Design of how you think a P2P service should work. You're allowed to describe an existing model, or come up with your own. Make sure you take care of multiple users and searching in your idea. You can emphasize different aspecs, like security, efficiency, robustness, etc. The description should be detailed enough to implement the model (don't leave any major open holes in the idea). Submit the description in TXT (or PDF) format. e.g. think BitTorrent, how would you make it better/different?