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."); } }
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(); } }