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(); } }
/** * Uses a cipher to transform the bytes in an input stream and sends the transformed bytes to an * output stream. * * @param in the input stream * @param out the output stream * @param cipher the cipher that transforms the bytes */ public static void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException, GeneralSecurityException { int blockSize = cipher.getBlockSize(); int outputSize = cipher.getOutputSize(blockSize); byte[] inBytes = new byte[blockSize]; byte[] outBytes = new byte[outputSize]; int inLength = 0; ; boolean more = true; while (more) { inLength = in.read(inBytes); if (inLength == blockSize) { int outLength = cipher.update(inBytes, 0, blockSize, outBytes); out.write(outBytes, 0, outLength); } else more = false; } if (inLength > 0) outBytes = cipher.doFinal(inBytes, 0, inLength); else outBytes = cipher.doFinal(); out.write(outBytes); }