State sharding is a common solution to the scalability problem in blockchain systems, allowing nodes to hold a partial view of the system state. With sharding, the processing of a transaction might not be completed locally within a node and potentially requires involvement of multiple shards. Such cross-shards transactions have a negative impact on system performance and are frequent with traditional state partition solutions which are often based on a simple mapping of data into shards. By locating together parts of the system state accessed by frequent transactions, the amount of cross-shard transactions can be reduced. On the other hand, the representation of such particular mappings can be memory intensive. In this article, we study traffic-aware sharding that can be described in memory-efficient mappings. We first survey existing mapping schemes in common blockchains. We indicate the tradeoff between the size of the mapping of data to shards and the required transaction processing time and suggest algorithms for finding memory-light sharding of low cross-shard rate. We generalize the approach towards an efficient incremental computation of shards and probabilistic representation of the mapping to shards. We examine the efficiency of the solutions and the required frequency of sharding computation based on real information of the Ethereum network.
Markus Nissl, Emanuel Sallinger, Stefan Schulte, Michael Borkowski
In recent years, manifold blockchain protocols have been proposed by researchers and industrial companies alike. This has led to a very heterogeneous blockchain landscape. Accordingly, it would be desirable if blockchains could interact with each other. However, current blockchain technologies offer only limited support for interoperability, thus preventing tokens or smart contracts from leaving the scope of a particular blockchain. As a first step towards a solution for cross-chain smart contract interactions, we introduce a framework which allows to invoke a smart contract from another blockchain. We offer support for continuing a smart contract after receiving a result from a different blockchain, and for calling smart contracts recursively across blockchains. We provide a reference implementation for Ethereum-based blockchains using Solidity and evaluate the performance regarding time and cost overheads.
Bram Andika Ahmad Al`Aziz, Parman Sukarno, Aulia Arif Wardana
The mechanism for distributing information on the source of the attack by combining blockchain technology with the Intrusion Prevention System (IPS) can be done so that DDoS attack mitigation becomes more flexible, saves resources and costs. Also, by informing the blacklisted Internet Protocol(IP), each IPS can share attack source information so that attack traffic blocking can be carried out on IPS that are closer to the source of the attack. Therefore, the attack traffic passing through the network can be drastically reduced because the attack traffic has been blocked on the IPS that is closer to the attack source. The blocking of existing DDoS attack traffic is generally carried out on each IPS without a mechanism to share information on the source of the attack so that each IPS cannot cooperate. Also, even though the DDoS attack traffic did not reach the server because it had been blocked by IPS, the attack traffic still flooded the network so that network performance was reduced. Through smart contracts on the Ethereum blockchain, it is possible to inform the source of the attack or blacklisted IP addresses without requiring additional infrastructure. The blacklisted IP address is used by IPS to detect and handle DDoS attacks. Through the blacklisted IP distribution scheme, testing and analysis are carried out to see information on the source of the attack on each IPS and the attack traffic that passes on the network. The result is that each IPS can have the same blacklisted IP so that each IPS can have the same attack source information. The results also showed that the attack traffic through the network infrastructure can be drastically reduced. Initially, the total number of attack packets had an average of 115,578 reduced to 27,165.
Incentivizing High-Quality Data Sets in Construction Using Blockchain: A Feasibility Study in the Swiss Industry Jens J. Hunhevicz, Tobias Schraner and Daniel M. Hall Pages 1291-1298 (2020 Proceedings of the 37th ISARC, Kitakyushu, Japan, ISBN 978-952-94-3634-7, ISSN 2413-5844) Abstract: Data sets are often incomplete and low-quality at the end of a construction project. This creates rework or hinders opportunities to use data during future activities of the facility lifecycle (e.g. facility management, renovation, demolition). This research prototypes and evaluates a novel process to use blockchain and smart contracts in construction projects to incentivize high quality data sets. The proposed solution is defined in collaboration with construction professionals. The process traces and saves project data while incentivizing participants to create high-quality data sets through reward tokens. To validate the process, an Ethereum-based blockchain prototype is developed. A simple case study is conducted in collaboration with local industry professionals to simulate how the prototype can function in a typical design bid build process used in Switzerland. The early findings and possible subsequent research steps are presented. Overall, it was found that such a blockchain based incentive systems has the potential to not only incentivize high-quality data sets, but also change the way of tendering and related construction processes. Keywords: Blockchain; Incentives; Data Management; Construction Projects DOI: https://doi.org/10.22260/ISARC2020/0177 Download fulltext Download BibTex Download Endnote (RIS) TeX Import to Mendeley
Crowdsourcing has attracted widespread attention in recent years and developed into various applications. An indispensable service of crowdsourcing systems is task recommendation, which means tasks should be accurately recommended to the workers with aligned interests. However, existing systems rely on their separate servers to conduct recommendation services, resulting in computing resources locked inside each isolated system. Moreover, due to the wide attacking surfaces of traditional centralized servers setting, existing systems are subject to single points of failure or malicious data breaches. Therefore, failure to address these inherent limitations properly will hinder the wide adoption of crowdsourcing. In this article, we propose and implement FedCrowd, the first federated and privacy-preserving crowdsourcing platform by using blockchain technology. Our main idea is to employ the smart contract as a trusted platform for systems to release encrypted tasks, and carefully craft matching protocols to enable efficient task recommendations in the ciphertext domain. Our task-matching protocols are highly customized for the decentralized settings, where users can securely perform keyword and range-based queries over federated task indexes without sharing secret keys. We formally analyze the security strengths and complete the prototype implementation on Ethereum. Experiment results demonstrate the feasibility and usability of the FedCrowd platform.
The Ethereum Blockchain is home to an alternative financial infrastructure. It is implemented in a highly transparent , trust-minimizing and interoperable way. In particular, everything is built on smart contracts and protocols are composable (meaning, that they may freely interact with each other). Moreover, there is no need for trusted third parties, such as custodians or central clearing houses - at least in theory. In reality, most Decentralized Finance protocols are subject to severe dependencies and centralized governance processes. The focus seems to have shifted towards interoperability and away from trust-minimization. Consequently, Decentralized Finance is starting to look a lot like open banking, or to be more precise, an actual realization of open banking's long-term vision.
Lucas M. Palma, Martín Vigil, Jean Everson Martina
Blockchains oferecem propriedades como descentralização, transparência, pseudo-anonimização e integridade de dados. Combinadas com contratos inteligentes, elas permitem o desenvolvimento de aplicativos e acordos descentralizados sem a necessidade de terceiros confiáveis. Elas também podem funcionar como ferramentas para a melhoria de processos de governança. Destacam-se os trabalhos que utilizam blockchain na automação e aprimoramento da emissão de certificados de graduação. Esses trabalhos variam de uma simples prova de existência de certificados de graduação até propostas mais sofisticadas, que incluem o registro de créditos obtidos em um sistema de ensino superior. Neste trabalho, propõe-se um modelo automatizado, transparente, auditável e seguro para registrar créditos e emitir certificados de graduação utilizando blockchain. Os principais objetivos são minimizar a burocracia dos processos envolvidos, facilitar a auditoria e reduzir a falsificação de certificados de graduação. O modelo proposto considera a existência de uma agência reguladora pública de ensino superior e instituições educacionais independentes. Diferentemente de trabalhos relacionados, esta proposta abrange toda a trajetória dos estudantes de graduação, desde o registro até a emissão do seu certificado de graduação. Apresenta-se um protótipo e uma análise de custos considerando dados oficiais do sistema de ensino superior brasileiro e a plataforma de blockchain do Ethereum.
E-voting is an application of in the election process. E-voting was developed to make the election process easier, safer and more practical. Blockchain technology is explained as a safe technology because of its distributed nature. Tso et al's e-voting is one of the e-voting mechanism that uses the ethereum smart contract blockchain. Tso et al e-voting application use asymmetric cryptography for the safety of its users in the form of Paillier's algorithm. This study proposed use of the AES-256 algorithm to secure key data on smart cards for e-voting process, SHA-256 for authentication, and secure communication protocols to secure the key in sending process. The key is stored in a ciphertext format with AES-256 encryption and SHA-256 as authentication algorithm. The results of implementing smart card prototypes as key storage in the Tso et al e-voting application shows that the proposed e-voting scheme has a key storage time of 0.774 seconds, a memory capacity of 572 bytes, with 0.472 seconds generation speed.
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Public trash bins have problems with lack of security and incentive design. In Japan, only a few number of bins can be found because of those reasons. In order to solve this problem, a strong security-featured incentive system is required. This research aims at encouraging more people to provide public trash bins by offering the benefit such as privacy, security and incentive scheme. We propose a blockchain-based incentive system which consists of a smart trash bin, a smartwatch as a wearable payment device, and an incentive scheme using ethereum smart contract.
Ruby Benita K, Ganesh Kumar S, B Murugamantham, A. Murugan
<span>Tracking drugs became more difficult using the centralized architecture. Decentralized architecture using blockchain technology overcomes the difficulties faced by the centralized network like availability and recovery. Avoiding duplicate or fake drugs created by fake manufacturers is a big challenge in the centralized network. Authentic stock is managed and the supply chain is tracked efficiently using this blockchain technology. This is addressed by using the smart contract which helps to track the movement of drugs from manufacturer to supplier, supplier to the reseller, reseller to pharmacies and finally pharmacies to patient. By default, duplicate drugs or fake drugs are completely avoided by using the blockchain technology. Patients buy drugs without any prescription and it creates a lot of problems in real life. So, Patients cannot buy drugs without authenticated doctor’s prescriptions with the help of a QR Code scanner attached with the prescription which will be implemented using a mobile application and cannot buy excess drugs which might lose someone’s life. With the help of inventory management, the maximum limit of drugs to avoid overdose and pharmacies cannot sell those overdose drugs. Consulting a doctor before buying a drug for even a simple illness is important and it is tracked by using prescriptions provided by authentic doctors. In this project, these challenges are addressed using the smart contract which is written in solidity language and runs on a public ethereum network.</span>
This chapter aims to employ the most up-to-date literature to shed light on the aims, working mechanisms and likely macroeconomic impact of Central Bank Digital Currency (CBDC). It describes payment systems to distributed ledger technology (DLT)-based ones. The chapter explains the working mechanisms of CBDC, providing some real-world examples. It discusses some of the potential benefits and macroeconomic risks associated with CBDC. A payment system is a collection of technologies, laws and contracts that allow payments to occur and determine when a payment effects a settlement. The volume of electronic payments processed by central banks’ clearinghouses has been rising. DLT-based payment systems have some potential benefits, and they also present some challenging aspects. Token-based retail CBDCs are meant to be the digital version of cash. Hence, the general public would be granted direct access to central banks’ liabilities. Turning to monetary policy, CBDCs’ effects on policy rates largely depend on CBDC design.
[ES] En este TFG se va a exponer un sistema de notarización de documentos digitales aprovechando las cualidades de transparencia e inmutabilidad de Ethereum para almacenar los registros. \n \nSe van a presentar dos posibles arquitecturas para este sistema, siendo la gestión de las cuentas Ethereum la principal diferencia. \n \nEn el primer diseño, el usuario debe tener una cuenta de Ethereum con fondos para interactuar con el sistema. Los dos componentes fundamentales son: la interfaz web y el Smart Contract en Ethereum. El usuario se conecta al sistema en la página web, usando un Wallet específico de navegador (MetaMask). Desde la web podrá guardar, recuperar o validar cualquier registro en Ethereum. \n \nEn el segundo diseño, no será necesario que el cliente tenga su propia cuenta de Ethereum. En su lugar, habrá un servidor que identificará a los usuarios e interactuará con Ethereum en su nombre. \n \nPor último, se hablará de un sistema de gestión de identidades, basado en el estándar de W3C, el cual dará una capa extra de seguridad a nuestro sistema de notarización.
A Large-Scale Heterogeneous Network (LS-HetNet) integrates different networks into one uniform network system to provide seamless one-world network coverage. In LS-HetNet, various devices use different technologies to access heterogeneous networks and generate a large amount of data. For dealing with a large number of access requirements, these data are usually stored in the HetNet Domain Management Server (HDMS) of the current domain, and HDMS uses a centralized Authentication/Authorization/Auditing (AAA) scheme to protect the data. However, this centralized method easily causes the data to be modified or disclosed. To address this issue, we propose a blockchain-empowered AAA scheme for accessing data of LS-HetNet. Firstly, the account address of the blockchain is used as the identity authentication, and the access control permission of data is redesigned and stored on the blockchain, then processes of AAA are redefined. Finally, the experimental model on Ethereum private chain is built, and the results show that the scheme is not only secure but also decentral, without tampering and trustworthiness.
Abstract Past international trade practices have been associated with opaque information flows that have hindered traceability and created hurdles in hassle‐free trade. Blockchain and allied technologies have been investigated as a panacea for the problems faced by the Cloud‐Based Manufacturing industry. However, previous literature has focused on limited aspects of a typical Cloud‐Based Manufacturing chain, such as monitoring assets and securing traceability, which is widely neglecting data integrity and data access. To overcome such drawbacks, the current paper proposes secure smart contracts based on the ERC20 interface in a permissioned blockchain with relevant processes and functions to obtain a holistic framework for securing Cloud‐Based Manufacturing operations. The efficacy of the proposed framework was demonstrated on the case study. It was found that critical loopholes in a current supply chain can be overcome using the proposed framework. Additionally, several outlines for future research are outlined.
Proofs of retrievability and proofs of replication are two cryptographic tools that enable a remote server to prove that the users' data has been correctly stored. Nevertheless, the literature either requires the users themselves to perform expensive verification jobs, or relies on a “fully trustworthy” third party auditor (TPA) to execute the public verification. In addition, none of existing solutions consider the underlying incentive issues behind a rational server who is motivated to collect users' data but tries to evade the replication checking in order to save storage resources. In this article, we propose the first decentralized system for proofs of data retrievability and replication-BOSSA, which is incentive-compatible for each party and realizes automated auditing atop off-the-shelf blockchain platforms. We deal with issues such as proof enforcements to catch malicious behaviors, new metrics to measure the contributions, and reward distributions to create a fair reciprocal environment. BOSSA also incorporates privacy-enhancing techniques to prevent decentralized peers (including blockchain nodes) from inferring private information about the outsourced data. Security analysis is presented in the context of integrity, privacy, and reliability. We implement a prototype based on BOSSA leveraging the smart contracts of Ethereum blockchain. Our extensive experimental evaluations demonstrate the practicality of our proposal.
The success of Bitcoin and Ethereum has attracted many efforts to build high-throughput blockchain systems. This paper focuses on transaction dissemination --- a rather overlooked issue in these systems. We argue that efficient transaction dissemination is the key for a blockchain system to sustain at high-throughput --- usually thousands of transactions per second --- and the existing solutions fell short at doing so.
Using intraday data, this study employs the VAR-DCC-GARCH model to examine return and volatility transmission among Bitcoin, Ethereum, and Litecoin during the pre-COVID-19 and COVID-19 periods. We find that the return spillovers differ across both periods for the Bitcoin-Ethereum, Bitcoin-Litecoin, and Ethereum-Litecoin pairs. The volatility transmission is not significant between cryptocurrencies during the pre-COVID-19 period. We also find that the volatility spillover is unidirectional from Bitcoin to Ethereum and bidirectional between Ethereum and Litecoin during the COVID-19 period. Moreover, volatility transmission is not significant between Bitcoin and Litecoin during the COVID-19 period. The dynamic conditional correlations between all pairs of cryptocurrencies are higher during the COVID-19 period than during the pre-COVID-19 period. Lastly, we compute the optimal portfolio weights, time-varying hedge ratios, and hedging effectiveness for all pairs of cryptocurrencies during the pre-COVID-19 and COVID-19 periods. Overall, our findings provide new insights into channels of information transmission, which may improve the investment decisions and trading strategies of portfolio investors during crisis and non-crisis periods.
The emergence of cryptocurrency has introduced a transformative force in the global financial landscape, challenging the conventional structures of traditional financial markets. This paper explores the dynamic relationship between digital currencies and established financial systems, focusing on areas such as investment behavior, regulatory responses, market volatility, and the evolving role of financial institutions. It highlights how cryptocurrencies, particularly Bitcoin and Ethereum, have begun to influence asset allocation strategies, capital flows, and risk perceptions among investors. Furthermore, the paper examines the integration of blockchain technology in financial services and how its decentralized nature poses both opportunities and threats to conventional banking practices. While cryptocurrencies have opened up avenues for innovation and financial inclusion, their unregulated nature raises concerns regarding market stability and security. This study aims to provide a comprehensive understanding of the implications of cryptocurrency growth for traditional financial markets, suggesting the need for adaptive regulatory frameworks and strategic responses from financial institutions.
Srinidhi Srinivasan, Rubasri Sundar, Sam Joy Herald Immanuel, Ramesh Belvadi · 5 authors
In light of the multiple legal issues, compliance and disruptions caused by the pandemic, organisations searching for new solutions need to know what smart contracts are and how they would function under the legal doctrine of force majeure in light of COVID-19. The Blockchains which use Bitcoin type of scripts have been popular as payment solutions, but it is less used as smart contracts. In the case of multi-level games and incremental project payments, there is a high potential to use Bitcoin type of scripts, but it is not being used currently. Interestingly, there have been attempts to associate smart contract mainly using Ethereum Blockchain but not with Bitcoin type of scripts. This article intends to demonstrate the novelty of designing smart contracts using Bitcoin type of scripts for hierarchical execution of smart contracts. An attempt is done to show its application in two use cases (multi-level reward games payment and incremental project payment). An evaluation is done with three methods each having a combination of pros and cons based on the requirements which aids in understanding for transparency and control over funds through Blockchain.
In recent times, Blockchain has become one of the most influential technology. Numerous industry projects are developed and are under the development phase for enhancing blockchain technology in every way possible and making it applicable to various application-domains. Since the inception of Ethereum, many blockchain platforms have been developed using different types of technologies. Blockchain platforms, from its security perspective, don't interact with the outside world and acts as an independent and standalone ledger. But blockchain technology can not meet the needs of today's world if different ledgers don't interact with each other and with the legacy systems. Hence, Blockchain platforms should be able to communicate with each other and provide services to each other. Researchers and developers around the world are already working to achieve blockchain interoperability. In this paper, we survey interoperability solutions provided for blockchain platforms, both by industry people and the research community.