Title: Simple Countermeasures to Mitigate the Effect of Pollution Attack in Network Coding Based Peer-to-Peer Live Streaming,
Abstract: Network coding based peer-to-peer streaming represents an effective solution
to aggregate user capacities and to increase system throughput in live
multimedia streaming. Nonetheless, such systems are vulnerable to pollution
attacks where a handful of malicious peers can disrupt the communication by
transmitting just a few bogus packets which are then recombined and relayed by
unaware honest nodes, further spreading the pollution over the network. Whereas
previous research focused on malicious nodes identification schemes and
pollution-resilient coding, in this paper we show pollution countermeasures
which make a standard network coding scheme resilient to pollution attacks.
Thanks to a simple yet effective analytical model of a reference node
collecting packets by malicious and honest neighbors, we demonstrate that i)
packets received earlier are less likely to be polluted and ii) short
generations increase the likelihood to recover a clean generation. Therefore,
we propose a recombination scheme where nodes draw packets to be recombined
according to their age in the input queue, paired with a decoding scheme able
to detect the reception of polluted packets early in the decoding process and
short generations. The effectiveness of our approach is experimentally
evaluated in a real system we developed and deployed on hundreds to thousands
peers. Experimental evidence shows that, thanks to our simple countermeasures,
the effect of a pollution attack is almost canceled and the video quality
experienced by the peers is comparable to pre-attack levels.