Extensive online knowledge sharing can be exploited to solve tasks better, faster and cheaper, and it garners considerable interest in institutional cooperation, learning communities, etc., while many technical problems, such as fair exchange in incentive design and security issues are waiting to be solved. Blockchain technique has high accountability and thus has potential to improve the transparency and security of knowledge sharing. In this paper, to address the above problems, first we propose a Reputation Based Knowledge Sharing system in blockchain, called RBKS. The aim of RBKS is to exploit the copyright protection of the knowledge owner using our proposed fine-grained access control system, and to achieve the paid-for content service which allows bystanders who are interested in the shared knowledge to pay a small fee for the access. Second, a reputation evaluation algorithm is introduced as the core of the incentive, and it may possibly be combined with stake in blockchain to form a hybrid stake for the RBKS system. Third, a blockchain and a trusted storage server are employed together for sharing and storing knowledge, and the main procedures are implemented with smart contract in blockchain to ensure secure execution and fairness. Finally, our analysis shows that the RBKS system is feasible and secure.
As cities become more digitally governed, centralized infrastructures face growing risks across identity, safety, and data domains. This chapter reframes blockchain as a foundational trust protocol for urban resilience, emphasizing its core features: immutability, decentralization, transparency, and consensus, as tools to address systemic privacy and security challenges. It explores blockchain's role in securing digital identities, logging infrastructure events, and enabling auditable governance. Real-world deployments in land registries, voting, procurement, and incident response, especially in Asia and Europe are analyzed. Privacy-preserving techniques like zero-knowledge proofs and decentralized identity are also examined. The chapter highlights integration hurdles such as interoperability, regulatory gaps, and ethical tensions, while outlining emerging trends like Blockchain 4.0, quantum-safe cryptography, and DAO-led civic participation. It offers a roadmap for decentralized citizen-centric governance in smart cities.
The digital payment system that uses cryptocurrency, such as Bitcoin, is a distributed ledger working on a peer-to-peer network. We present a method to make a scale-free network for such applications. Using some biased physical quantities that are observable in sites, we can make the scale-free network through processes of cooperating distributed sites. Each node only proposes connecting to the more attractive node among randomly known nodes. The candidate node that is found by each node agrees to set two-way links if the requesting node is more attractive than the old node that is already connected. Once they establish the new bidirectional relationship, they, respectively, remove the outgoing link to the less attractive node. We analytically calculate the connectivity distribution and show that the scaling exponent is 2.5. By Monte Carlo simulations, we confirm that a power law distribution of the scaling exponent 2.5 describes the degree distribution of the topology.
Regio A. Michelin, Ali Dorri, Marco Steger, Roben Castagna Lunardi · 7 authors
There is increased interest in smart vehicles acting as both data consumers and producers in smart cities. Vehicles can use smart city data for decision-making, such as dynamic routing based on traffic conditions. Moreover, the multitude of embedded sensors in vehicles can collectively produce a rich data set of the urban landscape that can be used to provide a range of services. Key to the success of this vision is a scalable and private architecture for trusted data sharing. This paper proposes a framework called SpeedyChain, that leverages blockchain technology to allow smart vehicles to share their data while maintaining privacy, integrity, resilience, and non-repudiation in a decentralized and tamper-resistant manner. Differently from traditional blockchain usage (e.g., Bitcoin and Ethereum), the proposed framework uses a blockchain design that decouples the data stored in the transactions from the block header, thus allowing fast addition of data to the blocks. Furthermore, an expiration time for each block is proposed to avoid large sized blocks. This paper also presents an evaluation of the proposed framework in a network emulator to demonstrate its benefits.
Phuc Thai, Laurent Njilla, Tuyet Duong, Lei Fan · 5 authors
Cryptocurrencies have recently gained huge popularity. It is desirable to come up with effective approaches to constructing better blockchain protocols. In this paper, inspired by the 2-hop design by Duong et al (ePrint 2016/716), we put forth a generic paradigm for blockchain design, called n-hop blockchain. It includes one main chain, which is supported by (n -- 1) supporting chains; hence, the main chain can achieve better security performance. In our paradigm, we show that our n-hop design can be easily extended to (n + 1)-hop design. To demonstrate the power of our paradigm, we showcase two instantiations: 2-hop blockchain variant, a combination of proof-of-stake and proof-of-work, and 3-hop blockchain variant, which is extended from 2-hop blockchain variant by adding Byzantine fault tolerance blockchain in 3rd hop.
Ashar Ahmad, Muhammad Saad, Mostafa Bassiouni, Aziz Mohaisen
Audit logs serve as a critical component in the enterprise business systems that are used for auditing, storing, and tracking changes made to the data. However, audit logs are vulnerable to a series of attacks, which enable adversaries to tamper data and corresponding audit logs. In this paper, we present BlockAudit: a scalable and tamper-proof system that leverages the design properties of audit logs and security guarantees of blockchains to enable secure and trustworthy audit logs. Towards that, we construct the design schema of BlockAudit, and outline its operational procedures. We implement our design on Hyperledger and evaluate its performance in terms of latency, network size, and payload size. Our results show that conventional audit logs can seamlessly transition into BlockAudit to achieve higher security, integrity, and fault tolerance.
Delegated Proof-of-Stake (DPoS) is an efficient, decentralized, and flexible consensus framework available in the blockchain industry. However, applying DPoS to the decentralized Internet of Things (IoT) applications is quite challenging due to the nature of IoT systems such as large-scale deployments and huge amount of data. To address the unique challenge for IoT based blockchain applications, we present Roll-DPoS, a randomized delegated proof of stake algorithm. Roll-DPoS inherits all the advantages of the original DPoS consensus framework and further enhances its capability in terms of decentralization as well as extensibility to complex blockchain architectures. A number of modern cryptographic techniques have been utilized to optimize the consensus process with respect to the computational and communication overhead.
BACKGROUND: Decentralization is promoted as a strategy to improve health system performance by bringing decision-making closer to service delivery. Some studies have investigated if decentralization actually improves the health system. However, few have explored the conditions that enable it to be effective. To determine these conditions, we have analyzed the perspectives of decision-makers in the Philippines where devolution, one form of decentralization, was introduced 25 years ago. METHODS: Drawing from the "decision space" approach, we interviewed 27 decision-makers with an average of 23.6 years of working across different levels of the Philippine government health sector and representing various local settings. Qualitative analysis followed the "Framework Method." Conditions that either enable or hinder the effectiveness of decentralization were identified by exploring decision-making in five health sector functions. RESULTS: These conditions include: for planning, having a multi-stakeholder approach and monitoring implementation; for financing and budget allocation, capacities to raise revenues at local levels and pooling of funds at central level; for resource management, having a central level capable of augmenting resource needs at local levels and a good working relationship between the local health officer and the elected local official; for program implementation and service delivery, promoting innovation at local levels while maintaining fidelity to national objectives; and for monitoring and data management, a central level capable of ensuring that data collection from local levels is performed in a timely and accurate manner. CONCLUSIONS: The Philippine experience suggests that decentralization is a long and complex journey and not an automatic solution for enhancing service delivery. The role of the central decision-maker (e.g. Ministry of Health) remains important to assist local levels unable to perform their functions well. It is policy-relevant to analyze the conditions that make decentralization work and the optimal combination of decentralized and centralized functions that enhance the health system.
Shifa Zhang, Anne Kim, Dianbo Liu, Sandeep C. Nuckchady · 13 authors
Artificial Intelligence (AI) incorporating genetic and medical information have been applied in disease risk prediction, unveiling disease mechanism, and advancing therapeutics. However, AI training relies on highly sensitive and private data which significantly limit their applications and robustness evaluation. Moreover, the data access management after sharing across organization heavily relies on legal restriction, and there is no guarantee in preventing data leaking after sharing. Here, we present Genie, a secure AI platform which allows AI models to be trained on medical data securely. The platform combines the security of Intel Software Guarded eXtensions (SGX), transparency of blockchain technology, and verifiability of open algorithms and source codes. Genie shares insights of genetic and medical data without exposing anyone's raw data. All data is instantly encrypted upon upload and contributed to the models that the user chooses. The usage of the model and the value generated from the genetic and health data will be tracked via a blockchain, giving the data transparent and immutable ownership.
Over the past few years, the importance of improving the product distribution structure has increased worldwide. Therefore, distribution prices are now disclosed and product information is shared with consumers. However, distribution channels are complex and supply chain management (SCM) is autonomously executed in each company. For this reason, it has been frequently pointed out that the distribution process is not transparent and the distribution margin is high. In this paper, we propose a system that guarantees the transparency of the product distribution structure by applying blockchain and smart contracts to the price-tracking portion of supply chain management systems. This approach allows companies to track their trades by enhancing transparency in the SCM, thereby discouraging companies from pursuing excessive profits. In addition, companies can cut management costs by automatically storing distribution details in a blockchain network and managing information more securely.
Permissioned Blockchain has become quite popular with enterprises forming consortium since it prioritizes trust over privacy. One of the popular platforms for distributed ledger solution,Hyperledger Fabric, requires a transaction to beendorsedor approved by a group of special members known as endorsers before undergoing validation. To endorse a transaction, an endorser mentions its identity along with the signature so that it can be verified later. However, for certain transactions, difference in opinion may exist among endorsers. Disclosing the identity of an endorser may lead to conflict within the consortium. In such cases, an endorsement policy which not only allows an endorser to support a transaction discreetly, but at the same time takes into account the decision of the majority is preferred. Thus we propose an Anonymous Endorsement System which uses a threshold endorsement policy in order to address the issue. To realize at-out-of-nendorsement policy, using any of the existing threshold ring signature for our endorsement system would have violated the privacy of endorsers as either the identity or the secret key of the endorsers get revealed to the party who recombines the signature after collecting each signature share. All these factors motivated us to design a new ring signature scheme, calledFabric’s Constant-Sized Linkable Ring Signature(FCsLRS) withTransaction-Orientedlinkability for hiding identity of the endorsers. We have implemented the signature scheme in Golang and analyzed its security and performance by varying the Rivest-Shamir-Adleman (RSA) modulus size. Feasibility of implementation is supported by experimental analysis. Signature and tag generation time is quite fast and remains constant irrespective of change in message length or endorsement set size for a given RSA modulus value, assuming all the endorsers generates their signature in parallel. Each verifier is required to count and check individual valid ring signature. If the aggregate is above the threshold value, stated by the endorsement policy, then it confirms that the transaction is valid. This increases the verification time depending on the threshold value, but has very little effect on the scalability since generally$t<\!\!\!<n$. Lastly, we also discuss the integration of the scheme on v1.2 Hyperledger Fabric.
Since its introduction in 2008, the value and popularity of Bitcoin have risen exponentially. Despite being 10 years old, the concept of crypto currency is fairly new in South Africa. The increase in the value of Bitcoin, together with extensive media coverage, has led to the creation of a Bitcoin economic system with many South Africans jumping on the Bitcoin bandwagon. This study aims to identify the determinants affecting end-user adoption of Bitcoin in South Africa and to determine the main use of the crypto currency by South Africans. A research model was developed utilising constructs from the technology acceptance model and theory of planned behaviour. The model was then tested empirically by utilising two survey-based questionnaires, one for current users of Bitcoin and one for non-users. For users, perceived usefulness and access to facilitating conditions were the primary determinants influencing their decision to adopt the crypto currency while lack of trust and social influences were the primary reasons non-users chose not to adopt Bitcoin.
Blockchains or distributed ledgers are an emerging technology that has drawn considerable interest from energy supply firms, startups, technology developers, financial institutions, national governments and the academic community. Numerous sources coming from these backgrounds identify blockchains as having the potential to bring significant benefits and innovation. Blockchains promise transparent, tamper-proof and secure systems that can enable novel business solutions, especially when combined with smart contracts. This work provides a comprehensive overview of fundamental principles that underpin blockchain technologies, such as system architectures and distributed consensus algorithms. Next, we focus on blockchain solutions for the energy industry and inform the state-of-the-art by thoroughly reviewing the literature and current business cases. To our knowledge, this is one of the first academic, peer-reviewed works to provide a systematic review of blockchain activities and initiatives in the energy sector. Our study reviews 140 blockchain research projects and startups from which we construct a map of the potential and relevance of blockchains for energy applications. These initiatives were systematically classified into different groups according to the field of activity, implementation platform and consensus strategy used. 1 Opportunities, potential challenges and limitations for a number of use cases are discussed, ranging from emerging peer-to-peer (P2P) energy trading and Internet of Things (IoT) applications, to decentralised marketplaces, electric vehicle charging and e-mobility. For each of these use cases, our contribution is twofold: first, in identifying the technical challenges that blockchain technology can solve for that application as well as its potential drawbacks, and second in briefly presenting the research and industrial projects and startups that are currently applying blockchain technology to that area. The paper ends with a discussion of challenges and market barriers the technology needs to overcome to get past the hype phase, prove its commercial viability and finally be adopted in the mainstream.
Mahadi Hasan Miraz, Mohamad Ghozali Hasan, Kamal Imran Mohd Sharif
Bangladesh garments industry plays a significant role for Bangla--desh economy. It helps millions of workers in Bangladesh. As difficulties to trade among nations have failed due to improved shipping systems, technology transfer and government coopera--tion, the industry has seen a rapid increase in globalization and struggle. The all Bangladesh apparels mills association and indi--viduals needs to enhance the quality of its goods. However, the promises in the RMG can be comprehended only if the challenges in some areas like - organizations, compliances, workforces sup--ply, dealers' performances, raw resources, political stability are tackled. In order to minimize the issues we need a proper supply chain using Blockchain.
Niniejszy artykuł ma na celu przybliżenie istoty bitcoin oraz jest próbą odpowiedzi na pytanie, jaką rolę elektroniczna moneta odegra na globalnym rynku finansowym w przyszłości. W pierwszej kolejności w artykule przedstawiono dwa sposoby definiowania bitcoin oraz mechanizm emisji tej monety i obrotu w Internecie. Na tej podstawie wyodrębniono zalety i wady elektronicznej monety w kolejności ich ważności. Następnie zaprezentowano dotychczasową genezę rynku bitcoin, co pozwoliło na zidentyfikowanie i uszeregowanie determinant jego rozwoju. Wśród nich za najistotniejsze uznano ograniczoną podaż bitcoin i rosnący nań popyt, pogłębianie się globalnego kryzysu zadłużeniowego, stopniowe wprowadzanie przejrzystych regulacji prawnych, utrzymanie wiarygodności dotyczącej emisji monet oraz rosnącą akceptację tej formy płatności przez użytkowników Internetu. Na koniec rozważań o bitcoin przedstawiono możliwe zastrzeżenia zgłaszane przez biernych obserwatorów rynku, które wciąż pozostają bez jednoznacznej odpowiedzi. W podsumowaniu przyjęto stanowisko pośrednie, nadające bitcoin status nowatorskiego wynalazku, który dzięki swojej hybrydowej naturze może być pierwszym krokiem do pieniądza przyszłości.
This paper proposes a trustable mold redesign knowledge-sharing platform, known as CKshare, based on private cloud and blockchain technology. Firstly, we use private cloud to store the mold redesign knowledge of each party to meet its own privacy and data format requirements. Secondly, a blockchain network is used for recording the knowledge and its transactions to ensure security and trustfulness. Thirdly, a simple retrieval mechanism is developed based on k-nearest neighbors for retrieving the codified knowledge on the platform. To realize CKshare, a prototype platform has been developed and explained based on real data from the case mold company.
Rubaiyat Islam, Yoshi Fujiwara, Shinya Kawata, Hiwon Yoon
In a closed economic system like blockchain, the total amount of generated cryptocurrency called bitcoin is conserved and the transaction patterns demonstrate an insight of money flow inside the blockchain. For the last 2 years, bitcoin market has grabbed an immense attention from the investors, technology entrepreneurs and currency enthusiasts. In this paper, we have come up with some findings in our investigation about the bitcoin time-series transaction patterns. We have graphically represented bitcoin’s weekly patterns as a real economic currency that has been minted, stored and exchanged inside the bitcoin blockchain network. We identified outliers’ activities with the help of descriptive statistical analysis. We also demonstrated transaction pattern behavioral change. The main implication of these findings is to understand some stylized facts of the time-series transaction of cryptocurrency-based fully digital financial system. Besides in our analysis, we have shown that the behavioral change of the transaction pattern is capable of explaining the system development events or major historical events that have a network impact.
Since the security and fault tolerance is the two important metrics of the data storage, it brings both opportunities and challenges for distributed data storage and transaction. The traditional transaction system of storage resources, which generally runs in a centralized mode, results in high cost, vendor lock-in, single point failure risk, DDoS attack and information security. Therefore, this paper proposes a distributed transaction method for cloud storage based on smart contract. First, to guarantee the fault tolerance and decrease the storing cost for erasure coding, a VCG-based auction mechanism is proposed for storage transaction, and we deploy and implement the proposed mechanism by designing a corresponding smart contract. Especially, we address the problem - how to implement a VCG-like mechanism in a blockchain environment. Based on private chain of Ethereum, we make the simulations for proposed storage transaction method. The results showed that proposed transaction model can realize competitive trading of storage resources, and ensure the safe and economic operation of resource trading.