A Rateless Approach to Physical-Layer Security

A majority of coding constructions for physical-layer security are based on linear block codes and their cosets. One issue with these codes is that they require knowledge of channel state information (CSI) for both the friendly party and the eavesdropper in the wiretap channel prior to constructing the code. In this paper, we present a framework for rateless physical-layer security codes over the wiretap channel by introducing both fixed and adaptive variants of rateless security coding schemes. These techniques can be used to reduce the requirements on CSI prior to code construction, because the codes will either adapt to the operating parameters of the legitimate user's channel on the fly and/or target a maximum allowable probability of intercept (POI) at the eavesdropper. All channels in play are packet erasure channels (PECs), as these channels are quite pervasive in most real-world network applications. We further present the details of an actual implementation of rateless physical-layer security coding over a Wi-Fi network.