


                EncryptedConnection c = new EncryptedConnection(s,connectionListener,key);

                connections.add(c);
                System.out.println("New Connection Established From"+s.getInetAddress().toString());
            }
        } 
        catch(java.net.SocketException e)
        {
            System.out.println("Listening thread terminated with exception.");
        }
        catch(IOException e) 
        {

            e.printStackTrace();
        }
    }

这里是创建套接字的客户端代码：

@Override
    public void actionPerformed(ActionEvent e) 
    {
        if(e.getSource() == connect)
        {
            try 
            {
                Socket s = new Socket(ipBox.getText(), Integer.parseInt(portBox.getText()));
                byte[] key = new byte[16];
                for(int i=0;i<key.length;i++)
                    key[i] = 0x01;
                EncryptedConnection c = new EncryptedConnection(s,parent,key);

                parent.connectionSuccessful(c);
            } 
            catch (NumberFormatException e1) 
            {
                JOptionPane.showMessageDialog(this, "Error! Port number must be a number", "Error", JOptionPane.ERROR_MESSAGE);             
            } 
            catch (UnknownHostException e1) 
            {
                JOptionPane.showMessageDialog(this, "Error! Unable to find that host", "Error", JOptionPane.ERROR_MESSAGE);
            } 
            catch (IOException e1) 
            {
                e1.printStackTrace();
            }   
        }
    }

我看过这篇文章，但没有发现它有帮助。 ObjectInputStream with CipherInputStream freezing, hanging 我也尝试过开启和关闭填充的不同 AES 加密模式，但得到了相同的结果。

这是可以正常工作的示例代码。我基本上在做同样的事情，但不是文件，而是使用套接字。

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class IOTest 
{
    public static void main(String[] args) 
    {
        FileOutputStream fos   = null;
        FileInputStream fis    = null;
        CipherInputStream cis  = null;
        CipherOutputStream cos = null;
        ObjectOutputStream oos = null;
        ObjectInputStream  ois = null;
        Key key                = null;
        Cipher cipherD         = null;
        Cipher cipherE         = null;
        byte[] keydata         = new byte[16];
        byte[] iv              = new byte[16];
        IvParameterSpec ivspect = new IvParameterSpec(iv);

        try
        {
            key = new SecretKeySpec(keydata,"AES");
            cipherE = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipherD = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipherE.init(Cipher.ENCRYPT_MODE, key,ivspect);
            cipherD.init(Cipher.DECRYPT_MODE, key, ivspect);

            fos = new FileOutputStream("hello.data");
            cos = new CipherOutputStream(fos,cipherE);
            oos = new ObjectOutputStream(cos);

            oos.writeObject(new String("H"));
            oos.flush();
            oos.close();


            fis = new FileInputStream("hello.data");
            cis = new CipherInputStream(fis, cipherD);
            ois = new ObjectInputStream(cis);

            String s = ois.readObject().toString();
            System.out.println(s);

            ois.close();

        }
        catch(Exception e)
        {

        }
    }
}

Answer 1

由于 AES 是块密码（块大小为 128 位），它以 16 字节块的形式处理数据.. 如果没有足够的数据用于完整的加密块，数据将只是坐在输入缓冲区中等待更多数据出现。在接收端，您只会被卡住。

只有当有足够的数据用于一个完整的块或如果流关闭时，才会处理卡住的数据。在关闭流的情况下，最终数据会根据使用的填充方案（例如 PKCS5Padding）修补到完整的块大小。