# Smart Grid Security: A PUF-Based Authentication and Key Agreement Protocol
## 2 Related Work  
In this section, some recent protocols are described. In Table 1, every protocol is evaluated considering communication overhead, time-consuming processes, encryption techniques, and vulnerability. The assessment is represented by triangles (\(\blacktriangledown\) for low and \(\blacktriangle\) for high). A check mark (\(\blacktriangledown\)) indicates a documented successful attack, whereas a multiplication symbol (\(\times\)) signifies an attack not yet published. Interest in the subject is reflected in the number of publications, which have increased exponentially over the last decade, particularly in the field of cyber security, which remains a major concern [10]. Recently substantial efforts have been directed towards establishing a reliable and secure communication infrastructure for smart metering. For example, [PERSON] et al. introduced the LAKA system, a lightweight authentication and key agreement scheme, aimed at ensuring an acceptable level of security and integrity in smart energy networks [11]. To ensure the confidentiality of messages, LAKA incorporates both hash functions and an ECC module. Moreover, it employs a message authentication code (MAC) function to maintain message integrity. This integration of multiple functions contributes to the heightened complexity of the smart meter (SM). Furthermore, as observed by [PERSON] et al. [12], this protocol exhibits susceptibility to traceability attacks. [PERSON] et al. introduced ECCAuth, a recent authentication protocol for smart grid applications that relies on ECC cryptography [13]. According to the authors, ECCAuth's primary objective is to establish a secure connection between a smart grid (SG) device and a utility center (UC), ensuring user privacy and the confidentiality of data. Nevertheless, ECCAuth, while maintaining acceptable communication costs, exhibits time-consuming authentication procedures and computational operations. Furthermore, ECCAuth's vulnerability has been exposed by [PERSON] et al., who identified security weaknesses, including session key disclosure, stolen devices, and masquerade, attacks [14]. In response, they proposed a new lightweight protocol that incorporates XOR and hash functions to rectify these shortcomings. [PERSON] et al. also suggested an ECC-based authentication protocol [15]. Although it secures message confidentiality through an ECC module and data encryption, the protocol's functionality falls short of an acceptable level. Notably, it exhibits high communication and computation overhead, leading to extended authentication processing times. [PERSON] et al. recently introduced another authentication protocol for SMs based on the ECC method [16]. Despite their claim of robustness against diverse attacks and reasonable computational expenses, our assessment highlights susceptibility to traceability and impersonation attacks. Additionally, the authors inaccurately calculated and underestimated computational costs. By utilizing the ECC technique, [PERSON] et al. [17], [PERSON] [18], and [PERSON] [19] also proposed some protocols, aiming to establish a secure infrastructure. However, they face efficiency challenges, which will be discussed in detail in Section 6. [PERSON] et al. introduced an innovative access control protocol for smart grids, known as RACP-SG [20]. This protocol utilizes lightweight-cryptography-based authenticated encryption with associative data (AEAD) techniques, hash functions, and elliptic curve cryptography (ECC) to successfully execute the authentication process. Moreover, RACP-SG enables mutual authentication between a service provider and an SM, allowing them to establish a session key during communication over the public channel. [PERSON] et al. recently introduced a new ECC-based protocol called LAS-SG, emphasizing its lightweight nature to ensure satisfactory security and privacy levels [21]. Their approach involves optimizing communication by utilizing only two transferred messages, containing 192 bytes.