With the deep integration of the Industrial Internet of Things (IIoT) into critical domains such as intelligent manufacturing and energy management, its cybersecurity risks are increasing. Traditional intrusion detection algorithms struggle to effectively handle the heterogeneity, sparsity, and complexity of intrusion patterns in IIoT systems, leading to performance limitations and the need for improved detection capabilities through new algorithms. Therefore, this paper proposes an intrusion detection framework based on Granular-Ball Intuitionistic Fuzzy Sets (GBIFS). The proposed framework introduces a novel class-wise granular-ball generation method integrated into intuitionistic fuzzy sets, improving intrusion pattern analysis by combining the adaptive multi-granularity representation of granular-ball theory with the capability of intuitionistic fuzzy sets to handle uncertainty. In this framework, the proposed generation method is used to construct Granular-Ball Intuitionistic Fuzzy Patterns (GBIFP) that conform to the feature distribution of IIoT data, and then an improved intuitionistic fuzzy distance metric is introduced to achieve precise classification between normal traffic and attack behavior. Extensive experiments on IIoT intrusion detection datasets (e.g., X-IIoTID, TON-IOT, WUSTL-IIOT) and classical network intrusion detection datasets (e.g., KDDCUP99, NSL-KDD, UNSW-NB15) demonstrate the superior performance of the proposed framework under heterogeneous and sparse data conditions. The GBIFS framework proposed in this paper significantly enhances the accuracy and efficiency of intrusion detection, providing a scalable and robust solution for IIoT cybersecurity. Code is available athttps://github.com/QzEylsia7/Intrusion-Detection-using-Granular-Ball-Intuitionistic-Fuzzy-Sets

Accurate traffic flow measurement is essential for the development of smart cities, yet the deployment of ubiquitous monitoring sensors using traditional methods is often cost-prohibitive. This paper proposes an innovative entropy-aware masked autoencoder framework, namely TMAE, for low-cost traffic flow inference. TMAE leverages a small number of selectively measured regions with few deployed sensors to infer traffic flow across entire urban areas, incorporating prior knowledge from road distribution maps. Specifically, TMAE employs a shared encoder to process traffic flow context, using self-attention scores to identify the importance of each region and guide a masking policy that retains regions rich in traffic flow information. The road distribution map, reflecting inherent traffic flow patterns, is incorporated as prior knowledge by substituting masked tokens during training. A cross-attention mechanism in the decoder further refines inference, where embeddings from the road distribution map serve as queries, and retained visible patches act as keys and values. Additionally, regional traffic entropy is introduced to quantify the information richness of each region, enabling the selection of minimal measurement regions to optimize inference for other areas. Extensive experiments conducted on datasets from various cities demonstrate the effectiveness and efficiency of TMAE, highlighting its potential as a scalable solution for low-cost traffic flow inference in urban environments. The source code of this work is released at https://github.com/TextGraph/TMAE.

With the emergence of edge computing, there is a growing need for advanced technologies capable of real-time, efficient processing of complex data on edge devices, particularly in mobile health systems handling pathological images. On edge computing devices, the lightweighting of models and reduction of computational requirements not only save resources but also increase inference speed. Although many lightweight models and methods have been proposed in recent years, they still face many common challenges. This article introduces a novel convolution operation, Dynamic Scalable Convolution (DSC), which optimizes computational resources and accelerates inference on edge computing devices. DSC is shown to outperform traditional convolution methods in terms of parameter efficiency, computational speed, and overall performance, through comparative analyses in computer vision tasks like image classification and semantic segmentation. Experimental results demonstrate the significant potential of DSC in enhancing deep neural networks, particularly for edge computing applications in smart devices and remote healthcare, where it addresses the challenge of limited resources by reducing computational demands and improving inference speed. By integrating advanced convolution technology and edge computing applications, DSC offers a promising approach to support the rapidly developing mobile health field, especially in enhancing remote healthcare delivery through mobile multimedia communication.

It is of the utmost importance to achieve flexible and fine-grained access control of electronic health records (EHR) in smart elderly healthcare (SEH) for providing high-quality healthcare services for the elderly and protecting their privacy simultaneously. In this paper, a flexible, fine-grained, and elderly-centric access control scheme is presented for EHR data in SEH. In the proposed scheme, Ciphertext Policy Attribute Based Encryption (CP-ABE), permission token, dual-key regression, and blockchain techniques are leveraged to realize multi-dimensional access control of EHR data in terms of data generation time, data user properties, access times, and access period. Moreover, a novel token segmentation algorithm is designed to transfer access rights between doctors efficiently for multi-party diagnosis and treatment. Since the elderly can define the attributes of users accessing his/her EHR data, the access number, the access time, and the access range of data from the time dimension of data generation with the cooperation of the Smart Elderly Healthcare (SEH) institution, the privacy of EHR data of the elderly is well protected. The security analysis demonstrates that our scheme can achieve EHR ciphertext indistinguishability under chosen-plaintext attacks and token unlinkability and unforgeability under data users’ collusion attacks. The experimental results show that our scheme performs well in terms of time cost and computational overhead.

Internet of Things (IoT) is one of the most representative application scenarios in the 5G and 6G era. The concurrent access of massive IoT devices definitely poses enormous communication, computation, and certificate management challenges to the wireless authentication. Moreover, the emergence of quantum computing makes classical cryptography-based authentication protocols, such as 5G-AKA, more easier to be broken. Facing the challenges posed by the massive concurrent authentication and quantum attacks, this paper proposes a lattice cryptography based group authentication scheme, where lattice-based aggregate signature algorithm and identity-based encryption (IBE) are leveraged to achieve simultaneous authentication of concurrent accessed devices. The proposed authentication scheme eliminates the process of public key certificate management, greatly reducing the storage overhead of core network. Moreover, the utilization of lattice cryptography enables the resistance of quantum attacks. The proposed solution does not rely on additional security assumptions such as security channel or trusted group center, making it more flexible to be deployed in actual network scenario. Finally, formal security analysis of the proposed protocol is provided with the tool ProVerif. It is demonstrated that the proposed protocol can satisfy the goals of identity privacy, authentication, data confidentiality and forward secrecy. In addition, compared with existing advanced solutions, the outperformance of the proposed scheme in terms of computation overhead, signaling overhead, communication overhead, and security properties is validated with simulations.

Task scheduling in large-scale industrial Internet of Things (IIoT) is characterized by the presence of diverse resources and the requirement for efficient and synchronized processing across distributed edge clouds, raising a significant challenge. This paper proposes a task scheduling framework across edge clouds, namely LsiA3CS, which employs deep reinforcement learning (DRL) and heuristic guidance to achieve distributed, asynchronous task scheduling for large-scale IIoT. Specifically, the Markov game-based model and the asynchronous advantage actor-critic (A3C) algorithm are leveraged to orchestrate diverse computational resources, effectively balancing workloads and reducing communication latency. Moreover, the incorporation of heuristic policy annealing and action masking techniques further refines the adaptability of the proposed framework to the unpredictable requirements of large-scale IIoT systems. Real-world task datasets are utilized to conduct extensive experimental evaluations on a simulated large-scale multi-edge cloud IIoT. The results shows that LsiA3CS significantly reduces task completion times and energy consumption while managing unpredictable task arrivals and variable resource capacities.

In this paper, we propose a novel Multi-keyword Fuzzy Symmetric Searchable Encryption (SSE) with patterns hidden, namely MFSSE. In MFSSE, the search trapdoor can be modified differently each time even if the keywords are the same when performing multi-keyword search to prevent the leakage of search patterns. Moreover, MFSSE modifies the search trapdoor by introducing random false negative and false positive errors to resist access pattern leakage. Furthermore, MFSSE utilizes efficient cryptographic algorithms (e.g., Locality-Sensitive Hashing) and lightweight operations (such as, integer addition, matrix multiplication, etc.) to minimize computational and communication, and storage overheads on mobile devices while meeting security and functional requirements. Specifically, its query process requires only a single round of communication, in which, the communication cost is linearly related to the number of the documents in the database, and is independent of the total number of keywords and the number of queried keywords; its computational complexity for matching a document is$O(1)$; and it requires only a small amount of fixed local storage (i.e., secret key) to be suitable for mobile scenarios. The experimental results demonstrate that MFSSE can prevent the leakage of access patterns and search patterns, while keeping a low communication and computation overheads.

In a blockchain-based data trading platform, data users can purchase data sets and computing power through encrypted smart contracts. The security of smart contracts is important as it relates to that of the data platform. However, due to the inability to apply to detection rules with complex structures and the inefficiency of detection, existing malicious code detection methods are not suitable for the encrypted smart contracts in blockchain-based data trading platforms with high transaction rate requirements. In this paper, a practical and privacy-preserving malicious code detection method is proposed for encrypted smart contract in blockchain-based data trading platform. Specifically, we design two kinds of miners to act as the malicious rule processor and the detector respectively for inspecting the encrypted smart contract. The rule processor generates an obfuscated map with the original open-source malicious rule set. The detector performs a malicious inspection algorithm by inputting the obfuscated map and the randomized tokens, where the latter is generated from smart contract. Then, we theoretically analyze the security syntax of the proposed method. The analysis results demonstrate the proposed scheme can achieve$\mathcal {L}$-secure against adaptive attacks. Extensive experiments are carried out through the open-source real rule sets, which show that the proposed scheme can reduce communication time and communication overhead.

Histopathology diagnosis is an important standard for breast tumors identifying. However, histopathology image analysis is complex, tedious and error-prone, due to the super-resolution image. In recent years, deep learning technology has been successfully applied to histopathology image analysis and made great progress. The well-known deep neural networks usually have tens of million parameters, which consume much memory to deploy the state-of-the-art model. In addition, deep neural networks rely on high-performance hardware resources, which impede the deployment of state-of-the-art model on portable equipment. In this work, a novel framework which consists of a weight accumulation method and a lightweight fast neural network (FastNet) was proposed for tumor fast identification (TFI) in mobile computer-assisted devices. The weight accumulation method was designed to obtain the tissue mask regions of interest and remove the useless background area in histopathology images, which greatly reduces the redundant computation cost. Furthermore, we proposed the lightweight FastNet to improve the computational efficiency on mobile devices. A novel attention loss function was designed and applied in FastNet. The attention loss function pays more attention on the positive samples and the indistinguishable samples, which greatly improves performance. The proposed FastNet was compared with three state-of-the-art methods commonly used for image classification and object detection. Experimental results indicated that FastNet achieves highest recall of 96.94%, highest F1 score of 97.33% and highest accuracy of 97.34%, besides least trainable parameters of 0.22M and smallest floating point operations of 210M FLOPs.

In the area of medical image segmentation, the spatial information can be further used to enhance the image segmentation performance. And the 3D convolution is mainly used to better utilize the spatial information. However, how to better utilize the spatial information in the 2D convolution is still a challenging task. In this paper, we propose an image segmentation network based on reinforcement learning (RLSegNet), which can translate the image segmentation process into a serial of decision-making problem. The proposed RLSegNet is a U-shaped network, which is composed of three components: the feature extraction network, the Mask Prediction Network (MPNet), and the up-sampling network with the cascade attention module. The deep semantic feature in the image is first extracted by adopting the feature extraction network. Then, the Mask Prediction Network (MPNet) is proposed to generate the prediction mask for the current frame based on the prior knowledge (segmentation result). And the proposed cascade attention module is mainly used to generate the weighted feature mask so that the up-sampling network pays more attention to the interesting region. Specifically, the state, action and reward used in the reinforcement learning are redesigned in the proposed RLSegNet to translate the segmentation process as the decision-making process, which performs as the reinforcement learning to realize the brain tumor segmentation. Extensive experiments are conducted on the BRATS 2015 dataset to evaluate the proposed RLSegNet. The experimental results demonstrate that the proposed method can achieve a better segmentation performance, in comparison with other state-of-the-art methods.

Forecasting the inflow of reservoirs plays an essential role in the hydropower industry. Existing studies are either limited to point estimates or inefficient in capturing higher-order dynamic correlations across data. It is nevertheless necessary to estimate data uncertainty in actual dam operation. This article presents a novel inflow prediction method that exploits generative flows to model complex multivariate hydrological time series. Our flow-to-flow method (F2F) augments the deterministic models with the normalizing flow-based generative networks to explicitly capture the multivariate correlations and approximate the predictive inflow distribution. Besides, F2F can quantify the prediction uncertainty to help interpret model behavior and predicted results while facilitating safety-critical decision-making on real-time reservoir operation. We conduct extensive experiments on real-world datasets collected from large-scale hydropower stations. The experimental results show that our method consistently outperforms existing methods while accounting for uncertain observations and providing tractable multistep ahead inflow forecasts.

To ensure the security of Internet of Things (IoT) communications, one can use deep packet inspection (DPI) on network middleboxes to detect and mitigate anomalies and suspicious activities in network traffic of IoT, although doing so over encrypted traffic is challenging. Therefore, in this article, an efficient and privacy-preserving encrypted traffic detection scheme is proposed. The scheme uses only lightweight cryptographic operations (i.e., symmetric encryption, hash functions, and pseudorandom functions) to achieve both privacy and security within an inspection round. A dispute resolution mechanism is also designed to address potential disputes between client(s) and server(s). We also present the corresponding security proof and experimental evaluation, which demonstrate that our proposed scheme achieves strong security and privacy preservation and good performance.

The integration of the space–air–ground-integrated network and the Internet of Vehicles (IoV) enables the IoV to achieve full network coverage and better network performance. However, the large scale of the network and the complex cooperation mechanism make the credibility of the nodes in the network and the service delivery questioned. In this article, the hardware trusted module is used as the root of trust to build the trust chain and the trusted running environment and provide protection and trusted state attestation for services. In order to overcome the large-scale and high-concurrency performance bottlenecks in the remote verification of trusted states in the IoV, a novel batch remote approach for trusted states is proposed. The simulation results show that the proposed approach can effectively attest to the trusted state of each network node and virtual service in the IoV and enhance the trustworthiness of the network.

Internet of Things (IoT) is vulnerable to various cyber attacks due to the massive deployment of IoT devices and the openness of wireless environments. In this article, taking IoT devices as the network resources competed between an attacker and a defender, we study the modeling and analysis of network resource competition in an attack-defense game. The attacker and defender inject different competition strength in each IoT device as their strategies. As a result, the security state of each IoT device will change, which is captured by differential equations. To study the interaction between the attacker and defender and the evolution of the system security states, a zero-sum differential game is formulated by modeling the competition of IoT devices. To achieve the equilibrium of the formulated differential game, optimal control theory is employed to solve the optimization problems of players. Further, a Gauss–Seidel-like implicit finite-difference method is utilized to obtain the saddle point strategy. Finally, numerical results are provided to demonstrate the evolution of network resource competition between the attacker and defender. The results show that our formulated model can effectively and accurately characterize the evolution of the system security states with strategic interactions between the attacker and defender.

In this paper, a novel message authentication model using the same key over wiretap channel is proposed to achieveinformation-theoretic security. Specifically, in the proposed model, there is a discrete memoryless channelW1:X→Ybetween transmitter Alice and receiver Bob, while an attacker Oscar is connected with Alice via discrete memoryless channelW2:X→Z. Alice encodes messageMto codeword (S,Xn), using an encoding function with secret keyK. Then,Sis sent to Bob over a one-way noiseless channel (fully controlled by Oscar), andXnis sent over the wiretap channel, sayX→(Y,Z). Building on this model, a new message authentication scheme is proposed. The scheme incorporates a secure channel coding, which uses random coding techniques to detect man-in-the-middle (MITM) attacks. The authentication channel capacity is studied in a specific channel model whenW2is not less noisy thanW1. We theoretically demonstrate that the authentication channel capacity is much larger than the secrecy capacity, since Bob does not need to recover information transmitted over the noisy channel.

As an emerging technology, industrial Internet of Things (IIoT) connects massive sensors and actuators to empower industrial sectors being smart, autonomous, efficient, and safety. However, due the large number of build-in sensors of IIoT smart devices, the IIoT systems are vulnerable to side-channel attack. In this article, a novel side-channel-based passwords cracking system, namely MAGLeak, is proposed to recognize the victim's passwords by leveraging accelerometer, gyroscope, and magnetometer of IIoT touch-screen smart device. Specifically, an event-driven data collection method is proposed to ensure that the user's keystroke behavior can be reflected accurately by the obtained measurements of three sensors. Moreover, random forest algorithm is leveraged for the recognition module, followed by a data preprocessing process. Extensive experimental results demonstrate that MAGLeak achieves a high recognition accuracy under small training dataset, e.g., achieving recognition accuracy 98% of each single key for 2000 training samples.

As a lightweight, flexible, and high-performance operating system virtualization, containers are used to speed up the big data platform. However, due to the imperfection of the resource isolation mechanism and the property of shared kernel, the meltdown and spectre attacks can lead to information leakage of kernel space and coresident containers. In this article, a noise-resilient and real-time detection system, named ContainerGuard, is proposed to detect meltdown and spectre attacks in the container-based big data platform. ContainerGuard uses a nonintrusive manner to collect lifecycle multivariate time-series performance event data of processes in containers and then uses ensemble of variational autoencoders as generative neural networks to learn the robust representations of normal patterns. Therefore, ContainerGuard meets the urgent need for information protection in the container-based big data platform. Our evaluations using real-world datasets show that ContainerGuard achieves excellent detection performance and only introduces about 4.5% of running performance overhead to the platform.

Resisting the adversarial sample attack on encrypted traffic is a challenging task in the Intelligent Transportation System. This paper focuses on the classification, adversarial samples attack and defense method for the encrypted traffic. To be more specific, the one-dimensional encrypted traffic data is firstly translated into the two-dimensional images for further utilization. Then different classification networks based on the deep learning algorithm are adopted to classify the encrypted traffic data. Moreover, various adversarial sample generation methods are employed to generate the adversarial sample to implement the attacking process on the classification network. Furthermore, the passive and active defense method are proposed to resist the adversarial sample attack: 1) the passive defense is used to denoise the perturbation in the adversarial sample and to restore to the original image; and 2) the active defense is used to resist the adversarial sample attack by leveraging the adversarial training method, which can improve the robustness of the classification network. We conduct the extensive experiments on the ISCXVPN2016 dataset to evaluate the effectiveness of classification, adversarial sample attacking and defending.

Internet of Medical Things (IoMT) can connect many medical imaging equipment to the medical information network to facilitate the process of diagnosing and treating doctors. As medical image contains sensitive information, it is of importance yet very challenging to safeguard the privacy or security of the patient. In this work, a deep-learning-based image encryption and decryption network (DeepEDN) is proposed to fulfill the process of encrypting and decrypting the medical image. Specifically, in DeepEDN, the cycle-generative adversarial network (Cycle-GAN) is employed as the main learning network to transfer the medical image from its original domain into the target domain. The target domain is regarded as “hidden factors” to guide the learning model for realizing the encryption. The encrypted image is restored to the original (plaintext) image through a reconstruction network to achieve image decryption. In order to facilitate the data mining directly from the privacy-protected environment, a region of interest (ROI)-mining network is proposed to extract the interesting object from the encrypted image. The proposed DeepEDN is evaluated on the chest X-ray data set. Extensive experimental results and security analysis show that the proposed method can achieve a high level of security with a good performance in efficiency.

The emerging of healthcare Industrial Internet of Things (HealthIIoT) cannot only facilitate high-quality care services for patients but also enable efficient telemedicine platform for healthcare practitioners. However, it faces several fundamental security and privacy challenges, such as secure fine-grained data delivery, privacy preserving keyword-based ciphertext retrieval, malicious key delegation, and efficiency of the system. To combat these issues, we propose a privacy-aware and traceable fine-grained system (PTFS) for secure data delivery in cloud-assisted HealthIIoT. Compared to the existing solutions that only implement some of the preceding features, the proposed solution enables secure fine-grained data delivery, privacy-preserving data retrieval, efficient encryption and decryption operations, and trace of malicious key delegation simultaneously. For security analysis, rigorous proofs of the proposed scheme are provided to prove its security. In addition, extensive simulations and experiments are conducted for performance evaluation, which demonstrate the feasibility and effectiveness of PTFS.

As one of the most important applications of industrial Internet of Things, intelligent transportation system aims to improve the efficiency and safety of transportation networks. In this article, we propose a novel Bayesian framework entitled variational graph recurrent attention neural networks (VGRAN) for robust traffic forecasting. It captures time-varying road-sensor readings through dynamic graph convolution operations and is capable of learning latent variables regarding the sensor representation and traffic sequences. The proposed probabilistic method is a more flexible generative model considering the stochasticity of sensor attributes and temporal traffic correlations. Moreover, it enables efficient variational inference and faithful modeling of implicit posteriors of traffic data, which are usually irregular, spatial correlated, and multiple temporal dependents. Extensive experiments conducted on two real-world traffic datasets demonstrate that the proposed VGRAN model outperforms state-of-the-art approaches while capturing innate ambiguity of the predicted results.

Key agreement is one the most essential steps when applying cryptographic techniques to secure device‐to‐device (D2D) communications. Recently, several PHY‐based solutions have been proposed by leveraging the channel gains as a common randomness source for key extraction in wireless networks. However, these schemes usually suffer a low rate of key generation and low entropy of generated key and rely on the mobility of devices. In this paper, a novel secret key extraction protocol is proposed by using interference in wireless D2D fading channel. It establishes symmetrical keys for two wireless devices by measuring channel gains and utilizing artificial jamming sent by the third party to change the measured value of channel gains. We give a theoretically reachable key rate of the proposed scheme from the viewpoint of the information theory. It shows that the proposed scheme can make hundred times performance gain than the existing approaches theoretically. Experimental results also demonstrate that the proposed scheme can achieve a secure key distribution with a higher key rate and key entropy compared with the existing schemes.

In this paper, we investigate physical (PHY) layer message authentication to combat adversaries with infinite computational capacity. Specifically, a PHY-layer authentication framework over a wiretap channel (W1; W2) is proposed to achieve information theoretic security with the same key. We develop a theorem to reveal the requirements/conditions for the authentication framework to be information-theoretic secure for authenticating a polynomial number of messages in terms of n. Based on this theorem, we design an authentication protocol that can guarantee the security requirements, and prove its authentication rate can approach infinity when n goes to infinity. Furthermore, we design and implement a feasible and efficient message authentication protocol over binary symmetric wiretap channel (BSWC) by using Linear Feedback Shifting Register based (LFSR-based) hash functions and strong secure polar code. Through extensive simulations, it is demonstrated that the proposed protocol can achieve high authentication rate, with low time cost and authentication error rate.

With emergence of Internet of Things (IoT), wireless traffic has grown dramatically, posing severe strain on core network and backhaul bandwidth. Proactive caching in mobile edge computing systems can not only efficiently mitigate the traffic congestion and relieve burden of backhaul but also can reduce the service latency for end devices. However, proactive caching heavily relies on the prediction accuracy of content popularity, which is typically unknown and change over time. In this paper, we propose an online proactive caching scheme based on bidirectional deep recurrent neural network (BRNN) model to predict time-series content requests and update edge caching accordingly. Specifically, on the first layer, a 1-D convolution neural network (CNN) is devised to reduce the computational costs. Then, BRNN is employed to predict time-varying requests from users. Afterward, a fully connected neural network (FCNN) is harnessed to learn and sample predicts from the BRNN. Finally, we conduct experiments based on real datasets, which demonstrate that the proposed approach can achieve considerably high prediction accuracy and significantly improve content hit rate of end devices.

Smart homes expects to improve the convenience, comfort, and energy efficiency of the residents by connecting and controlling various appliances. As the personal information and computing hub for smart homes, smartphones allow people to monitor and control their homes anytime and anywhere. Therefore, the security and privacy of smartphones and the stored data are crucial in smart homes. To protect smartphones from potential attacks, various built-in sensors can be utilized for user authentication/identification and access control to achieve enhanced security. In this paper, we propose a framework, smartphone sensor user identification (SSUI), in order to facilitate user identification based on the relationships between different types of sensor data and smartphone users. Specifically in SSUI, the time and frequency features are extracted and learned separately using convolution neural network (CNN). The CNN outputs are then processed using recurrent neural network, according to several time bins. Using both of our own dataset (collected from 17 participants) and a publicly available dataset (i.e., Heterogeneity Dataset for Human Activity Recognition), we demonstrate the effectiveness of the proposed SSUI framework, where we achieve an accuracy rate of over 91.45% in various scenarios.

Internet of Things (IoT) security becomes of great importance, as IoT is the foundation for many emerging services. To safeguard IoT security, cryptosystems at upper layer relying on sophisticated key management alone can face many challenges due to the massive deployment of resource constrained machine-type communication (MTC) devices. Physical layer (PHY) security can complement and enhance IoT security, by exploiting the characteristics of the bottom layer. In PHY security, channel state information (CSI) estimated through reverse pilot training is essential for the sender to select appropriate beamforming/precoder, which however is also vulnerable to adversaries. An adversary can actively launch pilot contamination attacks to affect the channel estimation and improve its signal reception quality. In this paper, we propose a relay-aided vectorized (RAV) secure transmission scheme, to safeguard the downlink communication in IoT networks under potential pilot contamination attacks. The proposed scheme does not distinguish the pilot sequences sent from an adversary and the receiver; and the sender utilizes what it receives to estimate the CSI for beamforming/precoder design. Then, a set of data symbols are presuperposed using a random complex matrix to form signal vectors to send. Through cooperation with a relay, the signal vectors can be recovered by the intended receiver whereas the adversary or the relay cannot, as proved through security analysis. The simulation results also demonstrate that the bit error rate (BER) of the adversary is 0.5 regardless of its channel quality, indicating perfect secrecy is achieved.

In this paper, we study physical layer message authentication with perfect security for wireless networks, regardless of the computational power of adversaries. Specifically, we propose an efficient and feasible authentication scheme based on low-density parity-check (LDPC) codes and ϵ-AU2hash functions over binary-input wiretap channel. First, a multimessage authentication scheme for noiseless main channel case is presented by leveraging a novel ϵ-AU2hash function family and the dual of large-girth LDPC codes. Concretely, the sender Alice first generates a message tag T with message M and key K by using a lightweight ϵ-AU2hash functions; then Alice encodes T to a codeword Xnwith the dual of large-girth LDPC codes; finally, Alice sends (M, Xn) to the receiver Bob noiselessly. An adversary Eve has infinite computational capacity, and he can obtain M and the output Znof the BEC with input Xn. Then, an authentication scheme over binary erasure channel and binary-input wiretapper's channel is further developed, which can reduce the noisy main channel case to noiseless main channel case by leveraging public discussion. We theoretically prove that, the proposed schemes are perfect secure if the number of attacks from Eve is upper bounded by a polynomial times in terms of n. Furthermore, the simulation results are provided to demonstrate that the proposed schemes can achieve high authentication rate with low time latency.

Next-generation intelligent transportation systems (ITS) are envisioned to greatly improve the transportation safety and efficiency by incorporating wireless communication and informatics technologies in the transportation system [1][2][3].As the cornerstone for ITS, vehicular communication networks enable vehicles to exchange information with other vehicles and the external environments and play a significant role in supporting a variety of services such as road safety, traffic management, and entertainment Vehicular communication networks face many technical challenges such as network scalability, highly dynamic topology, vulnerable wireless links, energy consumption of roadside units, poor network coverage, and bursty traffic.To address these challenges, various emerging technologies have been introduced in vehicular communication networks, such as software defined space-air-ground integrated vehicular network [4], fog computing in vehicular networks [5], droneassisted vehicular networks [6], and machine learning for data delivery [7].This special issue collection aims to present the vision, research, and dedicated efforts on the emerging technologies for vehicular communication networks.In this special issue, there are 15 submissions in total.After peerreview, 6 papers are selected for publication.The first article, "Software-Defined Collaborative Offloading for Heterogeneous Vehicular Networks" by W. Quan et al., proposes a software-defined collaborative offloading (SDCO) solution for heterogeneous vehicular networks, to efficiently manage the offloading nodes and paths.The offloading controller is equipped with two specific functions:

This paper proposes a Weighted fractional Fourier transform (WFRFT) based cooperation scheme to improve PHY layer security against eavesdropping in wireless communications. Rather than dissipating valuable transmission power to jam the eavesdropper, by leveraging the features of WFRFT, the information bearing signal can create “Artificial Noise” effect at the eavesdropper while imposing no effect on the legitimate receiver. Specifically, the proposed WFRFT based cooperation is performed in a two-phase manner, whereby the source first broadcasts its message to the intermediate nodes which then perform WFRFT operation to relay the message to the destination, with the objective of boosting the secrecy rate of the source-destination pair. Simulation results are provided, which demonstrate that the WFRFT-based user cooperation scheme can acehieve a significant performance gain, in terms of secrecy ergodic capacity, compared with conventional security-oriented user cooperation schemes.

In this paper, we investigate multi-message authentication to combat adversaries with infinite computational capacity. An authentication framework over a wiretap channel (W_1, W_2) is proposed to achieve information-theoretic security with the same key. The proposed framework bridges the two research areas in physical (PHY) layer security: secure transmission and message authentication. Specifically, the sender Alice first transmits message M to the receiver Bob over (W_1, W_2) with an error correction code; then Alice employs a hash function (i.e., ε-AWU_2 hash functions) to generate a message tag S of message M using key K, and encodes S to a codeword X^n by leveraging an existing strongly secure channel coding with exponentially small (in code length n) average probability of error; finally, Alice sends X^n over (W_1, W_2) to Bob who authenticates the received messages. We develop a theorem regarding the requirements/conditions for the authentication framework to be information-theoretic secure for authenticating a polynomial number of messages. Based on this theorem, we propose and implement an efficient and feasible authentication protocol over binary symmetric wiretap channel (BSWC) by using Linear Feedback Shifting Register based (LFSR-based) hash functions and strong secure polar code. Through extensive experiments, it is demonstrated that the proposed protocol can achieve low time cost, high authentication rate, and low authentication error rate.

Device authentication is a critical and challenging issue for the emerging Internet of Things (IoT). One promising solution to authenticate IoT devices is to extract a fingerprint to perform device authentication by exploiting variations in the transmitted signal caused by hardware and manufacturing inconsistencies. In this paper, we propose a lightweight device authentication protocol [named speaker-to-microphone (S2M)] by leveraging the frequency response of a speaker and a microphone from two wireless IoT devices as the acoustic hardware fingerprint. S2M authenticates the legitimate user by matching the fingerprint extracted in the learning process and the verification process, respectively. To validate and evaluate the performance of S2M, we design and implement it in both mobile phones and PCs and the extensive experimental results show that S2M achieves both low false negative rate and low false positive rate in various scenarios under different attacks.

In this paper, we propose a novel user cooperation scheme based on weighted fractional Fourier transform (WFRFT), to enhance the physical (PHY) layer security of wireless transmissions against eavesdropping. Specifically, instead of dissipating additional transmission power for friendly jamming, by leveraging the features of WFRFT, the information bearing signal of cooperators can create an identical artificial noise effect at the eavesdropper while causing no performance degradation on the legitimate receiver. Furthermore, to form the cooperation set in an autonomous and distributed manner, we model WFRFT-based PHY-layer security cooperation problem as a coalitional game with non-transferable utility. A distributed merge-and-split algorithm is devised to facilitate the autonomous coalition formation to maximize the security capacity while accounting for the cooperation cost in terms of power consumption. We analyze the stability of the proposed algorithm and also investigate how the network topology efficiently adapts to the mobility of intermediate nodes. Simulation results demonstrate that the WFRFT-based user cooperation scheme leads to a significant performance advantage, in terms of secrecy ergodic capacity, compared with the conventional security-oriented user cooperation schemes, such as relay-jamming and cluster-beamforming.

Message Authentication Code (MAC) is a keyed function fKsuch that when Alice, who shares the secret K with Bob, sends fK(M) to the latter, Bob will be assured of the integrity and authenticity of M. Traditionally, it is assumed that the channel is noiseless. Unfortunately, Maurer showed that in this case an attacker can succeed with probability equation after authenticating ∓ messages, where H(K) is the entropy of K. In this paper, we consider the setting where the channel is noisy. Specifically, Alice and Bob are connected by a discrete memoryless channel (DMC) W1and a noiseless but insecure channel. In addition, there is a DMC W2between Alice and attacker Oscar. We regard the noisy channel as an expensive resource and define the authentication rate ρauthas the ratio of message length to the number n of channel W1uses. The security of this model depends on the channel coding for fK(M). A natural coding scheme is to use the secrecy capacity achieving code of Csiszár and Körner. Intuitively, this is also the optimal strategy. However, we propose a coding scheme that achieves a higher ρauth. Our crucial point is that under a secrecy capacity code, Bob can fully recover fK(M) while in our model this is not necessary as we only need to detect the existence of the modification. How to detect the malicious modification without recovering fK(M) is the main contribution of this work. We achieve this through random coding techniques.

Leveraging a wireless multi-path channel as a source of common randomness, a number of key generation methods have been proposed according to information-theory security. However, by taking the advantages of node's mobility, existing schemes usually have low generation rate or low entropy. To overcome this limitation, we present a key generation protocol with known Artificial Interference, named Smoke Grenade, a new physical-layer approach for secret key generations in a narrowband fading channel. Our scheme utilizes artificial interference to contribute to the change of the measured values on channel states. The theoretical analysis shows that the key generation rate rises with the increment of the interference power. Particularly, the achievable key rate of Smoke Grenade achieves at least four times better than that of traditional key generation schemes when the average interference power is normalized to 1. Simulation results also show that Smoke Grenade has a higher generation rate and entropy compared with some known state-of-the-art approaches.

Leveraging a wireless multipath channel as the source of common randomness, many key generation methods have been proposed according to the information-theory security. However, existing schemes suffer a low generation rate and a low entropy, and mainly rely on nodes' mobility. To overcome this limitation, we present a key generation protocol with known artificial interference, named SmokeGrenade, a new physical-layer approach for secret key generation in a narrowband fading channel. Our scheme utilizes artificial interference to contribute to the change of measured values on channel states. Our theoretical analysis shows that the key generation rate increases with the increment of the interference power. Particularly, the achievable key rate of SmokeGrenade gains three times better than that of the traditional key generation schemes when the average interference power is normalized to 1. Simulation results also demonstrate that SmokeGrenade achieves a higher generation rate and entropy compared with some state-of-the-art approaches.