Healthcare is a crucial element of human lives that produces a substantial amount of medical data every year. A major difficulty faced by e-Health systems is the secure storage and sharing of this data without compromising its integrity and privacy. Being a trustless, traceable, and immutable technology, blockchain has the potential to address these issues. In this paper, we propose HierChain, a hierarchical blockchain-based data storage and sharing system for healthcare. This framework provides a trustless environment that is decentralized and tamper-resistant for efficient management of data. We first introduce an optimization problem aimed at identifying the optimal data storage solution for maximum efficiency. Next, we classify the health data based on its specific features, sensitivity, and storage requirements. This classified data is then stored on three different blockchains (Ethereum, Hyperledger Sawtooth, and MultiChain) according to their optimal attributes. We utilize fog nodes for providing computational services to the resource-constrained Internet of Things (IoT) nodes, enabling us to perform data preprocessing and eliminate redundant information from the collected data. Moreover, we use differential privacy on the fog layer to ensure that sensitive medical data remains protected throughout the analysis process. Finally, we present a comprehensive attack evaluation and performance analysis by implementing our framework on a real-world medical dataset. The simulation results indicate that HierChain outperforms existing algorithms in terms of scalability and security of health data without degrading the performance of the IoT network.
As a decentralized technology, blockchain has the characteristics of traceability and immutability. Using blockchain technology, each model update of federation information can be associated with each participant, and the traceability of transactions in the blockchain can be used to detect fraudulent transactions that attempt to tamper with data. At the same time, the blockchain is used to realize the decentralization of the system, which strengthens the fault tolerance and attack resistance of the system. Based on this, this chapter designs and implements a blockchain architecture to solve the problem of safe and trusted data sharing among participants in the decentralized federated learning model. A blockchain architecture is designed and implemented for decentralized federated learning, using the blockchain to store the model parameter information of participants in each round of training; in view of the shortcomings of existing consensus algorithms, combined with decentralized federated learning detection model, A new consensus algorithm - “High Performance Byzantine Fault Tolerance Based on Model Accuracy” consensus algorithm is proposed.
Smart home devices generate a substantial amount of local data, and finding effective ways to utilize this data while ensuring privacy has become an increasingly pressing concern. Technologies such as Smart Homes, Federated Learning and Blockchain offer promising solutions to address this challenge. We introduce a blockchain-based federated learning approach that leverages edge nodes to maintain a decentralized blockchain, thus mitigating the risks associated with single points of failure. Furthermore, this method utilizes local data from home IoT devices for model training, ensuring efficient learning while preserving data privacy. To address the challenges posed by non-independent and homogeneous data distribution, we propose a clustering method. This strategy effectively tackles the issues arising from non-homogeneous data distribution, consequently improving model accuracy. Finally, experimental results demonstrate that our proposed approach significantly enhances model accuracy and generalization while safeguarding user privacy.
Consensus protocol is a key technology enabling blockchain to provide secure and trustful services in wireless networks. However, most previous study on blockchain consensus protocols for wireless networks relies on reliable message transmissions and honest leaders. In practice, wireless blockchains inherently suffer from limited physical resources and unreliable wireless channels due to environmental noises and adversary attacks. This paper studies the design of Byzantine fault tolerant consensus protocol for blockchain in single-hop wireless networks subject to signal-to-noise constraint. For this purpose, we propose a low-latency and reliable Byzantine fault-tolerant consensus protocol LRBP, which incorporates the following three designs: 1) Randomized credit-based block proposer selection, which can prevent adversary corruption and improve the system throughput, 2) Enhanced threshold Boneh-Lynn-Shacham signature based voting mechanism, which can achieve communication-efficient block validity voting by using piggyback-based acknowledgment and criticality-based adaptive channel accessing probability adjustment, and 3) Random linear network coding based batch forwarding, which supports reliable block transmissions. We derive the consensus success probability and consensus time complexity of LRBP. We prove that LRBP simultaneously satisfies the properties of persistence and liveness. It is resistant to the 51% attack, Sybil attack, double-spending attack, and jamming attack. Simulation results show the high efficiency of LRBP as compared with existing work.
Jesús García-Rodríguez, Stephan Krenn, Jorge Bernal Bernabé, Antonio Skármeta
PREPRINT: The increasing user awareness and regulatory framework (e.g., GDPR) have contributed to considering data minimization and privacy-by-design as central guiding principles for new systems.<br> Among others, this has led to a paradigm shift towards Self-Sovereign Identity solutions to put the user in full control over their data.<br> Despite the promising landscape, privacy-preserving Attribute-Based Credentials (p-ABC) have not been widely adopted, mainly due to the lack of secure, flexible and efficient implementations that cover the basic and advanced needs in p-ABC systems. In this work, we tackle this gap by formalizing an improved zero-knowledge showing protocol of a distributed p-ABC scheme based on Pointcheval-Sanders Multi-Signatures to allow for modular extensions through commit-and-prove techniques. We use it to implement a flexible p-ABC system with decentralized issuance that, apart from the basic notions of p-ABCs, covers range proofs, pseudonyms, inspection and revocation. Lastly, we thoroughly evaluate the performance of the system under different testbed conditions, showing a significant efficiency improvement over previous implementations.
This work aims to analyze malicious communication behaviors that pose a threat to the security of digital twins (DTs) and safeguard user privacy. A unified and integrated multidimensional DTs Network (DTN) architecture is constructed. On this basis, the propagation process model of malware in the network is built to analyze the malicious propagation behavior that threatens network security. This model ensures the protection of mobile distributed machine learning system security. Blockchain technology is a distributed data protection mechanism with broad prospects. It is characterized by decentralization, transparency, and anonymity, which can help ensure secure network data sharing and privacy protection. Based on this, this work designs a secure distributed data sharing (DDS) architecture based on blockchain to improve the security and reliability of data protection with the support of the Internet of Things (IoT). Then, digital resource allocation based on semi-distributed learning is examined to propose a broad learning federated continuous learning (BL-FCL) algorithm combining blockchain and DTs. This algorithm significantly speeds up the model training process. Broad learning technology supports incremental learning. In this way, each client does not need to retrain when learning the newly generated data. In the experimental part, the prediction accuracy of BL-FCL on the mixed national institute of standards and technology data set is similar to that of the FedAvg-50 and FedAvg-80 schemes. As the number of devices increases from 1 to 6, the detection probability exhibits a rapid decrease. However, as the number of devices further increases from 6 to 10, the detection probability gradually decreases at a slower rate until it reaches 0. Comparatively, the prediction accuracy of the BL-FCL outperforms the federated averaging algorithm-based scheme by 20%–60%. The BL-FCL reported here can deal with the problem of inaccurate training while ensuring the privacy and security of users. This work is of great significance for ensuring the security of the DTN and promoting the development of the digital economy. The results can provide references for applying blockchain and distributed learning in the DT field.
With the increase of IoT (Internet of Things) application scenarios, traditional access control technology can no longer meet the security needs of device access control in IoT scenarios. There are problems such as inadequate security of stored information, difficulty in controlling access rights at a fine-grained level, and untimely handling of malicious access behavior in IoT. To address these problems, an ABAC(attribute based access control) model is used as the basis for access control, and a smart contract based on attribute and reputation access control model is proposed. The solution divides the access control process into four parts and uses a combination of smart contracts and the ABAC model to achieve traceable, automated and trusted access control to the entire IoT resources. Finally, the effectiveness and compatibility of the smart contract and reputation-based access control model is verified through simulation experiments and performance tests.
Machine learning has become increasingly popular in academic and industrial communities and has been widely implemented in various online applications due to its powerful ability to analyze and use data. Among all the machine learning models, decision tree models stand out due to their great interpretability and simplicity, and have been implemented in cloud computing services for various purposes. Despite its great success, the integrity issue of online decision tree prediction is a growing concern. The correctness and consistency of decision tree predictions in cloud computing systems need more security guarantees since verifying the correctness of the model prediction remains challenging. Meanwhile, blockchain has a promising prospect in two-party machine learning services as the immutable and traceable characteristics satisfy the verifiable settings in machine learning services. In this paper, we initiate the study of decision tree prediction services on blockchain systems and propose VDT, a Verifiable Decision Tree prediction scheme for decision tree prediction. Specifically, by leveraging the Merkle tree and hash function, the scheme allows the service provider to generate a verification proof to convince the client that the output of the decision tree prediction is correctly computed on a particular data sample. It is further extended to an update method for a verifiable decision tree to modify the decision tree model efficiently. We prove the security of the proposed VDT schemes and evaluate their performance using real datasets. Experimental evaluations show that our scheme requires less than one second to produce verifiable proof.
Mohamed Abdel‐Basset, Ibrahim Alrashdi, Hossam Hawash, Karam M. Sallam · 5 authors
In the aftermath of the COVID-19 pandemic, the need for efficient and reliable disease diagnosis in smart cities has become increasingly serious. In this study, we introduce a novel blockchain-based federated learning framework tailored specifically for the diagnosis of pandemic diseases in smart cities, called BFLPD, with a focus on COVID-19 as a case study. The proposed BFLPD takes advantage of the decentralized nature of blockchain technology to design collaborative intelligence for automated diagnosis without violating trustworthiness metrics, such as privacy, security, and data sharing, which are encountered in healthcare systems of smart cities. Cheon–Kim–Kim–Song (CKKS) encryption is intelligently redesigned in BFLPD to ensure the secure sharing of learning updates during the training process. The proposed BFLPD presents a decentralized secure aggregation method that safeguards the integrity of the global model against adversarial attacks, thereby improving the overall efficiency and trustworthiness of our system. Extensive experiments and evaluations using a case study of COVID-19 ultrasound data demonstrate that BFLPD can reliably improve diagnostic accuracy while preserving data privacy, making it a promising tool with which smart cities can enhance their pandemic disease diagnosis capabilities.
The maturing blockchain technology has gradually promoted decentralized data storage from cryptocurrencies to other applications, such as trust management, resulting in new challenges based on specific scenarios. Taking the mobile trust blockchain within a vehicular network as an example, many users require the system to process massive traffic information for accurate trust assessment, preserve data reliably, and respond quickly. While existing vehicular blockchain systems ensure immutability, transparency, and traceability, they are limited in terms of scalability, performance, and security. To address these issues, this paper proposes a novel decentralized vehicle trust management solution and a well-matched blockchain framework that provides both security and performance. The paper primarily addresses two issues: i) To provide accurate trust evaluation, the trust model adopts a decentralized and peer-review-based trust computation method secured by trusted execution environments (TEEs). ii) To ensure reliable trust management, a multi-shard blockchain framework is developed with a novel hierarchical Byzantine consensus protocol, improving efficiency and security while providing high scalability and performance. The proposed scheme combines the decentralized trust model with a multi-shard blockchain, preserving trust information through a hierarchical consensus protocol. Finally, real-world experiments are conducted by developing a testbed deployed on both local and cloud servers for performance measurements.
Zero-knowledge proof (ZKP) frameworks have the potential to revolutionize the handling of sensitive data in various domains. However, deploying ZKP frameworks with real-world data presents several challenges, including scalability, usability, and interoperability. In this project, we present Fact Fortress, an end-to-end framework for designing and deploying zero-knowledge proofs of general statements. Our solution leverages proofs of data provenance and auditable data access policies to ensure the trustworthiness of how sensitive data is handled and provide assurance of the computations that have been performed on it. ZKP is mostly associated with blockchain technology, where it enhances transaction privacy and scalability through rollups, addressing the data inherent to the blockchain. Our approach focuses on safeguarding the privacy of data external to the blockchain, with the blockchain serving as publicly auditable infrastructure to verify the validity of ZK proofs and track how data access has been granted without revealing the data itself. Additionally, our framework provides high-level abstractions that enable developers to express complex computations without worrying about the underlying arithmetic circuits and facilitates the deployment of on-chain verifiers. Although our approach demonstrated fair scalability for large datasets, there is still room for improvement, and further work is needed to enhance its scalability. By enabling on-chain verification of computation and data provenance without revealing any information about the data itself, our solution ensures the integrity of the computations on the data while preserving its privacy.
This article introduces${\sf FedRLChain}$, a novel framework for blockchain-based secure federated deep reinforcement learning, which allows users to securely and collaboratively train a Deep Reinforcement Learning (DRL) model by plugging appropriate aggregation and verification algorithms for specific problems. Unlike existing systems,${\sf FedRLChain}$adopts 1) a novel verification algorithm to prevent malicious clients, 2) an aggregation weight scheme from preventing the global model from getting biased toward any client, and 3) a variant of traditional FedAverage algorithm to accelerate the convergence process. We perform a rigorous experimental evaluation of${\sf FedRLChain}$considering the classic cart-pole problem, and we show a significant improvement in the number of epochs and time required for model convergence w.r.t. the state-of-the-art frameworks – DDQL, BAFFLE, and BASE-PIoT.
Najam Saqib, Saif Ur Rehman Malik, Adeel Anjum, Madiha Haider Syed · 7 authors
Recent developments in the Internet of Vehicles (IoV) and vehicular adhoc networks (VANET) have revolutionized our infrastructure, making it safer, more convenient, and efficient. VANET provide smart traffic control, event allocation, and real-time information. Existing vehicles in VANET are now equipped with intelligent navigation, entertainment, and emergency applications. However, the highly connected nature of these vehicles poses a significant safety and security risk to drivers and assets which can result in life-threatening consequences. Location privacy is critical, and robust network security techniques should be used to counter threats in VANET environments. Existing schemes like obfuscation, mix-zones, and silent periods have preserved location privacy to some extent but have poor Quality of Service (QoS) and lack both efficiency and security. To address these issues, a shadowing scheme is introduced, which is an improvement of earlier schemes used for location privacy. This approach ensures better service to the vehicle by allowing precise location-based service (LBS) requests to the LBS server and uses blockchain technology for storing vehicular certificates. The inclusion of a group leader significantly reduces the time taken for implementing the scheme, improving efficiency and scalability. The anonymity set size increases over time, offering better privacy protection especially in densely populated areas. The proposed scheme overcomes drawbacks of existing techniques which includes reduced location accuracy and low-quality service in spatial obfuscation techniques, limited applicability and high tracking rate in shadow-based approaches, and reduced utility in distance-based schemes. Moreover, single point of failure and resource-intensive group formation in group-based schemes, and dependency on additional infrastructure in mix-zone-based schemes are also overcome. The proposed scheme’s experimental results validate it, showing that it outperforms current state-of-the-art schemes based on metrics, such as anonymity set size, entropy, and tracking success ratio.
Abstract While blockchain technology (BT) is considered secure, there are several vulnerabilities that can breach its security. The study in artificial intelligence (AI) and BT is widely popular due to its expanding importance in enhancing security and computational prowess. In this study, we present a comprehensive and meticulous comprehensive review of AI and BT‐based privacy‐preserving smart healthcare. The selection for this study was based on a holistic and integrated approach which involved examining not only individual studies but also their relationships, and trends. Through a systematic analysis of various phases, we identified 91 primary studies pertaining to information needed to stockpile directions called for retorting the research queries. We have undertaken a descriptive comparison of foundational manuscripts, taking into account an array of essential factors, including performance metrics, security protocols, and computational prowess. Our thorough discussions and debates have led to the identification of research gaps in the current manuscript, as well as the direction for future research. We also propose our constructive approach for the aforementioned integration, highlighting its potential benefits and implications.
Open access
Blockchain Technology Applications and Security
Privacy-Preserving Technologies in Data
Artificial Intelligence in Healthcare and Education
With the advancement of Urban Rail Transits (URTs), the demand for artificial intelligence (AI) based URTs services grows exponentially. Edge intelligence (EI) leverages computing resources on the network edge to provide realtime intelligent services in close proximity. As it enables fast distributed learning, EI is envisioned to be a potential component of URTs, and ideal EI service provision is a critical concern for the intelligent development of URTs. The existing EI-related research concentrates on the computation offloading of general AI-based tasks, whereas both the edge server deployment and AI model training process are not explicitly designed for URTs. The URTs AI service characteristics such as model training demand, priority, and security are largely ignored. In this paper, we propose a novel collaborative EI service provision framework for URTs. Blockchain is used along with the EI server to construct a trusted computing infrastructure. To address the EI service credit crisis, a blockchain-based trust management mechanism including short-term reward incentives and long-term reputation evaluation is designed in the trusted computing infrastructure. An HRL-based collaborative training service optimization model is proposed to improve the learning efficiency and edge resource utilization rate in URTs. Specifically, the proposed two-stage collaborative optimization model jointly considers high-level service scheduling and low-level task offloading. In addition, we present an intelligent train control model based on the state-ofthe-art decision transformer (DT), with the training service as a case study to demonstrate the effectiveness of the proposed collaborative EI service provision. Extensive simulation results show that the proposed EI service provision framework can provide trusted, efficient, and high-quality AI training services, simultaneously improving URTs operational efficiency.
The unmanned aerial vehicle (UAV) equipped with mobile-edge computing (MEC) can act as an air base station to provide computing services for Artificial Intelligence of Things (AIoT) devices in remote areas. However, the computation offloading process poses a risk to users’ privacy due to potential information leaks resulting from interactions between UAVs or migration of data between AIoT devices and UAVs. In this article, we proposed a secure aerial computing network that integrates MEC and blockchain technologies to effectively guarantee privacy and security during computation offloading between AIoT devices and UAVs. Additionally, taking into account task offloading scheduling, radio spectrum resource allocation, and computation resource allocation, a joint optimization problem is formulated to minimize the weighted sum of delay and energy consumption throughout the entire computing process. To tackle this issue, we proposed a block coordinate descent (BCD)-based algorithm to solve the mixed-integer and nonconvex problem. Simulation results demonstrate that the proposed algorithm surpasses other baseline approaches.
Federated Learning (FL) has emerged as a privacy-preserving distributed Machine Learning paradigm, which collaboratively trains a shared global model across a number of end devices (clients) without exposing their raw data. However, FL typically assumes that all clients are benign and trust the coordinating central server, which is unrealistic for many real-world scenarios. In practice, clients can harm the FL process by sharing poisonous model updates while the server could malfunction or misbehave. Moreover, the deployment of FL for real-world applications is hindered by the high communication overhead between the server and clients that are often at the network edge with limited bandwidth. To address these key challenges, we propose a lightweight Blockchain-Empowered secure and efficient Federated Learning (BEFL) system. BEFL is built by integrating a communication-efficient and mutual-information guarded training scheme, a cost-effective Verifiable Random Function (VRF)-based consensus mechanism, and Inter-Planetary File System (IPFS)-enabled scalable blockchain architecture. Extensive simulation experiments using two benchmark FL datasets demonstrate that BEFL is resistant against byzantine clients launching data poisoning and model poisoning attacks, fault-tolerant against colluded malicious blockchain nodes, scalable to a large number of blockchain nodes, and communication-efficient at the network edge.
Roberto Aparici Marino, Lorenzo Carnevale, Massimo Villari
Federated Learning (FL) is a cutting-edge technology for distributed solving of large-scale problems using local data exclusively. The potential of Federated Learning is nowadays clear in different context from automatic analysis of healthcare data to object recognition in video sources coming from public video streams, from distributed search for data breach and finance frauds to collaborative learning of hand typing on mobile phone. Multi-robot systems can also largely benefit from FL concerning resolution of problems like trajectory prediction, non colliding trajectory generation, distributed localization and mapping or distributed reinforcement learning. In this paper we propose a multi-robot framework that includes distributed learning capabilities by using Decentralized Stochastic Gradient Descent on graphs. First of all we motivate the position of the paper discussing the privacy preserving problem for multi robot systems and the need of decentralized learning. Then we build our methodology starting from a set of prior definitions. Finally we discuss in details the possible applications in robotics field.
Training contemporary AI models requires investment in procuring learning data and computing resources, making the models intellectual property of the owners. Popular model watermarking solutions rely on key input triggers for detection; the keys have to be kept private to prevent discovery, forging, and removal of the hidden signatures. We present ZKROWNN, the first automated end-to-end framework utilizing Zero-Knowledge Proofs (ZKP) that enable an entity to validate their ownership of a model, while preserving the privacy of the watermarks. ZKROWNN permits a third party client to verify model ownership in less than a second, requiring as little as a few KBs of communication.
<ns3:p>Continuous improvement in transportation systems and smart vehicles' appearance make new highly intensive applications. Complex applications need high-performance capabilities, real-time responses, and generate massive amounts of data to process and exchange. This presents the idea of vehicular edge computing (VEC), which is proposed to handle complex applications and satisfy smart vehicle processing requirements. VEC enables computation offloading to an edge server to reduce communication latency, execution cost and energy consumption greatly. However, offloading to another node opens up new vulnerabilities regarding security and privacy. Moreover, trust issues in such an untrustworthy environment need an effective trust management solution and incentive mechanisms to improve overall security. This will increase the computation offloading success rate and the vehicles' willingness to share their resources. Particularly given the high transportability and heterogeneity of vehicular networks, the conventional security and trust management methods are inadequate. Blockchain, the rapidly emerging trend technology, is a unique solution that can help overcome security and privacy issues and meet trust management and incentive mechanism goals. Blockchain’s immutable distributed ledger, traceability, consensus validation system and smart contract features can improve vehicular network security. Although most research is focused on enhancing the performance of computation offloading algorithms, blockchain security solutions in computation offloading scenarios are not fully discussed. Thus, security and trust issues related to computation offloading in VEC environments need more consideration since supporting the new complex vehicular applications is essential. Therefore, this paper provides a review of recent surveys and studies, an overview of VEC, computation offloading and blockchain, in addition to discussing security, privacy and trust in vehicular networks and computation offloading while considering blockchain as a distributed security solution. We propose a new paradigm called blockchain edge of vehicle (BEoV) at the end, which enables several blockchain-based security services for vehicular computation offloading in particular.</ns3:p>
Healthcare data is increasing in amount and complexity with the advent of technological advancements like wearable devices are capturing continuous health data to track chronic diseases such as diabetes. Trust-less centralized servers manage and control such data, raising concerns on privacy and security. A decentralized, permissioned blockchain-based approach can potentially give patients more control over medical data. In this paper, a blockchain-based patient-centric healthcare architecture is proposed to address the concerns of privacy, interoperability, data fragmentation, data ownership by centralized servers, data integrity, data access and data sharing. Patients’ diabetic data can only be accessed as per their agreed-upon access policy given their consent which is implemented using Ethereum smart contracts to ensure controlled exchange of sensitive data among various stakeholders. The smart contracts were tested in Truffle to validate the accuracy of their logic. A hybrid model is employed for data storage, that combines MongoDB, as the off-chain secure database and IPFS technologies for on-chain storage. The architecture is designed to be integrated with existing Electronic Health Records (EHRs) systems, promoting efficient and secure data sharing in the healthcare industry.
The adoption of the General Data Protection Regulation (GDPR) has resulted in a significant shift in how the data of European Union citizens is handled. A variety of data sharing challenges in scenarios such as smart cities have arisen, especially when attempting to semantically represent GDPR legal bases, such as consent, contracts and the data types and specific sources related to them. Most of the existing ontologies that model GDPR focus mainly on consent. In order to represent other GDPR bases, such as contracts, multiple ontologies need to be simultaneously reused and combined, which can result in inconsistent and conflicting knowledge representation. To address this challenge, we present the smashHitCore ontology. smashHitCore provides a unified and coherent model for both consent and contracts, as well as the sensor data and data processing associated with them. The ontology was developed in response to real-world sensor data sharing use cases in the insurance and smart city domains. The ontology has been successfully utilised to enable GDPR-complaint data sharing in a connected car for insurance use cases and in a city feedback system as part of a smart city use case.
H Shriya, Vivek P. Marakumbi, N Soumya, D. G. Narayan · 6 authors
Blockchain is an emerging technology that offers a wide range of applications in various sectors such as financial services, industrial products, healthcare, and media, among others. The important component of any blockchain system is the consensus algorithm. It plays a major role in deciding the performance, efficiency, and security of the blockchain network. Currently, there are over 30 consensus algorithms in use, including Proof-of-Work (PoW), Proof-of-Stake (PoS), and Proof-of-Authority (PoA), among others. However, these algorithms have drawbacks in terms of security, stability, and productivity. While PoW is widely used by popular cryptocurrencies, it is unsustainable and inadequate for ensuring blockchain-based security solutions. PoS is more vulnerable to the concentration of wealth, leading to potential system destabilization by those with significant stakes. To address these issues, Delegated Proof-of-Stake (DPoS) is created, an algorithm that eliminates the competition for computing resources in block production. This approach reduces the cost of block generation and introduces a fully PoS-based election system, but still has security issues. This work introduces an enhanced version of DPoS called Improved Delegated Proof-of-Stake (iDPoS), which includes a downgraded mechanism to eliminate malicious nodes while maintaining security. Performance analysis demonstrates that the improved consensus algorithm is more efficient compared to PoS and DPoS consensus algorithms.