1mqScmwY

1private byte[] runSupportClient(int clientNonce) { //this client nonce is the server nonce from step 4 in tbe original client
2		Socket newConnection;
3		try {
4			newConnection = new Socket("localhost", portNo);
5		} catch (Exception e) {
6			System.out.println(e);
7			return null;
8		}
9		DataOutputStream outStream;
10	    DataInputStream inStream;
11	    try {
12		outStream = new DataOutputStream(newConnection.getOutputStream());
13		inStream = new DataInputStream(newConnection.getInputStream());
14		try {
15		    // Use crypto API to calculate x & g^x
16		    DHParameterSpec dhSpec = new DHParameterSpec(p,g);
17		    KeyPairGenerator diffieHellmanGen = KeyPairGenerator.getInstance("DiffieHellman");
18		    diffieHellmanGen.initialize(dhSpec);
19		    KeyPair serverPair = diffieHellmanGen.generateKeyPair();
20		    PrivateKey x = serverPair.getPrivate();
21		    PublicKey gToTheX = serverPair.getPublic();
22		    
23		    //Protocol message 1
24		    //PublicKey cert can vary in length, therefore the length is sent first
25		    outStream.writeInt(gToTheX.getEncoded().length);
26		    outStream.write(gToTheX.getEncoded());
27		    if (debug) System.out.println("g^x len: "+gToTheX.getEncoded().length);
28		    if (debug) System.out.println("g^x cert: "+byteArrayToHexString(gToTheX.getEncoded()));
29		    
30		    
31		    //Protocol message 2
32		    int publicKeyLen = inStream.readInt();
33		    byte[] message2 = new byte[publicKeyLen];
34		    inStream.read(message2);
35		    KeyFactory keyfactoryDH = KeyFactory.getInstance("DH");
36		    X509EncodedKeySpec x509Spec = new X509EncodedKeySpec(message2);
37		    PublicKey gToTheY = keyfactoryDH.generatePublic(x509Spec);
38		    if (debug) System.out.println("g^y len: "+publicKeyLen);
39		    if (debug) System.out.println("g^y cert: "+byteArrayToHexString(gToTheY.getEncoded()));
40		    
41		    //Calculate session key
42		    // This method sets decAESsessionCipher & encAESsessionCipher
43		    calculateSessionKeySupport(x, gToTheY);
44		    
45		    //Protocol Step 3
46		    byte[] encryptedClientNonce = encAESsessionSupport.doFinal(BigInteger.valueOf(clientNonce).toByteArray());
47		    outStream.write(encryptedClientNonce);
48		    
49		    if (debug) System.out.println("Client nonce: "+clientNonce);
50		    
51		    //Protocol Step 4
52		    byte[] encryptedMsg4 = new byte[32];
53		    inStream.read(encryptedMsg4);
54		    byte[] decryptedMsg4 = decAESsessionSupport.doFinal(encryptedMsg4);
55
56		    byte[] encryptedClientNonceInc = new byte[16];
57		    System.arraycopy(decryptedMsg4, 0, encryptedClientNonceInc, 0, 16);
58		    
59		    newConnection.close();
60		    System.out.println("Returning now");
61		    return encryptedClientNonceInc;
62		   
63		   
64		} catch (IllegalBlockSizeException e) {
65		    outStream.write("Bad block size".getBytes());
66		    if (debug) System.out.println("Doh "+e);
67		    myConnection.close();
68		    return null;
69		} catch (BadPaddingException e) {
70		    outStream.write("Bad padding".getBytes());
71		    myConnection.close();
72		    if (debug) System.out.println("Doh "+e);
73		    return null;
74		} catch (InvalidKeySpecException e) {
75		    outStream.write("Bad certificate for PublicKey (g^x)".getBytes());
76		    myConnection.close();
77		    if (debug) System.out.println("Doh "+e);
78		    return null;
79		} catch (NoSuchAlgorithmException e) {
80		    System.out.println(e);// Not going to happen, AES hard wired
81		} catch (InvalidAlgorithmParameterException e) {
82		    System.out.println(e);// Not going to happen, DH Spec hard wired
83		    e.printStackTrace();
84		} 
85		
86	    } catch (IOException e) {
87		//Nothing we can do about this one
88		if (debug) System.out.println("Your wi-fi sucks: "+e);
89		return null;
90	    }
91	    return null;
92	}