Ahmed Gomaa, Mohamed I. Gomaa, Salem Lotfi Boumediene, Magdy Farag
Blockchain technology has evolved beyond its original uses as a methodology to record cryptocurrency transactions to support various business applications. Over the past few years, it has gained increased attention in the accounting profession. The current paper proposes a new conceptual framework to implement and apply blockchain technology in the accounting profession that is based on a single-ledger model. The paper addresses the reconciliation problem if more than one party is involved in a transaction. It defines the requirements to have an accounting system without reconciliation challenges. Following the paper approach, transaction details are recorded on the blockchain ledger before inserting the transaction details in the transacting parties’ ERP systems. This ledger is a single point of truth that can be viewed directly without the need for creating information silos in the ERP systems of transacting parties, hence addressing the reconciliation challenge. The presented framework creates one truth for all parties involved in a transaction eliminating much of the redundancy involved in current accounting systems.
In this chapter we will learn how to configure and control our Wallet GUI. We will also learn how to prepare and execute transactions as well as message signing and verification. Bitcoin Core Wallet is a powerful tool that can do much more than executing monetary transactions. Properly used, it can function as a bank on your desk, or in your pocket.
In the previous chapter, we addressed user onboarding challenges, one of the two main issues for Ethereum mass adoption. The second of them, which we will tackle in this chapter, is scalability. The Ethereum network, as it is today, can handle about 15 transactions per second – this throughput must be shared among all Ethereum applications globally. This has led to single applications cluttering the entire network due to a spike in their usage to the point of rendering all dapps unusable for brief periods. In this chapter, we will introduce state channels and sidechains, two of the most widely used scalability solutions.
Yackolley Amoussou-Guenou, Antonella Del Pozzo, Maria Potop-Butucaru, Sara Tucci-Pergiovanni
Committee-based blockchains are among the most popular alternatives of proof-of-work based blockchains, such as Bitcoin. They provide strong consistency (no fork) under classical assumptions, and avoid using energy-consuming mechanisms to add new blocks in the blockchain. For each block, these blockchains use a committee that executes Byzantine-fault tolerant distributed consensus to decide the next block they will add in the blockchain. Unlike Bitcoin, where there is only one creator per block, in committee-based blockchain any block is cooperatively created. In order to incentivize committee members to participate in the creation of new blocks, rewarding schemes have to be designed. In this paper, we study the fairness of rewarding in committee-based blockchains and we provide necessary and sufficient conditions on the system communication under which it is possible to have a fair reward mechanism.
Jan 1, 2019·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
Leonardo Maria De Rossi, Nico Abbatemarco, Gianluca Salviotti
The increasingly need for companies to keep a high level of synchronization globally and the advent of new technologies are pushing more and more to move decision-making and operational power from the centre of organizations to their edges. The blockchain could be the key technology to make this change possible. However, there is no bridge yet capable of shortening the still long distance between this new technological phenomenon and today's business realities. Our work aims precisely at this goal; we propose a framework of blockchain models to help practitioners understanding and potentially implement new solutions based on this technological paradigm. In particular, we have developed an ontology that helps to identify and clarify in detail what are the concepts and structures revolving around this technology, and built a continuum of blockchain architectural solutions, ranging from a classic centralized IT architecture to one completely distributed within a public ecosystem.
In this chapter we will learn how to configure Bitcoin’s reference client, also called Bitcoin Core. We will explore some of its many configuration options and learn how to synchronize with its decentralized network. We will also try out the console-based tools and the GUI wallet software. For testing and development, we will learn how to use Bitcoin’s regtest and testnet networks.
Mona Taghavi, Jamal Bentahar, Hadi Otrok, Kaveh Bakhtiyari
This paper introduces a novel blockchain-based decentralized federation model that embodies quality verification for cloud providers who lease computing resources from each other. The blockchain structure removes the barriers of a traditional centralized federation and offers a fully distributed and transparent administration by enforcing the involved agents to maintain consensus on the data. For a blockchain-based federation, it is vital to avoid blind-trust on the claimed SLA guarantees and monitor the quality of service which is highly desirable considering the multi-tenancy characteristic of cloud services. Due to the fact that the blockchain network is unable to access the outside world, it cannot handle, by its own, providers misbehavior in terms of SLA violations. Thus, we introduce oracle as a verifier agent to monitor the quality of the service and report to the smart contract agents deployed on the blockchain. Oracle is a trusted third-party agent who can communicate with the outside world of the blockchain network. The interaction between cloud service providers (either providing a service or requesting it from another provider) and the oracle through smart contracts comprises a system of autonomous and utility maximizer agents. Cloud requesters seek to receive high quality services with constant monitoring at cheap prices or even with no charge, while cloud providers aim to have a balanced work-load with less preserved capacity, and the oracle tends to charge higher for their monitoring services. Therefore, to model this conflicting situation, we formulate a dynamic Stackelberg differential game to optimize the cost of using the oracle and maximize the profit of the agents with the role of provider agent as a leader, and the requester and verifier agents as followers. Our designed Stackelberg differential game can seize the dynamicity of users' demand and resource provisioning in a competitive cloud market. We implemented our proposed decentralized model using the Solidity language in the remix IDE on the Ethereum network. We further evaluated the optimal controls and agents' profit with real-world data simulated for three concrete cloud providers. The results revealed that the requester agent initiates most of the quality verification requests at the beginning to the middle time of the contract. Thus, the provider agent could reserve less computing resources considering the fact that it could share the workload among other customers' computing resources during the peak-time. Moreover, imposing a higher penalty on the provider agent increased the capacity and decreased the number of requests for quality verification at the equilibrium. The evaluation also disclosed that the impact of timing in the dynamic pricing strategy of the verifier agent is very minimal, and the provisioning capacity of the provider is strongly correlated with the monitoring price.
Katharina Zeuch, Kai Hendrik Wöhnert, Volker Skwarek
Due to increasing security requirements e. g. for transaction based smart-x-technologies in distributed systems, blockchain technologies are predestined for secure data exchange and keeping in distributed systems. Although the underlying principle of almost every blockchain is the Byzantine fault tolerance (BFT), its implementation differs significantly between the technologies so that migration or interoperability between systems is nearly impossible. Additionally, this missing interoperability also reduces the chance for scalability between different extents of implementation as there is usually not a one-size-fits-all-blockchain: Different technologies have their advantages for different systems. Therefore scalability and interoperability are tightly coupled. As a basis for further research on and the derivation of generally scalable and interoperable architectures of blockchains, current technologies have to be made comparable and interoperability criteria have to be developed. This paper analyses current literature and introduces technical criteria for the comparison of blockchainand distributed ledger technologies (BC/DLT).With a list of eleven criteria popular BC/DLTs such as Bitcoin, Ethereum, Hyperledger Fabric, Ripple and Corda are compared regarding general features.
Jan 1, 2019·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
With the advent of blockchain technology, some management tasks of IoT networks can be moved from central systems to distributed validation authorities. Cloud-centric blockchain implementations for IoT have shown satisfactory performance. However, some features of blockchain are not necessary for IoT. For instance, a competitive consensus. This research presents the idea of customizing and encapsulating the features of blockchain into software-defined components to host them on edge devices. Thus, blockchain resources can be provisioned by edge devices (e-miners) working together closer to the things layer in a cooperative manner. This research uses Edison SoC as e-miners to test the software-defined blockchain components.
Both blockchain technologies and cloud computing are contemporary emerging technologies. While the application of Blockchain technologies is being spread beyond cryptocurrency, cloud computing is also seeing a paradigm shift to meet the needs of the 4th industrial revolution (Industry 4.0). New technological ad-vancement, especially by the fusion of these two, such as Blockchain-as-a-Service (BaaS), is considered to be able to significantly generate values to the en-terprises. This article surveys the current status of BaaS in terms of technological development, applications, market potentials and so forth. An evaluative judge-ment, comparing amongst various BaaS platforms, has been presented, along with the trajectory of adoption, challenges and risk factors. Finally, the study suggests standardisation of available BaaS platforms.
To address the large amount of energy wasted by blockchains, we propose a decentralized consensus protocol for blockchains in which the computation can be used to search for good approximate solutions to any optimization problem. Our protocol allows the wasted energy to be used for finding approximate solutions to problems submitted by any nodes~(called clients). Our protocol works in a similar way to proof-of-work, and it makes nodes evaluate a large number of solution candidates to add a new block to the chain. A client provides a search program that implements any search algorithm that finds a good solution by evaluating a large number of solution candidates. The node that finds the best approximate solution is rewarded by the client. Our analysis shows that the probability of a fork and the variance in the block time with our protocol are lower than those in proof-of-work.
Research in the field of blockchain technology and applications is increasing at a fast pace. Although the Bitcoin whitepaper by Nakamoto is already ten years old, the field can still be seen as immature and at an early stage. Current research in this area is lacking a commonly shared knowledge and consensus about terms used to describe the technology and its properties. At the same time this research is challenging fundamental aspects of the Bitcoin core concept. It has to be questioned whether all of these new approaches still adequately could be described as blockchain technology. We propose to use the term Decentralized Consensus Technology as a general category instead. Decentralized Consensus Technology consists of decentralized ledger and non-ledger technologies. Blockchain technology in turn is only one of multiple implementations of the Decentralized Ledger Technology. Furthermore, we identified three main characteristics of Decentralized Consensus Technology: decentralization, trustlessness and ability to eventually reach consensus. Depending on the use case of the specific implementation the following additional properties have to be considered: privacy, participation incentive, irreversibility and immutability, operation purpose, confirmation time, transaction costs, ability to externalize transactions and computations and scalability possibilities.