Locating Byzantine Attackers in Intra-Session Network Coding Using SpaceMac

Intra-session network coding is known to be vulnerable to Byzantine attacks: malicious nodes can inject bogus packets, which get combined with legitimate blocks at downstream nodes, thus preventing decoding of original packets and degrading the overall performance. In this paper, we provide a novel approach that can identify the precise location of all Byzantine attackers in systems with intra-session network coding. A key ingredient of our approach is a novel homomorphic MAC scheme for expanding subspaces (SpaceMac) that allows to eliminate any uncertainty in identifying attackers via subspace properties. To the best of our knowledge, our scheme is the first that can identify precisely all Byzantine attackers, and at the same time has both low computation (sub- millisecond) and communication overhead (20 bytes per data block). Simulation results show that, even when there are multiple colluding attackers in a network, all of them can be successfully identified in a very short time.