Physical layer security in PLC networks: Achievable secrecy rate and channel effects

We consider confidential data communication over power line communication (PLC) networks. In particular, rather than analyzing cryptographic techniques, we focus on the security provided at the physical layer, named physical layer security (PLS). Although physical layer security is widely discussed for wireless systems, we can not say the same for the PLC context. As a starting point, the wireless case will be examined. Then, we highlight the differences with PLC and we compare the average secrecy rate that can be achieved in typical wireless and PLC fading channels. Both optimal and uniform power distributions are considered. The theoretical results show that wireless fading channels provide higher secrecy rate than PLC channels. This is due to different channel statistics and propagation scenario. To provide experimental evidence, we consider channel measures obtained in a in-ship and in a in-home measurement campaign. While log-normal fading fits well the former channels, the latter channels are not strictly log-normal. Furthermore, the considered in-home network topology introduces correlation among channels, and it is subject to the keyhole effect introduced by branches that depart from the same node. These effects can reduce the secrecy rate.