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Consensus Algorithms in Blockchain Technology: A Survey

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... Chowdhury et al 2019 [1] Deng et al 2019 [66] Juma et al 2019 [68] Kim et al 2019 [51] Khalilov et al 2018 [64] Belotti et al 2019 [62] Ali et al 2019 [63] Gonczol et al 2019 [97] Al-Jaroodi et al 2019 [70] Kuperberg 2019 [87] Sharma et al 2019 [7] Salman et al 2019 [35] Pahlajani et al [49] Bernabe et al 2019 [61] Chowdhury et al 2018 [56] Park et al 2019 [65] Liu et al 2020 [80] Siris et al 2019 [6] Weiss et al 2019 [78] Mylrea et al 2018 [22] Islam et al 2020 [28] Asif 2019 [82] Yousuf et al 2019 [11] Onik et al 2019 [13] Ojo et al 2018 [17] Nalavade 2018 [20] Epiphaniou et al 2020 [50] Al-Zaben et al 2018 [60] Mushtaq et 2019 [67] Al-Jaroodi et al 2019 [71] Vafiadis et 2019 [69] AlTaei et 2018 [72] Saino et at 2019 [74] Nakasumi et at 2017 [76] Dunphy et al 2018 [77] Moyne et al 2019 [81] Hammoudeh et al 2020 [83] Shen et al 2020 [89] Sudhan et al 2017 [88] Wu et al 2019 [95] Risk Management Stevens et al 2016 [16] Conti et al 2018 [32] Salman et al 2019 [35] Barron et al 2016 [53] Fu et al 2019 [21] Lu et al 2017 [54] Cyber Resilience Acharjamayum et al 2018 [30] Divey et al 2019 [99] Wang et al 2019 [47] Fraga-Lamas et 2019 [9] Shahaab et al 2019 [3] Ben?i? et al 2018 [10] Maple et al 2019 [29] Alotaibi 2019 [37] Hou et al 2019 [36] He et al 2018 [42] Onwubiko 2020 [41] Sharma et al 2019 [43] Saini et at 2019 [44] ...
... The security of data shared and stored in the network due to immutability of DLTs makes them invaluable to many industries including SC. Furthermore, Sharma et al [43] explains consensus mechanism as the decision making process which promotes and ensures fairness and equal opportunities in distributed networks whilst Saini et al [44] describes it as integrity maintaining algorithm. Shahaab et al [3] debate that it is difficult to achieve consensus in distributed systems as the protocols must be resilient to failure, network partitions, message delays, ordering and corruption. ...
... Other forms of BFT are Stellar consensus protocol [47] and Delegated BFT. Proof of work (PoW), Proof of stake (PoS), Proof of Elapsed Time (PoET), Proof of Storage and Proof of Authority (PoA) are also types of consensus protocols for validating transactions [32], [43], [48], [47]. Monrat et al [46] made several suggestions for improvement such as standardization and testing based on selected criteria to determine the capability of the system. ...
Article
Supply chains (SC) present performance bottlenecks that contribute to a high level of costs, infiltration of product quality, and impact productivity. Examples of such inhibitors include the bullwhip effect, new product lines, high inventory, and restrictive data flows. These bottlenecks can force manufacturers to source more raw materials and increase production significantly. Also, restrictive data flow in a complex global SC network generally slows down the movement of goods and services. The use of distributed ledger technologies (DLT) in SC management (SCM) demonstrates the potentials to reduce these bottlenecks through transparency, decentralization, and optimizations in data management. These technologies promise to enhance the trustworthiness of entities within the SC, ensure the accuracy of data-driven operations, and enable existing SCM processes to migrate from a linear to a fully circular economy. This article presents a comprehensive review of 111 articles published in the public domain in the use and efficacy of DLT in SC. It acts as a roadmap for current and future researchers who focus on SC security management to better understand the integration of digital technologies such as DLT. We clustered these articles using standard descriptors linked to trustworthiness, namely, immutability, transparency, traceability, and integrity.
... This is regarded as a waste of resources due to significant computational power put into doing no useful work. The requirement of high computational power ensures high security as the malicious user requires 51% of computation power to perform a potential attack [7]. Specific expensive hardware like Application-Specific Integrated Circuit (ASIC) makes the mining process unfair by giving some miners an unfair advantage. ...
... Delegated Proof of Stake (DPoS) is the most common variant of Proof of Stake, which resembles indirect democracy. In DPoS, instead of validating the block themselves, stakeholders elect validators/delegates. 21-100 validators are selected, and they keep changing according to an order to deliver blocks [7] [5]. This delegate, instead of competing with each other, join hands to create the block. ...
... To mitigate the unequal distribution of mining power among participating nodes over time, PoB uses the concept of periodic burning of cryptocurrency. The value of burnt coins reduces as new blocks in the blockchain are added [12] [7]. It maintains consistent activity by miners and consistent equipment up-gradation to compete in the system and, therefore, strengthening the infrastructure of the blockchain. ...
Chapter
Blockchain is the backbone of digital cryptocurrency systems, and it eliminates the need for a central authority in a decentralized network. Blockchain is a system that allows the sharing of information securely and transparently in a peer-to-peer connected decentralized network consisting of untrustable users. Blockchain technology ensures security, equality, and fairness of the system by following a well-defined set of rules known as a consensus protocol. These consensus protocols are at the core of blockchain technology and secure the network from various attacks and frauds. It is nearly impossible to breach a system following these protocols. There are various consensus protocols, each with its advantages and disadvantages. In this paper, we have discussed various consensus protocols in terms of performance, fairness, resource requirements, and security breaches. We have discussed the working of typical blockchain technology by describing major concepts in the implementation of Bitcoin technology. We also discussed the most common security breaches in decentralized systems.
... Blockchain is a distributed and immutable ledger of transactions duplicated across a network of nodes with no need for a central authority to achieve trust [9]. Most blockchains come with a built-in scripting language that can be limited or Turing complete. ...
... First, it creates an ACEL event by assigning an identifier to it (line 6) and extracting its attributes from the data according to the event mapping rule and placing them in the event attribute list (vmap) (line 7). It then creates the list of objects identifiers (omap) and relation identifiers (rmap) linked to this event (line [8][9]. Then, it creates all the ACEL objects identified in the (omap or simply fetch them for updating if they already exist (line [10][11][12][13][14]. ...
... It presents a detailed review on the recent design schemes used in developing different permissionless consensus algorithms. ( Sharma and Jain, 2019 ) 2019 It gives a summary of popular consensus algorithms along with their advantages and disadvantages. ( Sadek Ferdous et al., 2020 ) 2020 It presents different taxonomies of consensus algorithms from different perspectives to establish a baseline for a detailed comparison. ...
... Several variations of consensus algorithms have been proposed, each of which offers varying performance efficiency, security and reliability. Several surveys on consensus algorithms have been conducted in recent years ( Nguyen and Kim, 2018 ;Mingxiao et al., 2017 ;Cachin and Vukoli ć, 2017 ;Bano et al., 2017 ;Alsunaidi and Alhaidari, 2019 ;Wang et al., 2019 ;Sharma and Jain, 2019 ;Sadek Ferdous et al., 2020 ). Several of these surveys are summarized in Table 1 . ...
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Blockchain-based platforms, particularly those based on permissioned blockchain, are increasingly popular in a broad range of settings. In addition to security and privacy concerns, organizations seeking to implement such platforms also need to consider performance, especially in latency- or delay-sensitive applications. Performance is generally less studied in comparison to security and privacy, and therefore in this paper we survey existing empirical performance evaluations of different permissioned blockchain platforms published between 2015 and 2019, using a comparative framework. The framework comprises ten criteria. We then conclude the paper with a number of potential future research directions.
... PBFT is a BFT-based consensus protocol based on the voting of the majority to tackle the "Byzantine" fault [54] which relies on the network participation levels to determine vote weight. The PBFT consensus mechanisms are vulnerable to Sybil attacks [82], [83], [84]. PBFT is confronted by an imbalance of influence from falsely increasing the presence of individuals through Sybil attacks. ...
Article
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In the era of Fourth Industrial Revolution (Industry 4.0), blockchain technology emerges as an innovative solution to address the challenges of digital-based business networks, such as traceability, transparency, trust, and data authenticity. This transformative technology has shown promise across diverse domains, including finance, healthcare, and supply chain, by enabling secure data transmission and trust establishment between entities. However, blockchain technology experiences from an inherent trade-off issue between the core properties of security, decentralization and scalability in its type of network. While permissionless blockchain excel in security and decentralization, such network lack scalability and suitability for business transactions. Conversely, permissioned blockchains offer better performance but are vulnerable to cyber-attacks due to weaknesses in consensus mechanisms. Therefore, this paper provides an analysis of blockchain technology, emphasizing the pivotal role of consensus mechanisms in ensuring security and system performance. Additionally, it identifies practical threats, suggests countermeasures, and underscores the importance of resilient and secure consensus mechanisms. Furthermore, it compares and analyzes existing mechanisms for permissioned blockchains, discusses their limitations, and highlights the significance of ensuring system security and performance. Finally, it uncovers essential factors to consider when designing consensus mechanisms for specific blockchain-based applications, laying the foundation for future research in practical and secure permissioned blockchain applications.
... A consensus algorithm is executed within the consensus layer, which is the blockchain's premise and acts as a decision-making body to allow fairness across the entire network. It is used within a blockchain architecture (as seen in Fig. 10) to agree on the state of the blockchain between participants [15,65]. Interest in blockchain grew with the introduction of the Nakamoto consensus algorithm in 2008, which led to the first crypto-currency known as Bitcoin [66,64,67]. ...
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Industry 4.0 and beyond will rely heavily on sustainable Business Decision Modelling (BDM) that can be accelerated by blockchain and Digital Twin (DT) solutions. BDM is built on models and frameworks refined by key identification factors, data analysis, and mathematical or computational aspects applicable to complex business scenarios. Gaining actionable intelligence from collected data for BDM requires a carefully considered infrastructure to ensure data transparency, security, accessibility and sustainability. Organisations should consider social, economic and environmental factors (based on the triple bottom line approach) to ensure sustainability when integrating such an infrastructure. These sustainability features directly impact BDM concerning resource optimisation, stakeholder engagement, regulatory compliance and environmental impacts. To further understand these segments, taxonomies are defined to evaluate blockchain and DT sustainability features based on an in-depth review of the current state-of-the-art research. Detailed comparative evaluations provide insight into the reachability of the sustainable solution in terms of ideologies, access control and performance overheads. Several research questions are put forward to motivate further research that significantly impacts BDM. Finally, a case study based on an exemplary supply chain management system is presented to show the interoperability of blockchain and DT with BDM.
... The industrial application layer mainly analyzes and integrates the collected data information and applies the data information to the manufacturing industry, smart grid, supply chain, etc. Blockchain will revolutionize IIoT and big data technology. On the one hand, in the IIoT, the decentralized nature of blockchain technology will play a key role between two untrusted devices to maintain information about the summary of their interactions, state and exchanged data [31]. On the other hand, blockchain can significantly reduce the current risks faced by users and save business process costs [32]. ...
Article
Full-text available
With the development of Industry 4.0 and big data technology, the Industrial Internet of Things (IIoT) is hampered by inherent issues such as privacy, security, and fault tolerance, which pose certain challenges to the rapid development of IIoT. Blockchain technology has immutability, decentralization, and autonomy, which can greatly improve the inherent defects of the IIoT. In the traditional blockchain, data is stored in a Merkle tree. As data continues to grow, the scale of proofs used to validate it grows, threatening the efficiency, security, and reliability of blockchain-based IIoT. Accordingly, this paper first analyzes the inefficiency of the traditional blockchain structure in verifying the integrity and correctness of data. To solve this problem, a new Vector Commitment (VC) structure, Partition Vector Commitment (PVC), is proposed by improving the traditional VC structure. Secondly, this paper uses PVC instead of the Merkle tree to store big data generated by IIoT. PVC can improve the efficiency of traditional VC in the process of commitment and opening. Finally, this paper uses PVC to build a blockchain-based IIoT data security storage mechanism and carries out a comparative analysis of experiments. This mechanism can greatly reduce communication loss and maximize the rational use of storage space, which is of great significance for maintaining the security and stability of blockchain-based IIoT.
... Sharma and Jain cover the different consensus methods, how they operate, and their applications. Additionally, it looked at blockchain technology, including its benefits and drawbacks [21]. Meneghetti et al. (2020) presented a comprehensive survey of the PoW techniques, attacks, and their current use in cryptocurrency consensus algorithms. ...
Article
Full-text available
Blockchain is a decentralized ledger that serves as the foundation of Bitcoin and has found applications in various domains due to its immutable properties. It has the potential to change digital transactions drastically. It has been successfully used across multiple fields for record immutability and reliability. The consensus mechanism is the backbone of blockchain operations and validates newly generated blocks before they are added. To verify transactions in the ledger, various peer-to-peer (P2P) network validators use different consensus algorithms to solve the reliability problem in a network with unreliable nodes. The security and reliability of the inherent consensus algorithm used mainly determine blockchain security. However, consensus algorithms consume significant resources for validating new nodes. Therefore the safety and reliability of a blockchain system is based on the consensus mechanism's reliability and performance. Although various consensus mechanisms/algorithms exist, there is no unified evaluation criterion to evaluate them. Evaluating the consensus algorithm will explain system reliability and provide a mechanism for choosing the best consensus mechanism for a defined set of problems. This article comprehensively analyzes existing and recent consensus algorithms' throughput, scalability, latency, energy efficiency, and other factors such as attacks, Byzantine fault tolerance, adversary tolerance, and decentralization levels. The paper defines consensus mechanism criteria, evaluates available consensus algorithms based on them, and presents their advantages and disadvantages.
... Every transaction in the blockchain is considered secured and verified because of the presence of a consensus algorithm, which is an essential part of the blockchain network [34]. A consensus algorithm is a process through which all the nodes of the network agreed on a single source of truth or the present data state of the ledger [41]. Thus, a consensus mechanism ensures reliability and the establishment of trust between unknown nodes in a blockchain network. ...
Article
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Blockchain, the pillar of the Fourth Industrial Revolution (4IR), is being used to provide security to the data of traditional record-keeping systems. However, the implementation of blockchain technology is not easily possible in such systems. For instance, the execution cost of shifting the existing system to the blockchain is extremely high making it unfeasible for many organizations. Moreover, this technology is still immature and is not being fully adopted yet in all parts of the world and may have severe challenges and complexities to achieve its widespread adoption. Considering these two major concerns, the replacement of existing traditional systems with purely Blockchain-based systems will be risky especially in developing countries as it requires major social, legal, and political changes. In this paper, a hybrid Blockchain-based Academic Credential Verification System (B-ACVS) is proposed. The framework combines Blockchain technology with the off-chain centralized data storage that offers facilitation of high security at an affordable cost to any existing system. For a proof of concept, a prototype implementation of a fully transparent, time-saving cost-effective B-ACVS using the proposed hybrid framework is presented. Rich features like Legacy System Support, Hard Commit, and Auto Synchronization of on-chain and off-chain data provide significance to hybrid B-ACVS upon other Blockchain-based solutions. A cost analysis of the proposed hybrid framework along with purely Blockchain-based systems is also provided. The proposed hybrid B-ACVS framework not only provides integrity of data to detect any tempering in off-chain data as well as security of data by utilizing blockchain technology. Thie proposed system is fully recoverable if an attempt is made to destroy it or a part of it.
... Identity privacy refers to the association between user identity information and blockchain addresses [16]. The transaction records on the public chain are open and transparent, and users use pseudonyms to conduct transactions, which protects the identity information of both parties to the transaction [17]. Transaction privacy refers to the transaction records and inferred transaction information stored in the blockchain [18]. ...
... Proof of capacity (PoC) [27] is a blockchain consensus mechanism approach that enables network mining devices to identify mining rights and validate transactions by using available hard drive space. The computing power issue in proof-ofwork (PoW) as systems need a lot of energy, and proof-ofstake (PoS) systems use a lot of money, both can be addressed by PoC. ...
Article
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As the size of data is increasing exponentially, its security is a major concern. Emerging technology like blockchain is used to provide security to systems. Since the inception of blockchain, it has been adopted by researchers and industry both, however, it gained enormous attention after cryptocurrency. It can be defined as a means of storing information in such a way that modification and hacking the system is difficult or impossible. A blockchain is a decentralized ledger that is digital and public, consisting of records of transactions called blocks. A consensus technology assures that all nodes agree on a unique sequence for appending blocks. A comprehensive examination of these algorithms will aid in understanding how and why each blockchain operates in the manner that it does. In this study, we addressed extensively used consensus techniques in the blockchain and the importance of consensus protocol in blockchain technology. The underlying consensus algorithm is a critical component of every blockchain-based system which determine the performance and security of the system. Ensuring the correctness of consensus protocols is uttermost important to create trust in the blockchain-based systems and formal methods are the way to create that trust and develop correct and verified systems. Formal modeling is a method of writing a system mathematically and examining the correctness and verifying the developed system. This study analyzed the importance of consensus mechanisms and how formal methods are helping to develop a correct blockchain-based system. The current scenario of the application of formal methods in the consensus mechanism of blockchain for their verification is presented.
... It is the one described by bitcoin founder Satoshi Nakamoto [42] and was first used for bitcoin. Ethereum, IBM Blockchain, Ripple are using this consensus protocol. ...
Chapter
Blockchain technology is the “fifth evolution” in the era of computing. The characteristics of blockchain such as immutability, tamper-proof, decentralized, private, and permissioned blockchain have attracted the world's attention. This paper briefs about the core concepts of blockchain, smart contracts, and architecture behind the integration of IoT devices and blockchain. The proposed architecture using the blockchain and Inter Planetary File System (IPFS) improves the way of storing, handling, and sharing medical data and records. A comprehensive study on blockchain-based smart applications across diverse sectors such as financial, manufacturing, supply chain, healthcare sectors is also included in this paper. Finally, the paper also enumerates challenges, limitations, and future trends in the area of blockchain.
... However, among all the advanced technologies of the Blockchain platform, the consensus mechanism is the most prominent. A consensus algorithm is a decisive factor for the success of Blockchain technology [15,16]. As we all know, SDN is a system where large amounts of data are constantly being exchanged, so ensuring the reliability of all that data in real time is difficult and expensive. ...
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Software-Defined Networking (SDN) brought a groundbreaking idea to facilitate network system management by decoupling and abstracting the Control plane and Data plane of traditional networks. The centralised control offers network administrators many benefits such as a global view of the network, programmability, dynamic updating of forwarding rules, and software-based traffic analysis. The SDN architecture has been applied a lot in practice, and especially in Internet of Things (IoT) platforms. With the superiority of SDN, IoT devices can be managed and configured much more easily when combined. However, SDN also raises many challenges in terms of scalability, reliability, and security. Blockchain is another promising solution for secure information storage and transmission technology that operates without a centralised authority. Applying Blockchain technology into SDN can address some of the current issues of SDN by providing decentralised methods to authenticate exchanged network information. This study provides a comprehensive survey on Blockchain technologies applied to SDN in both security and non-security fields. First, related studies and an overview of SDN and the background of Blockchain technology are presented. Then, the authors review how Blockchain technologies are applied in SDN from two perspectives: non-security and security-aware approaches. Finally, challenges and broader perspectives are discussed.
... Other Consensus Algorithms: Several consensus algorithms focus on tackling many problems where scalability is one of them. Other mentionable consensus algorithms available in the literature include Delegated Proof of stake [81], Practical Byzantine Fault Tolerance [82], Hybrid Consensus [83], Proof of Authority [84], Proof of Capacity [85], Proof of Participation [86]. Surveys comparing consensus algorithms are available in [19], [20], [61], [53], and [73]. ...
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Recently, enormous interest has been shown by both academia and industry around concepts and techniques related to connecting heterogeneous IoT devices. It is now considered a rapidly evolving technology with billions of IoT devices expected to be deployed in the upcoming years around the globe. These devices must be maintained, managed, traced, and secured in a timely and flexible manner. Previously, the centralized approaches constituted mainstream solutions to handle the ever-increasing number of connected IoT devices. However, these approaches may be inadequate to handle devices at a massive scale. Blockchain as a distributed approach that presents a promising solution to tackle the concerns of IoT devices connectivity. However, current Blockchain platforms face several scalability issues to accommodate diverse IoT devices without losing efficiency. This paper performs a comprehensive analysis of the recent blockchain-based scalability solutions applied to the Internet of Things domain. We propose an evaluation framework of scalability in IoT environments, encompassing critical criteria like throughput, latency, and block size. Moreover, we conduct an assessment of the notable scalability solutions and conclude the results by highlighting six overarching scalability issues of blockchain-based solutions in IoT that ought to be resolved by the industry and research community.
... PoR was initially suggested by Juels et al. in 2007 as a cryptographic construction for a semi-trusted distribution archiving system. It was first used by the cryptocurrency Perm coin projected by Miller et al in 2014 [8]. Proof of Identity is a member of evidence that helps each individual to distinguish a sequestered key that suits the agreed cryptographically and uniqueness as an identity connected to a real transaction [7]. ...
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Due to the explosion of mobile users and the ever-increasing heterogeneity and scale of wireless networks, traditional communication protocols and optimizing methods can not satisfy future wireless network (FWN) requirements. As promising technologies, artificial intelligence (AI) and blockchain are deemed as the solution for the FWN. AI, famous for its big data processing ability, will enable the FWN to self-update itself to better adapt to the dynamic network condition. Blockchain, as a distributed ledger, can guarantee data integrity, security and privacy. In this survey, we overview the concept of AI and blockchain and present their state-of-the-art applications in wireless networks. The potential of AI and blockchain is still huge and waiting to be fully explored in wireless networks. Therefore, we introduce how AI and blockchain can assist each other in FWNs. Furthermore, we explore the current constraints of applying both technologies in the FWNs. In the final part, we discuss the future direction of the deployment of AI and blockchain in FWNs.
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Consensus algorithms are applied in the context of distributed computer systems to improve their fault tolerance. The explosive development of distributed ledger technology following the proposal of “Bitcoin” led to a sharp increase in research activity in this area. Specifically, public and permissionless networks require robust leader selection strategies resistant to Sybil attacks in which malicious attackers present bogus identities to induce byzantine faults. Our goal is to analyse the entire breadth of works in this area systematically, thereby uncovering trends and research directions regarding Sybil attack resistance in today’s blockchain systems to benefit the designs of the future. Through a systematic literature review, we condense an immense set of research records (N = 21,799) to a relevant subset (N = 483). We categorise these mechanisms by their Sybil attack resistance characteristics, leader selection methodology, and incentive scheme. Mechanisms with strong Sybil attack resistance commonly adopt the principles underlying “Proof-of-Work” or “Proof-of-Stake” while mechanisms with limited resistance often use reputation systems or physical world linking. We find that only a few fundamental paradigms exist that can resist Sybil attacks in a permissionless setting but discover numerous innovative mechanisms that can deliver weaker protection in system scenarios with smaller attack surfaces.
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Blockchain is a distributed decentralized peer-to-peer network aiming to facilitate the immutability and security of data. Towards the service orientation, blockchain is a collection of distributed blocks having unique hash codes without any point of failure. Each block is stored on distributed ledgers, and transactions with them are secure, transparent, immutable, and traceable. To create a new block and allow a transaction to complete, an agreement between all parties is required. To reach an agreement in a blockchain network, consensus algorithms are used. In this chapter, fundamental principles and algorithms of blockchain networks have been discussed, and a detailed review of the blockchain consensus algorithms PoW, PoS, DPoS, PoET, PoWeight, PoB, PoA, and PoC have been provided including the merits and demerits of consensus algorithms with analysis to provide a deep understanding of the current research trends and future challenges.
Chapter
Blockchain is the underlying technology behind Bitcoin, the first digital currency, and due to the rapid growth of Bitcoin, there is significant interest in blockchain as the enabler of digital currencies due to the consensus distributed ledger model. The rise and the success of alternative cryptocurrencies such as Ethereum and Ripple has supported the development of blockchain technology, but the performance of blockchain applications has been documented as a significant obstacle for adoption. At the core of blockchain is a consensus protocol, which plays a key role in maintaining the safety, performance and efficiency of the blockchain network. Several consensus protocols exist, and the use of the right consensus protocol is crucial to ensure adequate performance of any blockchain application. However, there is a lack of documented overview studies even though there is agreement in the literature about the importance and understanding of blockchain consensus protocols. In this study, we adopt a systematic literature review (SLR) to investigate the current status of consensus protocols used for blockchain together with the identified limitations of these protocols. The results of this study include an overview of different consensus protocols as well as consensus protocol limitations and will be of value for any practitioner or scholar that is interested in blockchain applications.
Book
This volume constitutes the proceedings of the 20th IFIP WG 6.11 Conference on e-Business, e-Services, and e-Society, I3E 2021, held in Galway, Ireland, in September 2021.* The total of 57 full and 8 short papers presented in these volumes were carefully reviewed and selected from 141 submissions. The papers are organized in the following topical sections: AI for Digital Transformation and Public Good; AI & Analytics Decision Making; AI Philosophy, Ethics & Governance; Privacy & Transparency in a Digitized Society; Digital Enabled Sustainable Organizations and Societies; Digital Technologies and Organizational Capabilities; Digitized Supply Chains; Customer Behavior and E-business; Blockchain; Information Systems Development; Social Media & Analytics; and Teaching & Learning. *The conference was held virtually due to the COVID-19 pandemic.
Article
Today’s modern vehicles contain anywhere from sixty to one-hundred sensors and exhibit the characteristics of Cyber-Physical- Systems (CPS). There is a high degree of coupling, cohesiveness, and interactions among vehicle’s CPS components (e.g., sensors, devices, systems, systems-of-systems) across sensing, communication, and control layers. Cyber-attacks in the sensing or communication layers can compromise the security of the control layer. This paper provides a detailed review of potential cyber threats related to the sensing layer. Notably, the focus is mainly towards two categories of sensors: vehicle dynamics sensors (e.g., Tire Pressure Monitoring Systems (TPMS), magnetic encoders, and inertial sensors) and environment sensors (e.g., Light Detection and Ranging (LiDAR), ultrasonic, camera, Radio Detection and Ranging (Radar) systems, and Global Positioning System (GPS) units). The paper also offers perspectives through existing countermeasures from literature and stresses the need for data-driven cybersecurity solutions
Conference Paper
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The underlying or core technology of Bitcoin cryptocurrency has become a blessing for human being in this era. Everything is gradually changing to digitization in this today’s epoch. Bitcoin creates virtual money using Blockchain that’s become popular over the world. Blockchain is a shared public ledger, and it includes all transactions which are confirmed. It is almost impossible to crack the hidden information in the blocks of the Blockchain. However, there are certain security and technical challenges like scalability, privacy leakage, selfish mining, etc. which hampers the wide application of Blockchain. In this paper, we briefly discuss this emerging technology namely Blockchain. In addition, we extrapolate in-depth insight on Blockchain technology.
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The concept of Bitcoin was first introduced by an unknown individual (or a group of people) named Satoshi Nakamoto before it was released as open-source software in 2009. Bitcoin is a peer-to-peer cryptocurrency and a decentralized worldwide payment system for digital currency where transactions take place among users without any intermediary. Bitcoin transactions are performed and verified by network nodes and then registered in a public ledger called blockchain, which is maintained by network entities running Bitcoin software. To date, this cryptocurrency is worth close to 150 billion of dollars and widely traded across the world. However, as Bitcoin’s popularity grows, security concerns are coming to the forefront. Overall, Bitcoin security inevitably depends upon the distributed protocols-based stimulant-compatible proof-of-work that is being run by network entities called miners, who are anticipated to primarily maintain the blockchain (ledger). As a result, many researchers are exploring new threats in the entire system, introducing new countermeasures, and therefore anticipating new security trends. In this survey paper, we introduce an intensive study that explores the key security concerns. We first start by presenting a global overview of the Bitcoin protocol as well as its major components. Next, we detail the existing threats and weaknesses of the Bitcoin system and its main technologies including the blockchain protocol. Last, we discuss the current existing security studies and solutions and summarize open research challenges and trends of future research for Bitcoin security.
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Blockchain technology has attracted tremendous attention in both academia and capital market. However, overwhelming speculations on thousands of available cryptocurrencies and numerous initial coin offering (ICO) scams have also brought notorious debates on this emerging technology. This paper traces the development of blockchain systems to reveal the importance of decentralized applications (dApps) and the future value of blockchain.We survey the state-of-the-art dApps and discuss the direction of blockchain development to fulfill the desirable characteristics of dApps. The readers will gain an overview of dApp research and get familiar with recent developments in the blockchain.
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Over the past several years, social networking sites have arisen to facilitate social interactions on the Internet while revolutionizing how online users interact with others. Most social networking sites offer the basic features of online interaction, communication, and interest sharing, letting individuals create online profiles that other users can view. Unfortunately, current trends in social networks indirectly require users to become system and policy administrators to protect their online contents. Social networks' security and privacy requirements still aren't well understood or fully defined. Nevertheless, it's clear that they'll be quite different from classic security and privacy requirements because social networks involve user-centric concerns and allow multiple users to specify security policies on shared data. So, we must bring a depth of security experience from multiple security domains and technologies to this field, as well as a breadth of knowledge about social networks.
Conference Paper
Nowadays, the blockchain is a favorite platform, for instance, for use with cryptocurrency, smart contracts, IoT, and so forth. Blockchains are distributed ledgers that enable parties who do not trust each other to maintain states. The parties agree on the existence, values, and histories of the states. The blockchain applies the consensus protocol to verify the block which is distributing the network node. Consensus has many practices such as, for example, Byzantine general problem, Proof of work, and Proof of stake. However, there have not been numerous papers that have undertaken analysis with regard to various aspects, and which have incorporated the adoption summary as appropriate to the application. In this paper, we have provided a technical verification review with regard to the consensus algorithm taken from previous research. The audience will receive a consensus protocol, and the algorithm typically analyzes the application to match which platform is appropriate by viewing the node identity, energy saving and the tolerated power of the adversary, the data model, language, execution, application, and examples. Finally, we finish by presenting several research directions with regard to the consensus protocol.
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Incorporating accountability mechanisms in online services requires effective trust management and immutable, traceable source of truth for transaction evidence. The emergence of the blockchain technology brings in high hopes for fulfilling most of those requirements. However, a major challenge is to find a proper consensus protocol that is applicable to the crowdsourcing services in particular and online services in general. Building upon the idea of using blockchain as the underlying technology to enable tracing transactions for service contracts and dispute arbitration, this paper proposes a novel consensus protocol that is suitable for the crowdsourcing as well as the general online service industry. The new consensus protocol is called “Proof-of-Trust” (PoT) consensus; it selects transaction validators based on the service participants' trust values while leveraging RAFT leader election and Shamir's secret sharing algorithms. The PoT protocol avoids the low throughput and resource intensive pitfalls associated with Bitcoin's “Proof-of-Work” (PoW) mining, while addressing the scalability issue associated with the traditional Paxos-based and Byzantine Fault Tolerance (BFT)-based algorithms. In addition, it addresses the unfaithful behaviors that cannot be dealt with in the traditional BFT algorithms. The paper demonstrates that our approach can provide a viable accountability solution for the online service industry. IEEE
Conference Paper
Blockchain is the basic technology of bitcoin. With the value appreciation and stable operation of bitcoin, blockchain is attracting more and more attention in many areas. Blockchain has the characteristics of decentralization, stability, security, and non-modifiability. It has the potential to change the network architecture. The consensus algorithm plays a crucial role in maintaining the safety and efficiency of blockchain. Using a right algorithm may bring a significant increase to the performance of blockchain application. In this paper, we reviewed the basic principles and characteristics of the consensus algorithms and analyzed the performance and application scenarios of different consensus mechanisms. We also gave a technical guidance of selecting a suitable consensus algorithm and summarized the limitations and future development of blockchain technology.
Article
A peer-to-peer crypto-currency design derived from Satoshi Nakamoto's Bitcoin. Proof-of-stake replaces proof-of-work to provide most of the network security. Under this hybrid design proof-of-work mainly provides initial minting and is largely non-essential in the long run. Security level of the network is not dependent on energy consumption in the long term thus providing an energy-efficient and more cost-competitive peer-to-peer crypto-currency. Proof-of-stake is based on coin age and generated by each node via a hashing scheme bearing similarity to Bitcoin's but over limited search space. Block chain history and transaction settlement are further protected by a centrally broadcasted checkpoint mechanism.
Blockchain consensus: An analysis of proof-of-work and its applications
  • A Porat
  • A Pratap
  • P Shah
  • V Adkar
Design and implementation of a proof-of-stake consensus algorithm for blockchain
  • Garcia Ribera