Secure Transmission in Unicast Wiretap Networks of Type II

This paper studies the secure network coding problem for a unicast wiretap network of type II, where an eavesdropper can intercept a bounded rate of the encoded information from the compromised links. We first discuss the upper bound on the secrecy rate and then figure out the upper bound can be tight for the unicast wiretap network II if each relay within the network is allowed to decode and encode the coset codes. Moreover, the relative proofs are presented in this paper.