The Internet of Things (IoT) includes a multitude of heterogeneous devices that operate on a large-scale, dynamic, and self-organizing swarm, making it an interesting target for attackers. Swarm attestation is a means to satisfy the security requirement in which a prover entity attempts to demonstrate its honesty to a verifier in the swarm. To date, various models have been proposed for swarm attestation in which public key infrastructure is used for authentication between different devices. However, public key infrastructure has some disadvantages, such as the problem of expired certification, which adds additional overhead to the system. Most previous works, have not explored key agreement and authentication subjects for swarm attestation. Therefore, in this paper, we propose a high speed and low-cost method for authentication and key agreement in swarm attestation. We also conduct a security evaluation of the proposed security protocol, including the ProVerif as a verification tool and also investigate the resistance of the proposed scheme against various well-known attacks. Informal security analysis shows that the proposed protocol is secure. The computational costs are estimated and evaluated through implementation on the NanoPi Fire3 platform. Our results indicate that the cost of our protocol is reasonable and it is suitable for swarm attestation.

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.

In smart grid, key exchange protocols play a vital role in providing secure channels to read consumption reports from the smart meters. Thus far, several key exchange schemes have been proposed for the networked smart meters. However, for the first time, quite recently, Sha et al. have presented an interesting two-phase authentication and key agreement scheme that exclusively aims at the isolated smart meters. In their scheme, they have properly addressed the computationally constrained smart meters by offering a lightweight key exchange protocol. Nevertheless, after meticulous observation, we found that their proposed scheme cannot resist the desynchronization attack and cannot provide the perfect forward secrecy. Moreover, there are some other weaknesses in their scheme. As a result, to tackle the existing security challenges, in this paper, by utilization of the extended Chebyshev chaotic maps, we propose an efficient anonymous password-authenticated key exchange protocol that not only is free from the limitations of Sha et al.'s scheme, but also provides the anonymity. The security analysis in the random oracle model and using the widely accepted ProVerif tool besides the computational and communication costs comparison demonstrate that the proposed scheme has reached a proper level of efficiency without sacrificing the desired security properties.

Investigating the literature reveals the fact that the key management protocols play a vital role in protecting the security and privacy of medical data in telecare medical information systems. Recently, Tseng et al. have proposed an interesting elliptic curve cryptosystem (ECC) based self-certified key management scheme that can yield secure channel for the communications of secure sensors (cluster members) and access point (cluster head). After careful consideration, we found that their scheme suffers from the cluster head impersonation, replay, and key replicating attacks. In addition, in the secure session phase, there are some errata and a point multiplication that is undefined in the ECC and hence is mathematically incorrect. Finally, yet importantly, their presented scheme has been adopted for a similar application by other authors with the same problem. Therefore, in this paper, we first try to elaborate the existing errata and security threats. Second, we propose a modified version, which is free from the challenges of their scheme. Eventually, we propose a novel anonymous ECC-based self-certified two-factor key management scheme that not only provides the desired security features, but also has much better efficiency than several recently-published schemes, such as the presented one by Tseng et al. Our formal security verification and proof besides the efficiency analysis support our claim.