# Smart Grid Security: A PUF-Based Authentication and Key Agreement Protocol
## 2 Related Work
Although the computation cost of LAS-SG is deemed acceptable, it remains higher than the protocol proposed in this paper. PUF-based techniques present an intriguing approach utilized in smart metering and grid applications [22]. Numerous PUF-based protocols have been developed for SG/SM, such as the Gope and Sikdar scheme--a key agreement method with privacy-aware authentication protocol to improve security in these kinds of applications [23]. Recognizing the potential impact of cyber attacks on electrical networks, such as real-time decision-making in demand and supply management as well as data manipulation, they created a method to boost the confidentiality of communication channels between UCs and SMs, guaranteeing physical security. Nevertheless, [PERSON] et al. discovered weaknesses in this approach, suggesting that it does not fulfill all the necessary security criteria [24]. Moreover, the Gope-Sikdar protocol relies on a hash function as its main security measure, rendering it susceptible to key compromise impersonation attacks due to its symmetric nature. Additionally, their protocol includes XORing a temporal value with the secret key before transmitting it on the public channel (i.e., \(np*=n_{p}\oplus K\)), where K becomes the main source of authentication afterward This vulnerability exposes the protocol to known session-specific temporary information attacks, allowing various malicious actions, including impersonation and de-synchronization. [PERSON] et al. introduced an authentication protocol, EPSG, for the smart grid in the IoT infrastructure [25]. This protocol, combining PUF functions and ECC encryption, establishes a secure environment, ensuring message confidentiality and integrity simultaneously. The authors conducted simulations of EPSG on an Arduino, assessing communication cost and energy consumption in a practical setting. Although EPSG's performance is acceptable, its ability to resist machine learning attacks is limited. [PERSON] et al. introduced a security scheme based on a ring oscillator physically unclonable function [26] to enhance information security in advanced metering infrastructures. Their primary goal was to create a robust and secure authentication approach for smart grid infrastructure. In the architecture named ROPUF, they created a secure connection between the utility center and the smart meter (SM) to transfer data. However, they did not provide details about the workings of this channel and how the SM utilizes it for communication. This channel imposes an additional burden on the SM, generating ciphertext, which was not factored into the protocol's computational cost. Moreover, the proposed protocol exhibited vulnerabilities to impersonation and tracing attacks when data exchanges occurred over a public channel. Furthermore, due to the absence of cryptographic primitives, the protocol was susceptible to advanced attacks, including insider attacks. In a recent development, [PERSON] et al. presented a scheme to secure key exchange mutually [27]. Their scheme utilized advanced encryption techniques, such as identity-based encryption (IBE), SHA-2, and the advanced encryption standard (AES), with the possibility of employing ECC encryption and physically unclonable function (PUF) functions. The authors implemented and tested this scheme in a practical environment to provide experimental results. However, the scheme's use of identity-based encryption (IBE) for credential management raised concerns. Currently, the most efficient IBE schemes rely on bilinear pairings on elliptic curves, such as Weil or Tate pairings, while previously published non-pairing-based schemes tend to be inefficient in encryption, decryption, key generation, ciphertext size, or key size [28; 29]. Considering that the scheme is designed for resource-constrained devices and involves various encryption methods in each authentication process, it exhibits high complexity and is time-consuming.