Traditional financial systems are based on trust in central authorities for secure transactions between parties. Blockchain on the other hand is a distributed ledger technology that stores data in a peer-to-peer decentralized network, where users can transfer money to each other without relying on centralized trusted intermediaries. Blockchain technology has received a lot of attention, mainly due to successful cryptocurrency applications (e.g., Bitcoin). Apart from cryptocurrency, blockchain can be used for supply chain, logistics, healthcare, energy industries, and other financial services.

Challenges with blockchain include the transaction processing time, resource-consuming network protocols (consensus algorithms), performance and scalability of the network, government regulations, etc. The government and private sectors are yet to consider blockchain-based solutions as a sustainable approach to building their business models. Inadequate insights about the tradeoffs and governance model for selecting the proper blockchain platforms have hindered the mass adoption of this technology.

The scope of this thesis is to investigate the opportunities, challenges, and tradeoffs of various blockchain technologies. We provide a tradeoff analysis considering technical properties such as the performance and scalability and important architectural/societal considerations about blockchain systems, based on the governance model and quality attributes.

There are four major contributions. First, we conduct a literature survey of blockchain from the perspective of applications, challenges, and opportunities. It presents some tradeoffs of blockchain, a comparison among different consensus mechanisms, and discusses challenges, including scalability, privacy, interoperability, energy consumption, and regulatory issues. Second, we evaluate the mobility gap for Electric vehicle (EV) charging transactions by leveraging blockchain-based solutions.  We also present a proof of concept using the Hyperledger consortium platform for the evaluation of the technical feasibility of the proposed approach. Third, we conducted a quantitative performance and scalability analysis of some popular private blockchain platforms, including Ethereum Quorum, Corda, and Hyperledger Fabric. Finally, we propose a taxonomy guideline that provides critical insights for determining a suitable blockchain platform.

Blockchain is a secured, shared, and distributed ledger system that records and tracks resources without requiring a centrally trusted authority. In addition to cryptocurrency, blockchain can be used for supply chain, logistics, healthcare, energy industries, and other financial services.

However, blockchain technology faces several challenges, including energy consumption, security risks, governance, performance, and scalability. Hence, the government and private sectors are yet to consider blockchain-based solutions as a sustainable approach to building their business models. Addressing these challenges will enable blockchain technology to reach its full potential and become a transformative force in various industries. Scalability is a major challenge in blockchain, as reaching consensus when there is a large number of participating nodes requires significant computational power or complex repetitive communications among the nodes. This issue could be addressed with blockchain sharding.

This thesis investigates various opportunities, challenges, and tradeoffs related to blockchain technologies. Based on the governance model and quality attributes, we provide a tradeoff analysis considering technical properties, such as the performance and important architectural considerations about blockchain systems. Furthermore, we address the scalability issues regarding traditional blockchain solutions and identify the possibilities of sharding solutions to improve the performance and scalability of blockchain. Sharding is a technique to improve scalability by dividing the network into smaller parts called shards. Sharding allows blockchain networks to process more transactions per second (TPS) by distributing the workload across different nodes in the network. While sharding can improve the scalability of blockchain networks, it introduces some new challenges due to the consensus process and the requirements to maintain consistency between shards, which are part of our studies.

There are six major contributions. First, we conduct a literature survey of blockchain from the applications, challenges, and opportunities perspective. It presents some tradeoffs of blockchain, a comparison among different consensus mechanisms, and discusses challenges, including scalability, privacy, interoperability, energy consumption, and regulatory issues. Second, we evaluate the mobility gap for Electric Vehicle (EV) charging transactions by leveraging blockchain-based solutions. We also present a proof of concept using the Hyperledger consortium platform to evaluate the technical feasibility of the proposed approach. Third, we present a quantitative performance and scalability analysis of some popular private blockchain platforms, including Ethereum Quorum, Corda, and Hyperledger Fabric. Fourth, we propose a taxonomy guideline that provides critical insights for determining a suitable blockchain platform. Fifth, we propose a guideline and Applicability Analysis Framework (AAF) to determine whether an application needs a blockchain solution or not. This framework is designed to ingest detailed user requirements to perform a weighted evaluation built on mathematical constructs to determine the scenario in which a blockchain-based solution is appropriate. Finally, we present a review of recent sharding technologies, including Polkadot, Ethereum Casper, and Cardano Hydra to discuss the performance challenges of blockchains and provide important insights on the tradeoffs regarding blockchain trilemma: Decentralization, Security, and Scalability (DSS).