/**
* Attempts to log a client in using the authentication server. Authentication server needs to run
* on the same host as the file server.
*
* @throws IOException Error reading from socket.
*/
private void login() throws IOException {
// set up required variables
DatagramSocket clientSocket = new DatagramSocket();
InetAddress authServerIP =
InetAddress
.getLocalHost(); // because authentication server runs on same host as file server
byte[] dataToSend;
byte[] receivedData = new byte[BUFFER_SIZE];
// get username and password
String userName = inFromClient.readLine().trim(); // get username
String password = inFromClient.readLine().trim(); // get password
dataToSend = new String(userName + " " + password).getBytes();
// send the username and password for processing by authentication server
DatagramPacket packetToSend =
new DatagramPacket(dataToSend, dataToSend.length, authServerIP, AUTHENTICATION_PORT);
clientSocket.send(packetToSend);
// receive the response from the authentication server
DatagramPacket receivedPacket = new DatagramPacket(receivedData, receivedData.length);
clientSocket.receive(receivedPacket);
String receivedString = new String(receivedPacket.getData()).trim();
receivedData = receivedString.getBytes();
if (receivedString.equals("yes")) {
outToClient.writeBytes(receivedString); // successful login
} else {
outToClient.writeBytes("no"); // unsuccessful login
}
}
public static void main(String[] args) throws IOException, NoSuchAlgorithmException {
DataOutputStream output = new DataOutputStream(new BufferedOutputStream(System.out));
LRC lrc = new LRC(output);
DataInputStream input = new DataInputStream(new BufferedInputStream(System.in));
lrc.writeStream(input);
output.flush();
}
private void flushRaw() throws IOException {
if (currentRaw != null && currentRaw.size() > 0) {
if (mode == Mode.Block) {
output.writeInt(-1);
}
System.err.println("Writing raw chunk : " + currentRaw.size());
rawChunks += currentRaw.size();
output.writeInt(currentRaw.size());
currentRaw.writeTo(output);
mode = Mode.Raw;
}
currentRaw = null;
}
public void run() // loop utama, utk nerima user input n kirim ke server&client laen
{
while (thread != null) {
try {
String a = console.readLine();
String b = cryptor.encrypt(a);
streamOut.writeUTF(cryptor.encrypt(a));
streamOut.flush();
} catch (IOException ioe) {
System.out.println("Sending error: " + ioe.getMessage());
stop();
}
}
}
/** Sends the user a list of the files contained in the same folder as the server. */
private void listFiles() throws IOException {
File folder = new File(".");
File[] listOfFiles = folder.listFiles();
for (File f : listOfFiles) {
outToClient.writeBytes(f.getName() + '\n');
}
}
/**
* Compute the hash an IP address. The hash is the first 8 bytes of the SHA digest of the IP
* address.
*/
private static byte[] computeAddressHash() {
/*
* Get the local host's IP address.
*/
byte[] addr =
(byte[])
java.security.AccessController.doPrivileged(
new PrivilegedAction() {
public Object run() {
try {
return InetAddress.getLocalHost().getAddress();
} catch (Exception e) {
}
return new byte[] {0, 0, 0, 0};
}
});
byte[] addrHash;
final int ADDR_HASH_LENGTH = 8;
try {
/*
* Calculate message digest of IP address using SHA.
*/
MessageDigest md = MessageDigest.getInstance("SHA");
ByteArrayOutputStream sink = new ByteArrayOutputStream(64);
DataOutputStream out = new DataOutputStream(new DigestOutputStream(sink, md));
out.write(addr, 0, addr.length);
out.flush();
byte digest[] = md.digest();
int hashlength = Math.min(ADDR_HASH_LENGTH, digest.length);
addrHash = new byte[hashlength];
System.arraycopy(digest, 0, addrHash, 0, hashlength);
} catch (IOException ignore) {
/* can't happen, but be deterministic anyway. */
addrHash = new byte[0];
} catch (NoSuchAlgorithmException complain) {
throw new InternalError(complain.toString());
}
return addrHash;
}
private void exchangeKeys() {
try {
output.write(modulus.toByteArray());
byte[] buffer = new byte[ciphertextBlockSize];
input.read(buffer);
recipModulus = new BigInteger(1, buffer);
} catch (IOException ioe) {
System.err.println("Error establishing keys");
}
}
// Close socket and IO streams, change appearance/functionality of some components
private void closeAll() throws IOException {
displayArea.append("\nConnection closing");
output.close();
input.close();
connection.close();
// We are no longer connected
connection = null;
// Change components
serverField.setEditable(true);
connectButton.setLabel("Connect to server above");
enterField.setEnabled(false);
}
public void stop() {
if (thread != null) {
thread.stop();
thread = null;
}
try {
if (console != null) console.close();
if (streamOut != null) streamOut.close();
if (socket != null) socket.close();
} catch (IOException ioe) {
System.out.println("Error closing ...");
}
client.close();
client.stop();
}
/** Generates a device- and invocation-specific seed to be mixed into the Linux PRNG. */
private static byte[] generateSeed() {
try {
ByteArrayOutputStream seedBuffer = new ByteArrayOutputStream();
DataOutputStream seedBufferOut = new DataOutputStream(seedBuffer);
seedBufferOut.writeLong(System.currentTimeMillis());
seedBufferOut.writeLong(System.nanoTime());
seedBufferOut.writeInt(Process.myPid());
seedBufferOut.writeInt(Process.myUid());
seedBufferOut.write(BUILD_FINGERPRINT_AND_DEVICE_SERIAL);
seedBufferOut.close();
return seedBuffer.toByteArray();
} catch (IOException e) {
throw new SecurityException("Failed to generate seed", e);
}
}
public static void main(String[] args) throws Exception {
// prompt user to enter a port number
System.out.print("Enter the port number: ");
Scanner scan = new Scanner(System.in);
int port = scan.nextInt();
scan.nextLine();
System.out.print("Enter the host name: ");
String hostName = scan.nextLine();
// Initialize a key pair generator with the SKIP parameters we sepcified, and genrating a pair
// This will take a while: 5...15 seconrds
System.out.println("Generating a Diffie-Hellman keypair: ");
KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH");
kpg.initialize(PARAMETER_SPEC);
KeyPair keyPair = kpg.genKeyPair();
System.out.println("key pair has been made...");
// one the key pair has been generated, we want to listen on
// a given port for a connection to come in
// once we get a connection, we will get two streams, One for input
// and one for output
// open a port and wait for a connection
ServerSocket ss = new ServerSocket(port);
System.out.println("Listeining on port " + port + " ...");
Socket socket = ss.accept();
// use to output and input primitive data type
DataOutputStream out = new DataOutputStream(socket.getOutputStream());
// next thing to do is send our public key and receive client's
// this corresponds to server step 3 and step 4 in the diagram
System.out.println("Sending my public key...");
byte[] keyBytes = keyPair.getPublic().getEncoded();
out.writeInt(keyBytes.length);
out.write(keyBytes);
System.out.println("Server public key bytes: " + CryptoUtils.toHex(keyBytes));
// receive the client's public key
System.out.println("Receiving client's public key...");
DataInputStream in = new DataInputStream(socket.getInputStream());
keyBytes = new byte[in.readInt()];
in.readFully(keyBytes);
// create client's public key
KeyFactory kf = KeyFactory.getInstance("DH");
X509EncodedKeySpec x509Spec = new X509EncodedKeySpec(keyBytes);
PublicKey clientPublicKey = kf.generatePublic(x509Spec);
// print out client's public key bytes
System.out.println(
"Client public key bytes: " + CryptoUtils.toHex(clientPublicKey.getEncoded()));
// we can now use the client's public key and
// our own private key to perform the key agreement
System.out.println("Performing the key agreement ... ");
KeyAgreement ka = KeyAgreement.getInstance("DH");
ka.init(keyPair.getPrivate());
ka.doPhase(clientPublicKey, true);
// in a chat application, each character is sendt over the wire, separetly encrypted,
// Instead of using ECB, we are goin to use CFB, with a block size of 8 bits(1byte)
// to send each character. We will encrypt the same character in a different way
// each time. But in order to use CFB8, we need an IVof 8 bytes. We will create
// that IV randomly and and send it to the client. It doesn't matter if somoene
// eavesdrops on the IV when it is sent over the wire. it's not sensitive info
// creating the IV and sending it corresponds to step 6 and 7
byte[] iv = new byte[8];
SecureRandom sr = new SecureRandom();
sr.nextBytes(iv);
out.write(iv);
// we generate the secret byte array we share with the client and use it
// to create the session key (Step 8)
byte[] sessionKeyBytes = ka.generateSecret();
// create the session key
SecretKeyFactory skf = SecretKeyFactory.getInstance("DESede");
DESedeKeySpec DESedeSpec = new DESedeKeySpec(sessionKeyBytes);
SecretKey sessionKey = skf.generateSecret(DESedeSpec);
// printout session key bytes
System.out.println("Session key bytes: " + CryptoUtils.toHex(sessionKey.getEncoded()));
// now use tha that session key and IV to create a CipherInputStream. We will use them to read
// all character
// that are sent to us by the client
System.out.println("Creating the cipher stream ...");
Cipher decrypter = Cipher.getInstance("DESede/CFB8/NoPadding");
IvParameterSpec spec = new IvParameterSpec(iv);
decrypter.init(Cipher.DECRYPT_MODE, sessionKey, spec);
CipherInputStream cipherIn = new CipherInputStream(socket.getInputStream(), decrypter);
// we just keep reading the input and print int to the screen, until -1 sent over
int theCharacter = 0;
theCharacter = cipherIn.read();
while (theCharacter != -1) {
System.out.print((char) theCharacter);
theCharacter = cipherIn.read();
}
// once -1 is received we want to close up our stream and exit
cipherIn.close();
in.close();
out.close();
socket.close();
}
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
// Client pressed enter in the message entry field-send it
if (source == enterField) {
// Get the message
message = e.getActionCommand();
try {
// Encipher the message
if (message.length() > plaintextBlockSize)
message = message.substring(0, plaintextBlockSize);
byte[] ciphertext =
Ciphers.RSAEncipherWSalt(message.getBytes(), BigIntegerMath.THREE, recipModulus, sr);
// Send to the server
output.write(ciphertext);
output.flush();
// Display same message in client output area
displayArea.append("\n" + message);
enterField.setText("");
} catch (IOException ioe) {
displayArea.append("\nError writing message");
}
} else if (source == connectButton) {
if (connection != null) { // Already connected-button press now means disconnect
try {
// Send final message of 0
byte[] lastMsg = new byte[1];
lastMsg[0] = 0;
output.write(Ciphers.RSAEncipherWSalt(lastMsg, BigIntegerMath.THREE, recipModulus, sr));
output.flush();
// close connection and IO streams, change some components
closeAll();
} catch (IOException ioe) {
displayArea.append("\nError closing connection");
}
} else { // Not connected-connect
// Get name of server to connect to
chatServer = serverField.getText();
displayArea.setText("Attempting connection to " + chatServer);
try {
// Set up the socket
connection = new Socket(chatServer, 55555);
displayArea.append("\nConnected to: " + connection.getInetAddress().getHostName());
// Set up the IO streams
output = new DataOutputStream(connection.getOutputStream());
output.flush();
input = new DataInputStream(connection.getInputStream());
// Exchange public keys with the server-send yours, get theirs
exchangeKeys();
// Change appearance/functionality of some components
serverField.setEditable(false);
connectButton.setLabel("Disconnect from server above");
enterField.setEnabled(true);
// Set up a thread to listen for the connection
listener =
new Thread(
new Runnable() {
public void run() {
go();
}
});
listener.start();
} catch (IOException ioe) {
displayArea.append("\nError connecting to " + chatServer);
}
}
}
}
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();
}
}
private void writeBlock(int offset) throws IOException {
flushRaw();
blockChunks += BLOCK_SIZE;
output.writeInt(offset);
mode = Mode.Block;
}
public LRC(DataOutputStream output) throws IOException {
this.output = output;
output.writeInt(BLOCK_SIZE);
check = new RollingChecksum(BLOCK_SIZE);
mode = Mode.Raw;
}
