Providing Physical Layer Security for IoTs in the Last Mile

Abstract

Communication security is one of the top security challenges for connected devices. Different from other links such as backhaul, the last mile technology also depends on the requirements of end users. Wireless technologies are generally selected for the mobility of users and ease of use. However, wireless medium has an open nature and thus wireless links are more prone to physical layer attacks compared to their wired counterparts. Moreover, simple end devices have constrained resources in both hardware and software, and it is not always feasible to apply conventional cryptographic approaches to provide security. We turn to chaos theory to provide security for simple devices at physical layer. The FM-DCSK and FM-CSK transmission system are built and implemented in the proposed secure communication system. The information message is embedded in wideband random-like signals, making the message remain covert. Transmission security is achieved by using the initial conditions and spreading factor as keys. To guard against active attacks, procedures for dynamic adjustment of initial conditions and other parameters are proposed. The scheme's cost effective features include the simplicity of communication setup and the low power consumption in generating and controlling the chaos signal. The sensitivity to initial condition and complex dynamic feature of chaotic function make it a promising approach for physical layer security.