Date Added: Sep 2009
Systems exploiting network coding to increase their throughput suffer greatly from pollution attacks which consist of injecting malicious packets in the network. The pollution attacks are amplified by the network coding process, resulting in a greater damage than under traditional routing. In this paper, the authors address this issue by designing an unconditionally secure authentication code suitable for multicast network coding. The proposed scheme is robust against pollution attacks from outsiders, as well as coalitions of malicious insiders. Intermediate nodes can verify the integrity and origin of the packets received without having to decode, and thus detect and discard the malicious messages in-transit that fail the verification.