Envoi avec Message Crypté

2026-05-13 17:21:54 +00:00 · 2022-11-29 14:57:30 +01:00
parent 35a08a9f1e
commit 121cf32f9f
6 changed files with 128 additions and 122 deletions
@@ -2,15 +2,13 @@
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+      <change beforePath="$PROJECT_DIR$/src/reseau/AES.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/reseau/AES.java" afterDir="false" />
      <change beforePath="$PROJECT_DIR$/src/serveur/Serveur.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/serveur/Serveur.java" afterDir="false" />
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-      <change beforePath="$PROJECT_DIR$/src/serveur/Serveur.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/serveur/Serveur.java" afterDir="false" />
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@@ -26,42 +24,6 @@
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@@ -73,18 +35,18 @@
    <option name="hideEmptyMiddlePackages" value="true" />
    <option name="showLibraryContents" value="true" />
  </component>
-  <component name="PropertiesComponent"><![CDATA[{
-  "keyToString": {
-    "RunOnceActivity.OpenProjectViewOnStart": "true",
-    "RunOnceActivity.ShowReadmeOnStart": "true",
-    "WebServerToolWindowFactoryState": "false",
-    "codeWithMe.voiceChat.enabledByDefault": "false",
-    "project.structure.last.edited": "Project",
-    "project.structure.proportion": "0.0",
-    "project.structure.side.proportion": "0.0"
+  <component name="PropertiesComponent">{
+  &quot;keyToString&quot;: {
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+    &quot;RunOnceActivity.ShowReadmeOnStart&quot;: &quot;true&quot;,
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  }
-}]]></component>
-  <component name="RunManager" selected="Application.AES">
+}</component>
+  <component name="RunManager" selected="Application.Client">
    <configuration name="AES" type="Application" factoryName="Application" temporary="true" nameIsGenerated="true">
      <option name="MAIN_CLASS_NAME" value="reseau.AES" />
      <module name="projet-mini-chat" />
@@ -177,6 +139,7 @@
      <updated>1668515473737</updated>
      <workItem from="1668515476841" duration="6049000" />
      <workItem from="1669119772164" duration="6834000" />
+      <workItem from="1669724625302" duration="5444000" />
    </task>
    <servers />
  </component>
@@ -0,0 +1,16 @@
+# Question 6
+
+## Avant la communication
+Utiliser le RSA, avant toute communication. 
+Le client et le serveur génèrent 2 clés (une publique et une privées)
+Ils s'échangent leurs clé publiques.
+
+![img](https://upload.wikimedia.org/wikipedia/commons/thumb/0/01/Asymmetric_cryptography_-_step_1.svg/800px-Asymmetric_cryptography_-_step_1.svg.png)
+
+## Pendant la communication
+Lors qu'un utilisateur veut envoyer un message, il crypte son
+message avec la clé pulique de son interlocuteur et lui envoie.
+La personne qui reçois le message, le décrypte le message avec
+sa propre clé privée.
+
+![img](https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Asymmetric_cryptography_-_step_2.svg/800px-Asymmetric_cryptography_-_step_2.svg.png)
@@ -1,29 +1,41 @@
 package client;

-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStreamReader;
-import java.io.PrintWriter;
+import java.io.*;
 import java.net.Socket;
+import java.nio.charset.StandardCharsets;
 import java.rmi.UnknownHostException;
+import java.security.Key;
+import java.util.Arrays;
 import java.util.Scanner;

+import reseau.AES;
+
 public class Client {

    public static final Scanner scan = new Scanner(System.in);

-    public static void main(String[] args) throws IOException {
+    public static void main(String[] args) {
        Socket serverSocket = null;
-        PrintWriter out = null;
-        BufferedReader in = null;
-        boolean ecoute = false;
+        ObjectOutputStream out = null;
+        ObjectInputStream in = null;
+
+        // Clé de chiffrage
+        Key key = AES.genererCle();
+        AES.sauvegarderCle(key);

        // Création des Sockets
        try {
            serverSocket = new Socket("localhost", 4444);
            System.out.println("Connecté au serveur");
-            out = new PrintWriter(serverSocket.getOutputStream(), true);
-            in = new BufferedReader(new InputStreamReader(serverSocket.getInputStream()));
+            out = new ObjectOutputStream(serverSocket.getOutputStream());
+            in = new ObjectInputStream(serverSocket.getInputStream());
+
+            // On envoie la clé de chiffrage
+            out.writeObject(key);
+
+            System.out.println("Clé envoyé");
+            System.out.println(Arrays.toString(key.getEncoded()));
+
        } catch (UnknownHostException e) {
            System.out.println("Destination unknown");
            System.exit(-1);
@@ -32,24 +44,28 @@ public class Client {
            System.exit(-1);
        }

-        String message = null;
+        // Communication
+        String message;
+        byte[] messageCrypte;
+        try {
            do {
-            //ecoute d'un message
-            if (ecoute) {
-                message = in.readLine();
-                System.out.printf("serveur > %s\n", message);
-            } else {
+                // Envoi du message
                System.out.print("client > ");
                message = scan.nextLine();
-                out.println(message);
-            }
-            ecoute = !ecoute;
+                messageCrypte = AES.encrypter(message, key);
+                out.writeObject(messageCrypte);
+
+                // Reception du message
+                messageCrypte = (byte[]) in.readObject();
+                message = AES.decrypter(messageCrypte, key);
+                System.out.printf("serveur > %s -> %s\n", new String(messageCrypte, StandardCharsets.UTF_8), message);
            } while (!message.equals("bye"));

-        //deconnexion
-        //fermeture des Sockets
            out.close();
            in.close();
            serverSocket.close();
+        }catch (IOException | ClassNotFoundException e) {
+           e.printStackTrace();
+        }
    }
 }
@@ -1,39 +1,30 @@
 package reseau;

 import javax.crypto.*;
-import java.nio.file.Files;
-import java.nio.file.Path;
+import java.io.*;
+import java.nio.charset.StandardCharsets;
 import java.security.*;
 import java.util.Arrays;

 public class AES {

-    public static byte[] genererCle() {
-        byte[] data;
-        byte[] result;
-        byte[] original = null;
+    public static Key genererCle() {
+        Key key = null;
+
        try {
-            KeyGenerator kg = KeyGenerator.getInstance("DES");
-            Key key = kg.generateKey();
-            return key.getEncoded();
-//            Cipher cipher = Cipher.getInstance("DES") ;
-//            cipher.init(Cipher.ENCRYPT_MODE, key) ;
-//            data = "Hello World".getBytes() ;
-//            result = cipher.doFinal(data) ;
-//            cipher.init(Cipher.DECRYPT_MODE, key) ;
-//            original = cipher.doFinal(result) ;
-//            System.out.println("Decrypted data :" + Arrays.toString(original)) ;
+            KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
+            key = keyGenerator.generateKey();
        } catch (Exception e) {
            e.printStackTrace();
        }
-        return original;
+        return key;
    }

-    public static byte[] decrypter(byte[] msg, Key key) {
+    public static String decrypter(byte[] msg, Key key) {
        try {
            Cipher cipher = Cipher.getInstance("DES") ;
            cipher.init(Cipher.DECRYPT_MODE, key);
-            return cipher.doFinal(msg);
+            return new String(cipher.doFinal(msg), StandardCharsets.UTF_8);
        } catch (Exception e) {
            e.printStackTrace();
        }
@@ -51,12 +42,22 @@ public class AES {
        return null;
    }

-    public static void sauvegarderFichier(Key key) {
-        Path fileName = Path.of("./cle.txt");
-        Files.writeString(fileName, new String(key));
+    public static void sauvegarderCle(Key key) {
+
+        try (ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("key.ser"))) {
+            objectOutputStream.writeObject(key);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
    }

-    public static void main(String[] args) {
-
+    public static Key chargerCle() {
+        Key key = null;
+        try (ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("key.ser"))) {
+            key = (Key) objectInputStream.readObject();
+        } catch (IOException | ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+        return key;
    }
 }
@@ -1,8 +1,13 @@
 package serveur;

+import reseau.AES;
+
 import java.io.*;
 import java.net.ServerSocket;
 import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+import java.security.Key;
+import java.util.Arrays;
 import java.util.Scanner;

 public class Serveur {
@@ -13,6 +18,7 @@ public class Serveur {
    public static void main(String[] args) {
        ServerSocket serverSocket = null;
        Socket clientSocket = null;
+        Key clientKey;

        // Connexion
        try {
@@ -26,30 +32,34 @@ public class Serveur {
        // Un client a été trouvé
        System.out.println("Client connecté");

-        boolean connectee = true;
-        boolean reception = true;
-
-        BufferedReader in = null;
-
-        PrintWriter out = null;
+        ObjectInputStream in;
+        ObjectOutputStream out;

        try {
-            in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
+            in = new ObjectInputStream(clientSocket.getInputStream());
+            out = new ObjectOutputStream(clientSocket.getOutputStream());

-            out = new PrintWriter(clientSocket.getOutputStream(), true);
+            // On récupère la clé du client
+            clientKey = (Key) in.readObject();

-            String message = null;
+            System.out.println("Clé reçue");
+            System.out.println(Arrays.toString(clientKey.getEncoded()));
+
+            // Communication
+            String message;
+            byte[] messageCrypte;
            do {
-                if (reception) {
-                    message = in.readLine();
-                    System.out.printf("client > %s\n", message);
-                } else {
+                // Envoi du message
+                messageCrypte = (byte[]) in.readObject();
+                message = AES.decrypter(messageCrypte, clientKey);
+                System.out.printf("client > %s -> %s\n", new String(messageCrypte, StandardCharsets.UTF_8), message);
+
+
+                // Reception du message
                System.out.print("serveur > ");
                message = scan.nextLine();
-                    out.println(message);
-                }
-
-                reception = !reception;
+                messageCrypte = AES.encrypter(message, clientKey);
+                out.writeObject(messageCrypte);
            } while (!message.equals("bye"));

            in.close();
@@ -59,8 +69,8 @@ public class Serveur {

        } catch (IOException e) {
            e.printStackTrace();
-        }
-
-
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        }
    }
 }