My flappy bird clone has already been hacked by someone who scored 9999 points. Since this is a highly unprobable score for a casual player it's obvious that the game has ben hacked.

This is really easy since the hiscore is sent in plain text directly through a websocket, you can do it directly using the web inspector.
0wn3d! Part II
How can you avoid this?
Here you can read some general advices dealing with security while using websockets but I wont be implementing them for now since I don't have enough free time for this.

Don't be evil! :)