A Replay Attack-Resistant 0-RTT Key Management Scheme for Low-Bandwidth Smart Grid Communications

With the increasing digitization of different components of Smart Grid, there is an ongoing effort to design secure protocols and deploy them for different applications. A major need along with these efforts is to deal with key management for a large number of devices which are resource constrained and deployed within a very legacy communication environment. As the utilities rightly request to build the new systems on top of the legacy systems with limited investment, the research community needs to re-think the adaptation of the existing security approaches to such non-traditional environments. Assuming a legacy (i.e., 2G) radio communication infrastructure with bandwidths in the order of kilobits, the goal of this study is to enable basic security services in Smart Grid via a lightweight key management scheme. Specifically, the proposed scheme provides mutual authentication, key agreement, and key refreshment by utilizing a 0-RTT message exchange that relies neither on PKI or session resumption. It depends on dynamic hash chains to enable authentication and prevent any replay attacks. The evaluations results show that the proposed scheme out-performs other conventional approaches such as TLS and IKE and is suitable for Smart Grid legacy environments.

I. Introduction

The existing power grid is currently going through a major transformation to enhance its reliability, resiliency and efficiency by enabling networks of intelligent electronic devices (IED), sensors, remote terminal units (RTU), distributed energy resources (DER), and dispersed loads[7], which is collectively referred to as Smart(er) Grid. The ongoing power grid automation process benefits from the information provided by these devices such as voltage, current, temperature, etc. for real-time monitoring of the grid. The information is conveyed to the SCADA control center through the existing communication infrastructure of the grid that covers all the geographic areas where these IEDs/DERs and RTUs are deployed with low density. This is typically through a Wide-Area Network (WAN) technology such as GPRS, 2/3G, and other proprietary radio communications [10].