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Three-party password-based authenticated key exchange (3PAKE) protocols allow two clients to establish a secure session key through a server over an insecure channel. Recently, the 3PAKE protocols have been developed based on Chebyshev chaotic maps, in which the clients utilize smart cards to login into the server and employ server’s public key to ensure the identity of the server or symmetric cryptosystems to encrypt the messages. However, this paper describes an efficient chaos-based 3PAKE protocol without smart cards, which requires neither server’s public key nor symmetric cryptosystems. The security of the proposed 3PAKE protocol is proved in the random oracle model using the chaos-based decisional Diffie–Hellman assumption. In comparison with the existing chaos-based 3PAKE protocols, our protocol individually provides better performance in terms of communication, computation, and security aspects, and is supported by the formal proof in the random oracle model.

Recently, Gong et al. (Nonlinear Dyn, doi: 10.1007/s11071-012-0628-3 , 2012 ) proposed a chaotic map-based key agreement protocol without using smart cards. They claimed that the protocol is secure against password-guessing attacks. However, we show that Gong et al.’s protocol is vulnerable to partition attacks, whereby the adversary can guess the correct password off-line. We also demonstrate that the protocol suffers from a a stolen-verifier attack along with password change pitfalls. Thereafter, we proposed an chaotic map-based key agreement protocol without using smart cards to conquer the mentioned weaknesses. The security analysis of the proposed protocol shows that it is suitable for the applications with higher security requirement.

This paper investigates the dynamic response of functionally graded piezoelectric plates using the finite element method based on first-order shear deformation theory. The plates are composed of materials with properties that vary across their thickness, following a simple power-law relationship with the volume fraction of the constituents. Different boundary conditions and configurations, such as FG plates with piezoelectric layers and FGP plates with piezoelectric layers, are considered to analyze the dynamic behavior of functionally graded piezoelectric material (FGPM) plates under mechanical and electrical loadings. Comparisons with previous studies validate the accuracy of the obtained results. Furthermore, the effects of various parameters, such as the power-law index, maximum displacement from static analysis, maximum displacement in the first vibration mode, and others, on the dynamic response of FGM and FGPM plates with piezoelectric layers are investigated. The results demonstrate the influence of different power-law exponents and piezoelectric layers on plate behavior. The findings show that the maximum static and dynamic deflections of the plate vary with the power-law index, but their ratio remains constant for all values of “n”. Additionally, the effect of electrical loading on the dynamic response of FGP plates is examined. The study reveals that the maximum dynamic displacement of the plates increases with the power-law constant under electrical loading. Overall, this study provides valuable insights into the dynamic response of functionally graded piezoelectric plates, contributing to the understanding and design of such structures in various engineering applications subjected to dynamic loading.

Cloud storage has significantly reduced data management costs for data owners. However, loss of physical control over the data after outsourcing, triggers some security concerns such as data integrity. Provable Data Possession (PDP) protocols, enable data owners to audit the integrity of their outsourced data without the need to retrieve the file from cloud server. However, most existing PDP schemes require resource-constrained users to perform costly operations for generating metadata on file blocks. In online/offline PDP mechanisms introduced most recently, the user’s computation is divided into online/offline phases, where the costly operations are allowed to be carried out in the offline phase. The users only require to perform lightweight operations in the real-time online phase. In this paper, we propose an identity-based (ID-based) online/offline PDP protocol which not only has lightweight computations at the users side, but also removes the complex certificate management/verification costs caused by expensive Public Key Infrastructure. The proposed scheme is based on an ID-based online/offline signature designed in this paper. The protocol is proven to be secure against a malicious cloud server in the random oracle model. We also prove the privacy preserving property of the protocol in the sense that it leaks no information of the outsourced data to the public verifier during the protocol execution. Moreover, our mechanism supports batch verification of multiple auditing tasks and fully dynamic data operations, efficiently. Experimental results demonstrate fine efficiency of our scheme in comparison to the recent proposals.

In this paper, the relay selection problem for two-way relaying networks in single and dual relay selection schemes is addressed. In the single relay selection scheme, the problem is to find the best relay node which leads to the minimum bit error rate (BER) between the source nodes. We then derive the upper and lower bounds for the signal to noise ratio and the end-to-end BER of this scheme. In the dual relay selection scheme, the problem is to find the two best relay nodes. In this scheme, Alamouti space-time coding and physical layer network coding are utilized in order to achieve the higher performance. For improving the system performance, optimal power allocation between the sources and the relays is considered based on decreasing the BER. Finally, simulation results are provided to verify the correctness of analytical results.

Radio transmissions in millimeter wave (mmWave) bands have gained significant interest for applications demanding precise device localization and trajectory estimation. This paper explores novel neural network (NN) architectures suitable for trajectory estimation and path determination in a mmWave multiple-input multiple-output (MIMO) outdoor system based on localization data from beamformed fingerprint (BFF). The NN architecture captures sequences of BFF signals from different users, and through the application of learning mechanisms, subsequently estimate their trajectories. In turn, this information is employed to find the shortest path to the target, thereby enabling more efficient navigation. Specifically, we propose a two-stage procedure for trajectory estimation and optimal path finding. In the first stage, a transformer network (TN) based on attention mechanisms is developed to predict trajectories of wireless devices using BFF sequences captured in a mmWave MIMO outdoor system. In the second stage, a novel algorithm based on Informed Rapidly-exploring Random Trees (iRRT*) is employed to determine the optimal path to target locations using trajectory estimates derived in the first stage. The effectiveness of the proposed schemes is validated through numerical experiments, using a comprehensive dataset of radio measurements, generated using ray tracing simulations to model outdoor propagation at 28 GHz. We show that our proposed TN-based trajectory estimator outperforms other methods from the recent literature and can successfully generalize to new trajectories outside the training set. Furthermore, our proposed iRRT* algorithm is able to consistently provide the shortest path to the target.

Recently, Chou et al. (J Supercomput 66(2): 973–988, 2013) Rroposed two identity-based key exchange protocols using elliptic curves for mobile environments. The first one is an two-party authentication key exchange protocol to establish a session key between a client and a remote server. The second one is an extended version for three-party setting to establish a session key between two clients with the help of a trusted server. However, this paper finds the first one vulnerable to impersonation attack and key-compromise impersonation attack, and the second one insecure against impersonation attack. To overcome the weaknesses, we propose an improved identity-based two-party authentication key exchange protocol using elliptic curves. The rigorous analysis shows that our scheme achieves more security than related protocols.

To guarantee the secure access by authorized subscribers in mobile pay-TV systems, user authentication is required. User authentication is a security mechanism used to verify the identity of a legal subscriber. In 2012, Yeh and Tsaur proposed an authentication scheme for access control in mobile pay-TV systems to improve the Sun and Leu’s scheme. Yeh and Tsaur claimed that their scheme meets all security requirements for mobile pay-TV systems. However, this paper indicates that Yeh and Tsaur’s scheme suffers from some critical weaknesses. An attacker without knowing secret information can successfully impersonate both mobile sets and head-end system. As a remedy, we propose an improved authentication scheme for mobile pay-TV systems using bilinear pairings. The proposed scheme maintains the merits and covers the demerits of the previous schemes, and provides a higher level of the efficiency for mobile pay-TV systems.

This study investigates the performance of two‐way decode‐and‐forward (DF) relaying networks, considering transmissions over independent but not necessarily identically distributed (i.n.i.d.) Rayleigh fading channels, in the presence of multiple co‐channel interferers at both the relay and end‐source nodes. Both asymmetrical and symmetrical cases, of whether the channels from source terminals to the relay are identically distributed or not, are considered. Specifically, closed‐form expressions for the cumulative distribution function of the equivalent signal‐to‐interference‐plus‐noise ratio (SINR) in different cases are derived, based on which the exact symbol error probability (SEP) and the systems’ achievable rate are derived and analysed. Based on the analytic results, the authors study the impacts of system parameters, such as interference power and number of interferers on the performance of the system. Furthermore, the system behavior at high signal‐to‐noise ratio (SNR) values is studied via deriving the asymptotic SEP. The results of this study are attested through Monte Carlo simulations.

Recently, Tso proposed a three-party password-based authenticated key exchange (3PAKE) protocol. This protocol allows two clients to authenticate each other and establish a secure session key through a server over an insecure channel. The main security goals of such protocols are authentication and privacy. However, we show that Tso’s protocol achieves neither authentication goal nor privacy goal. In this paper, we indicate that the privacy and authentication goals of Tso’s protocol will be broken by off-line password guessing attack and impersonation attack, respectively. To overcome the weaknesses, we propose an improved 3PAKE protocol to achieve more security and performance than related protocols. The security of the proposed improved protocol is proved in random oracle model.