Generare una chiave DES e passarla attraverso il socket in Java
Qualcuno potrebbe aiutarmi a capire il problema nel mio programma molto semplice?
Quando si emette il messaggio sul server, vorrei vedere lo stesso messaggio che è stato inviato sulla rete, ma non ne ricevo uno.
Ecco il mio codice per il cliente:
package encryption;
import java.io.*;
import java.net.*;
import java.security.*;
import java.util.*;
import javax.crypto.*;
public class CipherClient
{
public static void main(String[] args) throws Exception
{
String message = "The quick brown fox jumps over the lazy dog.";
String host = "localhost";
int port = 7999;
Socket s = new Socket(host, port);
// -Generate a DES key.
KeyGenerator generator = KeyGenerator.getInstance("DES");
generator.init(new SecureRandom());
Key key = generator.generateKey();
// -Store it in a file.
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("KeyFile.xx"));
out.writeObject(key);
out.close();
// -Use the key to encrypt the message above and send it over socket s to the server.
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key);
CipherOutputStream cipherOut = new CipherOutputStream(s.getOutputStream(), cipher);
System.out.println(message.getBytes().length);
cipherOut.write(message.getBytes());
}
}
Ed ecco il mio codice per il server:
package encryption;
import java.io.*;
import java.net.*;
import java.security.*;
import javax.crypto.*;
public class CipherServer
{
public static void main(String[] args) throws Exception
{
int port = 7999;
ServerSocket server = new ServerSocket(port);
Socket s = server.accept();
// -Read the key from the file generated by the client.
ObjectInputStream in = new ObjectInputStream(new FileInputStream("KeyFile.xx"));
Key key = (Key)in.readObject();
System.out.println(key.getClass().getName());
in.close();
// -Use the key to decrypt the incoming message from socket s.
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key);
CipherInputStream cipherIn = new CipherInputStream(s.getInputStream(), cipher);
byte[] stringInBytes = new byte[44];
cipherIn.read(stringInBytes);
String string = new String(stringInBytes);
// -Print out the decrypt String to see if it matches the orignal message.
System.out.println(string);
}
}
Uscita console sul lato server:
javax.crypto.spec.SecretKeySpec
}#ùÂ?°ô0íÿ| r|XÌ\?ñwŽ³{Í@nŠ?
Uscita console lato client:
44
Ecco il mio nuovo codice per cliente:
package encryption;
import java.io.*;
import java.net.*;
import java.security.*;
import javax.crypto.*;
public class CipherClient
{
public static void main(String[] args) throws Exception
{
// -Generate a DES key.
KeyGenerator generator = KeyGenerator.getInstance("DES");
generator.init(new SecureRandom());
Key key = generator.generateKey();
// -Store it in a file.
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("KeyFile.xx"));
out.writeObject(key);
out.close();
// -Connect to a server.
String message = "The quick brown fox jumps over the lazy dog.";
String host = "localhost";
int port = 7999;
Socket s = new Socket(host, port);
// -Use the key to encrypt the message above and send it over socket s to the server.
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = cipher.doFinal(message.getBytes());
DataOutputStream dOut = new DataOutputStream(s.getOutputStream());
dOut.writeInt(encVal.length); // write length of the message
dOut.write(encVal); // write the message
}
}
Ecco il mio nuovo codice per il server:
package encryption;
import java.io.*;
import java.net.*;
import java.security.*;
import javax.crypto.*;
public class CipherServer
{
public static void main(String[] args) throws Exception
{
int port = 7999;
ServerSocket server = new ServerSocket(port);
Socket s = server.accept();
// -Read the key from the file generated by the client.
ObjectInputStream in = new ObjectInputStream(new FileInputStream("KeyFile.xx"));
Key key = (Key)in.readObject();
in.close();
// -Use the key to decrypt the incoming message from socket s.
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key);
DataInputStream dIn = new DataInputStream(s.getInputStream());
int length = dIn.readInt(); // read length of incoming message
if(length>0)
{
byte[] messageInBytes = new byte[length];
dIn.readFully(messageInBytes, 0, messageInBytes.length); // read the message
// -Print out the decrypt String to see if it matches the orignal message.
System.out.println(new String(cipher.doFinal(messageInBytes)));
}
}
}
Ecco un errore che sto ricevendo sul lato server:
Exception in thread "main" java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.io.DataInputStream.readInt(Unknown Source)
at encryption.CipherServer.main(CipherServer.java:26)
E non ci sono errori sul lato client.
1 answers
Penso che ci sia una "gara" tra il client e il server per scrivere e leggere dal file chiave. Almeno lo ha fatto per me quando ho controllato il tuo codice.
Prova a mettere la generazione della chiave e la scrittura nel file della chiave prima di creare il tuo socket. In questo modo, quando il tuo client crea il suo socket, il server lo accetta e quando va al file, ottiene un file valido.
Funziona per me con quasi nessuna differenza dal tuo codice a parte la scrittura sul bit del file.
Il cliente:
public class CipherClient
{
public static void main(String[] args) throws Exception
{
// -Generate a DES key.
KeyGenerator generator = KeyGenerator.getInstance("DES");
generator.init(new SecureRandom());
Key key = generator.generateKey();
// -Store it in a file.
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("KeyFile.xx"));
out.writeObject(key);
out.close();
String message = "The quick brown fox jumps over the lazy dog.";
System.out.println("Message converted from Bytes = " + new String(message.getBytes()));
System.out.println("Length = " + message.getBytes().length);
String host = "localhost";
int port = 7999;
Socket s = new Socket(host, port);
// -Use the key to encrypt the message above and send it over socket s to the server.
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key);
CipherOutputStream cipherOut = new CipherOutputStream(s.getOutputStream(), cipher);
cipherOut.write(message.getBytes());
cipherOut.close();
s.close();
}
}
E il server:
public class CipherServer
{
public static void main(String[] args) throws Exception
{
int port = 7999;
ServerSocket server = new ServerSocket(port);
Socket s = server.accept();
// -Read the key from the file generated by the client.
ObjectInputStream in = new ObjectInputStream(new FileInputStream("KeyFile.xx"));
Key key = (Key)in.readObject();
in.close();
// -Use the key to decrypt the incoming message from socket s.
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key);
CipherInputStream cipherIn = new CipherInputStream(s.getInputStream(), cipher);
byte[] array = new byte[44];
cipherIn.read(array);
cipherIn.close();
s.close();
String message = new String(array);
System.out.println(message);
}
}