Entire Blockchain Research Articles

IoT Adaptive Dynamic Blockchain Networking Method Based on Discrete Heartbeat Signals.

The combination of blockchain technology and Internet of Things (IoT) technology has brought many significant advantages and new development directions. With the development of embedded technology and 5G communication technology, the performance limitations and network limitations that are traditionally believed to restrict the application of blockchain technology to IoT devices have been broken. The development of “blockchain + 5G + IoT” provides reliable data from the source for the blockchain, linking the credible mapping of physical assets and digital assets. However, at the beginning of the blockchain design, the application of the IoT was not fully considered, so there have been some obvious defects in applying the blockchain technology in the IoT. In the Byzantine fault tolerance (BFT) consensus algorithm of traditional blockchain, the entire blockchain network will become paralyzed when more than 1/3 of the nodes in the network are offline. However, in IoT applications, this situation is likely to occur and greatly limits the security and stability of the application of blockchain technology in the IoT. In order to solve this problem, we proposed an IoT adaptive dynamic blockchain networking method based on discrete heartbeat signals. The feature of the method is to set a different monitoring time for each group of nodes, that is, discrete heartbeat signals monitoring. When the number of nodes gradually decreases, the IoT adaptive dynamic blockchain network can dynamically adapt to this process. Even when more than 1/3 of the IoT are offline, the adaptive dynamic IoT blockchain network can maintain stable running. This method also has the advantages of a short network expectation recovery time and avoids instantaneous system paralysis caused by the thundering herd effect. This research improves the security and stability of the application of blockchain technology in the IoT, and provides the necessary technical foundation for the better combination of blockchain technology and IoT technology.

A Reliable Storage Partition for Permissioned Blockchain

The full-replication data storage mechanism, as commonly utilized in existing blockchains, is the barrier to the system's scalability, since it retains a copy of entire blockchain at each node so that the overall storage consumption per block is O(n) with n participants. Yet another drawback is that this mechanism may limit the throughput in permissioned blockchain. Moreover, due to the existence of Byzantine nodes, existing partitioning methods, though widely adopted in distributed systems for decades, cannot suit for blockchain systems directly, so that it is critical to devise new storage mechanism for blockchain systems. This article proposes a novel storage engine, called BFT-Store, to enhance storage scalability by integrating erasure coding with Byzantine Fault Tolerance (BFT) consensus protocol. The first property of BFT-store is that the storage consumption per block can be reduced to O(1) for the first time, which enlarges overall storage capability when more nodes attend the blockchain. Second, we design an efficient online re-encoding protocol for storage scale-out and a hybrid replication scheme to enhance reading performance. Analysis in theory and extensive experimental results illustrate the scalability, availability and efficiency of BFT-Store via the implementation in an open-source permissioned blockchain Tendermint.

Outsourced data integrity verification based on blockchain in untrusted environment

Outsourced data, as the significant component of cloud service, has been widely used due to its convenience, low overhead, and high flexibility. To guarantee the integrity of outsourced data, data owner (DO) usually adopts a third party auditor (TPA) to execute the data integrity verification scheme. However, during the verification process, DO cannot fully confirm the reliability of the TPA, and handing over the verification of data integrity to the untrusted TPA may lead to data security threats. In this paper, we focus on the problem of integrity verification of outsourced data in untrusted environment, that is, how to improve the security and efficiency of data integrity verification without utilizing untrusted TPA. To address the problem, we design a decentralized model based on blockchain consisting of some collaborative verification peers (VPs), each of which maintains a replication of the entire blockchain to avoid maliciously tampering with. Based on the model, we present an advanced data integrity verification algorithm which allows DO to store and check the verification information by writing and retrieving the blockchain. In addition, in order to improve the concurrent performance, we extend the algorithm by introducing the verification group (VG) constituting by some VPs organized by Inner-Group and Inter-Group consensus protocols. We conduct a completed security analysis as well as extensive experiments of our proposed approach, and the evaluation results demonstrate that our proposed approaches achieve superior performance.

Management and Monitoring of Blockchain Systems

Blockchain technology is based on a decentralized model, in which pairs collaborate and build trust on a corporate or public network. Each peer organization can be represented by one or more nodes and this network of nodes is used to broadcast transactions and reach consensus for each transaction submitted. secure data encryption and new transactions linked to previous ones make it nearly impossible to edit old records without having to edit subsequent ones. On the other hand, controlling more than half of the nodes in the network could allow Blockchain data corruption. However, adding a layer of oversight of each Blockchain node and the entire Blockchain network could ensure truly decentralized and robust operations.

Smart Contract Privacy Protection Using AI in Cyber-Physical Systems: Tools, Techniques and Challenges

Applications of Blockchain (BC) technology and Cyber-Physical Systems (CPS) are increasing exponentially. However, framing resilient and correct smart contracts (SCs) for these smart application is a quite challenging task because of the complexity associated with them. SC is modernizing the traditional industrial, technical, and business processes. It is self-executable, self-verifiable, and embedded into the BC that eliminates the need for trusted third-party systems, which ultimately saves administration as well as service costs. It also improves system efficiency and reduces the associated security risks. However, SCs are well encouraging the new technological reforms in Industry 4.0, but still, various security and privacy challenges need to be addressed. In this paper, a survey on SC security vulnerabilities in the software code that can be easily hacked by a malicious user or may compromise the entire BC network is presented. As per the literature, the challenges related to SC security and privacy are not explored much by the authors around the world. From the existing proposals, it has been observed that designing a complex SCs cannot mitigate its privacy and security issues. So, this paper investigates various Artificial Intelligence (AI) techniques and tools for SC privacy protection. Then, open issues and challenges for AI-based SC are analyzed. Finally, a case study of retail marketing is presented, which uses AI and SC to preserve its security and privacy.

RepuCoin: Your Reputation Is Your Power

Existing proof-of-work cryptocurrencies cannot tolerate attackers controlling more than 50 percent of the network’s computing power at any time, but assume that such a condition happening is “unlikely”. However, recent attack sophistication, e.g., where attackers can rent mining capacity to obtain a majority of computing power temporarily, render this assumption unrealistic. This paper proposes RepuCoin, the first system to provide guarantees even when more than 50 percent of the system’s computing power is temporarily dominated by an attacker. RepuCoin physically limits the rate of voting power growth of the entire system. In particular, RepuCoin defines a miner’s power by its ‘reputation’, as a function of its work integrated over the time of the entire blockchain, rather than through instantaneous computing power, which can be obtained relatively quickly and/or temporarily. As an example, after a single year of operation, RepuCoin can tolerate attacks compromising 51 percent of the network’s computing resources, even if such power stays maliciously seized for almost a whole year. Moreover, RepuCoin provides better resilience to known attacks, compared to existing proof-of-work systems, while achieving a high throughput of 10000 transactions per second (TPS).

No Need to Ask

This article will describe how permissionless metadata blockchains could be created to overcome two significant limitations in current cataloging practices: centralization and a lack of traceability. The process would start by creating public and private keys, which could be managed using digital wallet software. After creating a genesis block, nodes would submit either a new record or modifications to a single record for validation. Validation would rely on a Federated Byzantine Agreement consensus algorithm because it offers the most flexibility for institutions to select authoritative peers. Only the top tier nodes would be required to store a copy of the entire blockchain thereby allowing other institutions to decide whether they prefer to use the abridged version or the full version.

A hybrid framework for multimedia data processing in IoT-healthcare using blockchain technology

Through the propagation of technology in recent years, people communicate in a range of ways via multimedia. The use of multimedia technique in healthcare system also makes it possible to store, process and transfer the patient’s data presented in variety of forms such as images, text and audio through online using various smart objects. Healthcare organizations around the world are transforming themselves into more efficient, coordinated and user-centered systems through various multimedia techniques. However, the management of huge amount data such as reports and images of every person leads to increase the human efforts and security risks. In order to overcome these issues, IoT in healthcare enhances the quality of patients care and reduce the cost by allocating the medical resources in an efficient way. However, a number of threats can occur in IoT devices initiated by various intruders. Sometimes, in order to make their personal profit, even though the medical shop or pathology labs are not of good reputation, the doctors forced the patients to do the lab tests, or buy the medicines from those organizations only. Therefore, security should be at the staple of outlook in IoT elucidations. In order to prevent these issues, Blockchain technology has been encountered as the best technique that provides the secrecy and protection of control system in real time conditions. In this manuscript, we will provide a security framework of healthcare multimedia data through blockchain technique by generating the hash of each data so that any change or alteration in data or breaching of medicines may be reflected in entire blockchain network users. The results have been analyzed against conventional approach and validated with improved simulated results that offer 86% success rate over product drop ratio, falsification attack, worm hole attack and probabilistic authentication scenarios because of Blockchain technique.

PTAS: Privacy-preserving Thin-client Authentication Scheme in blockchain-based PKI

Recent years have witnessed tremendous academic efforts and industry growth in Internet of Things (IoT). Security issues of IoT have become increasingly prominent. Public Key Infrastructure (PKI) can provide authentication service to IoT devices which is a crucial element to the security of IoT. However, the conventional PKIs are organized as a tree-like centralized structure which has demonstrated serious usability and security shortcomings such as the single point of failure. Blockchain has numerous desirable properties, such as decentralized nature, cryptographic technology and unalterable transaction record, these properties make it a potential tool to build a decentralized blockchain-based PKI. Nevertheless, the latest proposals for blockchain-based PKI did not take thin-clients into consideration where thin-clients indicate those users who cannot download the entire blockchain due to the limited storage capacity of their equipment (most IoT devices fall into this category). To settle this problem, we firstly present a Privacy-preserving Thin-client Authentication Scheme (PTAS) employing the idea of private information retrieval (PIR), which enables thin-clients to run normally like full node users and protect their privacy simultaneously. Furthermore, in order to enhance security, we further propose a (m-1)-private PTAS which means thin-client’s information can be protected against a collusion of at most (m-1) full node users. Besides, security analysis and functional comparison are performed to demonstrate high security and comprehensive functionality of our schemes. Finally, extensive experiments are conducted to compare computational overhead and communication overhead of PTAS and (m-1)-private PTAS.

Blockchain-Based Outsourced Storage Schema in Untrusted Environment

Outsourced data, as significant service offered by the cloud service provider (CSP), can effectively facilitate the data owner (DO) overcoming the storage limitations on massive data. To ensure the availability of data, DO usually outsources the data replications to multiple CSPs (multi-CSPs) and utilizes a third party metadata management (TPMM) to dominate the metadata of the corresponding replications. However, during the outsourced procedures, DO can hardly confirm the confidence of the TPMM who may take some malicious behaviors to affect the reliability of data. Thus, DO inevitably faces data security issues caused by the over-reliance on the semi-trusted TPMM to manage the metadata of replications. In this paper, we focus on the problem of reliable outsourced data service among multi-CSPs in untrusted environment, that is, how to reliably store and verify the metadata of the data replications in untrusted multi-CSPs environment. To address the problem, we use the novel blockchain technology as a medium to build a trusted outsourced service platform. Moreover, we fully consider the innovative characteristics of blockchain including decentralized architecture, redundancy storage, collective maintenance, and tamper resistant to ensure the data cannot be changed maliciously. We first design a blockchain-based outsourced service framework for storing data replications in untrusted environment, which contains three key layers, that is, storage layer, verification layer, and blockchain layer. Then, we devise a novel concept of verification peer (VP) for maintaining metadata stored by a form of blockchain, and each of which holds the entire blockchain locally to prevent metadata from being maliciously tampered with. Finally, based on the proposed model, we introduce a collaborative algorithm invoked by VPs to store and verify the metadata of replications. We present a completed analysis and conduct extensive experiments on multi-CSPs scenario. The evaluation results demonstrate that our proposed approach achieves superior performance.

An Energy-Efficient Transaction Model for the Blockchain-Enabled Internet of Vehicles (IoV)

The blockchain is a safe, reliable, and innovative mechanism for managing numerous vehicles seeking connectivity. However, following the principles of the blockchain, the number of transactions required to update ledgers poses serious issues for vehicles as these may consume the maximum available energy. To resolve this, an efficient model is presented in this letter, which is capable of handling the energy demands of the blockchain-enabled Internet of Vehicles by optimally controlling the number of transactions through distributed clustering. Numerical results suggest that the proposed approach is 40.16% better in terms of energy conservation and 82.06% better in terms of the number of transactions required to share the entire blockchain data compared with the traditional blockchain.

A Low Storage Room Requirement Framework for Distributed Ledger in Blockchain

Traditional centralized commerce on the Internet relies on trusted third parties to process electronic payments. It suffers from the weakness of the trust-based model. A pure decentralized mechanism called blockchain tackles the above problem and has become a hot research area. However, since each node in a blockchain system needs to store all transactions of the other nodes, as time continues, the storage room required to store the entire blockchain will be huge. Therefore, the current storage mechanism needs to be revised to cater to the rapidly increasing need for storage. Network coded (NC) distributed storage (DS) can significantly reduce the required storage room. This paper proposes a NC-DS framework to store the blockchain and proposes corresponding solutions to apply the NC-DS to the blockchain systems. Analysis shows that the proposed scheme achieves significant improvement in saving storage room.