p2pnet - rss feed: Cheating and exploiting BitTorrent
p2p news / p2pnet: 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
Link to the article for more info: pdf | html
Torrentfreak - The Netherlands
[Note: Also see BitTorrent and free-riders - Jon]
May 17th, 2006 at 3:40 pm
Similar research was done before.
Of course bitttorrent can be cheated by a particular client, but the honor system has worked ok so far.
May 18th, 2006 at 11:38 am
There is one exploit that works well on sites that require a high ratio. I have tried this my self and I got max download speeds every time.
http://xyflar.blogspot.com/
May 18th, 2006 at 6:29 pm
Yeah use that “bug” and get banned from the site within a day
The admins of these sites aren’t stupid and they the bugs that are out there and how to spot/prevent them…
May 18th, 2006 at 9:35 pm
May 21st, 2006 at 2:39 am
Cheating in bittorrent only works where the tracker is collecting information outside of the protocol spec’s (like recieving information from peers on how much they’ve uploaded and downloaded).
Bram Cohen (the creater of Bittorrent) specifically wrote the protocol assuming that every peer is out for it’s best interest and will lie, cheat and steal.
My client tracks how much your client has uploaded to me, and if you don’t give to me, I don’t give to you. It’s that simple.