  Secure network coding realizes the secrecy of the message when the message is
transmitted via noiseless network and a part of edges or a part of intermediate
nodes are eavesdropped. In this framework, if the channels of the network has
noise, we apply the error correction to noisy channel before applying the
secure network coding. In contrast, secure physical layer network coding is a
method to securely transmit a message by a combination of coding operation on
nodes when the network is given as a set of noisy channels. In this paper, we
give several examples of network, in which, secure physical layer network
coding has advantage over secure network coding.
