Delegated proof of stake

Blockchain era is one of the rapidly evolving technologies in ultra-modern generation and quite a few studies has simply began out concerning this generation. It is a distributed ledger allowing the transactions take place without involving a central authority and at the same time ensures the security, immutability and transparency of the the records. It received popuparity with the launch of Bitcoin(a cryptocurrency or virtual currency) which is the most successful instance that enploys the blockchain technology. After the release of bitcoin many cryptocurrencies have been released using this technology. It is the interesting and current subject to evaluate and it is the breakthrough in technology revolutionizing the entire world. This paper represents a detailed evaluation on blockchain technology. Throughout this paper, a brief introduction in relation to this technology , its history, advantages and disadvantages are given. We will also go into the fundamentals of this emerging technology and some technical challenges. We will also discuss its implementation in various sectors. Some hints on destiny studies instructions are furnished for researchers. We additionally lay out feasible destiny developments for blockchain.

This chapter expounds the main principles behind blockchain technology and some of its cutting-edge applications. We first present the core concepts of the blockchain. Secondly, we discuss a definition put forward by Vitalik Buterin; we sketch out the shift toward hybrid solutions, and we sum up the main features of decentralized public ledger platforms. Thirdly, we show why the blockchain is a disruptive and foundational technology, but we expose the potential risks and drawbacks of public distributed ledgers that account for the shift toward hybrid solutions. Finally, we present a non-exhaustive list of important applications, bearing in mind the most recent developments.

In the past decade, blockchain technology has garnered significant attention from a diverse array of industries. Despite the fact that blockchain technology was initially developed for the Bitcoin P2P cryptocurrency network, there has been a recent surge in interest in its potential integration with other service sectors. In the domain of machine-to-machine commerce, distributed ledger technologies, as seen in blockchain systems, have recently been hailed as potential platforms. A decentralised network architecture, security, immutability, and transparency are among the primary attributes of blockchains. The unalterable nature of blockchain ledgers enables members to rely on one another, thereby increasing performance and participation. Scalability and security are substantial challenges for blockchain technology. This study provides a comprehensive analysis of the emergence of blockchain technology and various methods for addressing the scalability issues associated with distributed ledgers.

This study conducts a systematic literature review (SLR) of blockchain consensus mechanisms, an essential protocols that maintain the integrity, reliability, and decentralization of distributed ledger networks. The aim is to comprehensively investigate prominent mechanisms' security features and vulnerabilities, emphasizing their security considerations, applications, challenges, and future directions. The existing literature offers valuable insights into various consensus mechanisms' strengths, limitations, and security vulnerabilities and their realworld applications. However, there remains a gap in synthesizing and analyzing this knowledge systematically. Addressing this gap would facilitate a structured approach to understanding consensus mechanisms' security and vulnerabilities comprehensively. The study adheres to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and computer science standards and reviewed 3749 research papers from 2016 to 2024, excluding grey literature, resulting in 290 articles for descriptive analysis. The research highlights an increased focus on blockchain consensus security, energy efficiency, and hybrid mechanisms within 60% of research papers post-2019, identifying gaps in scalability, privacy, and interoperability for future exploration. By synthesizing the existing research and identifying the key trends, this SLR contributes to advancing the understanding of blockchain consensus mechanisms' security and guiding future research and structured innovation in blockchain systems and applications. KEYWORDS Blockchain consensus mechanisms; supply chain management; proof of work (PoW); proof of stake (PoS); practical byzantine fault tolerance (PBFT)

Blockchain has numerous benefits such as decentralization, persistency, anonymity and auditability. There is a wide spectrum of blockchain applications ranging from cryptocurrency, financial services, risk management, Internet of Things to public and social services. Although a number of studies focus on using the blockchain technology in various application aspects, there is no comprehensive survey on the blockchain technology in both technological and application perspectives. To fill this gap, we conduct a comprehensive survey on the blockchain technology. In particular, this paper gives the blockchain taxonomy, introduces typical blockchain consensus algorithms, reviews blockchain applications and discusses technical challenges as well as recent advances in tackling the challenges. Moreover, this paper also points out the future directions in the blockchain technology.

The successful adoption and operation of any new technology is dependent on the appropriate management of the risks associated with that technology. This is especially true when that technology is more than an application and is part of the organization’s core infrastructure. And distributed ledger technologies (DLT) like blockchain technology have the potential to be the backbone of many core platforms in the near future. The blockchain is an undeniably ingenious invention – the brainchild of a person or group of people known by the pseudonym, Satoshi Nakamoto. It has become a focus of global attention since its development as banks around the world seek to understand and harness its disruptive potential. Many of the industries has been exploring how to use blockchains across a variety of internal and client facing issues. Blockchain has the potential to transform our world. However, leading into 2018 the focus will move from “how to use a blockchain” to “how to secure a blockchain...

Government has numerous responsibilities of state and individual ministries in the country. The everyday working of government involves an enormous number of transactions of various operations that need to be carried out throughout the country. A major hurdle that the top government faces is the low-level corruption that is sometimes impossible to track which hinders the state progress. Tracking it is a very difficult task in the persistent modelling and structure of the government. Every detail is recorded either on paper or a simple database with first to second level authentication. A system that allows for a full proof, secure and authentic fund allocation and tracking is required to form an incorruptible government. It is the present requirement for transparent operations of the government. Blockchain technology is considered to be one among the many transformative technologies in present times with its prominent use case being the application in the crypto currency areas. It becomes very convenient to track the huge amount of data which is not possible in the current system. This makes the functioning of the government and fund flows transparent. Thus, might also prove to gain the trust of the citizens. The top-level government can track all the transactions that happen in the lowest levels. The vital objective of this project is to develop a smart system to track funds allocated to the state government as they traverse through the government process at each stage. This project leverage blockchain technology to secure the transactions at every stage while maintaining transparency in every transaction, sealing every transaction with proofs as the funds move ahead. The proposed system strives to achieve a more secure and an efficient system to maintain the transactional details of the government. Providing more efficient and user-friendly interface, this system allows every authorised individual to view the fund records and transaction details.

The internet of things (IoT) represents rapid development in research and industry that enables both virtual and physical objects to be linked and transfers information in order to produce various services that enhance our excellence of life. Traditional security and privacy methods are not applicable for IoT, mostly due to their topological constraints and versatility of IoT devices. Blockchain technology has started to fascinate younger generations because it works especially well in the digital world. Blockchain is suitable for internet of things applications. Advancements in IoT have propelled distributed systems. The blockchain concept demands a method for exchanging and storing data that is managed by a decentralized network. The rise of IoT applications is hindered by these obstacles. One option to fix these problems is to use a distributed ledger technology using blockchain technology. This chapter gives a comprehensive overview of blockchain's strengths and weaknesses with its applications.

Cryptocurrency is the innovation that has changed the way of life most significantly over the past ten years. Bitcoins is a term that often comes up when discussing the blockchain system. Although they are not identical, Ethereum and Cryptocurrency nevertheless remain widely misunderstood. Innovative technologies had to be created as a result from rising degrees of globalization. These groundbreaking innovations improve the speed of international trade. There are many technical experiments; some of them were successful, whereas others died or required development. The decentralized ledger technology, its benefits, and methods for consensus are described on this article.

Blockchain has proven to be successful in decision making using the streaming live data in various applications, it is the latest form of Information Technology. There are two broad Blockchain categories, public and private. Public Blockchains are very transparent as the data is distributed and can be accessed by anyone within the distributed system. Private Blockchains are restricted and therefore data transfer can only take place in the constrained environment. Using private Blockchains in maintaining private records for managed history or governing regulations can be very effective due to the data and records, or logs being made with respect to particular user or application. The Blockchain system can also gather data records together and transfer them as secure data records to a third party who can then take further actions. In this paper, an automotive road safety case study is reviewed to demonstrate the feasibility of using private Blockchains in the automotive industry. With...

Blockchain, the foundation of Bitcoin, has received extensive attentions recently. Blockchain serves as an immutable ledger which allows transactions take place in a decentralized manner. Blockchain-based applications are springing up, covering numerous fields including financial services, reputation system and Internet of Things (IoT), and so on. However, there are still many challenges of blockchain technology such as scalability and security problems waiting to be overcome. This paper presents a comprehensive overview on blockchain technology. We provide an overview of blockchain architechture firstly and compare some typical consensus algorithms used in different blockchains. Furthermore, technical challenges and recent advances are briefly listed. We also lay out possible future trends for blockchain.

Two double-spend attack strategies on a proof-of-stake consensus are considered. For each strategy, the probability of its success is obtained, which depends on the network parameters and the number of confirmation blocks. These results can be used to define how many confirmation blocks a vendor should wait after a correspondent transaction before sending goods or services.

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

Block chain technology is one which is evolving over time and is still brand new to the mindset of various people. The question of how to use it even if one has the want to use it arises thereby questioning its need in necessary functioning. This technology may be hand in hand if required for the following features:-Various distributed participants; lack of trust in mediating parties; if maximum work is done through transactions. A need to reduce manual labor and be comfortable with digital listing of activities to avoid disputes. When one has a real time need of sharing the various activities with other clients/partners and get a valid and crisp work history. In this paper the importance of block chain and its implications are presented along with various case studies of technical glitches whether in IoT or banking sectors, this paper covers it all.

Bitcoin emerged as decentralized peer-to-peer (P2P) cryptocurrency, not under the hood of any ascendant obligation and is completely digital not backed by any physical commodity. The ownership of the money in Bitcoin form is completely anonymous and private. To prevent double-spending, Bitcoin uses asymmetric cryptography to create ownership of funds as well as proof-of-work (PoW) for making a transaction backed by P2P storage of transaction log in the form of distributed append-only public ledger called blockchain. Every transaction is digitally signed using public key cryptography and is irreversible and secure. Bitcoin transactions have to rely on global peer-to-peer network of participants who help to validate and certify each transaction in a decentralized system. The participating peers acting as miners certify validity of transaction by proving the ownership of the fund from the blockchain. If endorsed, it now completes new data block to add to the blockchain. This new data b...

Nowadays, everyone is talking about digitalization. The entire world is intrigued by this word because the first thought that came to mind was "money," and in this context, we have "Bitcoins," which are money exchanging over the internet in the form of blockchain, the shared ledger technology. Bitcoin works electronically to create a digital currency, and its main purpose is to transfer money in the form of bitcoin. Not only bitcoin, but also other applications such as electronic voting systems, government systems, medical fields, and so on, rule the world. The field of transactions is very unsafe, so security is also a focus that can be achieved through this technology. As a result, we welcomed the World Wide Web. Along with security, other features are also guiding the work. All new things suffer through initial challenges, and blockchain also faces some initial challenges. In this paper, we discuss a few of the major challenges that blockchain technology faces, as well as the fundamental features of blockchain technology and applications.

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

Nowadays, everyone is talking about digitalization. The entire world is intrigued by this word because the first thought that came to mind was "money," and in this context, we have "Bitcoins," which are money exchanging over the internet in the form of blockchain, the shared ledger technology. Bitcoin works electronically to create a digital currency, and its main purpose is to transfer money in the form of bitcoin. Not only bitcoin, but also other applications such as electronic voting systems, government systems, medical fields, and so on, rule the world. The field of transactions is very unsafe, so security is also a focus that can be achieved through this technology. As a result, we welcomed the World Wide Web. Along with security, other features are also guiding the work. All new things suffer through initial challenges, and blockchain also faces some initial challenges. In this paper, we discuss a few of the major challenges that blockchain technology faces, as well as the fundamental features of blockchain technology and applications.

Bitcoin is a popular cryptocurrency that records all transactions in an allotted append-handiest public ledger referred to as a blockchain. The security of Bitcoin heavily relies on the motivation-suitable proof-of-work (PoW) founded dispensed consensus protocol, which is run with the aid of the community nodes known as miners. Because of its inception, blockchain technological know-how has proven promising application possibilities. The spectrum of blockchain functions stages from financial, healthcare, automobile, hazard administration, internet of matters (IoT) to public and social offerings. Several reports focal point on utilizing the blockchain information structure in various applications. These vulnerabilities result in the execution of different security threats to the ordinary functionality of Bitcoin. We then examine the feasibility and robustness of the brand new safety solutions. Moreover, we discuss the current anonymity concerns in Bitcoin and the privatenessrelated threats to Bitcoin customers together with the evaluation of the comprehensive privacy-keeping solutions.

Nowadays, everyone is talking about digitalization. The entire world is intrigued by this word because the first thought that came to mind was "money," and in this context, we have "Bitcoins," which are money exchanging over the internet in the form of blockchain, the shared ledger technology. Bitcoin works electronically to create a digital currency, and its main purpose is to transfer money in the form of bitcoin. Not only bitcoin, but also other applications such as electronic voting systems, government systems, medical fields, and so on, rule the world. The field of transactions is very unsafe, so security is also a focus that can be achieved through this technology. As a result, we welcomed the World Wide Web. Along with security, other features are also guiding the work. All new things suffer through initial challenges, and blockchain also faces some initial challenges. In this paper, we discuss a few of the major challenges that blockchain technology faces, as well as the fundamental features of blockchain technology and applications.

Blockchain technologies are gaining massive momentum in the last few years. Blockchains are distributed ledgers that enable parties who do not fully trust each other to maintain a set of global states. The parties agree on the existence, values, and histories of the states. As the technology landscape is expanding rapidly, it is both important and challenging to have a firm grasp of what the core technologies have to offer, especially with respect to their data processing capabilities. In this paper, we first survey the state of the art, focusing on private blockchains (in which parties are authenticated). We analyze both in-production and research systems in four dimensions: distributed ledger, cryptography, consensus protocol, and smart contract. We then present BLOCKBENCH, a benchmarking framework for understanding performance of private blockchains against data processing workloads. We conduct a comprehensive evaluation of three major blockchain systems based on BLOCKBENCH, namely Ethereum, Parity, and Hyperledger Fabric. The results demonstrate several trade-offs in the design space, as well as big performance gaps between blockchain and database systems. Drawing from design principles of database systems, we discuss several research directions for bringing blockchain performance closer to the realm of databases.

Blockchain technology has lately become widely regarded, partially because of the surge in cryptocurrencies such as Bitcoin and their ability to be a force for economic and financial shift. While tokenomics also helped push blockchain in mainstream, this technology's strengths are far more than crypt-monetary. Often known as distributed leader technologies, it is hypothesized that blockchain would serve like a catalyst for global disruptions and that blockchain-based applications in many industries such as the supply chain; the medical and legal fields are now being developed and implemented. By simultaneous research, we prove that the six confirms convention is vulnerable to peer-to-peer latency in the network and show just how readily PoW mining is broken. The divergences between these latest blocks open the transactions in question to the possibility that the blockchain fork will not be used. We concentrate on evaluating block detection accuracy and the breach of the six conf...

Blockchain is a decentralized and shared distributed ledger that records the transaction history done by totally different nodes within the whole network. The technology is practically used in the field of education for record-keeping, digital certification, etc. There have already been several papers published on this, but no one can't find a single paper covering the blockchain-based educational projects. So, There is a gap of latest trends to education. Blockchain-based educational projects resolve the issues of today's educators. On that basis, we conclude that there is a need for conducting a systematic literature review. This study, therefore, reviews the artistic gap between these two based on educational projects. For this purpose, the paper focuses on exploring some block-chain based projects and protocols that are used in these projects. It also analyses the block-chain features that are being used and the services are offered by the existing educational projects using block-chain features to improve the execution of this technology in education.

Organizations with high motivation for growth and cost-effective operation efficiencies, are always trying to bring new technologies to their operations. These organizations are very sensitive to change and value driven thus constant change is the only law for them to achieve their goals and to be in the market. When Bitcoin jumps into the market, the whole world wanted to own it but now after Bitcoin and Cryptocurrency bubble, there are significant shift towards Blockchain related products, services, solution developments, researches and use-case studies. From technical-financial opportunist, to evangelist, to researchers, to Tech enterprises, to financial institutions, to governments, the whole world is behind Blockchain and now it has the technological spot light. Blockchain has left behind all other technologies as far as research initiatives, investments and financial funding are concern. There are substantial research growth on, how Blockchain can be useful in specific area? Objectives of this paper are to highlight some facts about Blockchain that were misinterpreted and misrepresented due to this sudden shift. In this research article, authors are presenting comprehensive literature review of Blockchain Technologies and its applications in various sectors. Our research supports that Blockchain is revolutionizing and disrupting organizations across all industries. Blockchain is really a next big technological invention after Internet. In Blockchain Code is the law and Smart Contracts are the new way of doing business.

Electronic Government (e-Government) systems constantly provide greater services to people, businesses, organisations, and societies by offering more information, opportunities, and platforms with the support of advances in information and communications technologies. This usually results in increased system complexity and sensitivity, necessitating stricter security and privacy-protection measures. The majority of the existing e-Government systems are centralised, making them vulnerable to privacy and security threats, in addition to suffering from a single point of failure. This study proposes a decentralised e-Government framework with integrated threat detection features to address the aforementioned challenges. In particular, the privacy and security of the proposed e-Government system are realised by the encryption, validation, and immutable mechanisms provided by Blockchain. The insider and external threats associated with blockchain transactions are minimised by the employment of an artificial immune system, which effectively protects the integrity of the Blockchain. The proposed e-Government system was validated and evaluated by using the framework of Ethereum Visualisations of Interactive, Blockchain, Extended Simulations (i.e. eVIBES simulator) with two publicly available datasets. The experimental results show the efficacy of the proposed framework in that it can mitigate insider and external threats in e-Government systems whilst simultaneously preserving the privacy of information.

Blockchain technology has taken on a leading role in today's industrial applications by providing salient features and showing significant performance since its beginning. Blockchain began its journey from the concept of cryptocurrency and is now part of a range of core applications to achieve resilience and automation between various tasks. With the integration of Blockchain technology into different industrial applications, many application designs, security and privacy challenges present themselves, posing serious threats to users and their data. Although several approaches have been proposed to address the specific security and privacy needs of targeted applications with functional parameters, there is still a need for a research study on the application, security and privacy challenges, and requirements of Blockchain-based industrial applications, along with possible security threats and countermeasures. This study presents a state-of-the-art survey of Blockchain-based Industry 4.0 applications, focusing on crucial application and security and privacy requirements, as well as corresponding attacks on Blockchain systems with potential countermeasures. We also analyse and provide the classification of different security and privacy techniques used in these applications to enhance the advancement of security features. Furthermore, we highlight some open issues in industrial applications that help to design secure Blockchain-based applications as future directions.

The successful adoption and operation of any new technology is dependent on the appropriate management of the risks associated with that technology. This is especially true when that technology is more than an application and is part of the organization’s core infrastructure. And distributed ledger technologies (DLT) like blockchain technology have the potential to be the backbone of many core platforms in the near future. The blockchain is an undeniably ingenious invention – the brainchild of a person or group of people known by the pseudonym, Satoshi Nakamoto. It has become a focus of global attention since its development as banks around the world seek to understand and harness its disruptive potential. Many of the industries has been exploring how to use blockchains across a variety of internal and client facing issues. Blockchain has the potential to transform our world. However, leading into 2018 the focus will move from “how to use a blockchain” to “how to secure a blockchain...

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

Selfish mining is an attack against a blockchain where miners hide newly discovered blocks instead of publishing them to the rest of the network. The selfish miners continue to mine on their private chain while the honest miners waste resources mining on a shorter chain. According to the blockchain protocol, a longer chain takes precedent and shorter chains are discarded which allows the selfish miners to gain an advantage by keeping their chain secret. This attack can be used by malicious miners to earn a disproportionate share of the mining rewards or in conjunction with other attacks to steal money from cryptocurrency exchanges. Several of these attacks were launched in 2018 and 2019 with the attackers stealing as much as $18 Million. Developers made several different attempts to fix this issue, but the effectiveness of the fixes is currently unknown. Although this attack is possible against both Proof-of-Work and Proof-of-Stake blockchains, this research concentrates on detectio...

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

In this study, anonymity related to the cryptographic scheme is specified, especially the design of anonymous schemes limited to blockchain caused by the implementation of group signatures. In general, the output of this research is the implementation of group signature scheme based on elliptic curve cryptography on blockchain Ethereum. The resulting software aims to address money laundering using cryptocurrency particularly Ethereum.

Two double-spend attack strategies on a proof-of-stake consensus are considered. For each strategy, the probability of its success is obtained, which depends on the network parameters and the number of confirmation blocks. These results can be used to define how many confirmation blocks a vendor should wait after a correspondent transaction before sending goods or services.

As opposed to the current system, that is controlled by a central authority, blockchain was invented by Satoshi Nakamoto in 2008 as a distributed ledger system. A major development in the technology came with the introduction of virtual cryptocurrencies where transactions were recorded and verified by miners or validators at various nodes in different locations. Since these transaction records are available to everyone, this solved the current problem of excessive double spending. In a decentralized system like blockchain, a reliable mechanism was necessary to verify the integrity of all transactions. This led to the introduction of a variety of consensus mechanisms. This paper presents the results of a comparative study between Proof of Work and Delegated Proof of Stake, both of which have been widely used in Blockchain projects recently. Based on the above, this study will primarily discuss a brief explanation of the workings of both algorithms, comparisons between them, and vario...

Blockchains based on the celebrated Nakamoto consensus protocol have shown promise in several applications, including cryptocurrencies. However, these blockchains have inherent scalability limits caused by the protocol’s consensus properties. In particular, the consistency property demonstrates a tight trade-off between block production speed and the system’s security in terms of resisting adversarial attacks. This paper proposes a novel method, Ironclad, that improves blockchain consistency bound by assigning a different weight to randomly selected blocks. We apply our method to the original Nakamoto protocol and rigorously prove that such a combination can improve the consistency bound significantly by analyzing the fundamental consensus properties. Such an improvement enables a much faster block production rate than the original Nakamoto protocol under the same security guarantee with the same proportion of malicious mining power (see Figure 1).

Proof-of-stake cryptocurrencies avoid many of the computational and environmental costs associated with proof-ofwork protocols. However, they must address the nothing-at-stake problem, where a validator might attempt to sign off on competing blocks, with the hopes of earning coins regardless of which block becomes accepted as part of the blockchain. Cryptocurrencies such as Tendermint resolve this challenge by requiring validators to bond coins, which can be seized from a validator that is caught signing two competing blocks. Nevertheless, as the number of validators increases, it becomes more and more infeasible to effectively monitor all validators. In this work, we incentivize proper block monitoring by allowing validators to form tontines. Tontines are financial agreements where payouts to each member increase as the number of members decreases. In our system, a tontine is a group of validators that monitor each other's behavior, "murdering" any cheating tontine members to seize their stake. As the number of validators in a tontine is smaller than the number of validators in the currency as a whole, members can effectively police each other. We propose two methods whereby a Tendermint-like currency can be extended to allow for the creation of tontines: a pure proof-of-stake model, and a hybrid proof-of-stake/proofof-work model. We describe snitch mechanisms for both the inter-and intra-tontine setting, argue our incentive mechanisms increase monitoring, and describe how it handles a variety of possible attacks.

Proof-of-Stake cryptocurrencies avoid many of the computational and environmental costs associated with Proof-of-Work protocols. However, they must address the nothing-at-stake problem, where a validator might attempt to sign off on competing blocks, with the hopes of earning coins regardless of which block becomes accepted as part of the blockchain. Cryptocurrencies such as Tendermint resolve this challenge by requiring validators to bond coins, which can be seized from a validator that is caught signing two competing blocks. Nevertheless, as the number of validators increases, it becomes increasingly infeasible to effectively monitor all validators, and to reach consensus. In this work, we incentivize proper block monitoring by allowing validators to form tontines. In the real world, tontines are financial agreements where payouts to each member increase as the number of members decreases. In our system, a tontine is a group of validators that monitor each other's behavior, "murdering" any cheating tontine members to seize their stake. As the number of validators in a tontine is smaller than the number of validators in the currency as a whole, members can effectively police each other. We propose two methods whereby a Tendermint-like currency can be extended to allow for the creation of tontines: a pure Proof-of-Stake model, and a hybrid Proof-of-Stake/Proof-of-Work model. We describe snitch mechanisms for both the inter-and intra-tontine setting, argue our incentive mechanisms increase monitoring, and describe how it handles a variety of possible attacks. We extend our model to act as a validator delegated cryptocurrency, with the users having an incentive to partially participate. We show that these strategies

Recently, Blockchain-based applications have become immensely popular because of limited reliance on a single entity, unlike a centralized system. However, reaching a consensus among blockchain networks is a challenging and vital aspect of blockchain-based applications. There are various types of blockchain networks for different kinds of application scenarios. Among all of them, the consensus algorithm is the most crucial part of reaching an agreement in the complex blockchain network. Over the years, researchers have focused on dealing with the challenges like distributed computing, storage, transaction speed, security, validity, interoperability, and many more. However, only some of them are appropriate for all domains. Therefore, this paper presents an extensive study of different types of consensus protocols used in existing blockchain solutions with the strength and limitations of each algorithm. We also provide an inherent comparison among different algorithms to understand consensus protocol selection better. Moreover, we investigate operational and interoperability issues in existing blockchain-based applications to understand challenges and provide recommendations for future developers. INDEX TERMS Blockchain, consensus algorithm, interoperability, cross-chain transactions, architecture, operational issues, applications, research directions.

In this study, anonymity related to the cryptographic scheme is specified, especially the design of anonymous schemes limited to blockchain caused by the implementation of group signatures. In general, the output of this research is the implementation of group signature scheme based on elliptic curve cryptography on blockchain Ethereum. The resulting software aims to address money laundering using cryptocurrency particularly Ethereum.

Recently, Blockchain-based applications have become immensely popular because of limited reliance on a single entity, unlike a centralized system. However, reaching a consensus among blockchain networks is a challenging and vital aspect of blockchain-based applications. There are various types of blockchain networks for different kinds of application scenarios. Among all of them, the consensus algorithm is the most crucial part of reaching an agreement in the complex blockchain network. Over the years, researchers have focused on dealing with the challenges like distributed computing, storage, transaction speed, security, validity, interoperability, and many more. However, only some of them are appropriate for all domains. Therefore, this paper presents an extensive study of different types of consensus protocols used in existing blockchain solutions with the strength and limitations of each algorithm. We also provide an inherent comparison among different algorithms to understand consensus protocol selection better. Moreover, we investigate operational and interoperability issues in existing blockchain-based applications to understand challenges and provide recommendations for future developers. INDEX TERMS Blockchain, consensus algorithm, interoperability, cross-chain transactions, architecture, operational issues, applications, research directions. I. INTRODUCTION T HE blockchain concept was first introduced by Haber and Stornetta [1], which is considered one of the technologies with the most potential. After that the introduction of Bitcoin by Nakamoto [2], it has attracted intense attention from all over the world. In Blockchain systems, different cryptographic protocols, like hash functions, digital signatures, etc., are used to maintain the authenticity and security of the data. Blockchain is a distributed ledger system that keeps data secure from unauthorized access. Blockchain technology allows users to add, view, and validate transactions to the distributed ledger. These transactions often take place with the consent of all involved users. Blockchain uses a consensus mechanism to ensure that all transactions are accurate. In a trustless environment, blockchain provides users with desirable qualities like decentralization, autonomy, integrity, immutability, verification, fault-tolerance, anonymity, auditability, and transparency, which have received significant academic and industrial attention recently years [3]-[6]. However, the blockchain system is trustless and ensures blockchain-enabled trust through other cryptographic peerto-peer communication in the decentralized network. Further verification and validation mechanisms are employed

Bitcoin is a popular cryptocurrency that records all transactions in an allotted append-handiest public ledger referred to as a blockchain. The security of Bitcoin heavily relies on the motivation-suitable proof-of-work (PoW) founded dispensed consensus protocol, which is run with the aid of the community nodes known as miners. Because of its inception, blockchain technological know-how has proven promising application possibilities. The spectrum of blockchain functions stages from financial, healthcare, automobile, hazard administration, internet of matters (IoT) to public and social offerings. Several reports focal point on utilizing the blockchain information structure in various applications. These vulnerabilities result in the execution of different security threats to the ordinary functionality of Bitcoin. We then examine the feasibility and robustness of the brand new safety solutions. Moreover, we discuss the current anonymity concerns in Bitcoin and the privatenessrelated threats to Bitcoin customers together with the evaluation of the comprehensive privacy-keeping solutions.

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

Reputation-based consensus algorithms are one of the most promising, but least investigated types of consensus algorithms. Its limitation to persmissioned node identity management shades its potential and causes many applications to find blockchain unsuitable. In this paper, we upgrade PoRX, an existing consensus algorithm, into becoming the first permissionless pure reputation-based consensus algorithm. This upgrade is highly potential since it only affects the admission process and does not intervene with the consensus process, thus can be extended into other types of consensus algorithms. K E Y W O R D S consensus algorithm, permissionless blockchain, reputation-based consensus algorithm 1 INTRODUCTION Consensus algorithms lay at the core of blockchain technology and are responsible for its success, emergence, and disruption. Proof-of-Work (PoW) is greatly suitable for public networks but suffers from resource inefficiency, probabilistic consensus, and low throughput. Proof-of-Authority (PoA) is very efficient, deterministic and has very high throughput but is not applicable to public networks. We cannot find one consensus algorithm to rule them all, since they differ in many criteria such as node identity management, 1 resource efficiency, scalability, 2 security threshold, 2 confirmation time, 2 throughput, 2 incentives, 3 fairness 4 and many others. It would be a good idea to cluster them into consensus strategies/incentives and compare the algorithms within each cluster. Nguyen and Kim 5 divided the consensus algorithms into two main strategies, proof-based and vote-based. A finer clustering can be as follows: Resource-based, Leader-based, Economy-based, Voting-based and Reputation-based. While studying the reputation-based consensus algorithms we noticed that all pure reputation-based consensus algorithms are permissioned and only the hybrid ones are permissionless. This motivated us to investigate the possibility of having a permissionless pure reputation-based consensus algorithm. In this paper, we modify an existing permissioned pure reputation-based consensus algorithm into becoming the first permissionless pure reputation-based consensus algorithm. The remaining of this paper is organized as follows: Section 2 presents the consensus algorithms that include reputation. Section 3 describes PoRX, the algorithm we are going to upgrade. Section 4 discusses the proposed upgrade, while Section 5 concludes the work.

Blockchain is a decentralized and shared distributed ledger that records the transaction history done by totally different nodes within the whole network. The technology is practically used in the field of education for record-keeping, digital certification, etc. There have already been several papers published on this, but no one can't find a single paper covering the blockchain-based educational projects. So, There is a gap of latest trends to education. Blockchain-based educational projects resolve the issues of today's educators. On that basis, we conclude that there is a need for conducting a systematic literature review. This study, therefore, reviews the artistic gap between these two based on educational projects. For this purpose, the paper focuses on exploring some block-chain based projects and protocols that are used in these projects. It also analyses the block-chain features that are being used and the services are offered by the existing educational projects using block-chain features to improve the execution of this technology in education.

Bitcoin is a popular cryptocurrency that records all transactions in an allotted append-handiest public ledger referred to as a blockchain. The security of Bitcoin heavily relies on the motivation-suitable proof-of-work (PoW) founded dispensed consensus protocol, which is run with the aid of the community nodes known as miners. Because of its inception, blockchain technological know-how has proven promising application possibilities. The spectrum of blockchain functions stages from financial, healthcare, automobile, hazard administration, internet of matters (IoT) to public and social offerings. Several reports focal point on utilizing the blockchain information structure in various applications. These vulnerabilities result in the execution of different security threats to the ordinary functionality of Bitcoin. We then examine the feasibility and robustness of the brand new safety solutions. Moreover, we discuss the current anonymity concerns in Bitcoin and the privatenessrelated threats to Bitcoin customers together with the evaluation of the comprehensive privacy-keeping solutions.

Voltage controls the majority of the processes around us, starting from lighting an incandescent lamp to running huge machines in industries. Therefore, voltage monitoring becomes essential, which demands efficient measurement and storage of voltage data. However, there is hardly any system till date that fulfils both the goals of voltage monitoring and voltage data storage. To achieve this goal, we propose the application of the Internet of Things along with the server-based framework and Distributed Ledger Technology to build systems for smart voltage monitoring. Two models - a centralised model and a decentralised model have been presented and analysed thoroughly in this paper. The centralised model is built on client-server architecture, whereas the decentralised model is based on a peer-to-peer architecture. Blockchain and InterPlanetary File System have been used for the implementation of the decentralised system. Potential improvements to make these systems robust have also b...

We present two attacks targeting the Proof-of-Stake (PoS) Ethereum consensus protocol. The first attack suggests a fundamental conceptual incompatibility between PoS and the Greedy Heaviest-Observed Sub-Tree (GHOST) fork choice paradigm employed by PoS Ethereum. In a nutshell, PoS allows an adversary with a vanishing amount of stake to produce an unlimited number of equivocating blocks. While most equivocating blocks will be orphaned, such orphaned ‘uncle blocks’ still influence fork choice under the GHOST paradigm, bestowing upon the adversary devastating control over the canonical chain. While the Latest Message Driven (LMD) aspect of current PoS Ethereum prevents a straightforward application of this attack, our second attack shows how LMD specifically can be exploited to obtain a new variant of the balancing attack that overcomes a recent protocol addition that was intended to mitigate balancing-type attacks. Thus, in its current form, PoS Ethereum without and with LMD is vulner...

The paper presents a BlockChain based distributed framework to manage Antimalware database efficiently. With increased efficiency in computation and network connectivity, systems are delivering better performances day by day. However, the opportunities of initiating malicious activities through malwares are being increased as well. In this work, we propose a distributed framework of Antimalware database management using customized BlockChain that enhances system security by initiating distributed malware prevention program. Due to distributed in nature, BlockChain can ensure better data management without involving any third party.

Blockchain technology is a sustainable technology that offers a high level of security for many industrial applications. Blockchain has numerous benefits, such as decentralisation, immutability and tamper-proofing. Blockchain is composed of two processes, namely, mining (the process of adding a new block or transaction to the global public ledger created by the previous block) and validation (the process of validating the new block added). Several consensus protocols have been introduced to validate blockchain transactions, Proof-of-Work (PoW) and Proof-of-Stake (PoS), which are crucial to cryptocurrencies, such as Bitcoin. However, these consensus protocols are vulnerable to double-spending attacks. Amongst these attacks, the 51% attack is the most prominent because it involves forking a blockchain to conduct double spending. Many attempts have been made to solve this issue, and examples include delayed proof-of-work (PoW) and several Byzantine fault tolerance mechanisms. These att...