Comprehensive Analysis of Blockchain Algorithms

In some liberal democracies, governments allow people to legally own guns to protect their lives and property. However, gun crime has been increasing in recent years. Taking the United States, for example, a report pointed out that Americans are 10 times more likely to be shot than citizens of other countries. Murder using guns in the United States is 25 times more than that in the other 22 high-income countries. Most of these guns came from other cities. These illegally circulating guns are directly linked to deadly street violence. This means that effective firearm management can reduce deadly violence. In the past few years, Radio Frequency IDentification (RFID) technology was often used to track the supply chain. However, in the traditional supply chain, only the participants of the supply chain can query information. Furthermore, only the participants can verify the correctness of the data. This result causes information to be not transparent. On the other hand, blockchain technology, with a unique combination of features such as distributed notes, decentralized structure, consensus algorithm, storage mechanism, asymmetric encryption, and smart contract, ensures network visibility, transparency, and security. Therefore, we combine blockchain and RFID technology to propose a traceable firearm management system based on blockchain and Internet of Things (IoT) technology. The proposed method achieves several goals. First of all, the characteristic data through the blockchain can be publicly verified and the information will not be modified. The traceability of the data and the application of RFID can effectively manage the production chain. In addition, we used Burrows–Abadi–Needham logic (BAN logic) logic to prove mutual authentication, and the nonrepudiation and integrity method can also be achieved in our proposed scheme.

Blockchain has been a breakthrough in the technology since the last decade and is anticipated as the go-to thing due to features presented by it. The features such as secure, immutable, transparent, and anonymous makes Blockchain technology the frontrunner in the untrustworthy distributed environment. The driving force behind the Blockchain technology are the consensus algorithms that are at the heart of any Blockchain technology. These algorithms determine the security and performance of any Blockchain. The most popular consensus algorithm is the Proof-of-Work which was first used in the Bitcoin. Since then, a number of consensus algorithms have been proposed. This paper presents a brief overview of the Blockchain Technology and popular cryptocurrencies based on Blockchain. Next, the most popular consensus algorithms in the context of Blockchain and cryptocurrencies are discussed.

In general, the Internet of Things (IoT) relies on centralized servers due to limited computing power and storage capacity. These server-based architectures have vulnerabilities such as DDoS attacks, single-point errors, and data forgery, and cannot guarantee stability and reliability. Blockchain technology can guarantee reliability and stability with a P2P network-based consensus algorithm and distributed ledger technology. However, it requires the high storage capacity of the existing blockchain and the computational power of the consensus algorithm. Therefore, blockchain nodes for IoT data management are maintained through an external cloud, an edge node. As a result, the vulnerability of the existing centralized structure cannot be guaranteed, and reliability cannot be guaranteed in the process of storing IoT data on the blockchain. In this paper, we propose a multi-level blockchain structure and consensus algorithm to solve the vulnerability. A multi-level blockchain operates on IoT devices, and there is an IoT chain layer that stores sensor data to ensure reliability. In addition, there is a hyperledger fabric-based monitoring chain layer that operates the access control for the metadata and data of the IoT chain to lighten the weight. We propose an export consensus method between the two blockchains, the Schnorr signature method, and a random-based lightweight consensus algorithm within the IoT-Chain. Experiments to measure the blockchain size, propagation time, consensus delay time, and transactions per second (TPS) were conducted using IoT. The blockchain did not exceed a certain size, and the delay time was reduced by 96% to 99% on average compared to the existing consensus algorithm. In the throughput tests, the maximum was 1701 TPS and the minimum was 1024 TPS.

Since the outbreak of the epidemic, people not only need to pay attention to their own safety and health, but also need insurance services to protect themselves. However, there are some problems in the traditional insurance system. First, the information of clients is incomplete or untrue. Second, privacy is compromised. Third, transaction information is tampered with. These problems lead to various insurance disputes. Therefore, this paper develops an insurance system based on blockchain by using the characteristics of decentralization, transparency, and immutability. The construction of the system is divided into three steps. First, insurance contracts are published on the Merkel tree. Next, RSA encryption technology is used to protect clients' information security. Last, SHA256 secure hash algorithm and consensus mechanism are used to resist the external attack of the blockchain. On this basis, this paper designs and develops a safe insurance system. Also, it studies the performance of insurance systems and the consensus mechanism of blockchain. The former compares the differences between the traditional insurance system and the blockchain insurance system in each performance index during operation. The result shows that some performance indices of blockchain insurance system are lower than those of traditional insurance system. However, because of its higher security than traditional insurance system, blockchain technology is selected as the core technology of this system. Also, two consensus algorithms, PoW and PBFT, compares with each other in blockchain technology. The experimental results show that the PoW consensus algorithm is more suitable for blockchain insurance system.

Internet of Things (IoT) refers to the network of interconnected smart physical objects that collect and exchange information for enabling smart applications and services. IoT devices are often battery powered and lack computational resources and as a consequence, traditional measures of providing security is not feasible in IoT systems which leads to major security vulnerabilities. Blockchain technology has proven to be a secure medium of transaction in trustless public networks and has the potential to resolve the security vulnerabilities intrinsic to IoT systems. However, reaching consensus throughout a blockchain network is computationally demanding and requires large amount of energy. Moreover, typical transactions in blockchain based applications are slow, compounding the issues in adopting blockchain technology in IoT systems. In this work, a lightweight consensus algorithm called Proof-of-Authentication (PoAh), was implemented on resource-constrained IoT edge nodes and evaluated in terms of latency and energy consumption. The implemented consensus algorithm reduces latency in block validation to 29.35 ms and energy consumption to 44.31 mJ for each transaction, demonstrating promise and potential, to feasibly implement blockchain technology in IoT systems.

Blockchain technology is an emerging decentralized and distributed technology that can maintain data security. It has the potential to transform many sectors completely. The core component of blockchain networks is the consensus algorithm because its efficiency, security, and scalability depend on it. A consensus problem is a difficult and significant task that must be considered carefully in a blockchain network. It has several practical applications such as distributed computing, load balancing, and blockchain transaction validation. Even though a lot of consensus algorithms have been proposed, the majority of them require many computational and communication resources. Similarly, they also suffer from high latency and low throughput. In this work, we proposed a new consensus algorithm for consortium blockchain for a leader selection using the reputation value of nodes and the voting process to ensure high performance. A security analysis is conducted to demonstrate the security of the proposed algorithm. The outcomes show that the proposed algorithm provides a strong defense against the network nodes’ abnormal behavior. The performance analysis is performed by using Hyperledger Fabric v2.1 and the results show that it performs better in terms of throughput, latency, CPU utilization, and communications costs than its rivals Trust-Varying Algo, FP-BFT, and Scalable and Trust-based algorithms.

Healthcare Blockchains (HBC) are grooming nowadays due to the requirements of flexible Electronic Health Records (EHR) management, privacy needs, and controlled medical data access. Blockchain technology very much suits these requirements and support in various healthcare data access control methods. More focus on improved block generation time gives the expected blockchain performance. Block generation time can be significantly improved by the consensus algorithms used by the system. Traditional consensus algorithm of Proof of Work (PoW) and Proof of Stake (PoS) require heavy computational resources and hence by computational overheads. The proposed system introduces a new privacy-preserving HBC consensus protocol as a consequence of member attribute values and significantly reduced computational resources. The new attribute-based consensus algorithm for HBC called Proof of Policy (PoP) is constructed using Attribute-Based Ring Signature (ABRS). This signature agrees on the stake of attribute-based ring membership and can be considered as an extension of Proof of Stake (PoS). It is also found that the proposed PoP consensus algorithm requires less computational resources than popular PoW and PoS.

Blockchain being a leading technology in the 21st century is revolutionizing each sector of life. Services are being provided and upgraded using its salient features and fruitful characteristics. Businesses are being enhanced by using this technology. Countries are shifting towards digital currencies i.e., an initial application of blockchain application. It omits the need of central authority by its distributed ledger functionality. This distributed ledger is achieved by using a consensus mechanism in blockchain. A consensus algorithm plays a core role in the implementation of blockchain. Any application implementing blockchain uses consensus algorithms to achieve its desired task. In this paper, we focus on provisioning of a comparative analysis of blockchain’s consensus algorithms with respect to the type of application. Furthermore, we discuss the development platforms as well as technologies of blockchain. The aim of the paper is to provide knowledge from basic to extensive from blockchain architecture to consensus methods, from applications to development platform, from challenges and issues to blockchain research gaps in various areas.

One of the modern trends in the development of information and communication technologies that have evolved into the Internet of Things (IoT) paradigm is the progressive idea of using blockchain technology in IoT. This trend is described in a large number of modern literature sources, which point out the significant advantages of using blockchain, primarily related to decentralization, immutability, transparency and security. This allows us to conclude that the implementation of blockchain technology in IoT information and communication systems is highly relevant. However, the authors of different studies describe significant problems, including the problem of scalability of the blockchain itself, as well as the problems of energy efficiency and limited resources in IoT devices. Due to these problems, the implementation of blockchain technology in the Internet of Things is becoming a challenge and determines the relevance and feasibility of researching this topic and finding effective solutions related to the integration of two very powerful technologies in modern information and communication systems. The article presents an analytical overview of the issues of integrating blockchain technology into IoT, in particular, the use of the Proof-of-Work (PoW) consensus algorithm in IoT and the use of alternative blockchain protocols, including IOTA, Ethereum Light Client and Litecoin, which allow increasing the efficiency of performing tasks in IoT infrastructure, taking into account the limited resources of devices; existing problems and implementation methods, such as the use of light clients and proxy servers. The article also considers the feasibility of using a full blockchain node on IoT devices and ways to increase system efficiency by pre-processing data before sending it to the blockchain network. The article also highlights the problem of insufficient implementation of blockchain technology in various spheres of human life, as well as the search for the reasons for this problem. The results of the analytical review make it possible to substantiate the purpose and advantages of integrating blockchain technology into the Internet of Things, as well as to summarize the main issues and substantiate a number of tasks for relevant and progressive scientific research in the field of modern information and communication systems.

A new emerging technology, i.e., blockchain technology, is a distributed, encrypted database model and Peer-to-Peer (P2P) network transaction system that lay outs secure execution of operations that are implemented on a decentralized ledger database shared among multiple nodes which are useful in building the blockchain network; for this, the third party is not needed and it can be done with the help of consensus algorithms. Blockchain depends on cryptography and consensus mechanisms accompanying other algorithms for establishing strong security. The most widely used algorithms are the hashing and the consensus algorithms. But only these two algorithms cannot serve the requirements of every application. So, this paper presents a comprehensive overview of blockchain technology and also focuses on all the different types of algorithms used in blockchain technology. This paper also illuminates the future study directions.KeywordsBlockchainDigital signatureHashingPeer-to-Peer networkZero-Knowledge ProofsConsensus algorithms

Blockchain verifies security using a distributed mechanism. For several new and developing products and services, blockchain technology is touted as a game-changer. Providing a distributed architecture to manage and sustain an open voting system would be the aim of such a plan. A system called blockchain stores data in a way that makes it difficult or almost impossible to make changes to it. The sharing economy may be benefited by a very wide variety of applications made possible by blockchain technology. That will be used to quantify how blockchain technology may be used to facilitate distributed electronic voting. The suggested solution implements a voting mechanism using the Aadhar API on an Ethereum network on a blockchain platform. Electronic voting is expected to promote openness, and voters are required to lessen dishonesty and irregularities in the voting procedures. Voters will be able to cast their ballots from home by using this technology. The technology seeks to improve voting process transparency and strengthen fraud prevention by supplanting the conventional pen and paper method. Key Words: Blockchain, Distributed General Ledger, Ethereum, Smart Contracts, P2P network, Consensus Algorithm, PoW Algorithm, Cryptography, Voter Privacy, Trustless Environment, Electrical integrity.

Introduction: Blockchain technology is one of the emerging technologies that implements the concept of decentralization. The first application of this technology was with Bitcoin, which is a decentralized application. However, the decentralization of Bitcoin has become problematic due to the formation of mining pools. In this work, decentralization is intended to be maximized. Problem: Decentralization is the main concept of blockchain technologies. However, decentralization suffers mainly from mining pools in the Bitcoin network. Objective: In this work, the proposed solution to maximize upon the decentralized nature of Bitcoin is to revise the consensus protocol of Bitcoin. The proposed novel consensus protocol called Signature Proof-of-Work uses signatures instead of hashes. The proposed method aims to minimize the number of mining pools and maximize the number of solo miners by arguing that no one can share their private keys with others, which would ensure greater decentralization of the network. Methodology: The consensus algorithm in Bitcoin is Proof-of-Work. Proof-of-Work allows for the formation of mining pools. Mining pools control the Bitcoin network and reduce decentralization. Therefore, a novel Proof-of-Work consensus algorithm is proposed to empower decentralization. Results: The proposed consensus algorithm called Signature Proof-of-Work uses signatures instead of hashes. The proposed method aims to minimize the number of mining pools and maximize the number of solo miners by arguing that no one can share their private keys with others, which would ensure greater decentralization of the network. Conclusion: The proposed consensus algorithm minimizes mining pools by enforcing non-shareable private keys. Originality: The proposed consensus algorithm is an enhancement of the default Proof-of-Work algorithm of Bitcoin. The proposed algorithm uses signatures instead of hashes, which differentiates it from the default algorithm. Limitations: In the proposed algorithm, the main argument is that no one shares their private keys. In other words, miners cannot share their private keys with others. If they share their private keys, others can control their own money. Therefore, each miner does not want to collaborate with other miners to mine new blocks. As a result, the mining pools will not be formed.

The blockchain technology has shown promise of transforming a variety of industries, it has captured significant interest for its ability to revolutionize multiple sectors through the facilitation of decentralized and secure transactions. Peer-to-peer architecture of blockchain provides strong security and trust-oriented guarantees, such as immutability, verifiability and decentralization. Nonetheless, it remains a considerable challenge to ensure the safety and efficiency of blockchain networks. Through consensus algorithms, existing blockchain can still maintain its integrity and safety; however, existing consensus tools face hurdles in addressing security threats and attacks. We need an advance method to improve security without slowing down the blockchain network. This paper proposes an advanced technique used to identify anomalous nodes in a blockchain network through the use of a machine learning technique that enhances the security and reliability of new node addition or a new transaction. A novel model for a blockchain network based on a vote-based consensus algorithm is presented, which enhances its fault-tolerant. The proposed method will monitor the network pattern by implementing machine learning algorithms to detect anomalies and prevent fraud. We will be making use of the vote-based approach, which will be performed by the nodes or the validators to check whether to approve or validate the transaction. Through simulations and experiments, the effectiveness of the approach can be evaluated. The model will attain an F1 of 0.68, precision of 0.70, and recall of 0.66 in the case of the Elliptic Bitcoin Transaction dataset in the context of unsupervised learning, which is better than the literature. Further, the inclusion of the machine learning-based node filtering approach to the consensus process will result in the reduction of the consensus latency of PBFT/DBFT by approximately 15%. The result shows that adding the functionality would enhance blockchain security, allowing for additional advancements.

In the white book of Bitcion, Satoshi Nakamoto described a bitcoin system that can realize point-to-point online payment without a third-party organization. After supporting this magical application scenario and subverting the traditional centralized system, the blockchain technology has attracted worldwide attention, triggered a research upsurge of blockchain consensus algorithm, and produced a large number of innovative applications. Although various consensus algorithms continue to evolve with the iteration of blockchain products and applications, Proof of Work (POW) and Proof of Skake (POS) algorithms are still the core of consensus algorithms. This paper discussestwo algorithms of POW and POS in blockchain consensus mechanism, and analyzes the advantages and the existing problems of the two consensus mechanisms. Since consensus mechanism is the main focus of blockchain technology and has many influencing factors, this paper discusses the current problems and some improved ideas, and selectes some typical algorithms for a more systematic introduction. In addition, some important issues related to safety and performance are also discussed. This paper provides the researchers a great reference on blockchain consensus mechanism.

Today, agriculture remains the most important economic activity in the world. Food care is a major concern for the whole society. For agriculture-based supply chain management, traceability is considered as the major requirement. Traceability helps in providing quality assurance and transparency to the end user. The antiquated traceability system has the complications of centralized systems, non-transparency of information, unpredictable data, and the very easy formation of false data. The World Health Organization (WHO) reports that one out of ten people is affected by having tainted food. Globalization involving different food production processes and automation pushes the food supply chain into a complicated web. Numerous advancements have been investigated lately to determine food vulnerability and carry productivity to food related issues. One of the expected advances is block chain, which is as of now being effectively executed in monetary areas, for example, bit coin. Block chain can also be used in the food supply chain industries to improve traceability and help in the danger decrease of fakes and different types of unlawful occupation. This paper presents a systematic survey on agrifood supply chain traceability issues using various block chain platforms such as Ethereum and Hyperledger, as well as IOT techniques such as barcodes, RFID, NFC, and QR codes. The performance of several consensus algorithms is also investigated.