The journey towards Industry 4.0 have driven the workforce with the need for continuous competency development to stay on top of their profession and remain attractive to their employers. In this context, E-Portfolio has been conceived as a promising tool for both professionals and employers, in assessing and providing guidance for further workplace learning. Nevertheless, the challenges in implementing E-Portfolio are daunting, particularly with regard to lack of interoperability while collecting and sharing the competency evidences across multiple organizations and institutions. The increasing move towards professional (learner)-centered interoperability poses additional challenges that needs to be addressed to realize the full potential of E-Portfolio in the context of Industry 4.0. This work puts emphasize on realization of professional-centered interoperability and proposes a framework leveraging the advantage of blockchain, decentralized storage system interplanetary file system, smart contract and session management for E-Portfolio creation and sharing evidences across multiple organizations without comprising the confidentiality, integrity and availability of the shared evidences. The proof of concept simulation on Ethereum official test network Rinkeby demonstrates the feasibility of proposed framework in practice. In addition, the evaluation of the proposed framework demonstrates its effectiveness from the aspects of cost and security as a potential solution for implementing E-Portfolio and helping the professional to remain competitive in global labor market.
Blockchain is a technology that allows the recording of information in a way that it is difficult or practically impossible to alter, hack, or cheat. It is a new, promising technology, considered by many as a general-purpose technology (GPT). GPTs are technologies that have the potential to affect an entire economy, impacting economic growth and transforming both everyday life and the ways in which we conduct business. We present a bibliometric analysis of the relevant literature, followed by a discussion about monetary mediums and the evolution of bitcoin, as the first digital medium managing to solve the “double-spending” problem and the first successful implementation of blockchain technology. The computational operations involved in blockchain are presented, together with the cryptographic technologies associated with it, its unique characteristics, and the advantages it offers as a technology. A comprehensive literature review is provided, of the current state of the art in blockchain in the fields of civil engineering, architecture and the construction industry. Six important application areas are identified, and the relevant literature is investigated. Namely, building information modelling and computer aided design, contract management and smart contracts, construction project management, smart buildings and smart cities, construction supply chain management, and real estate. Finally, we discuss the future applications, the challenges and the opportunities that blockchain technology brings to these fields.
Muhammad Asif, Zeeshan Aziz, Maaz Bin Ahmad, Adnan Khalid · 6 authors
Security has always been the main concern for the internet of things (IoT)-based systems. Blockchain, with its decentralized and distributed design, prevents the risks of the existing centralized methodologies. Conventional security and privacy architectures are inapplicable in the spectrum of IoT due to its resource constraints. To overcome this problem, this paper presents a Blockchain-based security mechanism that enables secure authorized access to smart city resources. The presented mechanism comprises the ACE (Authentication and Authorization for Constrained Environments) framework-based authorization Blockchain and the OSCAR (Object Security Architecture for the Internet of Things) object security model. The Blockchain lays out a flexible and trustless authorization mechanism, while OSCAR makes use of a public ledger to structure multicast groups for authorized clients. Moreover, a meteor-based application is developed to provide a user-friendly interface for heterogeneous technologies belonging to the smart city. The users would be able to interact with and control their smart city resources such as traffic lights, smart electric meters, surveillance cameras, etc., through this application. To evaluate the performance and feasibility of the proposed mechanism, the authorization Blockchain is implemented on top of the Ethereum network. The authentication mechanism is developed in the node.js server and a smart city is simulated with the help of Raspberry Pi B+. Furthermore, mocha and chai frameworks are used to assess the performance of the system. Experimental results reveal that the authentication response time is less than 100 ms even if the average hand-shaking time increases with the number of clients.
In this digital world, information technology is growing day by day. Due to this, a large amount of data is generated every day from various domains, and one of the domains is medical health records. A large amount of medical data is generated every day. Such as electronic medical records, medical images, diagnostic reports, X-rays, MRI scans, etc. These medical records can help in treating a patient when needed and can be shared with different medical institutions. There are systems built that are used to store all the medical records of patients. But they are centralized and may not be secured, and a user may not know how and where these records are shared. However, if these medical records are leaked or shared with a third party, the owner of that medical record may not know how and where these medical records are used, thus sabotaging the patient's privacy. Therefore, controlling the access rights to medical data is an urgent issue. On the other hand, patients do not have any proper application that will help them store and view their history of medical records and have control over them. This project aims to build a decentralized application to store the medical records of patients on the Ethereum Blockchain and Inter Planetary File System (IPFS). This app will help users to keep electronic medical records in one place, and the user will have full control over their data. This app will help doctors diagnose the patients by seeing their medical history. This will also help researchers to research various diseases. This app will store the data of patients from doctors and pathology labs. Users will be able to control who can add the medical details and see them. They can give access and revoke it. This application will store the file in DICOM, JPEG, JPG, PNG, and PDF format. In this application, there is no centralized authority. This application is secured because of peer-to-peer and distributed networks, it is tamper-proof. User has control over their data. They can choose whom to share their data with, and blockchain is reliable.
Filipe Pinto, Catarina Ferreira da Silva, Sérgio Moro
To understand how distributed ledger technology (DLT) enables people-centered IoT solutions we conducted a systematic literature review of tested implementations since 2017. We created a people-centered classification to analyze 39 implementations. We found that people-centered DLT-IoT architectures are in their infancy and detected no evidence of emerging patterns. We observed that Ethereum is the most used DLT. Fit-for-purpose technologies like IOTA and concepts like Self-Sovereign Identity (SSI) were underrepresented. We noted an increased interest in privacy-preserving and edge-computing mechanisms, and identified three areas for future research. We hope this survey will assist others learning more about people-centered IoT solutions.
Sultan Algarni, Fathy Eassa, Khalid Ali Almarhabi, Abdullah Algarni · 5 authors
Software-defined networking (SDN) has emerged as a flexible and programmable network architecture that takes advantage of the benefits of global visibility and centralized control over a network. One of the main properties of the SDN architecture is the ability to offer a northbound interface (NBI), which enables network applications to access the SDN controller resources. However, the NBI can be compromised by a malicious application due to the lack of standardization and security aspects in the most current NBI designs. Therefore, in this paper, we propose a novel comprehensive security solution for securing the application–controller interface, named BCNBI. We propose a controller-independent lightweight blockchain architecture and exploit the security features of blockchain while limiting the blockchain’s computational overhead. BCNBI automatically verifies application and SDN controller credentials through token-based authentication. The proposed solution enforces fine-grained access control for each application’s API request and classifies the permission set into strict and normal policies, in order to add an extra level of security. In addition, the trustworthiness of applications is evaluated in order to prevent malicious activities. We implemented our blockchain-based solution to analyze its security, based on the confidentiality–integrity–availability model criteria, and evaluated the introduced overhead in terms of processing time and packet overhead. The experimental results demonstrate that the BCNBI can effectively secure the NBI, based on the fundamental security goals, while introducing insignificant overhead.
Kelechi G. Eze, Cajetan M. Akujuobi, Shermar Hunter, Shumon , Alam · 6 authors
The Internet of Things (IoT) is growing at a very fast pace and being increasingly adopted in many scenarios of industrial applications such as energy (smart grid), automobile (smart cars), healthcare (smart healthcare), manufacturing (smart manufacturing and supply chain) and other application such as homes (smart home) and cities (smart city). Nonetheless, these IoT technologies (devices, systems, protocols, and applications) are faced with many security-related issues. IoT Systems have different layers that are vulnerable to various kinds of attacks. To defend against these attacks, one must consider appropriate security approaches and mechanisms to ensure privacy, security, and trust within the various components and layers that make up the IoT system. Appropriate security mechanism is needed at every layer of an IoT system to keep them secure. Hence, finding suitable mechanism for each IoT layer is a necessity to keep IoT systems secure in the 21st-century applications and implementations. The paper first investigates the IoT layers and protocols, their vulnerability issues, and methods to resolve the issues from existing literatures. We then present a blockchain-based security architecture for the internet of things and practically investigated its security feature through implementation of various security mechanism. Analysis and discussion of the blockchain implementation results are carried for the purpose of meeting the security, privacy, and trust requirements of IoT.
Wen Hai-ying, Meiyan Wei, Danlei Du, Xiangdong Yin
With the rapid development of mobile medical, how to establish an effective security mechanism to protect data security and privacy while users enjoy medical services has become an urgent problem to be solved. Aiming at the easy leakage of privacy in mobile medical terminals and untrustworthy data, we make use of a role-separated mechanism to generate trusted anonymous certificates. We propose a lightweight identity authentication scheme and adopt blockchain to protect the security of medical data. Meanwhile, in view of the problems of transparency and visibility of blockchain information, we adapt the searchable encryption algorithm to realize ciphertext processing in the whole life cycle. Experiments show that our scheme can reduce the cost of computation on the basis of ensuring traffic. In the process of dynamic updating of ciphertext keywords, except the keyword identifier, less information is leaked to the server, which protects privacy of users.
Akram Alofi, Mahmoud A. Bokhari, Rami Bahsoon, Robert Hendley
Blockchain technology has gained recognition in industrial, financial, and various technological domains for its potential in decentralizing trust in peer-to-peer systems. A core component of blockchain technology is a consensus algorithm, most commonly Proof of Work (PoW). PoW is used in blockchain-based systems to establish trust among peers; however, it does require the expenditure of an enormous amount of energy that affects the environmental sustainability of blockchain-based systems. Energy minimization, whilst ensuring trust within blockchain-based systems that use PoW, is a challenging problem. The solution has to consider how energy consumption can be minimized without compromising trust, whilst still ensuring, for instance, scalability, security, and decentralization. In this paper, we represent the problem as a subset selection problem of miners in a blockchain-based system. We formulate the problem of blockchain energy consumption as a Search-Based Software Engineering problem with four objectives: energy consumption, carbon emission, decentralization, and trust. We propose a model composed of multiple fitness functions. The model can be used to explore the complex search space by selecting a subset of miners that minimizes the energy consumption without drastically impacting the primary goals of the blockchain technology (i.e., security/trustworthiness and decentralization). We integrate our proposed fitness functions into five evolutionary algorithms to solve the problem of blockchain miners selection. Our results show that the environmental sustainability of blockchain-based systems (e.g. reduced energy use) can be enhanced with little degradation in other competing objectives. We also report on the performance of the algorithms used.
This article surveys the latest developments in the technological landscape that enables remote health care. First, the most important technologies that are crucial for remote health care such as 5G, medical IoT, big data analytics, machine learning, and distributed ledger technologies, etc., are outlined, and then a thorough survey on those technologies with latest state-of-the-art applications in remote health care is conducted. Furthermore, very important research challenges and future research directions are laid out to initiate further research on those very important technologies that enable remote health care.
Filippos Pelekoudas‐Oikonomou, Georgios Zachos, Μαρία Παπαϊωάννου, Marcus de Ree · 7 authors
Despite the significant benefits that the rise of Internet of Medical Things (IoMT) can bring into citizens' quality of life by enabling IoMT-based healthcare monitoring systems, there is an urgent need for novel security mechanisms to address the pressing security challenges of IoMT edge networks in an effective and efficient manner before they gain the trust of all involved stakeholders and reach their full potential in the market of next generation IoMT-based healthcare monitoring systems. In this context, blockchain technology has been foreseen by the industry and research community as a disruptive technology that can be integrated into novel security solutions for IoMT edge networks, as it can play a significant role in securing IoMT devices and resisting unauthorized access during data transmission (i.e., tamper-proof transmission of medical data). However, despite the fact that several blockchain-based security mechanisms have already been proposed in the literature for different types of IoT edge networks, there is a lack of blockchain-based security mechanisms for IoMT edge networks, and thus more effort is required to be put on the design and development of security mechanisms relying on blockchain technology for such networks. Towards this direction, the first step is the comprehensive understanding of the following two types of blockchain-based security mechanisms: (a) the very few existing ones specifically designed for IoMT edge networks, and (b) those designed for other types of IoT networks but could be possibly adopted in IoMT edge networks due to similar capabilities and technical characteristics. Therefore, in this paper, we review the state-of-the-art of the above two types of blockchain-based security mechanisms in order to provide a foundation for organizing research efforts towards the design and development of reliable blockchain-based countermeasures, addressing the pressing security challenges of IoMT edge networks in an effective and efficient manner.
Internet of Vehicles (IoVs) consist of smart vehicles, Autonomous Vehicles (AVs) as well as roadside units (RSUs) that communicate wirelessly to provide enhanced transportation services such as improved traffic efficiency and reduced traffic congestion and accidents. IoVs, however, suffer from issues of security, privacy and trust. Blockchain technology has been emerged as a decentralized approach for enhanced security without depending on trusted third parties to run services. Blockchain offers the benefits of trustworthiness, immutability, and mitigates the problem of single point of failure and other attacks. In this work, we present the state-of-the-art of Blockchain-enabled IoVs (BIoV) with a particular focus on their applications such as crowdsourcing-based applications, energy trading, traffic congestion reduction, collision and accident avoidance and infotainment and content cashing. We also present in-depth applications federated learning (FL) applications for BIoVs. The key challenges resulted from the integration of Blockchain with IoV is investigated in several domains such as edge computing, ML, and FL. Lastly, a number of open issues and challenges as well as future opportunities in the area of AI-enabled BIoV, hardware-assisted security for BIoV and quantum computing attacks on BIoV.
Nguyen Khoi Tran, Muhammad Ali Babar, Andrew J. Walters
Blockchain network deployment and evaluation have become prevalent due to the demand for private blockchains by enterprises, governments, and edge computing systems. Whilst a blockchain network's deployment and evaluation are driven by its architecture, practitioners still need to learn and carry out many repetitive and error-prone activities to transform architecture into an operational blockchain network and evaluate it. Greater efficiency could be gained if practitioners focus solely on the architecture design, a valuable and hard-to-automate activity, and leave the implementation steps to an automation framework. This paper proposes an automation framework called NVAL (Network Deployment and Evaluation Framework), which can deploy and evaluate blockchain networks based on their architecture specifications. The key idea of NVAL is reusing and combining the existing automation scripts and utilities of various blockchain types to deploy and evaluate incoming blockchain network architectures. We propose a novel meta-model to capture blockchain network architectures as computer-readable artefacts and employ a state-space search approach to plan and conduct their deployment and evaluation. An evaluative case study shows that NVAL successfully combines seven deployment and evaluation procedures to deploy 65 networks with 12 different architectures and generate 295 evaluation datasets whilst incurring a negligible processing time overhead.
Because of its many advantages, big data has been extending to various domains of science, health, education, and commerce. Despite its many applications, big data sharing typically suffers from some key issues, such as user control, lack of incentives, cost, and the right of data. This paper proposes a decentralized big data sharing prototype to improve the applications and services of big data. The method makes use of Ethereum blockchain and related technologies to systematically recommend the implementation guidelines. The research provides a detailed description of the design and implementation of each sublayer of a big data system. As the method is based on blockchain technology, the key technical points are properly addressed in each of the layers. For evaluation, relevant data were collected, and functional testing was performed. A comparison was performed about the sharing frequency and blockchain consensus performance of similar platforms. The dual mining node of the proposed prototype succeeded in processing 1366 blocks and 300 messages. A comparatively satisfactory file access time in the range of 10 m to 20 s and file transmission time between 100 m and 200 s were achieved. The results obtained show that this prototype can effectively verify the feasibility of the model, the layered architecture, and the related sharing mechanism. For the functional and performance testing, practical projects were implemented and evaluated. The promising results obtained testify that the research offers a theoretical background for innovative research in the domain and specialized guidelines for practical implementation.
The Industrial Internet of Things (IIoT) plays an important role in Industry 4.0, but the existing IIoT systems could be vulnerable to a single point of failure and malicious attacks, failing to provide reliable services. IIoT devices have some particularities, such as mobility, limited performance, and distributed deployment, which are challenging to traditional centralized access control methods in the large-scale IIoT environment. To resolve the challenges, we propose an access control system for the Industrial Internet of Things. The system contains three smart contracts: device contract (DC), policy contract (PC), and access contract (AC). The device contract provides a method of storing the URL of the resource data generated by the equipment and a query method. The policy contract provides the function of managing the attribute-based access control (ABAC) of the administrator user. The access contract is the core program that implements the access control method for ordinary users. Combining ABAC and blockchain technology provides decentralized, fine-grained, and dynamic access control management for IIoT.
Identity (ID) management systems have evolved based on traditional data modelling and authentication protocols that are facing security, privacy, and trust challenges with the growth of Internet of Things (IoT). Research surveys reveal that blockchain technology offers special features of self-sovereign identity and cryptography that can be leveraged to address the issues of security breach and privacy leaks prevalent in existing ID management systems. Although research studies are recently exploring the suitability of blockchain based support to existing infrastructure, there is a lack of focus on IoT ecosystem in the secured ID management with data provenance of digital assets in businesses. In this paper, we propose a blockchain based ID management system for computing assets in an IoT ecosystem comprising of devices, software, users, and data operations. We design and develop a proof-of-concept prototype using a federated and distributed blockchain platform with smart contracts to support highly trusted data storage and secure authentication of IoT resources and operations within a business case scenario.
Since Facebook officially changed its name to Metaverse in Oct. 2021, the metaverse has become a new norm of social networks and three-dimensional (3D) virtual worlds. The metaverse aims to bring 3D immersive and personalized experiences to users by leveraging many pertinent technologies. Despite great attention and benefits, a natural question in the metaverse is how to secure its users' digital content and data. In this regard, blockchain is a promising solution owing to its distinct features of decentralization, immutability, and transparency. To better understand the role of blockchain in the metaverse, we aim to provide an extensive survey on the applications of blockchain for the metaverse. We first present a preliminary to blockchain and the metaverse and highlight the motivations behind the use of blockchain for the metaverse. Next, we extensively discuss blockchain-based methods for the metaverse from technical perspectives, such as data acquisition, data storage, data sharing, data interoperability, and data privacy preservation. For each perspective, we first discuss the technical challenges of the metaverse and then highlight how blockchain can help. Moreover, we investigate the impact of blockchain on key-enabling technologies in the metaverse, including Internet-of-Things, digital twins, multi-sensory and immersive applications, artificial intelligence, and big data. We also present some major projects to showcase the role of blockchain in metaverse applications and services. Finally, we present some promising directions to drive further research innovations and developments towards the use of blockchain in the metaverse in the future.
In recent years, due to the wide implementation of mobile agents, the Internet-of-Things (IoT) networks have been applied in several real-life scenarios, servicing applications in the areas of public safety, proximity-based services, and fog computing. Meanwhile, when more complex tasks are processed in IoT networks, demands on identity authentication, certifiable traceability, and privacy protection for services in IoT networks increase. Building a blockchain system in IoT networks can greatly satisfy such demands. However, the blockchain building in IoT brings about new challenges compared with that in the traditional full-blown Internet with reliable transmissions, especially in terms of achieving consensus on each block in complex wireless environments, which directly motivates our work. In this study, we fully considered the challenges of achieving a consensus in a blockchain system in IoT networks, including the negative impacts caused by contention and interference in wireless channel, and the lack of reliable transmissions and prior network organizations. By proposing a distributed consensus algorithm for blockchains on multi-hop IoT networks, we showed that it is possible to directly reach a consensus for blockchains in IoT networks, without relying on any additional network layers or protocols to provide reliable and ordered communications. In our theoretical analysis, we showed that our consensus algorithm is asymptotically optimal on time complexity and is energy saving. The extensive simulation results also validate our conclusions in the theoretical analysis.
Metaverse depicts a vista of constructing a virtual environment parallel to the real world so people can communicate with others and objects through digital entities. In the real world, communication relies on identities and addresses that are recognized by authorities, no matter the link is established via post, email, mobile phone, or landline. Metaverse, however, is different from the real world, which requires a single identity belongs to the individual. This identity can be an encrypted virtual address in the metaverse but no one can trace or verify it. In order to achieve such addresses to hide individuals in the metaverse, re-mapping the virtual address to the individual's identity and a specific spectrum to support the address-based communication for the metaverse are needed. Therefore, metaverse native or meta-native communications based on blockchain could be a promising solution to directly connect entities with their native encrypted addresses that gets rid of the existing network services based on IP, cellular, HTTP, etc. This paper proposes a vision of blockchain, encrypted address and address-based access model for all users, devices, services, etc. to contribute to the metaverse. Furthermore, the allocation architecture of a designated spectrum for the metaverse is proposed to remove the barrier to access to the metaverse/blockchain in response to the initiatives of metaverse and decentralized Internet.
Blockchain was always associated with Bitcoin, cryptocurrencies, and digital asset trading. However, its benefits are far beyond that. It supports technologies like the Internet-of-Things (IoT) to pave the way for futuristic smart environments, like smart homes, smart transportation, smart energy trading, smart industries, smart supply chains, and more. To enable these environments, IoT devices, machines, appliances, and vehicles, need to intercommunicate without the need for centralized trusted parties. Blockchain replaces these trusted parties in such trustless environments. It provides security enforcement, privacy assurance, authentication, and other key features to IoT ecosystems. Besides IoT-Blockchain integration, other technologies add more benefits that attract the research community. Software-Defined Networking (SDN), Fog, Edge, and Cloud Computing technologies, for example, play a key role in enabling realistic IoT applications. Moreover, the integration of Artificial Intelligence (AI) provides smart, dynamic, and autonomous decision-making capabilities for IoT devices in smart environments. To push the research further in this domain, we provide in this paper a comprehensive survey that includes state-of-the-art technological integration, challenges, and solutions for smart environments, and the role of these technologies as the building blocks of such smart environments. We also demonstrate how the level of integration between these technologies has increased over the years, which brings us closer to the futuristic view of smart environments. We further discuss the current need to provide general-purpose Blockchain platforms that can adapt to unique design requirements of different applications and solutions. Finally, we provide a simplified architecture of futuristic smart environments that integrate these technologies, showing the advantage of such integration.
Ahmed G. Gad, Diana T. Mosa, Laith Abualigah, Amr A. Abohany
At present times, Blockchain technology is gaining more attraction with every passing day, as it has revolutionized the traditional trade due to its distributed ledger feature, every record in this ledger is secured by rules of cryptography which makes it more secure and tamper-free. This naturally led to the emergence of various types of cryptocurrency, such as Bitcoin, which builds on a technology commonly known as Blockchain. The rapid evolution of research on Blockchain calls for more research studies for investigating and analyzing the current knowledge in this field through a systematic technical study that shows the impact and significance of the related literature since the inception of the technology in 2013. From this point, in this paper, a state-of-the-art review is conducted on the most influential articles, conference papers, and review papers related to Blockchain published from 2013 to 2020 and indexed by the Web of Science Core CollectionTM (WoS) world’s literature database. To attain the desired objective, after presenting an inevitable, brief overview of Blockchain technology, the collected papers have closely been analyzed along seven key research questions. Subsequently, vital valuable findings, such as the top 10 influential papers, yearly publications and citation trends, the favorite publication venues, the hottest research areas, and the most supportive funding bodies are reported, which may offer several implications about the status quo and emerging trends and frontiers of Blockchain, to guide towards establishing a baseline for both fresh and experienced researchers and practitioners before initiating a future research project on Blockchain. Furthermore, a rigorous discussion is provided on Blockchain application in diversified domains, along with different versatile use cases. Lastly, a brief insight is presented into open challenges and potential future advancements in the field of Blockchain. Summing up, this paper is meant to assist newbies in exploring and designing new Blockchain solutions, bearing in mind existing demands and challenges.
Andi Arniaty Arsyad, Irawan Widi Widayat, Mario Köppen
For more than a decade, various farm-specific models have been developed by collaborating and integrating sensing technologies as a step toward successful data-farm documentation and effective decision-making. However, the stored and gathered data continues to rely on cloud infrastructure or centralized platform control, which is particularly vulnerable to threats such as data tampering, data distortion, confidentiality, and manipulation, which caused the farm product data difficult to trace to its provenance. In this paper, we propose a farm transaction model by demonstrating a flow of farm transaction simulation implicated by MBC sensing instrument with an array of sensors, controllers, networking hardware, computing equipment, and internal memory functions to enhance data integrity and security farm object. Based on the proposed model, a proof-of-concept experimental system called Encapsulating Block Mesh (EBM) integrates blockchain technology with the specific application case of cocoa production has been implemented. Results have shown that farm objects represented by MBC take turn recording information on the process of generating, transacting, and consuming a farm product and encrypting it into a block was validated and linked in the EBM with the hash of transaction data that connected to each cocoa farm object in a simulation environment.
Ana Margarida Cachada, Hasmik Badikyan, Camilo Anzola-Rojas, Javier Parra-Domínguez · 6 authors
Agriculture traceability demands a large volume of data that needs to be collected across the supply chain. Very early tracking and traceability systems used workers to record the information manually which entails risks, such as faulty information recording as well as inefficient resource usage. The implementation of tamper proof semi-automated digital ledgers will have a great impact on issues such as compliance with regulations, food provenance, food fraud, and many others, and therefore will gradually increase the trust within the supply chain. This paper provides an overview on the different stages of the AgriFood supply chain and of the fundamentals of a Distributed Ledger Technology, namely Blockchain, which can be used to mitigate some of the issues related to transparency and traceability of this sector. It also presents some solutions that already implement this technology to enable the traceability in the AgriFood sector. The authors also present the most important challenges and opportunities identify regarding the application of Blockchain based traceability systems for the AgriFood supply chain.
Song Tang, Zhiqiang Wang, Jian Jiang, Suli Ge · 5 authors
With the continuous development of blockchain technology, the application scenarios of alliance blockchain are also increasing. The consensus algorithm can achieve distributed consensus among nodes in the network. At present, the practical byzantine fault tolerance algorithm (PBFT) consensus algorithm commonly used in alliance blockchain requires all nodes in the network to participate in the consensus process. Experiments show that when the number of consensus nodes in the system exceeds 100, the bandwidth consumption and consensus delay will greatly increase, resulting in the inability of PBFT to be applied. In scenes with many nodes. How to improve the performance of alliance blockchains safely and efficiently has become an urgent problem to be solved at present. For the PBFT commonly used in alliance blockchains, there are some problems, such as large communication overhead, simple selection of master nodes, and inability to expand and exit nodes dynamically in the network. This paper proposes an improved algorithm tPBFT (trust-based practical Byzantine algorithm), which is suitable for high-frequency trading scenarios of consortium chains. By introducing a trust equity scoring mechanism between nodes in the network, the list of consensus nodes can be dynamically adjusted. tPBFT simplifies the pre-prepare stage of the PBFT consensus process, and realizes the verification of the hash transaction list in the reply stage, thereby reducing the interaction overhead between network nodes. Theoretical analysis and experiments show that when the number of nodes in the network is greater than 30, with the further increase of the number of nodes, the improved tPBFT algorithm has a relatively large performance in terms of node communication overhead, consensus efficiency and scalability outperforms the PBFT algorithm.