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5,430 results ¡ page 124 of 227
Gennaro Avitabile, Vincenzo Botta, Daniele Friolo, Ivan Visconti
No abstract is available for this record.
Yao Liu, Zhonghao Yuan, Yunhan Hu
No abstract is available for this record.
Wei Zhou, Hao Wang, Ghulam Mohiuddin, Dan Chen ¡ 5 authors
As the basis of cloud computing, distributed storage technology mainly studies how data centers store, organize and manage data. Blockchain has become the most secure solution for cloud storage due to its decentralization and immutability. Consensus mechanism is one of the core technologies of blockchain, which affects the transaction processing capability, security and scalability of blockchain. The current mainstream consensus algorithms such as Proof of Work, Proof of Stake, and Delegated Proof of Stake all have the problem of wasting resources. And with the explosive growth of data, cloud storage nodes store a large amount of redundant data, which inevitably increases storage overhead and computing cost. To this end, we propose to use the Proof of Retrievability with deduplication algorithm as the consensus mechanism of the blockchain system and design a blockchain consensus protocol suitable for distributed storage. First, the data integrity verification protocol in the scheme guarantees that storage nodes correctly store the data they promise to store. Second, the deduplication algorithm in the protocol can optimize data auditing, greatly reduce the need for data storage space, and improve the scalability of data transmission. In addition, the scheme uses ring signatures in the audit process to ensure user anonymity and data unlinkability, while providing highly reliable data storage, and ensuring data storage security through blockchain. Finally, we demonstrate the security of the proposed scheme and evaluate its performance. The evaluation results show that our scheme is efficient and scalable.
Xiaofang Qiu, Zhi Qin, Wunan Wan, Jinquan Zhang ¡ 7 authors
In recent years, Blockchain is gaining prominence as a hot topic in academic research. However, the consensus mechanism of blockchain has been criticized in terms of energy consumption and performance. Although Proof-of-Authority (PoA) consensus mechanism, as a lightweight consensus mechanism, is more efficient than traditional Proof-of-Work (PoW) and Proof-of-Stake (PoS), it suffers from the problem of centralization. To this end, on account of analyzing the shortcomings of existing consensus mechanisms, this paper proposes a dynamic reputation-based consensus mechanism for blockchain. This scheme allows nodes with reputation value higher than a threshold apply to become a monitoring node, which can monitor the behavior of validators in case that validators with excessive power cause harm to the blockchain network. At the same time, the reputation evaluation algorithm is also introduced to select nodes with high reputation to become validators in the network, thus increasing the cost of malicious behavior. In each consensus cycle, validators and monitoring nodes are dynamically updated according to the reputation value. Through security analysis, it is demonstrated that the scheme can resist the attacks of malicious nodes in the blockchain network. By simulation experiments and analysis of the scheme, the result verifies that the mechanism can effectively improve the fault tolerance of the consensus mechanism, reduce the time of consensus to guarantee the security of the system.
Matteo Campanelli, Felix Engelmann, Claudio Orlandi
No abstract is available for this record.
Alaa Haddad, Mohamed Hadi Habaebi, Md. Rafiqul Islam, Nurul Fadzlin Hasbullah ¡ 5 authors
Electronic health records (EHRs) are digitally saved health records that provide information about a person’s health. EHRs are generally shared among healthcare stakeholders, and thus are susceptible to power failures, data misuse, a lack of privacy, security, and an audit trail, among other problems. Blockchain, on the other hand, is a groundbreaking technology that provides a distributed and decentralized environment in which nodes in a list of networks can connect to each other without the need for a central authority. It has the potential to overcome the limits of EHR management and create a more secure, decentralized, and safer environment for exchanging EHR data. Further, blockchain is a distributed ledger on which data can be stored and shared in a cryptographically secure, validated, and mutually agreed-upon manner across all mining nodes. The blockchain stores data with a high level of integrity and robustness, and it cannot be altered. When smart contracts are used to make decisions and conduct analytics with machine-learning algorithms, the results may be trusted and unquestioned. However, Blockchain is not always indestructible and suffers from scalability and complexity issues that might render it inefficient. Combining AI and blockchain technology can handled some of the drawbacks of these two technical ecosystems effectively. AI algorithms rely on data or information to learn, analyze, and reach conclusions. The performance of AI algorithms is enhanced through the data obtained from a data repository or a reliable, secure, trustworthy, and credible platform. Researchers have identified three categories of blockchain-based potential solutions for the management of electronic health records: conceptual, prototype, and implemented. The purpose of this research work is to conduct a Systematic Literature Review (SLR) to identify and assess research articles that were either conceptual or implemented to manage EHRs using blockchain technology. The study conducts a comprehensive evaluation of the literature on blockchain technology and enhanced health record management systems utilizing artificial intelligence technologies. The study examined 189 research papers collected from various publication categories. The in-depth analysis focuses on the privacy, security, accessibility, and scalability of publications. The SLR has illustrated that blockchain technology has the potential to deliver decentralization, security, and privacy that are frequently lacking in traditional EHRs. Additionally, the outcomes of the extensive analysis inform future researchers about the type of blockchain to use in their research. Additionally, methods used in healthcare are summarized per application area while their pros and cons are highlighted. Finally, the emphasized taxonomy combines blockchain and artificial intelligence, which enables us to analyze possible blockchain and artificial intelligence applications in health records management systems. The article ends with a discussion on open issues for research and future directions.
Ammar Battah, Mohammad Madine, Ibrar Yaqoob, Khaled Salah ¡ 6 authors
The demand for high-quality Artificial Intelligence (AI) models is ever-increasing in this digital era. However, most of the existing methods leveraged for managing the ownership, trading, and access of AI models fall short of providing traceability, transparency, audit, security, and trustful features. In this paper, we propose a solution based on blockchain and Non-fungible Tokens (NFTs) to manage ownership rights and exchange of AI models in a transparent, traceable, auditable, secure, and trustworthy manner. Smart contracts are employed to enforce ownership, ease of access, and exchange policies for the unique NFT linked to an AI model. We use decentralized storage of the InterPlanetary File System (IPFS) and proxy re-encryption oracles to securely fetch, store, and share data related to AI models. We present algorithms along with their implementation, testing, and validation details. The proposed solution is evaluated using cost and security analyses to show its affordability and resiliency against security threats and attacks. All smart contract codes are made publicly available on GitHub.
Han Liu, Dezhi Han
No abstract is available for this record.
Maoguang Wang, Tianming Wang, Haoyue Ji
No abstract is available for this record.
Kaifeng Zhang, Zhao Qiu, Tao Chen, Jiale Lin ¡ 11 authors
No abstract is available for this record.
Amrutanshu Panigrahi, Ajit Kumar Nayak, Rourab Paul, Bibhuprasad Sahu ¡ 5 authors
The decentralization feature of public and private blockchain-based applications is achieved by selecting different nodes as validator or Certificate Authority (CA) for each transaction. Public blockchain uses Proof of Work (PoW) to search for the validator. PoW causes an enormous amount of energy. Therefore, Proof of Stake (PoS), and Proof of Authority (PoA) emerged as alternate solutions. Selection of a newCAusingPoSorPoAalgorithms for each transaction may improve transaction security. However, a network may have a large number of transactions, and selecting aCAfor each transaction usingPoSorPoAmay cause a significant amount of block propagation delay. Moreover, an increase in the number of participant nodes may increase the block propagation delay even further. Therefore, higher block propagation delay reduces network efficiency drastically. This paper proposes a different approach to increase the efficiency of Blockchain-based Public Key Infrastructure (BC â PKI). The proposed approach creates clusters of participant nodes based on their validation time, response time, and trust. This method selects a cluster based on the budget of response time and validation time given by the node that intends to start a transaction. Thereafter, the node which has the highest trust in that cluster is chosen as aCAfor the next transaction. Instead of searching on all participant nodes, our approach searches on the nodes of the chosen cluster which reduces the searching space of theCAselection process. This research work adopts a trust evaluation approach where the trust factor is quantified based on its experience and reputation. The node trust is reevaluated after every successful and unsuccessful transaction. A node that performs more successful transactions has more trust value. The node that has a higher trust value has a higher probability to be selected as aCAfor a transaction. The trust reevaluation process is followed by the clustering process. The result shows the proposed approach can reduce ~38.5% response time and ~2.2% validation time as compared to infrastructure which does not implement clustering. Additionally, the proposedCTB â PKIcan be used in Blockchain 2.0 and Blockchain 3.0-related applications.
Tennakoon, Deepal, Gramoli, Vincent
By supporting decentralized applications (DApps), modern blockchains have become the technology of choice for the Web3, a decentralized way for people to interact with each other. As the popularity of DApps is growing, the challenge is now to allocate shard or subnetwork resources to face the associated demand of individual DApps. Unfortunately, most sharding proposals are inherently static as they cannot be adjusted at runtime. Given that blockchains are expected to run for years without interruption, these proposals are insufficient to cope with the upcoming demand. In this paper, we present dynamic blockchain sharding, a new way to create and close shards on-demand, and adjust their size at runtime without requiring to hard fork (i.e., creating duplicated instances of the same blockchain). The novel idea is to reconfigure sharding through dedicated smart contract invocations: not only does it strengthen the security of the sharding reconfiguration, it also makes it inherently transparent as any other blockchain data. Similarly to classic sharding, our protocol relies on randomness to cope with shard-takeover attacks and on rotating nodes to cope with the bribery of a slowly-adaptive adversary. By contrast, however, our protocol is ideally suited for open networks as it does not require fully synchronous communications. To demonstrate its efficiency, we deploy it in 10 countries over 5 continents and demonstrate that its performance increases quasi-linearly with the number of shards as it reaches close to 14,000 TPS on only 8 shards.
Ruizhong Du, Xiaoya Li, Yan Liu
No abstract is available for this record.
Craig Gentry, Shai Halevi, Vadim Lyubashevsky
No abstract is available for this record.
Sunil Anasuri, Guru Pramod Rusum, kiran Kumar Pappula
The emergence of decentralized applications (dApps) has posed a challenge to the current identity management system, which is often centralized authority, mostly exposed to security breaches, information silos, and poor control of users. Blockchain technology introduces a disruptive technology with its decentralized, transparent and tamper-proof architecture, which can usher in new solutions to digital identity. The paper is an investigation of blockchain-based identity management systems, their architecture, working life cycle and dApp integration with identity management solutions. It explores three prominent identity frameworks, centralized, federated, and self-sovereign identity (SSI), and puts blockchain in the group of the very drivers of user-centric and verifiable identity resolutions. The analysis of smart contracts applied to identity operations, consensus mechanisms used in establishing trust, and numerous security and privacy improvements, such as zero-knowledge proofs, is discussed. The potential of blockchain-based identity can be seen in terms of its use in real-world business processes in the areas of decentralized finance (DeFi), healthcare data sharing, and supply chain management. Moreover, the document argues about the use of interoperability mechanisms like Decentralized Identifiers (DIDs) or Verifiable Credentials (VCs), and covers the most important points of scalability, compliance considerations, and trans-chain identity management. The future research directions, such as AI-powered verification, quantum-resistant protocols, or wider ecosystem adoption, are discussed as well. The research behind this project aims to provide a detailed background for scholars and practitioners who wish to implement safe, productive, and privacy-protected identity management in decentralised digital environments
Song Tang, Zhiqiang Wang, Jia Dong, Yandong Ma
With the development of the times, the existing social security system can no longer meet people’s needs in terms of providing transparent, distributed sharing, tamper-proof, traceable, consensus trust and trustworthy services. Furthermore, they are centralized and subject to a single point of control and failure. In this context, we propose a consortium blockchain-based solution to establish and improve social security informatization to meet the above challenges. In this article, we present specific business situations for three important social security services. Namely, apply for social insurance, apply for social assistance and social benefits online. Our proposed solution also provides a multi-party trust and data sharing mechanism, and also demonstrates the integration of blockchain and Interplanetary File System (IPFS) storage systems to facilitate the security of approval documents, photos and videos related to the processing of social security services Accessibility and traceability. It also introduces the implementation and testing details of the algorithm in the smart contract, and expounds how to apply it in the automatic approval of social security business to reduce the workload of existing manual review. Finally, by comparing with the existing system, it is discussed that our solution has great advantages in promoting the online processing of social security business, and the safe access and traceability of approval documents, photos and videos.
Yu Zhou, Zeming Wei, Shansi Ma, Tang Hua
No abstract is available for this record.
Hao Guo, Jieren Cheng, Janghao Wang, Tao Chen ¡ 7 authors
No abstract is available for this record.
Zachary Stucke, Theodoros Constantinides, John Cartlidge
Transactions sent to a public blockchain network, such as Ethereum, are initially held in the mempool before they are accepted in a block. While waiting in the mempool, these âÂÂin-flightâ transactions are publicly visible and vulnerable to front-running attacks, such that malicious parties use information in the transaction for their own gain and at a direct cost to the transaction owner. In this work, we introduce open-source simulation software for identifying and mitigating these attacks on Ethereum blockchains. Designed for education and research, the software introduces simple smart contracts that elaborate front-running vulnerabilities such as displacement attacks, sandwich attacks, and priority gas auctions. Users can run these attacks in a safe environment, monitor the detailed mechanics of attacks, and mitigate attacks using the MEV-geth protocol for in-flight transaction privacy.
Valli S. Kumar, John J. Lee, Qin Hu
Abstract With an increasing affinity towards patientâcentric care, sharing realâtime sensitive data for collaboration between multiple parties with finer access control becomes critical. Most existing studies based on the blockchain technology in the medical field discuss various application scenarios and security aspects, without focusing on data ownership, secure data sharing, or finer access control. In this work, a nonâfungible token (NFT)âbased system is proposed to implement a health record marketplace. The system leverages the NFT technology to provide dual ownership along with finer access control and efficiency in data sharing. The advantage of permissioned blockchain along with InterPlanetary File System (IPFS) are taken for offâchain data storage to improve security and efficiency. Because price determination is critical in the market, Stackelberg game theory is utilized to determine pricing strategies for both data owners and consumers. Also, to efficiently achieve finer access control, a popularityâbased adaptive NFT management scheme using reinforcement learning is proposed. Simulation experiments are carried out to demonstrate accuracy and efficiency of our proposed schemes.
Yuyu Wang, Jiaxin Pan
No abstract is available for this record.
Houyu Zheng, Lin You, Gengran Hu
It is crucial to ensure the privacy and authenticity of patientsâ medical data in the medical insurance claim process, but in the current medical insurance claim process, there are some problems such as low efficiency, complex service, unreliable data and data leakage. Therefore, considering the privacy and sensitivity of patientsâ medical data, we can improve the current issues by employing blockchain, smart contracts and zero-knowledge proof technology. In this paper, we propose a novel medical insurance claim scheme based on smart contracts, blockchain and zero-knowledge proof. Our scheme mainly involves two scenarios: medical insurance purchasing and medical insurance claiming. In the privacy-preserving transaction phases of the two scenarios, we can ensure the legitimacy and privacy of the transactions between the patients and the insurance companies by using a non-interactive zero-knowledge proof and the homomorphic encryption algorithm under the Decisional Bilinear DiffieâHellman (DBDH) assumption. In the identity privacy-preserving phases of the two scenarios, we can ensure the legitimacy and the privacy of patientsâ identities by integrating Schnorr protocol and FiatâShamir heuristic method. The security analysis, the computation cost and the communication cost of our scheme are given. Compared with our referred schemes, the performance evaluation shows that our scheme not only meets the requirements of the legality of the medical insurance claim, but also ensures the authenticity and privacy of the patientsâ medical data. Moreover, the experimental results demonstrate that our scheme is feasible and has an acceptable time overhead.
Kang Yang, Xiao Wang
No abstract is available for this record.
Aviv Bick, Gillat Kol, Rotem Oshman
Zero knowledge proofs are one of the most influential concepts in theoretical computer science. In the seminal definition due to Goldwasser, Micali and Rackoff dating back to the 1980s, a computationally-bounded verifier interacts with a powerful but untrusted prover, with the goal of becoming convinced that the input is in some language. In addition to the usual requirements of completeness and soundness, in a zero knowledge proof, we protect the prover's knowledge: assuming the prover is honest, anything that the verifier can deduce after interacting with the prover, it could have deduced by itself. Zero knowledge proofs have found many applications within theoretical computer science and beyond, e.g., in cryptography, client-cloud computing, blockchains and cryptocurrencies, electronic voting and auctions, and in the financial industry. We define and study the notion of distributed zero knowledge proofs, reconciling the computational notion of zero-knowledge with the communication-based paradigm of distributed graph algorithms. In our setting, a network of verifiers interacts with an untrusted prover to decide some distributed language. As is usually the case in distributed graph algorithms, we assume that the verifiers have local views of the network and each only knows its neighbors. The prover, on the other hand, is assumed to know the entire network graph, as well as any input that the verifier may possess. As in the computational centralized setting, the protocol we design should protect this knowledge. In particular, due to the dual role of the underlying graph in distributed graph algorithms, serving as both the communication topology and the input to the problem, our protocol must protect the graph itself. We construct communication-efficient distributed zero knowledge proofs for two central problems: the 3-coloring problem, one of the poster children of computational zero-knowledge, and for the spanning-tree verification problem, a fundamental building block for designing graph algorithms. We also give a general scheme for converting proof labeling-schemes to distributed zero-knowledge protocols with related parameters. Our protocols combine ideas from computational complexity, distributed computing, and cryptography.