Providing security and privacy in today's digital era is very crucial. In order to ensure that the sensitive user data can only be accessed by a valid server, the user and server should agree on a common key in advance. To do so, in the last decade, a number of dynamic ID-based authenticated key agreement (DIDAKA) protocols have been proposed, which can guarantee subsequent secure communications of users and servers. Nevertheless, investigating the related works indicates that the existing DIDAKA schemes suffer from one or more security challenges. Quite recently, Xie et al. have presented an interesting anonymous DIDAKA protocol to cover the security weaknesses of previous schemes; nonetheless, we found that their scheme is susceptible to three attacks. Therefore, to remedy the security limitations, in this paper, we propose a security-enhanced anonymous DIDAKA protocol, which not only keeps the merits of Xie et al.'s scheme, but also offers better execution time compared to their proposed one. To demonstrate the security of the proposed scheme, we present both formal security proof and automatic formal verification of security and to show its efficiency, we present an extensive comparative performance analysis. In conclusion, the results are indicative of the priority of the proposed scheme.

Security is an indispensable part of smart grid (SG). Key establishment protocols play a vital role in fulfilling the security requirements in SG. In recent years, many key establishment schemes have been proposed for SG. However, only three of them offer the strong smart meter anonymity. In 2015, Tsai and Lo presented an anonymous key establishment scheme to be employed in SG. Recently, Odelu et al. have demonstrated that Tsai and Lo's scheme suffers from the ephemeral secret leakage attack. Furthermore, another scheme has been proposed recently by He et al. that has improved the efficiency of Tsai and Lo's scheme. However, besides its merits, we indicate that He et al.'s scheme suffers from both known session-specific temporary information attack and private key leakage. Additionally, these three anonymous schemes have the key escrow problem since the trusted anchor is aware of entities' private key. Hence, to cover the existing issues, in this paper we propose a key establishment scheme that not only is free from the security challenges of the previous anonymous schemes and key escrow problem, but also is efficient in terms of both computational and communication costs. Finally, yet importantly, we present the performance analysis of our proposed scheme on a state-of-the-art advanced RISC machine (ARM) chip, namely NXP LPC1788, as a suitable hardware for the smart meters.

Security and privacy concerns necessitate the careful management of shared keys in the vehicle to grid (V2G) networks. To do so, in recent years, several interesting key agreement protocols have been proposed to be employed in the context of V2G networks. As the efficiency is of prime significance in V2G networks, many of these protocols have been designed to be as light as possible. Nevertheless, review of the previous works indicates that the existing lightweight schemes cannot provide the desired security properties. Furthermore, the existing secure protocols are not so proper to be used by computationally limited devices in the V2G networks. Therefore, in this article, by utilizing the efficient Chebyshev chaotic map-based public key cryptosystem, we propose an anonymous key agreement scheme, which can not only provide the expected security requirements, but also has a proper level of performance. To demonstrate the security of the proposed scheme, we present a rigorous formal security proof using the random oracle model. In addition, to show its outperformance, we both compare it with several recently published well-known schemes and perform the experimental study. In general, the results indicate the efficiency of the proposed protocol in comparison to the related ones.