Federated learning (FL) as a distributed machine learning paradigm can be applied to edge intelligence scenarios for collaborative machine learning model building. Unfortunately, existing privacy-preserving FL applied to this scenario still faces three challenges: data heterogeneity, model heterogeneity, and privacy heterogeneity. Despite numerous privacy-preserving FL techniques proposed, they still cannot effectively address these three challenges. To solve this problem, we propose HeteroFed, a heterogeneous privacy-preserving FL framework for edge intelligence. Our HeteroFed contains heterogeneous model construction, dynamic gradient clipping, adaptive noise addition, and deviation-aware model aggregation. Specifically, we first use the heterogeneous model construction mechanism to enable personalized model training for different smart devices. Then, we propose a dynamic gradient clipping mechanism to perform dynamically adjusted gradient clipping on models uploaded by smart devices to limit the magnitude of gradients. Finally, we propose an adaptive noise addition mechanism to customize differential privacy protection for smart device models based on their convergence status. Furthermore, to mitigate the influence of noise perturbations on model performance, we propose a deviation-aware model aggregation mechanism for accurate model aggregation. Theoretical analysis demonstrates that HeteroFed achieves heterogeneous differential privacy. Extensive experiments show that HeteroFed outperforms similar methods, improving global model accuracy by 18%, 15%, 13%, and 18% on the MNIST, Fashion-MNIST, CIFAR-10, and THUCNews datasets, respectively.

Deep Neural Networks (DNNs) play a crucial role in the smart Internet of Things (IoT), with widespread applications in inference tasks like interactive games, intelligent driving, and augmented reality. Along with these promising applications, various task-offloading methods were proposed to improve the utilization of system resources, given that DNN model inference typically requires substantial computational power. However, existing offloading methods focus primarily on a specific model, and research addressing heterogeneous DNN models (with different structures and layers) remains limited in practical IoT environments. Directly integrating these methods would require frequent re-initialization to adapt to changes in the search space during the offloading of mixed heterogeneous DNN inference tasks, resulting in insufficient flexibility and the waste of computational resources. Thus, we propose AutoCut, a global heterogeneous model offloading service based on a customized multi-objective differential evolution algorithm, to find low-latency and energyefficient offloading partitions. AutoCut utilizes a group-layer granularity partitioning that avoids frequent changes in the search space when continuously offloading heterogeneous DNN inference tasks, thereby improving search efficiency. Experiments with six popular models show that AutoCut significantly improves inference performance regarding latency and energy efficiency.

The emerging paradigm Social Internet of Things (SIoT) integrates social networking elements into the Internet of Things, enabling smart devices to establish and manage interactions autonomously. This enhances collaboration and adaptability but also increases complexity and vulnerability, particularly from malicious devices exploiting these relationships. To address this, trust evaluation of devices becomes crucial. Traditional approaches, like weighted sums and Bayesian inference, struggle with the dynamic nature of SIoT environments. Recent advancements in Graph Neural Networks (GNNs) show promise, yet existing models often fail to capture the complexities of SIoT's dynamic and heterogeneous nature. In this paper, we propose TrustLive, a GNN-based framework for real-time trust evaluation in dynamic SIoT settings. TrustLive first employs a heterogeneous graph to represent smart devices and their interactions, which are then encoded via a customized graph embedding technique for trust feature extraction. It further incorporates Graph Convolutional Networks for trust aggregation and Temporal Convolutional Networks to capture trust evolution. Moreover, a Memory-Augmented Incremental Update mechanism is added to ensure low-latency updates by processing only the latest data while preserving accuracy with historical results. Experimental results demonstrate that TrustLive outperforms current methods in both accuracy and efficiency, offering a robust solution for trust evaluation in SIoT.

Centralized trading platforms have long been the preferred choice for users, despite growing concerns regarding data privacy. Users have to place their trust in these platforms and provide sensitive personal information, like identities and financial accounts. However, these centralized platforms often lack transparency, making it challenging to ensure fairness, privacy, and security against both external and internal risks. In contrast, a decentralized fair trading paradigm, harnessing the potential of blockchain technology, is rapidly emerging. It empowers individuals to engage in the exchange of digital assets with others while guaranteeing fairness, efficiency, and privacy. In this paper, we conduct a comprehensive survey of decentralized fair trading. We commence by providing fundamental definitions of fair trading and tracing its evolution over time. We then delve into the essential framework of on-chain and off-chain trading and highlight key improvements that enhance the efficiency of decentralized fair trading within various application scenarios. Furthermore, we undertake a thorough analysis of privacy and security enhancements within the scope, summarizing defenses against known attacks. Finally, we outline the challenges and offer insights into the future prospects of decentralized fair trading, with the aim of inspiring the development of more innovative and promising designs in this evolving trend.

Recently, blockchain-based decentralized mobile crowdsensing systems have emerged to eliminate traditional centralized trust and to achieve transparent task assignments via smart contracts. It allows workers to select tasks freely, thereby maximizing their benefits. However, prior designs rarely considered the globally optimal task assignment that significantly impacts the efficiency and quality of task performance, like maximizing the task completion ratio and minimizing the total travel distance of workers. So in this paper, we propose DCrowd, a new blockchain-based mobile crowdsensing system, to realize the decentralized, transparent, and globally optimal task assignment. In brief, we first introduce the Proof of Task Assignment consensus mechanism. This allows miners to conduct globally optimal task assignments off-chain, leverages smart contracts to perform lightweight verification for task assignment results on-chain, and stores the globally optimal task assignment in a customized block. Then, we devise the Weight-Prioritized Task Selection strategy and Threshold-based Adaptive Minimum Cost Flow algorithm, to further optimize the system performance and guide miners in competing for minting rights. A thorough theoretical analysis is provided. Extensive experiments on real-world datasets indicate that DCrowd can reduce the broadcast and consensus latency by over 50% and improve the throughput by over 87% compared with existing systems.

With the integration of IoT and 5G technologies, UAV crowd sensing has emerged as a promising solution to overcome the limitations of traditional Mobile Crowd Sensing (MCS) in terms of sensing coverage. As a result, UAV crowd sensing has been widely adopted across various domains. However, existing UAV crowd sensing methods often overlook the semantic information within sensing data, leading to low transmission efficiency. To address the challenges of semantic extraction and transmission optimization in UAV crowd sensing, this paper decomposes the problem into two sub-problems: semantic feature extraction and task-oriented sensing data transmission optimization. To tackle the semantic feature extraction problem, we propose a semantic communication module based on Multi-Scale Dilated Fusion Attention (MDFA), which aims to balance data compression, classification accuracy, and feature reconstruction under noisy channel conditions. For transmission optimization, we develop a reinforcement learning-based joint optimization strategy that effectively manages UAV mobility, bandwidth allocation, and semantic compression, thereby enhancing transmission efficiency and task performance. Extensive experiments conducted on real-world datasets and simulated environments demonstrate the effectiveness of the proposed method, showing significant improvements in communication efficiency and sensing performance under various conditions.

The use of log files in digital forensics highlights the importance of ensuring their data integrity for auditing purposes. However, traditional centralized audit log systems face challenges in maintaining data integrity due to log injection attacks and single-point failures. Although blockchain technology can accurately process and replicate log files, existing blockchain-based audit log systems still suffer from security and reliability issues due to their weak threat models and limited scalability. To address these concerns, we propose a blockchain-based audit log system that ensures data integrity under a general threat model where a part of the nodes, including loggers and auditors, are untrusted. First, our proposed system resists collusion attacks by incorporating multiple nodes for system processes and utilizing smart contracts to enforce consensus algorithms. Second, to save blockchain storage space, we design an efficient log integrity proof method, which generates a sub-Non-Fungible Token (sub-NFT) for each log file and keeps it on the blockchain as integrity proof. The single-point failure problem is resolved by outsourcing log files to a distributed file system. To evaluate the proposed system, we implement a prototype based on Hyperledger Fabric. Experimental results show that our proof generation method can reduce storage space usage in comparison to other blockchain-based audit log systems, saving approximately 50% of space in Hyperledger Fabric. The security analysis proves that our system can ensure log file data integrity under the proposed threat model.

With the growing reliance on digital systems in today's mobile Internet era, robust authentication methods are crucial for safeguarding personal data and controlling access to resources. Conventional methods, such as knowledge-based and biometric-based authentication, are widely used but still have some usage limitations and potential security concerns, like wearing protective suits/masks or being imitated by attackers with ulterior motives. In this paper, we propose another earphone-based authentication system, namely EarPass, that leverages users' unique head motion patterns in response to a very short period of music segment. Here, we employ a Convolutional Neural Network (CNN)-based feature extractor to capture and map distinct head motions into a well-separated latent space, achieving high-dimensional data extraction. We demonstrate the consistency, uniqueness, and robustness of head motion patterns through extensive experiments and reach a 98.2% F1-score, indicating superior performance compared to conventional authentication methods. Additionally, EarPass is user-friendly, secure, and adaptable to various environments, including noisy and movement-oriented scenarios. By integrating the authentication system into Android devices, we showcase its real-world applicability and low energy consumption with minimal latency. The source code of EarPass will be open-source to further research and collaboration within the community.

Web 3.0 has been proposed as a new generation of the Internet, which shifts towards system decentralization, improved data security, and self-sovereign identity. With the proliferation of networked entities, the proper management and verification of their identities play a vital role in Web 3.0. Decentralized identity is a promising paradigm to enhance data security and restore sovereignty over personal data to users. However, the data security in existing centralized solutions is often severely limited. In this paper, we propose vDID, a novel blockchain-enabled verifiable decentralized identity management system for Web 3.0. First, we design a generic verifiable DID structure, which is capable of capturing and expressing the inherent relationships between different entities with high granularity. Second, we develop an identity verification scheme to support efficient integrity verification for identities and their relationships in the decentralized framework. We implement vDID and conduct experiments to evaluate the system performance. Experimental results demonstrate the effectiveness of our proposed system.

The learning capabilities of single-modality images are often severely limited and fail to meet the requirements of complexity defect detection in industrial settings. For instance, traditional visible light images are susceptible to environmental factors such as lighting and occlusions, while infrared images cannot capture texture details due to their low spatial resolution. Consequently, employing multiple image modalities typically yields better results than relying on a single modality. However, utilizing data from multiple modalities inevitably introduces additional computational costs, posing high hardware demands on edge computing devices, and the need for real-time detection in industrial environments is critical. To address these challenges, we propose a multimodal distillation approach that uses visible and infrared images as inputs to train a complex teacher model, while the student model continues to operate with a single-modal image input. Through knowledge transfer, the student model is enhanced, and model light-weighting is implemented to ensure that it can acquire multi-modal feature information while still meeting real-time performance requirements.

Relying on the development of crowdsourcing ideas and mobile crowd sensing (MCS) technology, many tasks that originally required a lot of manpower and material resources have been solved efficiently. However, with the development of urbanization, the traditional MCS systems have gradually been unable to cope with the demands of massive sensing tasks and high spatio-temporal sensing coverage. The challenges are as follows: 1) The scarcity of participants and the limitation of human motion rules lead to the existence of spatio-temporal blind spots in the process of collecting sensing data; 2) The single type of participants limits the sensing ability of the system and the types of data that can be collected, which affects sensing precision and quality. With the emergence of various intelligent sensing terminals in the city, the heterogeneous crowd sensing that integrates human, machine and things participants has become a new generation of sensing mode. In the spatio-temporal related sensing scenarioes, this article designs a new human-machine-things cooperative scheduling (HMT-CS) algorithm framework by comprehensively considering the diverse sensing skills, spatio-temporal trajectories, sensing costs of heterogeneous participants and system total budget constraints. The algorithm can match suitable heterogeneous participants for each task, which greatly improves the sensing quality, sensing fairness and overall utility of heterogeneous MCS systems. We combined multiple public real urban datasets to conduct an in-depth comparative analysis and comprehensive evaluation of the algorithm, and the results show that our method is superior to other baselines in all indicators.

Recently, smart contracts have been widely applied in security-sensitive fields yet are fragile to various vulnerabilities and attacks. Regarding this, existing research efforts either statically scrutinize smart contracts’ code or detect suspicious transaction execution flows. However, they either fail to timely protect contracts or only handle a small subset of well-known vulnerabilities. In the paper, we propose$\mathtt {EVM}$-$\mathtt {Shield}$that secures vulnerable smart contracts in real-time via fine-grained access control over sensitive states. The behind rationale is most of attacks aim to manipulate money-related states (e.g., tokens) for profits. Specifically, transaction-level state access control policies are first defined by developers and then translated into EVM-level policies with contract-aware function-level state access permissions. In policy enforcement,$\mathtt {EVM}$-$\mathtt {Shield}$introduces a hybrid storage analyzer to accurately identify (dynamic-allocated) storage locations for policy-involved states and a multi-stage cache based filter to fast revert bad transactions with unexpected state access behaviors. Finally, we conduct thorough experiments using 12 types of real-world contract vulnerabilities and all open-source smart contracts on the first$8M$blocks of Ethereum. The results demonstrate that$\mathtt {EVM}$-$\mathtt {Shield}$outperforms two state-of-the-art runtime analysis tools in terms of attack detection. Extensive performance evaluations with$185M$real-world transactions show that$\mathtt {EVM}$-$\mathtt {Shield}$can block 100% unexpected state accesses at the cost of 8% throughput degradation (compared with the native EVM).

Mobile Crowdsensing (MCS) has become a popular sensing paradigm, where a number of participants use their mobile devices to collectively share and extract information related to a certain common interest. In this trend, many typical applications, such as environmental monitoring, intelligent transportation, and public safety, are emerging in our daily lives, and the need to quickly develop various new applications is becoming more urgent. However, existing programming frameworks for MCS applications either target specific scenarios that lack extensibility or require considerable development effort and expertise, hindering innovation in this direction. In order to reduce the burden of developing new MCS applications, we devise a developer-oriented generic programming framework, namely CrowdKit. It abstracts the common and fundamental data models and functions of MCS applications and makes them reusable. Meanwhile, it follows the principles of modular design, visual development, and automatic code generation to further bring extensibility and drastically reduce the difficulty and time cost of developers. Moreover, its algorithm modules can accommodate various advanced MCS algorithms, thus narrowing the gap between theory and practice. We implement and release a full-fledged version of CrowdKit, and conduct comprehensive case study and user study to demonstrate its simplicity, generality, extensibility and high efficiency.

The prosperity of Decentralized Finance (DeFi) unveils underlying risks, with reported losses surpassing 3.2 billion USD between 2018 and 2022 due to vulnerabilities in Decentralized Applications (DApps). One significant threat is the Price Manipulation Attack (PMA) that alters asset prices during transaction execution. As a result, PMA accounts for over 50 million USD in losses. To address the urgent need for efficient PMA detection, this article introduces a novel detection service,DeFiGuard, using Graph Neural Networks (GNNs). In this article, we propose cash flow graphs with four distinct features, which capture the trading behaviors from transactions. Moreover,DeFiGuardintegrates transaction parsing, graph construction, model training, and PMA detection. Evaluations on the collected transactions demonstrate thatDeFiGuardwith GNN models outperforms the baseline MLP model and classical classification models in Accuracy, TPR, FPR, and AUC-ROC. The results of ablation studies suggest that the combination of the four proposed node features enhancesDeFiGuard’s efficacy. Moreover,DeFiGuardclassifies transactions within 0.892 to 5.317 seconds, which provides sufficient time for the victims (DApps and users) to take action to rescue their vulnerable funds. In conclusion, this research offers a significant step towards safeguarding the DeFi landscape from PMAs using GNNs.

An increasing number of energy-recycling consensus mechanisms are being employed to address the drawback of proof of work (PoW) wasting computation and energy. For instance, the computing power wasted in solving difficult but meaningless PoW puzzles is used to conduct practical federated learning tasks and train deep learning models. However, there remains a neglected issue of task difficulty adjustment. To address this problem, we propose a method for measuring task difficulty and an algorithm for adjustment to achieve controlled minting and stable transaction processing capacity for cryptocurrency based on energy-recycling consensus mechanisms. Our research evaluates the effectiveness of this algorithm and highlights the potential benefits of this approach.

The rapid evolution of public knowledge is the trend of the present era; rendering previously collected data susceptible to obsolescence. The continuously generated new knowledge could further affect the performance of the model trained with previous data, such a phenomenon is called temporal misalignment. A vanilla mitigation approach is to periodically update the model in a centralized learning scheme. However, in a decentralized learning framework like Federated Learning (FL), such a patch requires clients to upload the data, which contradicts FL's intention to protect clients' privacy. Furthermore, considering the stationary defenses in FL, new knowledge could be misjudged and rejected as malicious attacks, which hinders the further update of the model. Yet dynamically adapting defenses requires meticulous fine-tuning and harms the scalability. Thus in this poster, we raise such practical concern and discuss it in the context of FL. We then build a prototype of a GPT2-based FL framework and conduct experiments to demonstrate our perspective. The performance in new knowledge drops by 33.47% compared with the previous data, which justify the FL with defenses strategy can misjudge the new knowledge.

The rising popularity of ear-wear devices equipped with motion sensors has brought concerns regarding privacy issues due to their powerful sensing capabilities. Previous studies have shown the potential for speech eavesdropping using earphone motion sensors with a sampling frequency of 1000 Hz. However, as the risks of such attacks continue to escalate, mobile operating systems like Android have imposed limitations on the sampling frequency, typically no more than 200 Hz, to avoid such attacks. The lower sampling frequency reduces the amount of collected information within the same timeframe, potentially leading to decreased accuracy. In this paper, we further investigate the effectiveness of utilizing earphone motion sensors for inferring sensitive information at a sampling frequency of 200 Hz while directly using raw data without any data transformation to prevent information loss. We employ a channel attention mechanism to dynamically adjust axis weights to address the varying energy levels across different sensor axes. Meanwhile, we analyze the impact of sampling frequency, environment, and volume on speech recognition performance. Additionally, we explore the extraction of other information from speech signals, such as speaker identity and gender. Our experiments on two datasets demonstrate high recognition accuracy for all three tasks at the 200Hz sampling frequency. We expect our work to raise awareness among manufacturers regarding the privacy issues associated with earphone motion sensors.

Cloud-edge collaboration, as an emerging computing paradigm, aims to solve the shortcomings of remote transmission of conventional cloud computing. More precisely, it combines the powerful resource service capability of cloud computing with the advantages of low latency and relatively low energy consumption of edge computing to achieve the goal of optimization of various applications. However, with the rapid growth of computation-intensive industrial tasks, the overload problem of edge networks is becoming increasingly serious. Prior studies usually assume that the real-time state of edge resources has been known when selecting the offloading strategy so as to classify and execute tasks, but do not consider the fragmentation and heterogeneity features of edge computing resources. In light of these, we first generalize and model the computing resources of the edge nodes uniformly and then propose new heterogeneous task classification and recognition methods empowered by edge intelligence. We conduct intensive experiments to justify that our proposed design can minimize the data transmission delay caused by repeated computational tasks while saving energy consumption.

As important indicators of urban public safety, public safety and environmental security (PSES) is related to residents’ living security and greatly affects their quality of life and happiness index. Due to PSES characteristics, such as diverse forms, wide distribution, and unpredictable occurrence times, traditional solutions consume huge manpower, and time in the implementation process. Although some professional software and hardware systems have emerged to assist in solving the problems, there are still challenges, such as limited sensing coverage and monotonous sensing modes, lack of interaction and understanding between systems and tasks, and scarcity of effective system architecture and functional modules. To meet these challenges, we design a PSES multiterminal fusion system (SafeCity) based on the idea and technology of heterogeneous mobile crowd sensing. With collaboration among humans, machines, and things (H-M–T), the proposed system makes full use of the idle mobility, sensing, and computing resources in the city, and systematically provides a solution to the various PSES issues. Apart from the system architecture, functions, core mechanism, and algorithm libraries, the task execution flow is explained in depth through the description of several cases. We implement a prototype to verify the rationality and effectiveness of SafeCity. And, comprehensive comparison and evaluation show that SafeCity is far superior to other solutions in terms of function, performance, and stability.

To keep web users away from unsafe websites, modern web browsers enable the embedded feature of safe browsing (SB) by default. In this work, through theoretical analysis and empirical evidence, we reveal two major shortcomings in the current SB infrastructure. First, we derive a feasible tracking technique for industry best practice. We show that the current mitigation techniques cannot eliminate the threat of de-anonymization permanently. Second, we gauge the effectiveness of blacklists provided by major vendors. Our discovery indicates the urge for blacklist integration in order to boost service quality. In light of this, we propose a new three-party paradigm${{\sf PEBA}}$with an intermediate third party decoupling the direct interaction of users and proprietary blacklist vendors. To satisfy practical usage requirements, we instantiate our design with trusted hardware, detailing how it can be leveraged to fulfill the requirements of privacy enhancement and broader content coverage at the same time. We also tackle numerous implementation challenges that emerged from this proxy-based and hardware-enabled solution. Extensive evaluation confirms that${{\sf PEBA}}$can balance well among desirable goals of security, usability, performance, and elasticity, making it suitable for deployment in practice.

Accurately predicting Origin-Destination (OD) passenger flow can help metro service quality and efficiency. Existing works have focused on predicting incoming and outgoing flows for individual stations, while little attention was paid to OD prediction in metro systems. The challenges are that OD flows 1) have high temporal dynamics and complex spatial correlations, 2) are affected by external factors, and 3) have sparse and incomplete data slices. In this paper, we propose an Adaptive Feature Fusion Network (AFFN) to a) adaptively fuse spatial dependencies from multiple knowledge-based graphs and even hidden correlations between stations and b) accurately capture the periodic patterns of passenger flows based on the auto-learned impact from external factors. To deal with the incompleteness and sparsity of OD matrices, we extend AFFN to multi-task AFFN to predict the inflow and outflow of each station as a side-task to further improve OD prediction accuracy. We conducted extensive experiments on two real-world metro trip datasets collected in Nanjing and Xi’an, China. Evaluation results show that our AFFN and multi-task AFFN outperform the state-of-the-art baseline techniques and AFFN variants in various accuracy metrics, demonstrating the effectiveness of AFFN and each of its key components in OD prediction.

Intelligent bots are evolving with the development of artificial intelligence, especially the deep learning method. Many skills like semantic judgment, speech recognition, and text generation have been added, making bots more like real persons. The latest ones, such as Microsoft XiaoIce, Amazon Alexa, and Apple Siri, focus on enhancing general functionalities but still overlook the personality of the bot itself nevertheless, e.g., unchanging name and its virtual appearance. To further personalize the user experience, we desire to make the appearance of intelligent bots more diverse, i.e., appearing capable of autonomously changing its characteristic appearance according to users’ contexts like the changing geolocation. In this paper, we designe a personalized appearance transformation framework for the next generation intelligent bots. Specifically, Multi-modal crowd-intelligence technology is used for differential analysis of various regions, and generative adversarial network (GAN) is customized to render the bot appearance target domain. We also collecte new region-specific data sets from social media platforms, implement a fully-fledged prototype, and demonstratedthe effectiveness of our proposed framework.

In the era of mobile computing and sharing econ-omy, spatial crowdsourcing has become an emerging paradigm where participants who meet the spatial requirements are actively joined in various tasks. However, previous work did not fully consider the heterogeneous nature of tasks with both spatio-temporal and sensing requirements. And for the participants, they contribute different amounts and types of sensing data due to the fact that their devices usually have various sensing capabilities. In light of this, it is desired to study the task allocation problem in such a heterogeneous spatial crowdsourcing scenario. Specifically, to accommodate the dynamic and complex features of this scenario, we design a Multi-Agent Soft Actor-Critic algorithm (TA-DSAC) that relies on spatio-temporal con-straint. Firstly, we construct available task allocation regions according to the spatio-temporal characteristics of the tasks and participants, as well as the matching degree and aggregate sensing quality, and then set an agent for each region. Next, the agents are trained based on discretized Soft Actor-Critic (SAC) and Centralized Training with Decentralized Execution (CTDE), making the agents self-adaptive to changes in this crowdsourcing environment. Extensive evaluations with real datasets justify the effectiveness of our proposed algorithm.

Surface inspection of industrial equipment defection plays a vital role in real production. Traditional inspection routines require a large number of inspection workers, which not only affects production efficiency but also leads to unreliable results. Computer vision-based detection approaches, e.g., using the deep learning method, have shown great potential in this trend. Specifically, the semantic segmentation algorithm based on Convolutional Neural Network (CNN) can extract relatively complete feature information. And the Transformer, which emerged from the field of Natural Language Processing (NLP), also performs well in maintaining and transmitting semantic information. In light of these, we propose to design a segmentation model called eSwin-UNet, i.e., enhanced Swin-UNet, that leverages the advantages of the CNN and Transformer. It uses multi-scale information fusion to better integrate the feature information in the CNN and Transformer branches. Moreover, it also utilizes deep supervision and makes two branches for collaborative training to further improve accuracy. By testing with the MVTec ITODD dataset, Fl-Score and Jaccard achieve results of 0.7891 and 0.6516 respectively, which outperform most current models.

The Industrial Internet of Things (IIoT) is deemed a promising direction to drive a new industrial revolution. However, due to the isolation of the existing OT network and IT network, the requirements of low latency, low jitter, and high reliability for transmission and processing of industrial time-sensitive tasks data traffic in IIoT scenarios with strong dynamic and complex topology face a series of non-trivial challenges. In this paper, we propose a hierarchical computing network collaboration architecture for IIoT based on edge/fog computing. Our architecture is built upon the Time-Sensitive Networking (TSN) to flexibly support different requirements of large-scale industrial production applications by constructing the hierarchical computing network collaboration domain, combined with an improved Cyclic Queuing and Forwarding (CQF) scheduling shaper mechanism. We tackle the critical problems of architecture design by presenting three essential components. Moreover, we build and implement our simulation testbed based on Omnet++, and evaluate our design.

We witnessed great advancement in Artificial Intelligence (AI) powered technologies in recent years, and yet, when applied to certain high-stake contexts, such as medical diagnosis, automatic driving and criminal justice, they are not qualified. This matter can be greatly settled by Human-Machine Computing (HMC), which is an effective computing paradigm that couples the expertise and demonstration abilities of humans with the high-performance computing power of machines. This work studies an optimal task scheduling problem for HMC systems, where various tasks are decomposed and dispatched to humans and AI-enabled machines to provide significantly better benefits compared to either type of computing resources in isolation. However, designing such optimal task scheduling is challenging because of the stochastic hybrid features of machines, as well as various human professional abilities. Considering the Quality of Service (QoS) and the heterogeneity of human-machine computing resources, we propose CoupHM, a feasible task scheduler using gradient based optimization for HMC systems. In particular, we firstly present the underlying architecture of HMC system and details of the task-driven workload model. On that basis, we then formulate the objective optimization problem to be solved and describe the composition of the CoupHM scheduler. Finally, the performance of our solution is evaluated by the simulation experiments, and the results indicate that the proposed scheduler has preferable performance both in balancing resources and guaranteeing QoS, which can serve as guidelines for future research on HMC systems.

Safe Browsing (SB) is an important security feature in modern web browsers to help detect new unsafe websites. Although useful, recent studies have pointed out that the widely adopted SB services, such as Google Safe Browsing and Microsoft SmartScreen, can raise privacy concerns since users' browsing history might be subject to unauthorized leakage to service providers. In this paper, we present a Privacy-Preserving Safe Browsing (PPSB) platform. It bridges the browser that uses the service and the third-party blacklist providers who provide unsafe URLs, with the guaranteed privacy of users and blacklist providers. Particularly, in PPSB, the actual URL to be checked, as well as its associated hashes or hash prefixes, never leave the browser in cleartext. This protects the user's browsing history from being directly leaked or indirectly inferred. Moreover, these lists of unsafe URLs, the most valuable asset for the blacklist providers, are always encrypted and kept private within our platform. Extensive evaluations using real datasets (with over 1 million unsafe URLs) demonstrate that our prototype can function as intended without sacrificing normal user experience, and block unsafe URLs at the millisecond level. All resources, including Chrome extension, Docker image, and source code, are available for public use.

In modern online advertising systems, the click-through rate (CTR) is an important index to measure the popularity of an item. It refers to the ratio of users who click on a specific advertisement to the number of total users who view it. Predicting the CTR of an item in advance can improve the accuracy of the advertisement recommendation. And it is commonly calculated based on users’ interests. Thus, extracting users’ interests is of great importance in CTR prediction tasks. In the literature, a lot of studies treat the interaction between users and items as sequential data and apply the recurrent neural network (RNN) model to extract users’ interests. However, these solutions cannot handle the case when the sequence length is relatively long, e.g., over 100. This is because of the vanishing gradient problem of RNN, i.e., the model cannot learn a users’ previous behaviors that are too far away from the current moment. To address this problem, we propose a new Core Interest Network (CIN) model to mitigate the problem of a long sequence in the CTR prediction task with sequential data. In brief, we first extract the core interests of users and then use the refined data as the input of subsequent learning tasks. Extensive evaluations on real dataset show that our CIN model can outperform the state-of-the-art solutions in terms of prediction accuracy.

Privacy-preserving similarity search plays an essential role in data analytics, especially when very large encrypted datasets are stored in the cloud. Existing mechanisms on privacy-preserving similarity search were not able to support secure updates (addition and deletion) efficiently when frequent updates are needed. In this article, we propose a new mechanism to support parallel privacypreserving similarity search in a distributed key-value store in the cloud, with a focus on efficient addition and deletion operations, both executed with sublinear time complexity. If search accuracy is the top priority, we further leverage Yao's garbled circuits and the homomorphic property of Hash-ElGamal encryption to build a secure evaluation protocol, which can obtain the top-R most accurate results without extensive client-side post-processing. We have formally analyzed the security strength of our proposed approach, and performed an extensive array of experiments to show its superior performance as compared to existing mechanisms in the literature. In particular, we evaluate the performance of our proposed protocol with respect to the time it takes to build the index and perform similarity queries. Extensive experimental results demonstrated that our protocol can speedup the index building process by up to 800x with 2 threads and the similarity queries by up to -7x with comparable accuracy, as compared to the state-of-the-art in the literature.

In-network storage is recognized as a vital component of many emerging network architectures, which facilitates high-quality and efficient content-centric services. In this trend, providing content-based near-duplicate detection (NDD) services among in-network storage becomes naturally necessary for network traffic alleviation and resource optimization. However, due to the increasing attacking surfaces, storing data in the networked environment inevitably raises new concerns about user privacy exposure and unauthorized data access. Therefore, we aim to design a secure NDD service in the context of encrypted in-network storage. For efficiency, we first leverage the fingerprint techniques and locality-sensitive hashing to convert the problem of NDD into the keyword search. We then adopt an efficient multi-key searchable encryption scheme, which requires only one encrypted query from the user even the data are from multiple content providers encrypted with different keys. As simply combining the above methods does not appear to directly locate accurate results, we then devise a secure result refining scheme via Yao's garbled circuits to avoid user-side post-processing. Furthermore, we enhance our design to address the potential malicious behavior of in-network servers. Extensive evaluations of real-world image dataset demonstrate that our design can achieve comparable accuracy to the plaintext with modest security overhead.

The emerging hardware-assisted security technologies facilitate the deployment of secure and trustworthy applications in today's cloud computing infrastructure. Despite promising, the advantages appear to diminish due to limited resources of trusted execution environments and ever-increasing workload to be processed inside. Different from existing task-specific and system-level optimizations, our key observation is that those redundant computations occur commonly among several applications when handling the same input data. In light of this, we propose SPEED, a secure and generic computation deduplication system in the context of Intel SGX. It allows SGX-enabled applications to identify redundant computations and reuse computation results, while protecting the confidentiality and integrity of code, inputs, and results. To maximize the benefit of computation deduplication, we design a cross-application deduplication scheme, empowering multiple applications to securely utilize the shared results as long as they perform identical computations. To ease the use of SPEED, we implement a fully functional prototype and provide a concise and expressive API for developers to deduplicate rich computations with minimal effort, as few as 2 lines of code per function call. Extensive evaluations of four popular applications demonstrate that SPEED improves performance by up to 400 times. The source code is available on GitHub for public use.

Android is the primary target for mobile malware. To protect users, phone vendors (e.g., Samsung and Huawei) usually leverage third-party security service providers (e.g., VirusTotal and Qihoo 360) to detect malicious apps in app stores and collect apps' runtime behaviors on users' phones to further spot malware missed in the previous step. However, this practice could cause privacy concerns to phone vendors, users and security service providers. Specifically, phone vendors do not want to share apps (including the paid ones) with security service providers, while the latter do not want to share the malware signatures with the former. Moreover, users do not want to expose apps' runtime behaviors to third parties. These concerns would cause a real dilemma for each involved party. In this paper, we propose a privacy-preserving malware detection system for Android, in which the privacy (or assets) of phone vendors, users, and security service providers are protected. It detects malicious apps in phone vendor's app stores and on users' phones, without directly sharing apps, apps' runtime behaviors, and malware signatures to other parties. We implement a prototype system called PPMDroid and apply several optimizations to save bandwidth and speed up the process. Extensive evaluation results with real malware samples demonstrate the effectiveness and efficiency of our system.

Along with the rapid advancement of digital image processing technology, image denoising remains a fundamental task, which aims to recover the original image from its noisy observation. With the explosive growth of images on the Internet, one recent trend is to seek high quality similar patches at cloud image databases and harness rich redundancy therein for promising denoising performance. Despite the well-understood benefits, such a cloud-based denoising paradigm would undesirably raise security and privacy issues, especially for privacy-sensitive image data sets. In this paper, we initiate the first endeavor toward privacy-preserving image denoising from external cloud databases. Our design enables the cloud hosting encrypted databases to provide secure query-based image denoising services. Considering that image denoising intrinsically demands high quality similar image patches, our design builds upon recent advancements on secure similarity search, Yao's garbled circuits, and image denoising operations, where each is used at a different phase of the design for the best performance. We formally analyze the security strengths. Extensive experiments over real-world data sets demonstrate that our design achieves the denoising quality close to the optimal performance in plaintext.

Nowadays, large volumes of multimedia data are outsourced to the cloud to better serve mobile applications. Along with this trend, highly correlated datasets can occur commonly, where the rich information buried in correlated data is useful for many cloud data generation/dissemination services. In light of this, we propose to enable a secure and efficient cloud-assisted image sharing architecture for mobile devices, by leveraging outsourced encrypted image datasets with privacy assurance. Different from traditional image sharing, we aim to provide a mobile-friendly design that saves the transmission cost for mobile clients, by directly utilizing outsourced correlated images to reproduce the image of interest inside the cloud for immediate dissemination. First, we propose a secure and efficient index design that allows the mobile client to securely find from encrypted image datasets the candidate selection pertaining to the image of interest for sharing. We then design two specialized encryption mechanisms that support secure image reproduction from encrypted candidate selection. We formally analyze the security strength of the design. Our experiments explicitly show that both the bandwidth and energy consumptions at the mobile client can be saved, while achieving all service requirements and security guarantees.

Near-duplicate detection (NDD) plays an essential role for effective resource utilization and possible traffic alleviation in many emerging network architectures, leveraging in-network storage for various content-centric services. As innetwork storage grows, data security has become one major concern. Though encryption is viable for in-network data protection, current techniques are still lacking for effectively locating encrypted near-duplicate data, making the benefits of NDD practically invalidated. Besides, adopting encrypted innetwork storage further complicates the user authorization when locating near-duplicate data from multiple content providers under different keys. In this paper, we propose a secure and effective NDD system over encrypted in-network storage supporting multiple content providers. Our design bridges locality-sensitive hashing (LSH) with a newly developed cryptographic primitive, multi-key searchable encryption, which allows the user to send only one encrypted query to access near-duplicate data encrypted under different keys. It relieves the users from multiple rounds of interactions or sending multiple different queries respectively. As simply applying LSH does not ensure the detection quality, we then leverage Yao's garbled circuits to build a secure protocol to obtain highly accurate results, without user-side post-processing. We formally analyze the security strength. Experiments demonstrate our system achieves practical performance with comparable accuracy to plaintext.

In storage outsourcing, highly correlated datasets can occur commonly, where the rich information buried in correlated data can be useful for many cloud data generation/dissemination services. In light of this, we propose to enable a secure and efficient cloud-assisted image sharing architecture for mobile devices, by leveraging outsourced encrypted image datasets with privacy assurance. Different from traditional image sharing, the proposed design aims to save the transmission cost from mobile clients, by directly utilizing outsourced correlated images to reproduce the image of interest inside the cloud for immediate dissemination. While the benefits are obvious, how to leverage the encrypted image datasets makes the problem particular challenging. To tackle the problem, we first propose a secure and efficient index design that allows the mobile client to securely find from the encrypted image datasets the candidate selection pertaining to the image of interest for sharing. We then design two specialized encryption mechanisms that support the secure image reproduction inside the cloud directly from the encrypted candidate selection. We formally analyze the security strength of the design. Our experiments show that up to 90% of the transmission cost at the mobile client can be saved, while achieving all service requirements and security guarantees.