Update readme. Embed demo.

README.md

 # mobile-sec-notifier
 
-Two chat participants [A]lice and [B]ob.
-Send encrypted messages indirectly via the server between A and B.
-A and B in distinct networks.
+![Demo](presentation/figures/Demo-MobSec-AndroidNotifier.mp4)
+
+* Two chat participants [A]lice and [B]ob.
+* Send encrypted messages indirectly via the server between A and B.
+* A and B in distinct networks.
 
 # Usage
+The default mode of operation requires:
+* A server
+* One python client in receiver mode
+* One android client in sender mode
+
 1. Start server with `python server.py`
 2. Start client
     * Python: `python client.py MODE`, where `MODE` is 0 (receiver) or 1 (sender)
     * Android: 
-        0. Set notification permissions if necessary.
+        1. Set notification permissions if necessary.
         1. Enter IP address and port of server.
         2. Click `Open communication` 
         3. Enter generated id_code in other client.
@@ -22,10 +29,7 @@ A and B in distinct networks.
 * The android client can be started easily with Android Studio.
 * Otherwise, there is a built APK available in the folder `releases/`
 
-## Demo
-There is a demo video available as well.
-
-# TODO:
+# Implemented:
 
 - [x] Protocol
 - [x] Server (python)
@@ -56,7 +60,7 @@ There is a demo video available as well.
 # Prototype 3:
 
 - [ ] grpc secure connection
-- [ ] Harden against attacks (for reference: https://core.telegram.org/techfaq#protection-against-known-attacks)
+- [x] Harden against attacks (for reference: https://core.telegram.org/techfaq#protection-against-known-attacks)
 
 # TODO: