# Smart Grid Security: A PUF-Based Authentication and Key Agreement Protocol
###### Abstract  
A smart grid is an electricity network that uses advanced technologies to facilitate the exchange of information and electricity between utility companies and customers. Although most of the technologies involved in such grids have reached maturity, smart meters--as connected devices--introduce new security challenges. To overcome this significant obstacle to grid modernization, safeguarding privacy has emerged as a paramount concern. In this paper, we begin by evaluating the security levels of recently proposed authentication methods for smart meters. Subsequently, we introduce an enhanced protocol named PPSG, designed for smart grids, which incorporates physical unclonable functions (PUF) and an elliptic curve cryptography (ECC) module to address the vulnerabilities identified in previous approaches. Our security analysis, utilizing a real-or-random (RoR) model, demonstrates that PPSG effectively mitigates the weaknesses found in prior methods. To assess the practicality of PPSG, we conduct simulations using an Arduino UNO board, measuring computation, communication, and energy costs. Our results, including a processing time of 153 ms, a communication cost of 1376 bits, and an energy consumption of 13.468 mJ, align with the requirements of resource-constrained devices within smart grids. smart grid; smart meter; authentication; Internet of Things; security; elliptic curve cryptography +
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computing, and the Internet of Things (IoT). Within this context, IoT technologies are instrumental in transforming the sector from a centralized to a distributed, smart, and integrated energy system [3]. Indeed, in the age of digital transformation, IoT-enabled smart grids empower utilities to sense, analyze, control, and optimize their grids and explore new revenue streams by building innovative business models. Among the components shaping this transformation in the electricity sector, grid sensors such as smart meters (SMs) not only monitor and transmit electricity consumption data to utility offices but also eliminate the need for manual meter readings. Indeed, SMs, as connected devices, automatically communicate with gateways such as neighborhood area networks (NANs) or other base stations using various communication technologies, such as LoraWAN, cellular, or satellite. SMs capture the date and time of electricity consumption, allowing the implementation of effective energy management systems. For instance, dynamic pricing strategies, where utilities charge higher rates during peak demand periods, enable consumers and businesses to manage their energy consumption remotely, shifting it to off-peak hours when costs are lower. Additionally, smart meters enhance utility services by detecting tampering and theft, offering faster responses to meter failures and power outages. The interest in efficient and accurate metering solutions is reflected by the smart meters market size (gas, water, and electricity), which surpassed USD 22 billion in 2021 and is expected to grow at a CAGR of 13 percent between 2022 and 2028. [4]. Electricity metering has the largest share of this market, with over 60 percent of the global market value [5]. While SMs play a vital role in efficient energy management, their intricate design introduces new security challenges. The ability of smart meters to communicate with nearby IoT devices raises concerns about grid resilience in the face of potential disruptions leading to increased operational costs loss of productivity and loss of sales as well as [6] user security and privacy. Hackers could potentially access personal data and exploit the system for financial gains. Consequently, ensuring privacy has become a top priority in the realm of smart metering.