public ComService(User user, String server, SigService sigServ)
			throws ConnectException, InvalidURIException,
			IllegalArgumentException, IOException, InvalidKeyException,
			IllegalBlockSizeException, BadPaddingException,
			NoSuchAlgorithmException {

		this.sigServ = sigServ;
		this.user = user;
		notificationHandle = null;
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		ObjectOutput out = null;

		try {
			out = new ObjectOutputStream(bos);
			out.writeObject(this.sigServ.getPublicKey());
		} catch (IOException e1) {
			shutdown();
			System.exit(0);
		}

		sigPublicKey = bos.toByteArray();

		elvin = new Elvin(server);
		elvin.closeOnExit();
	}