Review

finding-16

/mubench/checkouts/chensun/cf23b99/build/CS5430/src/crypto/SharedKeyCryptoComm.java

send(byte[], OutputStream, Cipher, SecretKey, BigInteger)

class SharedKeyCryptoComm {
	public static boolean send(byte[] msgbytes, OutputStream os, Cipher c, SecretKey sk, 
			BigInteger sendNonce) throws ConnectionException {
		int blockSize = c.getBlockSize();
		
		SecureRandom sr = createSecureRandom();
		try {
			//iv and msg
			byte[] iv = createIV(sr, blockSize);
			IvParameterSpec ivp = new IvParameterSpec(iv);
			try {
				c.init(Cipher.ENCRYPT_MODE, sk, ivp);
			}
			catch (Exception e) {/*This cannot happen*/}
			
			byte[] encmsg = null;
			try {
				encmsg = c.doFinal(msgbytes);
			} catch (Exception e) { //exception should not happen...
				e.printStackTrace();
			}
			byte[] encmsglen = ByteBuffer.allocate(4).putInt(encmsg.length).array();
			
			byte[] sendNonceArray = sendNonce.toByteArray();
			byte[] sendNonceArrayMsg = Arrays.copyOf(sendNonceArray, NONCE_LENGTH);
			
			byte[] totalmsg = new byte[NONCE_LENGTH + iv.length + encmsglen.length + msgbytes.length];
			//nonce, iv, msglen, and msgbytes.
			System.arraycopy(sendNonceArrayMsg, 0, totalmsg, 0, NONCE_LENGTH);
			System.arraycopy(iv, 0, totalmsg, NONCE_LENGTH, iv.length);
			System.arraycopy(encmsglen, 0, totalmsg, NONCE_LENGTH + iv.length, encmsglen.length);
			System.arraycopy(msgbytes, 0, totalmsg, NONCE_LENGTH + iv.length + encmsglen.length, msgbytes.length);
			
			//get checksum
			byte[] checksum = Hash.generateChecksum(totalmsg);
			
			// zero out totalmsg.
			Arrays.fill(totalmsg, (byte)0x00);

			os.write(checksum); //128 bits
			os.write(sendNonceArrayMsg);
			os.write(iv);
			os.write(encmsglen);
			os.write(encmsg);
			os.flush();
		}
		catch (IOException e) {
			System.out.println("Error/Timeout sending the message (msg in bytes so it is not printed) ");
			System.out.println("Closing the connection");
			throw new ConnectionException();
		}
		return true;
	}

}