BitTorrent is believed to be one of the fairest P2P protocols. The built in tit-for-tat mechanism makes sure that you get what you give. But there are several ways to cheat and exploit BitTorrent in order to increase your download speed.
But how vulnerable is BitTorrent?
Nikitas Liogkas, Robert Nelson, Eddie Kohler, Lixia Zhang from the UCLA Computer Science Department, tested three ways to cheat BitTorrent.
1. Download only from seeds
2. Download from fastest peers
3. Advertise false pieces
They conclude from their research:
“BitTorrent appears quite robust against this kind of exploit: selfish peers can sometimes obtain more bandwidth, and honest peers’ download rates suffer slightly in consequence, but we
observe no considerable degradation of the system’s quality of service.”
Additionally they propose five mechanisms that they believe will contribute to BitTorrent’s robustness.
1. parallel downloading: maintain parallel interactions with multiple peers; enables adaptivity in dynamic conditions
2. client memory: the torrent client remembers where a piece comes from, and is able to punish cheating peers.
3. problem partitioning: decouple data needs from provided service; prevents manipulation by declaring false info
4. export minimal information: hide exploitable information, who’s a seed for example.
5. keep the network connected: random choice in optimistic unchoking prevents clustering and starvation