Blockchain Papers

Timothy Arndt

No abstract is available for this record.

He Zhu, Yichuan Wang, Xinhong Hei, Wenjiang Ji · 5 authors

Application services in cloud computing model have complex scheduling, composition, configuration and deployment conditions, even in the multi-condition requirements, it can also be based on the change of time to schedule virtual services. Therefore, the demand of optimizing cloud computing scheduling strategy to ensure cloud data security and recovery ability is increasingly prominent. This paper proposes a trusted distributed audit method for cloud task scheduling, which is used for the trusted storage of cloud task scheduling information in the cloud cluster. This method mainly uses a distributed solution that combines block chain technology and traditional cloud server to solve the problem of integrity and security of cloud task scheduling, in order to prevent potential. The vulnerabilities in the system cause significant losses to the system. The architecture of this paper is composed of four parts: cloud cluster, control system, block chain network, and cloud database. We store the hash data of cloud task scheduling information into blockchain network and store the original data to the cloud data base, which guarantees the cloud task within the cloud cluster. Data security and integrity, and provide a new idea for future research system recovery.

Abdellatif Kobbane, Charkaoui Abdelmouttalib

Since it first appears in 2008 as the underlying technology of the Bitcoin payment system, Blockchain has gained further interests, since it offers a distributed peer-to-peer ledger where non-trusting members can interact with each other, in addition, members can now run applications without the need for a central authority with the same level of certainty. however blockchain suffers from certain limitations and challenges, specifically, when combined with Internet of things (iot) infrastructure, namely the high cost needed in the mining process due to restricted computation resources of iot devices, in this paper we will focus on a survey on three of most relevant papers that discuss resources management in mobile blockchain then we we will propose a matching model based on graph theory for optimal resources allocation between services offered by an Edge service provider and demands from miners of a blockchain network.

Dongho Kim, Hye-Won Kim

As the complexity of software increases, the importance of software quality is ever increasing, as everyone recognizes. In order to secure software quality, various engineering methods have been proposed. However, because these methods are very specialized, the reality is that it is difficult to apply them to a distributed and small-scale development environment. So, to solve this problem, a tool to analyze the quality of source code is used. Still, it is not easy to rely on code quality in a distributed development environment. In this study, source code quality data measured in a distributed development environment is stored in a blockchain ledger based on a graph database. In this way, the reliability of code quality in a distributed development environment can be enhanced.

Bin Wu, Yinsheng Li

By letting students simulate operations and games on a digital education operation system, schools are able to inspect learning achievement and teaching quality. In digital education area, we are able to use blockchain technology to improve competition mode. It's helpful to simplify process, improve efficiency and avoid the problem of opaque and falsification messages. Besides, it can provide unchangeable digital certification of academic achievement. Based on existing research foundation, against features on related users and services, especially the standard and trustful problem in competitions and evaluation mode nowadays, I studied competition mode based on blockchain technology, designed blockchain's application mode and frame, analyzed evaluation criteria and algorithm, designed an operational skill evaluation model, developed an operational skill competition evaluation system based on e-business sandbox and experimented it.

Kai Zheng, Ying Liu, Chuanyu Dai, Yanli Duan · 5 authors

Now blockchain network is used in many areas such as healthcare, energy trading and so on. However, the research about how to evaluate the performance of the blockchain network is insufficient. In some papers, the performance of blockchain is analyzed by running real blockchain applications. However, the devices and services cost is a burden. In this paper, we aim to use continuous-time Markov chain (CTMC) models to simulate the time response of PBFT (Practical Byzantine Fault Tolerance)-based healthcare blockchain network. Some influencing factors such as replica nodes delay and primary node delay will be analyzed. The simulation results also contribute to the optimization design of blockchain network.

Michele Marchesi, Lodovica Marchesi, Roberto Tonelli

Cryptocurrencies and their foundation technology, the Blockchain, are reshaping finance and economics, allowing a decentralized approach enabling trusted applications with no trusted counterpart. More recently, the Blockchain and the programs running on it, called Smart Contracts, are also finding more and more applications in all fields requiring trust and sound certifications. Some people have come to the point of saying that the "Blockchain revolution" can be compared to that of the Internet and the Web in their early days. As a result, all the software development revolving around the Blockchain technology is growing at a staggering rate. The feeling of many software engineers about such huge interest in Blockchain technologies is that of unruled and hurried software development, a sort of competition on a first-come-first-served basis which does not assure neither software quality, nor that the basic concepts of software engineering are taken into account. This paper tries to cope with this issue, proposing a software development process to gather the requirement, analyze, design, develop, test and deploy Blockchain applications. The process is based on several Agile practices, such as User Stories and iterative and incremental development based on them. However, it makes also use of more formal notations, such as some UML diagrams describing the design of the system, with additions to represent specific concepts found in Blockchain development. The method is described in good detail, and an example is given to show how it works.

Kazim Rifat Ozyilmaz, Harsh Patel, Ankit Malik

The Bitcoin protocol is a significant milestone in the history of money. However, its adoption is currently constrained by the transaction limits of the system. As the chief problem of blockchain technology, the scaling issue has attracted many valuable solutions both on-chain and off-chain. In this paper, our goal is to explore the notion of unspent transaction outputs (UTXOs) to propose an augmented Bitcoin protocol that can scale gracefully. Our proposal aims to increase the transaction throughput by partitioning the UTXO space and splitting the blockchain. In addition, a new type of Bitcoin node is introduced to preserve the capability to run validating nodes in low-bandwidth environments, despite the increased transaction throughput.

Sanjay Prasad, Ravi Shankar, Rachita Gupta, Sreejit Roy

Purpose Over last few years, a major innovation known as blockchain technology has emerged as potentially one of the most disruptive technology of recent times. The purpose of this paper is to identify and analyze various critical success factors (CSFs) that can facilitate success of blockchain-based cloud services. Further, this paper aims to analyze and understand mutual interactions among these CSFs. Design/methodology/approach In this paper, 19 CSFs have been identified through literature review and expert opinions. The hierarchical framework developed using total interpretive structural modeling has revealed the inter-dependencies among these CSFs. The methodology employed in this study provides a mechanism to conduct an exploratory study by identifying the factors and analyzing their interactions through the development of a hierarchical framework. This research further categorizes CSFs into multiple clusters based on their driving power and dependence power. Findings This paper has identified 19 CSFs, namely, user engagement, industry collaboration, rich ecosystem, blockchain technology standardization, regulatory clarity, cost efficiency, energy efficiency (wasted resources), handling blockchain bloat, miner incentives, business case alignment to blockchain capability, sidechains development, blockchain talent pool availability, leadership readiness for a decentralized consensus based technology, technology investment and maturity, trust on blockchain networks, integration with other cloud services, robust and mature smart contracts platform, blockchain security and user control on data (privacy). Further, driver and dependent variables have been identified. Research limitations/implications Future research can discover and detail the sub-factors behind the 19 CSFs identified in this paper. Additionally, more work can be done to extend the current structural model for blockchain-based services to a more functional form. Practical implications It provides a comprehensive list of CSFs that are relevant for development of blockchain-based cloud services. This will help industry leaders to strategically focus on the main drivers that will ensure that businesses get maximum benefit of this disruptive technology. Originality/value This study makes a significant contribution in the literature of blockchain-based cloud services, which captures the perspective of different stakeholders. This study is one of the first (if not the first) systematic research on adoption of blockchain-based services. It creates the foundation to carry out further research in this area.

Parwat Singh Anjana, Sweta Kumari, Sathya Peri, Sachin Rathor · 5 authors

Blockchain platforms such as Ethereum and several others execute complex transactions in blocks through user-defined scripts known as smart contracts. Normally, a block of the chain consists of multiple transactions of smart contracts which are added by a miner. To append a correct block into the blockchain, miners execute these transactions of smart contracts sequentially. Later the validators serially re-execute the smart contract transactions of the block. If the validators agree with the final state of the block as recorded by the miner, then the block is said to be validated. It is then added to the blockchain using a consensus protocol. In Ethereum and other blockchains that support cryptocurrencies, a miner gets an incentive every time such a valid block successfully added to the blockchain. In most of the current day blockchains the miners and validators execute the smart contract transactions serially. In the current era of multi-core processors, by employing the serial execution of the transactions, the miners and validators fail to utilize the cores properly and as a result, have poor throughput. By adding concurrency to smart contracts execution, we can achieve better efficiency and higher throughput. In this paper, we develop an efficient framework to execute the smart contract transactions concurrently using optimistic Software Transactional Memory systems (STMs). Miners execute smart contract transactions concurrently using multi-threading to generate the final state of blockchain. STM is used to take care of synchronization issues among the transactions and ensure atomicity. Now when the validators also execute the transactions (as a part of validation) concurrently using multi-threading, then the validators may get a different final state depending on the order of execution of conflicting transactions. To avoid this, the miners also generate a block graph of the transactions during the concurrent execution and store it in the block. This graph captures the conflict relations among the transactions and is generated concurrently as the transactions are executed by different threads. The miner proposes a block which consists of set of transactions, block graph, hash of the previous block, and final state of each shared data-objects. Later, the validators re-execute the same smart contract transactions concurrently and deterministically with the help of block graph given by the miner to verify the final state. If the validation is successful then proposed block appended into the blockchain and miner gets incentive otherwise discard the proposed block. We execute the smart contract transactions concurrently using Basic Time stamp Ordering (BTO) and Multi-Version Time stamp Ordering (MVTO) protocols as optimistic STMs. BTO and MVTO miner achieves 3.6x and 3.7x average speedups over serial miner respectively. Along with, BTO and MVTO validator outperform average 40.8x and 47.1x than serial validator respectively.

Parwat Singh Anjana, Sweta Kumari, Sathya Peri, Sachin Rathor · 5 authors

It is commonly believed that blockchain is a revolutionary technology for doing business on the Internet. Blockchain is a decentralized, distributed database or ledger of records. It ensures that the records are tamper-proof but publicly readable. Blockchain platforms such as Ethereum [3] and several others execute complex transactions in blocks through user-defined scripts known as smart contracts. Normally, a block of the chain consists of multiple transactions of smart contracts which are added by a miner. To append a correct block into the blockchain, miners execute these transactions of smart contracts sequentially. Later the validators serially re-execute the smart contract transactions of the block. If the validators agree with final state of the blocks as recorded by the miner, then the block is said to be valid and added to the blockchain using a consensus protocol.

Marco Conoscenti, Antonio Vetrò, Juan Carlos De Martin, Federico Spini

The Lightning Network (LN) is one of the most promising off-chain scaling solutions for Bitcoin, as it enables off-chain payments which are not subject to the well-known blockchain scalability limit. In this work, we introduce CLoTH, a simulator for HTLC payment networks (of which LN is the best working example). It simulates input-defined payments on an input-defined HTLC network and produces performance measures in terms of payment-related statistics (such as time to complete payments and probability of payment failure). CLoTH helps to predict issues and obstacles that might emerge in the development stages of an HTLC payment network and to estimate the effects of an optimisation action before deploying it. We conducted simulations on a recent snapshot of the HTLC payment network of LN. These simulations allowed us to identify network and payments configurations for which a payment is more likely to fail than to succeed. We proposed viable solutions to avoid such configurations.

F. Richard Yu

A wide range of services and applications can be improved and/or solved by\nusing distributed ledger technology (DLT). These services and applications have\nwidely varying quality of service (QoS) requirements. However, most existing\nDLT systems do not distinguish different QoS requirements, resulting in\nsignificant performance issues such as poor scalability and high cost. In this\nwork, we present vDLT -- a service-oriented blockchain system with\nvirtualization and decoupled management/control and execution. In vDLT,\nservices and applications are classified into different classes according to\ntheir QoS requirements, including confirmation latency, throughput, cost,\nsecurity, privacy, etc. This is a paradigm shift from the existing\n"blockchain-oriented" DLT systems to next generation "service-oriented" DLT\nsystems. Different QoS requirements are fulfilled by advanced schemes inspired\nby the development of the traditional Internet, including classification,\nqueuing, virtualization, resource allocation and orchestration, and\nhierarchical architecture. In addition, management/control and execution of\nsmart contracts are decoupled to support QoS provisioning, improve\ndecentralization, and facilitate evolution in vDLT. With virtualization,\ndifferent virtual DLT systems with widely varying characteristics can be\ndynamically created and operated to accommodate different services and\napplications.\n

Wei‐Tek Tsai, Zihao Zhao, Chi Zhang, Lian Yu · 5 authors

Recently digital currency has received significant attention, and among many topics within digital currency, CBDC (Central Bank issued Digital Currency) has been a hot topic as it will affect national currency systems. RSCoin is the first CBDC model sponsored by Bank of England, and it uses the UTXO model from Bitcoin. This paper proposes a new CBDC model Panda model that can store account balance like current banking systems, but use efficient consensus protocols to ensure that relevant parties have consistent views of transactions and accounts. The Panda model is scalable as it can include as many financial institutions or individuals as possible in the system with increasing or decreasing workloads. The model has been simulated in the TaiShan Sandbox in Qingdao.

N. Jones

No abstract is available for this record.

Alin Bogdan Popa, Ioan Mihail Stan, Răzvan Rughiniş

Blockchain is one of the most important technological trends today since it has a wide spectrum of use cases (financial industry applications, supply-chain tracking, MedTech EHR management, energy grid etc.) and it offers a wide range of implementations. However, the main goal of the Blockchain remains the transfer of value-bearing assets between an owner of a resource and a client. Due to CPU intensive consensus algorithms, transaction prioritization based on potential earnings, the validation process and so on, Blockchain implementations are not able to support real-time services and, also, to enable a varied cloud computing service catalog on top of the existing infrastructure. Our solution is addressing this drawback by developing a system supporting late payments through our innovative concept called latent-transactions. We also provide the instruments through which we make viable off-chain agreements, between the parties involved in a transaction. Therefore, one can benefit from a service, prior to actual payment. In addition, we offer a service enlargement mechanism by providing a catalog where any member of Blockchain can subscribe and from where one can sell services in a real-time manner with adaptive pricing, based on the context (demand, activity at runtime etc.).

Amjad Aldweesh, Maher Alharby, Ellis Solaiman, Aad van Moorsel

A defining feature of the Ethereum blockchain is its ability to execute smart contracts, providing a Turing complete programming model for distributed applications in non-trusted environments. The successful operation of the Ethereum blockchain depends on whether the miners' incentives (in the form of fees) to execute contracts is proportional to the miners' cost (in terms of energy usage, and thus CPU usage). In general, if the received fee is not proportional to the computational cost, miners would prefer some tasks over others, thus potentially adversely affecting the continuing dependable operation of the blockchain. In this paper we design a benchmark to compare smart contract execution time with the award a miner would receive, to determine if incentives align. We present the design of the benchmarking approach and provide initial results for the Python Ethereum client running on a Mac. The results indicate that for functions in Ethereum's most popular contracts the difference of reward per CPU second can be up to a factor of almost 50. In addition, contract creation, which is done once for each new contract, can be up to 6 times more lucrative than the regular execution of contract functions. Potentially, these discrepancies result in misaligned incentives that impact the dependable operation of the blockchain.

Evangelos Georgiadis, Doron Zeilberger

In 2008, Satoshi Nakamoto famously invented bitcoin, and in his (or her, or their, or its) white paper sketched an approximate formula for the probability of a successful double spending attack by a dishonest party. This was corrected by Meni Rosenfeld, who, under more realistic assumptions, gave the exact probability (missing a foundational proof); and another formula (along with foundational proof), in terms of the Incomplete Beta function, was given later by Cyril Grunspan and Ricardo Pérez-Marco, that enabled them to derive an asymptotic formula for that quantity. Using Wilf-Zeilberger algorithmic proof theory, we continue in this vein and present a recurrence equation for the above-mentioned probability of success, that enables a very fast compilation of these probabilities. We next use this recurrence to derive (in algorithmic fashion) higher-order asymptotic formulas, extending the formula of Grunspan and Pérez-Marco who did the leading term. We then study the statistical properties (expectation, variance, etc.) of the duration of a successful attack.

Paul Rimba, An Binh Tran, Ingo Weber, Mark Staples · 6 authors

No abstract is available for this record.

Sandi Gec, Dejan Lavbič, Marko Bajec, Vlado Stankovski

Today, container-based virtualization is very popular due to the lightweight\nnature of containers and the ability to use them flexibly in various\nheterogeneously composed systems. This makes it possible to collaboratively\ndevelop services by sharing various types of resources, such as\ninfrastructures, software and digitalized content. In this work, our home made\nvideo-conferencing (VC) system is used to study resource usage optimisation in\nbusiness context. An application like this, does not provide monetization\npossibilities to all involved stakeholders including end users, cloud\nproviders, software engineers and similar. Blockchain related technologies,\nsuch as Smart Contracts (SC) offer a possibility to address some of these\nneeds. We introduce a novel architecture for monetization of added-value\naccording to preferences of the stakeholders that participate in joint software\nservice offers. The developed architecture facilitates use case scenarios of\nservice and resource offers according to fixed and dynamic pricing schemes,\nfixed usage period, prepaid quota for flexible usage, division of income,\nconsensual decisions among collaborative service providers, and constrained\nbased usage of resources or services. Our container-based VC service, which is\nbased on the Jitsi Meet Open Source software is used to demonstrate the\nproposed architecture and the benefits of the investigated use cases.\n

Raphael Vicente Rosa, Christian Esteve Rothenberg

Envisioned 5G use cases arise challenges around the realization of inter-domain relationships beyond traditional Border Gateway Protocol (BGP) peering, e.g. end-to-end service deployments tailored to specific business needs (a.k.a. slices). Blockchain technologies bring consensus among decentralized non-trusting counterparts as a shared ledger, offering potential approaches for multi-administrative domain networking seeking agile, transparent end-to-end sliceable Service Level Agreements (SLAs). This demo showcases an experimental prototype based on best of breed open source components (e.g., Ethereum, OVS, Neo4j, Ryu/OpenFlowv1.3, ARIA/TOSCA) illustrating blockchain Decentralized Application (DApp) functionalities for life cycle management of multi-administrative domain network services.

Yung-Chen Hsieh, Chih-Wen Hsueh, Ja‐Ling Wu

Blockchain and smart contract provide a convenient vehicle to build decentralize applications. Among varies Decenrtalized applications (DAPPs), exchange is one of the most mentioned ones. To fully-decentralized an exchange looks somehow like an utopia. Most works tried to use different methods to solve different problems on this subject. According to our observations, the problems caused by blockchain include 1) Long confirmation time, 2) Vulnerable to front running attack, 3) wasting on-chain resource, all these problems make a blockchain based exchange not user friendly. To deal with the above-mentioned problems, a hybrid centralized and decentralized exchange is presented in this work. By simulating the transaction execution processes and eliminating all the unwanted uncertainties, we are confident that the transactions in the proposed exchange center (EC) will be confirmed and executed well on the blockchain, that is, our system allows users to conclude their trades without need of waiting for a long blockchain confirmation time. In conclusion, a Hybrid Centralized and Decentralized Application (HCDAPP) provides a better-quality service, just like a centralized server; at the same time, it also provides a higher-level security, like a decentralized smart contract.

Jonathan Coignard, Eric Munsing, Jason MacDonald, Jonathan Mather

The increased penetration of Distributed Energy Resources (DERs) on the distribution network creates local challenges in balancing consumption and generation. To coordinate the roll-out and the operation of DERs, distribution-level energy markets have been proposed, but there are currently few tools for simulating the operation of DERs in these proposed markets. We present a framework which utilizes a grid co- simulation platform (Mosaik) to simulation DER operation, while simulating market clearing operations with a blockchain network (Ethereum). The use of blockchains, an emerging technology for decentralized computing and data storage, allows us to model secure decentralized execution of market clearing functions and payment processes. By unifying simulation of market clearing rules and the physical grid, we are able to ensure that economic incentives are aligned with physical constraints, helping facilitate the development of more effective distributed energy markets. We demonstrate the use of this new simulation platform on a small feeder, for which a market mechanism to incentivize DER integration is explored.

Chelsea Hinds-Charles, Jenelee Adames, Ye Yang, Yusong Shen · 5 authors

As one of the most successful Blockchain systems, Bitcoin evolved over the past 8 years. The collaborative contribution of its online software development community gradually shaped the functionality and performance of Bitcoin. To date, most discussions around Bitcoin are from technologies underlying the product, as well as market applications. There are very few studies on the development and evolution processes of the Bitcoin software. It is important to investigate on such developmental issues, in order to better understand the development methodologies and lessons learnt from such a spearheaded Blockchain system. This paper serves this purpose by examining the issues data extracted from the Bitcoin GitHub repository from 2011 to 2018. It reports the trends of the major development issues from a longitude perspective. The main results include: 1) the average lifespan of an issue in Bitcoin issue repository is approximately 57 days; and 2) the Top-7 issue types including refactoring, tests, doc, RPC.REST.ZMQ, GUI, bugs, and wallet, accounting for 64.3% of all issues; 3) topic modeling techniques are beneficial in mining popularity and evolution of key issue topics and most problematic architecture components. Using data analysis and visualization techniques, this paper suggests the insights for significant development decisions such as better managing issue repository and strategic allocating of bug resolution effort.