Security is one of the major concerns in network coding. Although intrinsic confidential security is provided because different flows of information are mixed, network coding is still vulnerable to modification attack and wiretapping attack if the wire tapper knows the transmission mechanism. In this paper, a kind of encryption scheme is proposed to secure the network. This scheme has such advantages as the number of encryption is small and the wire tappers are not restricted to only part of the transmission links, but all the links are admissible. In general, the number of encryption is only 1/n of traditional encryption, in which n is the degree of one dimension of source message. Whats more, the integrity of network is also checked in every intermediate node which could make the scheme more efficient compared to the sinks detection only.
Protection of keys against modification attack