This paper presents a set of exploits an adversary can use to continuously spy on most BitTorrent users of the Internet from a single machine and for a long period of time. Using these exploits for a period of 103 days, we collected 148 million IPs downloading 2 billion copies of contents. We identify the IP address of the content providers for 70 of the BitTorrent contents we spied on. We show that a few content providers inject most contents into BitTorrent and that those content providers are located in foreign data centers. We also show that an adversary can compromise the privacy of any peer in BitTorrent and identify the big downloaders that we define as the peers who subscribe to a large number of contents. This infringement on users' privacy poses a significant impediment to the legal adoption of BitTorrent.
BitTorrent is the most successful open Internet application for content distribution. Despite its importance, both in terms of its footprint in the Internet and the influence it has on emerging P2P applications, the BitTorrent Ecosystem is only partially understood. We seek to provide a nearly complete picture of the entire public BitTorrent Ecosystem. To this end, we crawl five of the most popular torrent-discovery sites over a ine-month period, identifying all of 4.6 million and 38,996 trackers that the sites reference. We also develop a high-performance tracker crawler, and over a narrow window of 12 hours, crawl essentially all of the public Ecosystem's trackers, obtaining peer lists for all referenced torrents. Complementing the torrent-discovery site and tracker crawling, we further crawl Azureus and Mainline DHTs for a random sample of torrents. Our resulting measurement data are more than an order of magnitude larger (in terms of number of torrents, trackers, or peers) than any earlier study. Using this extensive data set, we study in-depth the Ecosystem's torrent-discovery, tracker, peer, user behavior, and content landscapes. For peer statistics, the analysis is based on one typical snapshot obtained over 12 hours. We further analyze the fragility of the Ecosystem upon the removal of its most important tracker service.