Towards securing data delivery in peer-to-peer streaming

The goal of enabling ubiquitous video broadcasting on the Internet has been a long cherished vision in the networking community. Prior efforts aimed at achieving this goal based on the IP Multicast architecture have been unsuccessful. In recent years, peer-to-peer (P2P) streaming has emerged as a promising alternative technology, which has matured to the point that there are several commercial offerings available to users. While these developments are encouraging, P2P streaming systems are susceptible to attacks by malicious participants, and their viability depends on how effectively they can perform under such attacks. In this paper, we explore this issue in the context of mesh-based designs, which have emerged as the dominant architecture for P2P streaming. We provide a taxonomy of the implicit commitments made by nodes when peering with others. We show that when these commitments are not enforced explicitly, they can be exploited by malicious nodes to conduct attacks that degrade the data delivery service. We consider an important class of attacks where malicious nodes deliberately become neighbors of a large number of nodes and do not upload data to them. We focus on these attacks given the limited attention paid to them, and the significant impact they can have on overall data delivery. We present mechanisms that can enhance the resilience of mesh-based streaming against such attacks. A key part of the solution is a novel reputation scheme that combines feedback from both the control and data planes of the overlay. We evaluate our design with real-world experiments on the PlanetLab testbed and show that our design is effective. Even when there are 30% attackers, nodes can receive 92% of the data with our schemes compared to 10% of the data without our schemes. Overall these results indicate the feasibility of enabling effective P2P streaming even under the presence of malicious participants.