Example #1
0
  public void run() {
    try {
      ObjectInputStream ois = new ObjectInputStream(s.getInputStream());
      ObjectOutputStream oos = new ObjectOutputStream(s.getOutputStream());

      BigInteger bg = dhSpec.getG();
      BigInteger bp = dhSpec.getP();
      oos.writeObject(bg);
      oos.writeObject(bp);

      KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH");
      kpg.initialize(1024);
      KeyPair kpa = (KeyPair) ois.readObject();
      KeyAgreement dh = KeyAgreement.getInstance("DH");
      KeyPair kp = kpg.generateKeyPair();

      oos.writeObject(kp);

      dh.init(kp.getPrivate());
      Key pk = dh.doPhase(kpa.getPublic(), true);

      MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
      byte[] rawbits = sha256.digest(dh.generateSecret());

      Cipher c = Cipher.getInstance(CIPHER_MODE);
      SecretKey key = new SecretKeySpec(rawbits, 0, 16, "AES");
      byte ivbits[] = (byte[]) ois.readObject();
      IvParameterSpec iv = new IvParameterSpec(ivbits);
      c.init(Cipher.DECRYPT_MODE, key, iv);

      Mac m = Mac.getInstance("HmacSHA1");
      SecretKey mackey = new SecretKeySpec(rawbits, 16, 16, "HmacSHA1");
      m.init(mackey);

      byte ciphertext[], cleartext[], mac[];
      try {
        while (true) {
          ciphertext = (byte[]) ois.readObject();
          mac = (byte[]) ois.readObject();
          if (Arrays.equals(mac, m.doFinal(ciphertext))) {
            cleartext = c.update(ciphertext);
            System.out.println(ct + " : " + new String(cleartext, "UTF-8"));
          } else {
            // System.exit(1);
            System.out.println(ct + "error");
          }
        }
      } catch (EOFException e) {
        cleartext = c.doFinal();
        System.out.println(ct + " : " + new String(cleartext, "UTF-8"));
        System.out.println("[" + ct + "]");
      } finally {
        if (ois != null) ois.close();
        if (oos != null) oos.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  /**
   * Sends the specified file to the client. File must exist or client and server threads will hang
   * indefinitely. Generates a session key to encrypt the file over transfer; session key is
   * encrypted using the client's public (asymmetric) key.
   *
   * @param aFile The name or path of the file to send.
   * @throws IOException Error reading from socket.
   */
  private void sendFile(String aFile) throws IOException {
    try {
      // get client public key
      ObjectInputStream clientPubIn = new ObjectInputStream(connectedSocket.getInputStream());
      PublicKey clientPublicKey = (PublicKey) clientPubIn.readObject();

      // generate key string and send to client using their public key encrypted with RSA
      // (asymmetric)
      String keyString = generateKeyString();
      Cipher keyCipher = Cipher.getInstance("RSA");
      keyCipher.init(Cipher.ENCRYPT_MODE, clientPublicKey);
      SealedObject sealedKeyString = new SealedObject(keyString, keyCipher);
      ObjectOutputStream testOut = new ObjectOutputStream(outToClient);
      testOut.writeObject(sealedKeyString);
      testOut.flush();

      // generate key spec from keyString
      SecretKeySpec keySpec = new SecretKeySpec(keyString.getBytes(), "DES");

      // set up encryption
      Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
      cipher.init(Cipher.ENCRYPT_MODE, keySpec);
      CipherOutputStream cipherOut = new CipherOutputStream(outToClient, cipher);

      // send file
      byte[] fileBuffer = new byte[BUFFER_SIZE];
      InputStream fileReader = new BufferedInputStream(new FileInputStream(aFile));
      int bytesRead;
      while ((bytesRead = fileReader.read(fileBuffer)) != EOF) {
        cipherOut.write(fileBuffer, 0, bytesRead);
      }
      cipherOut.flush();
      cipherOut.close();
      disconnect();
    } catch (NoSuchPaddingException nspe) {
      System.out.println("No such padding.");
    } catch (NoSuchAlgorithmException nsae) {
      System.out.println("Invalid algorithm entered");
    } catch (ClassNotFoundException cnfe) {
      System.out.println("Class not found.");
    } catch (InvalidKeyException ike) {
      System.out.println("Invalid key used for file encryption.");
    } catch (FileNotFoundException fnfe) {
      System.out.println("Invalid file entered.");
      return;
    } catch (IllegalBlockSizeException ibse) {
      System.out.println("Illegal block size used for encryption.");
    }
  }
Example #3
0
  public static void main(String[] args) {
    try {
      if (args[0].equals("-genkey")) {
        KeyPairGenerator pairgen = KeyPairGenerator.getInstance("RSA");
        SecureRandom random = new SecureRandom();
        pairgen.initialize(KEYSIZE, random);
        KeyPair keyPair = pairgen.generateKeyPair();
        ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(args[1]));
        out.writeObject(keyPair.getPublic());
        out.close();
        out = new ObjectOutputStream(new FileOutputStream(args[2]));
        out.writeObject(keyPair.getPrivate());
        out.close();
      } else if (args[0].equals("-encrypt")) {
        KeyGenerator keygen = KeyGenerator.getInstance("AES");
        SecureRandom random = new SecureRandom();
        keygen.init(random);
        SecretKey key = keygen.generateKey();

        // wrap with RSA public key
        ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
        Key publicKey = (Key) keyIn.readObject();
        keyIn.close();

        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.WRAP_MODE, publicKey);
        byte[] wrappedKey = cipher.wrap(key);
        DataOutputStream out = new DataOutputStream(new FileOutputStream(args[2]));
        out.writeInt(wrappedKey.length);
        out.write(wrappedKey);

        InputStream in = new FileInputStream(args[1]);
        cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        crypt(in, out, cipher);
        in.close();
        out.close();
      } else {
        DataInputStream in = new DataInputStream(new FileInputStream(args[1]));
        int length = in.readInt();
        byte[] wrappedKey = new byte[length];
        in.read(wrappedKey, 0, length);

        // unwrap with RSA private key
        ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
        Key privateKey = (Key) keyIn.readObject();
        keyIn.close();

        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.UNWRAP_MODE, privateKey);
        Key key = cipher.unwrap(wrappedKey, "AES", Cipher.SECRET_KEY);

        OutputStream out = new FileOutputStream(args[2]);
        cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, key);

        crypt(in, out, cipher);
        in.close();
        out.close();
      }
    } catch (IOException e) {
      e.printStackTrace();
    } catch (GeneralSecurityException e) {
      e.printStackTrace();
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
  }