Systems exploiting network coding 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, we address this issue
with unconditionally secure multi-receiver authentication codes designed for
network coding. Our scheme is robust against pollution attacks from outsiders
and even from a coalition of k-1 malicious insiders. With our authentication
code, intermediate nodes can verify the message integrity and origin of the
packets received without having to decode and thus detect and discard the malicious packets in-transit that fail
the verification. This way, the pollution is canceled out before reaching the destinations.Accepted versio