The Arms Race in P2P

Peer-to-peer (P2P) networks have recently grown in popularity for a variety of applications such as content distribution, streaming multimedia and voice-over IP. P2P networks are built around a decentralized architecture to distribute data in a manner that offers high availability of content, inherent fault-tolerance and efficiency. While P2P networks offer several important advantages over traditional client/server architectures, experience has shown that these networks are file sharing copyright protected content, which presents significant problems for network management and copyright enforcement. P2P networks utilize a large amount of bandwidth, complicating network management for broadband Internet service providers (ISPs), particularly during times of peak network utilization. In addition, the illegal dissemination of copyright protected media is an obvious problem for the respective copyright holders that may result in a loss of revenue. As a consequence, there is ample incentive for both broadband ISPs and copyright holders to work to stop the proliferation of file sharing within P2P networks. Our primary goal in this paper is to understand the current techniques for distributing and hiding copyright protected content within P2P networks. We focus our discussion primarily on BitTorrent, since it is currently the most popular P2P protocol for file sharing. We observe that an arms race has already begun between file traders and copyright holders in which the file traders have started to develop techniques for hiding their involvement in the transfer of a copyright protected media file. In response, the investigative tactics used by copyright holders are evolving to match these changing strategies. We provide a survey of the current tactics used by file traders to hide their involvement in illegal file transfers and speculate about future strategies that may emerge on both sides of the arms race. In this paper we provide an introduction to BitTorrent, the most common P2P protocol for file sharing in use today. Next, we describe the most common techniques that copyright holders have employed to track the distribution of their copyright protected content. These strategies often include investigative tactics, locating individual users and issuing DMCA take-down letters, or even pursuing more serious legal actions against suspected file sharers. We then discuss the past tactics used by broadband ISPs to throttle BitTorrent traffic. In response to the copyright holder’s desire to protect their content, there is now significant incentive for P2P users to shed their network identities and seek a certain degree of anonymity. In addition, to avoid traffic shaping, P2P users have incentive to try to hide the nature of their traffic by using encryption. We consider the current tactics used to evade ISP traffic shaping practices and copyright enforcement, describe the most common methods for achieving anonymity online, and present evidence from a prior study by the authors that P2P users are using BitTorrent anonymously. We next briefly outline a variety of proposals to incorporate anonymity mechanisms into P2P networks and speculate about the future tactics that may be employed to distribute copyright protected content. To conclude, we examine some of the policy implications of this arms race and consider what impact they may have on copyright and broadband policy