Bitcoin is an electronic cryptocurrency developed based on Blockchain technology. With its decentralized feature, it has become incredibly popular since its invention. However, the Bitcoin network suffers from 51% attacks, where if malicious attackers’ control over half of the computing power, they are able to rewrite the network. The attackers are capable of doing so by initiating the Eclipse attack first, which aims to monopolize all communications from and to a controlled Bitcoin node. In this paper, we model and analyze the dependability of the Bitcoin network subject to the Eclipse and 51% attacks. We propose a hierarchical model that encompasses a continuous-time Markov chain method for the node-level dependability analysis and a multi-valued decision diagram method for the system-level dependability analysis. Detailed case studies on Bitcoin systems with homogeneous and heterogeneous nodes are conducted to demonstrate the proposed model and investigate the impacts of several critical parameters on Bitcoin network dependability.
Mohamed Litoussi, Khalid El Makkaoui, Abdellah Ezzati
Blockchain technology has been gaining popularity in recent years, with many industries exploring its potential applications. This innovative technology has the potential to revolutionize the way we do business and interact with each other. It has emerged as a revolutionary innovation that promises to transform various industries by enabling secure, transparent, and decentralized transactions. The blockchain is a distributed ledger technology that uses cryptography to ensure the integrity and immutability of data. In this article, we will provide an overview of blockchain, including definitions, architecture, security, applications, and future directions
Julião Braga, Francisco Regateiro, Itana Stiubiener, Juliana Cristina Braga
Human-algorithm interaction is a crucial issue for humanity in light of the impacts of the recent release of ChatGPT3 and 4, among others. These advanced chatbots provoked a worldwide debate in March/2023, when a manifesto signed by several stakeholders was published and widely discussed in the media and academia. This work assumes that human-algorithm interactions are influenced by a context of diverse interests and perspectives, which adds high complexity to the problem. Therefore, this work proposes a solution to enable the effective participation of stakeholders from different domains and society in a constructive dialogue, using digital platforms as a medium. Inspired by the successful governance of the Internet infrastructure ecosystem, the proposal involves the creation of an Autonomous Decentralized Organization (DAO) implemented in the blockchain environment of the Ethereum network. However, before implementing the DAO, it is necessary to build a knowledge base, that is, an ontology, which guides its development in a safe and adequate way. A preliminary version of this knowledge base was manually built using Protégé with over 4,000 axioms.
John Robert Bautista, Daniel Toshio Harrell, Ladd Hanson, Eliel Oliveira · 7 authors
Patients' control over how their health information is stored has been an ongoing issue in health informatics. Currently, most patients' health information is stored in centralized but siloed health information systems of healthcare institutions, rarely connected to or interoperable with other institutions outside of their specific health system. This centralized approach to the storage of health information is susceptible to breaches, though it can be mitigated using technology that allows for decentralized access. One promising technology that offers the possibility of decentralization, data protection, and interoperability is blockchain. In 2019, our interdisciplinary team from the University of Texas at Austin's Dell Medical School, School of Information, Department of Electrical and Computer Engineering, and Information Technology Services developed MediLinker-a blockchain-based decentralized health information management platform for patient-centric healthcare. This paper provides an overview of MediLinker and outlines its ongoing and future development and implementation. Overall, this paper contributes insights into the opportunities and challenges in developing and implementing blockchain-based technologies in healthcare.
The Internet of Things (IoT) has become a pervasive technology with various applications ranging from smart homes and cities to industrial automation and healthcare. However, the increasing adoption of IoT devices has also raised significant concerns about cybersecurity and privacy. Blockchain, as a distributed and immutable ledger technology, has been proposed as a potential solution to enhance the security and privacy of IoT systems. Blockchain-based IoT systems offer several benefits, such as decentralization, transparency, and data integrity. However, they also pose unique cybersecurity challenges that need to be addressed for their secure and reliable deployment. In this paper, we review the existing literature and highlight the key challenges in cybersecurity for blockchain-based IoT systems. We categorize these challenges into three main areas: (i) IoT device security, (ii) blockchain security, and (iii) integration of IoT devices with blockchain (network security). Through an in-depth analysis, we present the current state of research and discuss potential solutions for each challenge. Additionally, we contribute by identifying future research directions to address these challenges and enhance the cybersecurity of blockchain-based IoT systems.
Open access
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques
Abstract With the increase of IoT devices generating large amounts of user-sensitive data, improper firmware harms users’ security and privacy. Latest home appliances are integrated with features to assure compatibility with smart home IoT. However, applying complex security mechanisms to IoT is limited by device hardware capabilities, making them vulnerable to attacks. Such attacks have recently become frequent. To address this issue, we developed a secure verification mechanism for firmware released by the device’s manufacturer. We proposed an IoT gateway for secure firmware verification and updating for smart home IoT devices utilizing the IOTA MAM (Masked Authenticated Messaging) protocol and a distributed file system with IPFS (Inter-Planetary File System) protocol. These two communication protocols ensure decentralized communication and firmware file distribution between the IoT device vendor and the IoT end device. The proposed scheme securely shares latest firmware content over IOTA and IPFS networks, performs a secure firmware update on IoT end devices and ensures authenticity and integrity of the firmware. Two types of validation methods were proposed for firmware updating and validation. We implemented the proposed scheme using three entities, Vendor, IoT gateway, and IoT end device. Our system yielded promising results in performing secure automated firmware updates on IoT end devices with very low computational power. The system’s functionality was implemented using IOTA’s MAM run on Raspberry Pi as an IoT gateway along with an ESP8266 Wi-Fi microcontroller, demonstrating the effectiveness of our approach. Our proposed methodology can be used for secure firmware distribution on home IoT applications.
Tao Huang, Renchao Xie, Yuzheng Ren, F. Richard Yu · 10 authors
In recent years, the Industrial Internet and Industry 4.0 came into being. With the development of modern industrial intelligent manufacturing technology, digital twins, Web3 and many other digital entity applications are also proposed. These applications apply architectures such as distributed learning, resource sharing, and arithmetic trading, which make high demands on identity authentication, asset authentication, resource addressing, and service location. Therefore, an efficient, secure, and trustworthy Industrial Internet identity resolution system is needed. However, most of the traditional identity resolution systems follow DNS architecture or tree structure, which has the risk of a single point of failure and DDoS attack. And they cannot guarantee the security and privacy of digital identity, personal assets, and device information. So we consider a decentralized approach for identity management, identity authentication, and asset verification. In this paper, we propose a distributed trusted active identity resolution system based on the inter-planetary file system (IPFS) and non-fungible token (NFT), which can provide distributed identity resolution services. And we have designed the system architecture, identity service process, load balancing strategy and smart contract service. In addition, we use Jmeter to verify the performance of the system, and the results show that the system has good high concurrent performance and robustness.
As the fusion of the Internet of Things (IoT) and blockchain technology advances, it is increasingly shaping diverse fields. The potential of this convergence to fortify security, enhance privacy, and streamline operations has ignited considerable academic interest, resulting in an impressive body of literature. However, there is a noticeable scarcity of studies employing Latent Dirichlet Allocation (LDA) to dissect and categorize this field. This review paper endeavours to bridge this gap by meticulously analysing a dataset of 4455 journal articles drawn solely from the Scopus database, cantered around IoT and blockchain applications. Utilizing LDA, we have extracted 14 distinct topics from the collection, offering a broad view of the research themes in this interdisciplinary domain. Our exploration underscores an upswing in research pertaining to IoT and blockchain, emphasizing the rising prominence of this technological amalgamation. Among the most recurrent themes are IoT and blockchain integration in supply chain management and blockchain in healthcare data management and security, indicating the significant potential of this convergence to transform supply chains and secure healthcare data. Meanwhile, the less frequently discussed topics include access control and management in blockchain-based IoT systems and energy efficiency in wireless sensor networks using blockchain and IoT. To the best of our knowledge, this paper is the first to apply LDA in the context of IoT and blockchain research, providing unique perspectives on the existing literature. Moreover, our findings pave the way for proposed future research directions, stimulating further investigation into the less explored aspects and sustaining the growth of this dynamic field.
Zainab Khalid Mohammed, A. A. Zaidan, Hazleen Aris, Hassan A. Alsattar · 7 authors
Abstract Metaverse is a new technology expected to generate economic growth in Industry 5.0. Numerous studies have shown that current bitcoin networks offer remarkable prospects for future developments involving metaverse with anonymity and privacy. Hence, modelling effective Industry 5.0 platforms for the bitcoin network is crucial for the future metaverse environment. This modelling process can be classified as multiple-attribute decision-making given three issues: the existence of multiple anonymity and privacy attributes, the uncertainty related to the relative importance of these attributes and the variability of data. The present study endeavours to combine the fuzzy weighted with zero inconsistency method and Diophantine linear fuzzy sets with multiobjective optimisation based on ratio analysis plus the multiplicative form (MULTIMOORA) to determine the ideal approach for metaverse implementation in Industry 5.0. The decision matrix for the study is built by intersecting 22 bitcoin networks to support Industry 5.0's metaverse environment with 24 anonymity and privacy evaluation attributes. The proposed method is further developed to ascertain the importance level of the anonymity and privacy evaluation attributes. These data are used in MULTIMOORA. A sensitivity analysis, correlation coefficient test and comparative analysis are performed to assess the robustness of the proposed method.
Rafael Belchior, Jan Süßenguth, Qi Feng, Thomas Hardjono · 6 authors
Blockchain interoperability conflates the need for distributed systems to communicate with third- party systems without the existence of a canonical chain or orchestration layer. As there is not “a chain to rule them all” (due to reasons such as performance, privacy, and market forces), these distributed systems rely on exchanging data and value across network boundaries. Interconnected systems achieve a higher value than the sum of their parts, similar to how the Internet emerged as a set of isolated Local Area Networks (LANs) - and, by force of surprising synergies, such networks fundamentally transformed society, forever. Concurrently, in the last decade, we have witnessed the astonishing development of blockchain technologies, which seem more connected than ever: via bridges [13, 15, 16, 31], oracles [45], and other interoperability mechanisms [4, 9, 17, 48, 89]. These recent developments have, slowly but steadily, contributed to the improvement of the scalability of blockchain networks, as well as providing new functionality and use cases [66], but there is still a long way to go until mass adoption. In this paper, we will dive into the rabbit hole of blockchain interoperability and explain why it is needed, what has been done in the last decade, and where it is going.
The Lightning Network (LN), a second-layer protocol built atop Bitcoin, promises swift, low-cost transactions, thereby addressing blockchain scalability and enhancing user privacy. As the global financial technology landscape evolves, the LN’s importance in the future of fintech and the Fourth Industrial Revolution (4IR) becomes increasingly pivotal. The anticipated rise of blockchain-based payments and smart contracts in businesses demands a more agile and secure payment system. However, the LN’s early stage raises valid concerns about security and reliability, especially when implemented on a huge asymmetric network such as the Internet, potentially hindering its broader adoption. Malicious nodes could intentionally cause payment failures or initiate attacks, such as DDoS attacks, by overwhelming other nodes in the network with channel-opening requests. As a result, users will be discouraged from using the LN; hence, the technology will become obsolete as individuals will not waste the time and power investment required for using this technology. Addressing these issues, this paper proposes an innovative invitation model protocol (IMP) to reinforce the LN’s security and reliability. The IMP creates an exclusive ‘Club’ within the LN, admitting only nodes verified as honest, thereby bolstering network security and reliability. The protocol empowers Club Founders to expel members exhibiting malicious activities, thereby preserving the invested time, energy, and funds of the network’s users. The IMP was rigorously tested using Amazon Web Services Virtual Machines within the Bitcoin and Lightning Network’s Testnet environment, which is a highly asymmetric network. The results demonstrated the protocol’s efficacy in fulfilling its objectives, marking a significant step towards a safer and more efficient blockchain transaction network. As the blockchain continues to revolutionize the financial sector, implementing robust security measures such as the IMP becomes essential. This research paper introduces a novel approach to enhancing the reliability and security of a Lightning Network (LN), and thus distinguishes itself from the existing literature, by introducing an additional step before establishing or joining such a network. The research underscores the critical role of such protocols in realizing the potential of the LN in powering the next wave of fintech and industrial innovation.
Modern blockchains supporting smart contracts implement a new form of state machine replication with a trusted and decentralized paradigm. However, inefficient smart contract transaction execution severely limits system throughput and hinders the further application of blockchain.
Saeed Banaeian Far, Azadeh Imani Rad, Maryam Rajabzadeh Asaar
Without a doubt, the blockchain is one of the most valuable technological advancements to have been introduced over the past decade and has played a significant role in the industrial revolution. The emergence of technologies derived from blockchain, such as decentralized finance (DeFi) and the Metaverse, has fundamentally transformed people's daily lives and profoundly impacted future versions of digital businesses. This study explored the evolution of digital businesses in the near future, with a specific focus on the two primary technologies mentioned above. First, we reviewed DeFi-based technologies, including GameFi, SciFi, SocialFi, and others, which serve as foundational building blocks for future jobs and businesses. Second, we examined Metaverse-based jobs, such as Metaverse-based academies and markets, which are expected to be launched as commonly used businesses. Ultimately, this study provides several guidelines, such as how to use DeFi 2.0 and apply centralized decentralized finance (CeDeFi)-based platforms. Additionally, it offers future directions for launching these businesses, including controlling the progress of artificial intelligence (AI) in practical applications, utilizing cloud-assisted models for the Metaverse, and providing conditional privacy for future Metaverse-based businesses.
With the enhanced interoperability of information among vehicles, the demand for collaborative sharing among vehicles increases. Based on blockchain, the classical consensus algorithms in collaborative IoV (Internet of Vehicle), such as PoW (Proof of Work), PoS (Proof of Stake), and DPoS (Delegated Proof of Stake), only consider the node features, which is hard to adapt to the immediacy and flexibility of vehicles. On the other hand, classical consensus algorithms often require mass computing, which undoubtedly increases the communication overhead, resulting in the inability to achieve collaborative IoV under asymmetric networks. Therefore, proposing a low failure rate consensus algorithm that takes into account running time and energy consumption becomes a major challenge in IoV applications. This paper proposes an AI-enabled consensus algorithm with vehicle features, combining vehicle-based metrics and neural networks. First, we introduce vehicle-based metrics such as vehicle online time, performance, and behavior. Then, we propose an integral model and a hierarchical classification method, which combine with a BP neural network to obtain the optimal solution for interconnection. Among them, we also use Informer to predict the future online duration of vehicles, which effectively solves the situation that the primary node vehicle drops off in collaborative IoV. Finally, the experimentations show that the vehicle-based metrics eliminate the problem of the primary node vehicle being offline, which realizes the collaborative IoV considering vehicle features. Meanwhile, it reduces the vehicle network system delay and energy consumption.
The emerging field of the Internet of Vehicles (IoV) has garnered significant attention due to its potential to revolutionize transportation and mobility. IoV enables the development of innovative services and applications that can enhance the efficiency, safety, and sustainability of transportation systems. However, ensuring secure and reliable communication among different components of an IoV system poses a critical challenge. This study proposes a blockchain-based communication framework for secure and trustworthy IoV applications. The framework utilizes blockchain technology’s decentralization and security features to create secure communication channels between IoV system components, including vehicles, infrastructure, and service providers. An identity management system is also integrated into the framework to authenticate and authorize users and devices, thereby preventing unauthorized access and data breaches. To assess the proposed framework’s effectiveness, real-world IoV scenarios were used to conduct experiments, and the results demonstrate that the framework can provide secure and trustworthy communication for IoV applications. The proposed blockchain-enabled communication framework provides a promising solution for addressing security and trust challenges in IoV communication systems.
The exponential growth of the Internet of Things (IoT) is being witnessed nowadays in different sectors. This makes IoT data communications more complex and harder to manage. Addressing such a challenge using a centralized model is an ineffective approach and would result in security and privacy difficulties. Technologies such as blockchain provide a potential solution to enable secure and effective management of IoT data communication in a distributed and trustless manner. In this paper, a novel lightweight blockchain-centric IoT architecture is proposed to address effective IoT data communication management. It is based on an event-driven smart contract that enables manageable and trustless IoT data exchange using a simple publish/subscribe model. To maintain system complexity and overhead at a minimum, the design of the proposed system relies on a single smart contract. All the system operations that enable effective IoT data communication among the different parties of the system are defined in the smart contract. There is no direct blockchain–IoT-device interaction, making the system more useable in wide IoT deployments incorporating IoT devices with limited computing and energy resources. A practical Ethereum-based implementation of the system was developed with the ability to simulate different IoT setups. The evaluation results demonstrated the feasibility and effectiveness of the proposed architecture. Considering varying-scale and varying-density experimental setups, reliable and secure data communications were achieved with little latency and resource consumption.
Despite the recent increase in the popularity of blockchain, the technology suffers from the trilemma trade-off between security decentralisation and scalability prohibiting adoption, and limiting the efficiency and effectiveness of the induced system. Addressing the trilemma trade-off calls for dynamic management and configuration of the blockchain system. In particular, choosing an effective and efficient consensus protocol for balancing the trilemma trade-off when inducing the blockchain-based system is acknowledged to be a challenging problem given the dynamic and complex nature of the blockchain environment. DDDAS approaches are particularly suitable for this challenge, and in previous work, the authors presented a novel DDDAS-based blockchain architecture and demonstrated that it offers a promising approach for dynamically adjusting the parameters of a system and optimising for the trade-off. This paper presents a novel simulation tool that can support and satisfy the DDDAS requirements for a dynamically re-configurable blockchain system. The tool supports the simulation and the dynamic switching of consensus protocols, analysing their trilemma trade-off. The simulator design is modular and allows the implementation and analysis of a wide range of consensus protocols and their implementation scenarios, along with the ability for parallelization. The paper also presents a quantitative evaluation of the tool.
Yu Qiu, Haijun Zhang, Kai Sun, Keping Long · 5 authors
Recently, Web3 has received extensive attention as the next generation Internet and is in rapid development, which can highly integrate the physical world with the digital world. The blockchain that can build trust and fog computing with distributed computing mode can fit well with the decentralization idea of Web3. The combination of the two can provide an effective solution for the implementation of Web3. This article proposes a new network architecture, fog-assisted blockchain radio access network (FogBC-RAN), which supports stable and mutual trust connections on a global scale, and can smoothly coordinate multi-dimensional resources to support new services such as holographic communication, digital twin, and sensory interconnection. With the interconnection of ten thousand chains in the future Web3, the cross-chain information transfer process based on Polkadot for charging sharing is presented, which can realize flexible cross-chain transactions. Meanwhile, for the mainstream computing-intensive applications of Web3, considering the latency, energy consumption and transaction cost, a computing offloading strategy based on matching game is proposed to minimize the system cost. Finally, the simulation results demonstrate the effectiveness of the offloading mechanism proposed in FogBC-RAN.
Internet of Things (IoT) has made significant strides in energy management systems recently. Due to the continually increasing cost of energy, supply-demand disparities, and rising carbon footprints, the need for smart homes for monitoring, managing, and conserving energy has increased. In IoT-based systems, device data are delivered to the network edge before being stored in the fog or cloud for further transactions. This raises worries about the data's security, privacy, and veracity. It is vital to monitor who accesses and updates this information to protect IoT end-users linked to IoT devices. Smart meters are installed in smart homes and are susceptible to numerous cyber attacks. Access to IoT devices and related data must be secured to prevent misuse and protect IoT users' privacy. The purpose of this research was to design a blockchain-based edge computing method for securing the smart home system, in conjunction with machine learning techniques, in order to construct a secure smart home system with energy usage prediction and user profiling. The research proposes a blockchain-based smart home system that can continuously monitor IoT-enabled smart home appliances such as smart microwaves, dishwashers, furnaces, and refrigerators, among others. An approach based on machine learning was utilized to train the auto-regressive integrated moving average (ARIMA) model for energy usage prediction, which is provided in the user's wallet, to estimate energy consumption and maintain user profiles. The model was tested using the moving average statistical model, the ARIMA model, and the deep-learning-based long short-term memory (LSTM) model on a dataset of smart-home-based energy usage under changing weather conditions. The findings of the analysis reveal that the LSTM model accurately forecasts the energy usage of smart homes.
Chengzu Dong, Jingwen Zhou, Qi An, Frank Jiang · 6 authors
The rapid advancements in technology have led to the emergence of innovative concepts like Unmanned Aerial Vehicle (UAV) delivery systems, the Metaverse, and Blockchain. As these technologies gain traction, their integration is expected to revolutionize various industries. In this paper, we propose a Blockchain-based Metaverse UAV delivery solution and a secure consensus protocol for UAV deliveries in Metaverse. Also, we conduct throughput tests using Ethereum permissioned chain. The results are promising, demonstrating that drone delivery will be an important element in future Metaverse shopping experiences. This research investigates the convergence of UAV delivery systems, the Metaverse, and Blockchain, and their implications for the future of virtual shopping experiences. The study investigates the opportunities and challenges arising from the integration of these technologies and assesses their potential synergies through the literature review and real-world case studies. Also, the experimental results demonstrate the effectiveness of our proposed architecture and consensus algorithm for drone deliveries, highlighting its ability to handle increasing network loads and maintain optimal performance.
Abstract This entire system stands upon blockchain technology. The system is initially broken down in sections like different modules for patient, doctor, pharmacy and insurance agent. It is completed utilising a personal blockchain from Corda and Ethereum called Ganache as well as a private blockchain. This supports the development, testing, and general deployment of dApps. An Ethereum development framework is called Truffle Suite. Completely control the lifetime of modern contracts that includes bespoke installations, linking with different libraries and intricate applications on Ethereum. In dApps, Meta Mask is usefull for account creation, login and bitcoin transcations. The storage of all huge files and documents is done using the IPFS technology. Because IPFS is a P2P network circuit for decentralised data storage and the produced hash is simple to store on the blockchain, it is used. ReactJS was used to build the system’s front end. The Remix online compiler for Solidity is used to build and test smart and modern contracts that are written in the Solidity blockchain programming language.
The alliance chain system is a distributed ledger system based on blockchain technology, which can realize data sharing and collaboration among multiple parties while ensuring data security and reliability. The Practical Byzantine Fault Tolerance (PBFT) consensus algorithm is the most popular consensus protocol in the alliance chain, but the algorithm has problems such as high complexity and too simple election of the master node, which will make PBFT unable to be applied in scenarios with too many nodes. At the same time, there are certain security issues. In order to solve these problems, this paper proposes an improved Byzantine consensus algorithm, Polymerization Signature and Reputation Value PBFT (P-V PBFT). Firstly, the consistency protocol process is improved based on the aggregate signature technology. The simulation results show that the P-V PBFT algorithm can effectively reduce the overhead of network transmission, and the time complexity of the algorithm decreases exponentially, which improves the efficiency of the consensus process. Secondly, the node reputation election mechanism is introduced to elect the primary node, and the security analysis is carried out to verify the fairness and security of the primary node election of the P-V PBFT algorithm. Therefore, as a feasible improvement of the blockchain consensus protocol, the P-V PBFT algorithm can provide more efficient and secure guarantee for the blockchain system in practical application.
Engin Zeydan, Jorge Baranda, Josep Mangues‐Bafalluy, Yekta Türk
In the coming years, blockchain technologies will be used in a variety of industries, including telecommunications. In this article, due to strict governance of telecommunication infrastructure, we propose a blockchain supported architecture, based on a permissioned distributed ledger (PDL) scheme, for a network management and orchestration platform. The main goal is to create a trusted environment for multiple-stakeholders, such as Cloud Service Providers (CSPs), a Mobile Network Operator (MNO), Vertical Service Providers (SPs), Legal and Regulation Authorities, and Responsible Ministry so that the life cycle of automated vertical network services (e.g., instantiation, scaling, termination, and migration/reallocation) can be managed securely and transparently in a multi-cloud and multi-domain environment. The proposed approach is also validated with an experimental Industry 4.0 scenario using the Quorum blockchain network (BCN) to measure various performance metrics (e.g., number of transactions and blocks, and time to write) of various service orchestrator (SO)-related instantiation metrics. At the end of the article, we present the main discussions on the evaluation results and existing standardization efforts for the convergence of BCN, Management and Orchestration (MANO), and network services for a given telecommunication infrastructure.
Healthcare is an emerging sector with the integration of emerging technologies aiming to improve Quality of Life of an individual through various medical services. Most of the healthcare services work with sensitive information of patients either collected in real-time using body implanted sensors or through various IoT enabled medical devices during the diagnosis in a centrally controlled model. But, the traditional IoT based medical services suffer from several challenges such as data security, privacy, interoperability, single point of failure, scalability, and data integrity. However, by considering the advantages of Blockchain technology and the disadvantages of IoT systems, the amalgamation of a decentralised, distributed ledger technology with the IoT for various healthcare applications will strengthen the system by resolving the major challenges. Thus, this research article conducts a comprehensive survey on the integration of Blockchain and IoT (BCIoT) for Healthcare services, focusing mainly on existing approaches, possibilities, applications and challenges. First, we present a detailed overview of Blockchain, IoT and the motivation for BCIoT along with the survey on existing healthcare applications. Next we discuss the enabling platforms for BCIoT based healthcare services. For the better understanding, we review the role of BCIoT in Remote patient monitoring, electronic heath record management, Health asset tracing, Covid-19 infected patient contact tracking. Finally challenges and future directions are discussed to improve the Quality of Life of patients through Healthcare applications.