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();
}
}
