A Review of Blockchain Architecture and Consensus Protocols: Use Cases, Challenges, and Solutions

Abstract

Over the last decade the blockchain technology has emerged to provide solutions to the complexity and privacy challenges of using distributed databases. Its adoption is motivated by cost reduction for customers. Over this time, the concept of blockchain has shifted greatly due to its potential in business growth for enterprises and the rapidly evolving applications in a collaborative smart cities ecosystem, healthcare, and governance. Many platforms, with different architectures and consensus protocols, have been introduced. Consequently, it becomes challenging for an application developer to chose the right platform. Furthermore, blockchain has misaligned with the goals for efficient green collaborative digital ecosystem. Therefore, it becomes critical to address this gap and to build new frameworks to align blockchain with those goals. In this paper, we discuss the evolution of blockchain architecture and consensus protocols, bringing a retrospective analysis and discussing the rationale of the evolution of the various architectures and protocols, as well as capturing the assumptions conducting to their development and contributions to building collaborative applications. We introduce a classification of those architectures, helping developers to chose a suitable platform for applications and providing insights for future research directions in the field in building new frameworks. blockchain architecture and consensus protocol, it becomes more and more difficult to foresee the uses and applications of blockchain, therefore compounding the difficulty in achieving the goals. In 2017, the bitcoin mining used around 30.14 TerraWatt hours (TWh) of energy, which is equivalent to energy usage of the entire Ireland in a year [3]. According to a research, the annual carbon dioxide emissions by the bitcoin network are as high as 22.9 million metric tons, almost equivalent to the amount produced by the countries like Sri Lanka and Jordan [4].Further challenges have been placed on distributed applications by the expanding industrial market growth to serve a wide number of customers. Growing business requires trust and transparency between the customers and business providers. Customers require to eliminate intermediaries to reduce transactions cost. The issues of data communication overhead with increasing number of network participants further hinders the real-time services of the developed applications. Addressing these problems of energy consumption and scalability often trades off with security, and privacy. As such, the goals of this paper are four-fold: 1) we aim to provide a temporal evolution of blockchain applications development platforms architectures and consensus protocols with a retrospective analysis to their introduction. We classify the platforms and the consensus protocols under unifying architectures, and discuss various existing and upcoming blockchain applications, 2) help developers to choose the right platform architecture for applications, 3) we evaluate the current research on the topic, blockchai...

Blockchain technology and traceability in the agrifood industry

“…BC is a tool that belongs to the Distributed Ledger Technology (DLT), a software tool based on a common database shared among all participants (Casino, Dasaklis, & Patsakis, 2019; Crosby, Pattanayak, Verma, & Kalyanaraman, 2016; Scott, Loonam, & Kumar, 2017; Ismail & Materwala, 2019). Differently from centralized systems, BCTs and distributed ledgers are not based on data stored in a single place (e.g., a server) with a single subject controlling and sharing them (Figure 2).…”

“…Differently from centralized systems, BCTs and distributed ledgers are not based on data stored in a single place (e.g., a server) with a single subject controlling and sharing them (Figure 2). In the distributed ledger, each participant owns an identical copy of the ledger and any change in the data is applied to every single copy owned by participants, so that the BC acts as a trusted and dependable third party (Cachin & Vukolic, 2017; Ismail & Materwala, 2019).…”

“…In a BC, every transaction between two participants is recorded permanently and these records take the name of blocks , whereas each computer that is used for BC processing is called node (Ismail & Materwala, 2019). The addition of a transaction can be performed by mining, which is a process that adds new records to the BC using complex computing problems that are at the basis of the security of the BCTs (Li, Li, Peng, Cui, & Wu, 2018; Ismail & Materwala, 2019). The shared data are also encrypted to ensure a further high level of security, which is an important benefit of these technologies.…”

“…Blockchain technologies (BCTs) may represent a possible answer to this consumers’ request, because they are trust‐proof systems, where nontrusting members can verifiably interact with each other without the need for a trusted authority (Brandão, São Mamede, & Gonçalves, 2018; Cachin & Vukolic, 2017; Ismail & Materwala, 2019; Treiblmaier & Beck, 2019a, 2019b). Indeed, they can provide a cryptographically secure and immutable record of transactions and associated metadata (origin, contracts, process steps, environmental variations, microbial records, etc.)…”

Focus on Blockchain: A Comprehensive Survey on Academic and Application

“…Consensus algorithm plays an important role in the whole blockchain, and any progress of consensus algorithm could dramatically change the development process of blockchain in the future. The future consensus algorithm will develop to superior performance, high adaptability and scalability [98].…”