Blockchain Papers

Miguel Pincheira, Massimo Vecchio, Raffaele Giaffreda

No abstract is available for this record.

Vaikkunth Mugunthan, Ravi Rahman, Lalana Kagal

No abstract is available for this record.

Heesang Kim, Dohoon Kim

Blockchain is not widely applied in various fields due to the critical issue of scalability as part of the blockchain trilemma. This issue arises during consensus among the nodes in a public blockchain. To address the issue of low scalability with proof-of-work (PoW) consensus, various methods have been proposed for transaction per second (TPS) improvement. However, no such methods include an improvement in the consensus step. Therefore, to improve PoW public blockchain scalability, it is important to shorten the time required for PoW consensus. This paper proposes a method for minimizing the block intervals that occur during consensus over a PoW blockchain network. A shortened block interval leads to an increase in the probability of three different attacks: selfish mining, double-spending, and eclipse attacks. According to an experiment using Ethereum, with a typical PoW blockchain, it is inevitable to provide rewards for stable block mining in competition between mining pools. To find an optimal block interval in the PoW consensus algorithm, we conducted a four-step experiment. The purpose of this experiment was to verify the difficulty level and issues with Mainnet security. Therefore, considering stale block mining rewards, an optimal block interval is proposed. The Ethereum TPS was improved by at least 200%. Given this finding, it is considered possible to achieve a similar improvement in a different PoW blockchain. On balance, even if the block interval is shorter than that of the PoW Mainnet, network security falls by only 1.21% in Testnet, even with a rise in the stale block rate, while performance is increased at up to 120 TPS, which is three times higher than that in Mainnet.

Yuxin Wang, Zhiying Tu, Yu Bai, Haochen Yuan · 6 authors

The distributed services from different domains, organizations, and regions in the real and virtual world are converged together to form the Internet of Services (IoS). It is required to provide a trusted, orderly and efficient platform environment for service collaboration and delivery. Blockchain is currently recognized as the best practice technique to solve the problem of orderly and trusted execution of system. However, the efficiency issue introduced by it is also a problem that every platform needs to take seriously. Therefore, this paper proposes a blockchain-based IoS architecture, which uses the virtual chain and the embedded EVM(Ethereum Virtual Machine) notary technology to ensure the security and credibility of the service collaboration process in the IoS, and also the efficient operation of the entire system. This architecture has been compared with non-blockchain architecture without credible guarantees and also blockchain-only architecture. This comparative experiment shows that the proposed architecture not only ensures the orderly and trusted execution of the system, but also effectively controls the loss of performance.

Pedro Pablo Chambi Condori

Objetivo: Organizar en forma experimental carteras de inversión con los criptoactivos bajo la teoría moderna de estructuración de portafolios de inversión de Markowitz. Método: La investigación fue del tipo cuantitativa y experimental, abarcando el proceso de estructuración de portafolios de inversión con criptomonedas bajo la teoría de Markowitz, mediante el modelo de programación no lineal cuantitativa. Resultados: Se pudo observar que el periodo de cotización más pronunciado se presentó en el periodo comprendido entre 2017 a 2018. Una rentabilidad mayor le corresponde a Ethereum, seguido de Bitcoin y de Ripple; consecuentemente, Ethereum es el que tiene el mayor indicador de volatilidad. La opción de cartera eficiente se obtuvo cuando se invirtió el 70% en Bitcoin, 14% en Ethereum, 6% en Ripple y 10% en Thether y, como efecto de la diversificación de carteras de inversión, se verifica el comportamiento inverso de la volatilidad. Conclusiones: En el estudio en referencia, se demostró el efecto del número de activos en la conformación del portafolio de inversiones en la reducción de la volatilidad y las opciones que provee el mapa de la frontera eficiente para que los inversionistas opten por las opciones que calcen mejor con sus expectativas de riesgo y rentabilidad.

Florian Breuer, Vipul Goyal, Giulio Malavolta

Blockchain-based cryptocurrencies offer an appealing alternative to Fiat currencies, due to their decentralized and borderless nature. However the decentralized settings make the authentication process more challenging: Standard cryptographic methods often rely on the ability of users to reliably store a (large) secret information. What happens if one user's key is lost or stolen? Blockchain systems lack of fallback mechanisms that allow one to recover from such an event, whereas the traditional banking system has developed and deploys quite effective solutions. In this work, we develop new cryptographic techniques to integrate security policies (developed in the traditional banking domain) in the blockchain settings. We propose a system where a smart contract is given the custody of the user's funds and has the ability to invoke a two-factor authentication (2FA) procedure in case of an exceptional event (e.g., a particularly large transaction or a key recovery request). To enable this, the owner of the account secret-shares the answers of some security questions among a committee of users. When the 2FA mechanism is triggered, the committee members can provide the smart contract with enough information to check whether an attempt was successful, and nothing more. We then design a protocol that securely and efficiently implements such a functionality: The protocol is round-optimal, is robust to the corruption of a subset of committee members, supports low-entropy secrets, and is concretely efficient. As a stepping stone towards the design of this protocol, we introduce a new threshold homomorphic encryption scheme for linear predicates from bilinear maps, which might be of independent interest. To substantiate the practicality of our approach, we implement the above protocol as a smart contract in Ethereum and show that it can be used today as an additional safeguard for suspicious transactions, at minimal added cost. We also implement a second scheme where the smart contract additionally requests a signature from a physical hardware token, whose verification key is registered upfront by the owner of the funds. We show how to integrate the widely used universal two-factor authentication (U2F) tokens in blockchain environments, thus enabling the deployment of our system with available hardware.

Erdoğan Kaygın, Yunus Zengin, Ethem Topçuoğlu, Serdal Özkes

Abstract Technological developments have always led to changes in all aspects of our lives. Crypto currency is one of those changes. As a result of those changes, thousands of currencies such as bitcoin, ripple, litecoin and ethereum have evolved and have found a use in business. The present study focuses upon Ripple and tries to explain its effects on banks and business theoretically. It has been stated that the money transfer performed through Ripple is faster and more economical when compared to present systems. Additionally, it has been realised that the present SWIFT system has been influenced by that speed and economy, and therefore taken considerable technologic steps with an effort to improve its system.

Huajian Wang, Huan Zhou, Yang Guogui, Tao Xiao

Crowdsourcing provides a new way of group intelligence interaction in recent years. Traditional crowdsourcing service models rely on centralized third-party platforms, which are bottlenecks in credibility. Blockchain is a potential solution. We therefore propose DCrowd, a Decentralized and Credible crowdsourcing model based on game theory and smart contracts. The workers in DCrowd are organized in a decentralized manner. However, information on the blockchain is open, which may cause data leakage and privacy issues. To tackle the data transparency issue, a commitment scheme is leveraged for data submission among workers. Then, an unbiased random selection algorithm is further designed to select independent workers from the dispersed worker pool to avoid possible collusion. Through the Nash equilibrium principle, it is proved that workers in DCrowd have to perform honestly to maximize their rewards. Finally, the feasibility of our model design is demonstrated through experiments on Ethereum.

Zhang Haiyang, Lei Yu, Duan Yucong

With the development of Internet technology, the number of Web services is growing rapidly, and various types of service recommendation systems emerge in a rapid stream. Although all major service recommendation systems show efficient data processing and service recommendation performance, most of the existing service recommendation systems are developed based on a centralized platform, with functions and data concentrated on a central server. There are still many problems with this over-centralized authority, such as data tamper, data leakage and so on. In response to the above problems, we designed and implemented a service recommendation system based on smart contracts and DIKW (Data, Information, Knowledge and Wisdom). The system data is stored in the blockchain, which effectively prevents data from being tampered. At the same time, the operating environment of the system is the decentralized environment of the Ethereum alliance chain, which overcomes the centralization drawbacks of the traditional service recommendation system and provides a new solution to the existing problems in the service recommendation domain.

Serhii Kozlovskyi

Cryptocurrency has appeared recently but become important part of the global financial sector. Some experts predict that cryptocurrency has changed the world forever because of its utility to transfer payments across borders with little cost or delay. Cryptocurrencies are traded with no broker and tracked on digital ledgers. Dramatic changes in the value of the cryptocurrency attract the investors' attention. Some of the have a one-day trading strategy, other investors construct crypto portfolio for a long time periods. The object of this study is value of Bitcoin, Ethereum, and Litecoin on short time periods and long time periods. The subject of the study is the statistical analysis methods to assess the different cryptocurrencies investment efficiency on the different time periods. The aim of the study is to find out what cryptocurrency strategy is better to use for investors. The analysis is carried out on randomly generated periods for 8 samples cryptocurrencies value. The result of the study allows to state that investor does not need to construct crypto portfolio based on its profitability. An effective strategy is to invest money for long time periods in any cryptocurrencies whose utilities meet the investor's requirements.

Di Zhu, Jianmin Pang, Xin Zhou, Wenjie Han

As the mainstream of smart contract research, most Ethereum smart contracts do not open their source code, and the bytecode of smart contracts has attracted the attention of researchers. Based on the similarity measurement of smart contract bytecode, a series of tasks such as vulnerability mining, contract upgrading and malicious contract detection can be carried out. This paper proposes a method to measure the similarity of smart contract bytecode. Firstly, the key opcode combination of smart contract is summarized. When traversing the CFG(control flow graph) constructed by decompilation of smart contract bytecode, the opcodes in the basic block are pattern matched, and the features between the basic blocks are extracted according to the in-out degree, so as to enhance the similarity measurement effect of contract semantics in vector space. The experimental results show that the proposed method is greatly improved compared with the baseline.

Aqsa Rashid, Asif Masood, Haider Abbas, Yin Zhang⋆

Public Key Infrastructure (PKI) has been considered to be an enabler of secure communication, while, due to its complex and centralized design, there have been instances in the past for Certification Authority's (CA) misbehaving and publishing rogue certificates for targeted attacks. This research aims to present a blockchain-based mechanism that lays down a concrete foundation for creating a transparent and secure block-chain-based mechanism for the issuance and management of digital certificates that enables prevention against CA misbehaving. A prototype is deployed and tested on the Ethereum test network, and the results are made publicly available for verification and validation. As a result, the proposed Ethereum blockchain-based PKI mechanism enables secure, transparent, and auditable issuance and management of digital certificates together with the solution of Sybil, Spoofing, and Man-in-the-Middle (MITM) attacks.

Md Jobair Hossain Faruk, Hossain Shahriar, Maria Valero, Sweta Sneha · 6 authors

Traditional data collection, storage and processing of Electronic Health Records (EHR) utilize centralized techniques that pose several risks of single point of failure and lean the systems to a number of internal and external data breaches that compromise their reliability and availability. Blockchain is an emerging distributed technology that can solve these issues due to its immutability and architectural nature that prevent records manipulation or alterations. In this paper, we discuss the progress and opportunities of remote patient monitoring using futuristic blockchain technologies and its two primary frameworks: Ethereum and Hyperledger Fabric. We also discuss the possible blockchain use cases in software engineering for systematic, disciplined, and quantifiable application development. The study extends by introducing a system architecture for EHR data management using Ethereum as a model. We discuss the challenges and limitations along with the initial evaluation results of the proposed system and draw future research directions in this promising area.

Namrata Thakur, Vinayak D. Shinde

Many implementation of blockchain technology are widely available today. This Project explains how blockchain technology improves efficiency and builds faith in funding process of startup process which affect today’s business and industries. Designing Block chain based a decentralized, distributed ledger, which records transactions or events of funding process in Start-up is discussed.Start –ups facing an issue of raising a required fund. Although there are many sources are available to entrepreneurs who wish to begin new businesses or expand existing ones, like family, friends, friends of friends, bank loan, use of internet, online crowd funding platform and many more. However, to look at the proper distribution and utilization of money and to keep track of it is main problem. This proposed system may provide the solution with blockchain technology for issues related to crowdfunding contract. Through the notion of smart contract automated interaction between and existing transaction system is discussed. A solution for the issues like security, abuse of investor and illegal transactions in crowdfunding process is prompted in this project.The idea behind model is to use ethereum based smart contract for securely and effectively handling connection between fundraisers,vendors and project manager/idea person. Blockchain enabled,distributed platforms is used to avoid fraud and to view proper utilization and distribution of money raised by different contributors.

Gerardo Canfora, Andrea Di Sorbo, Michele Fredella, Anna Vacca · 5 authors

Blockchain is increasingly revolutionizing a variety of sectors, from finance to healthcare. Indeed, the availability of public blockchain platforms, such as Ethereum, has stimulated the development of hundreds of decentralized apps (dApps) that combine smart contract(s) and a front-end user interface. Smart contracts are software, as well, and, as traditional software, they require to be developed and maintained or evolved. Among all the quality properties that must be assessed and guaranteed, readability is a key aspect of source code: a highly readable code facilitates its maintainability, portability, and reusability. This is especially true when considering smart contracts, where code reuse is widely adopted. Indeed, smart contract developers often integrate code portions from other smart contracts in their artifacts. To help developers and researchers more easily estimating and monitoring the code readability of smart contracts, in this demo, we present iSCREAM. iSCREAM automatically inspects Solidity smart contracts and computes a set of metrics that previous research demonstrated being related to code readability. We evaluated iSCREAM on 90 real-world smart contract functions, showing that our tool correctly computes all the aforementioned metrics. Demo webpage: https://github.com/mfredella/iSCREAM

Yue Gao, Jinqiao Shi, Xuebin Wang, Ruisheng Shi · 6 authors

Ethereum is the second-largest cryptocurrency, which is an open-source public blockchain platform with smart contract functionality. With the increasing popularity of Ethereum, considerable attention has been paid to its privacy and anonymity. Previous work in Ethereum deanonymization mostly focused on the analysis of its transaction graph and user behaviors. In this paper, for the first time we explored the feasibility of deanonymizing Ethereum users based on P2P network analysis. By measurement and analysis, we observed that the attacker can make connections with approximately 90% mainnet synced full nodes. Based on the well-connected supernode, the deanonymization experiments with basic estimators preliminarily indicate that the anonymity of Ethereum P2P network is pretty limited. To further improve the effect of deanonymization, we implemented and evaluated a machine learning based estimator, which reduces the influence of network delay on deanonymization and thus increases the success rate to 88%. At last, we provide the discussion about the anonymity and efficiency of the propagation mechanisms.

Yanmei Zhang, Siqian Kang, Wei Dai, Shiping Chen · 5 authors

The prevalence of Bitcoin has attracted a mass of investors into the blockchain ecosystem. Unfortunately, benefiting from its anonymity and immutability, scammers deploy various traps in smart contracts to exploit other participants and seize illegal proceeds. To identify smart Ponzi contracts-a classic fraud widely popular on Ethereum, previous studies present several machine learning-based models with considerable accuracy. However, the performance of their models relies on the behavioral features of smart contracts to a large margin, which are extracted from the transaction records only after a contract has been running for some time. In this paper, we borrow ideas from text feature extraction from Natural Language Processing (NLP) to build a classification model based on an improved CatBoost algorithm. A novel feature extraction pattern is applied in our model to deeply mine the logic of smart contract code. This approach can be used to detect Ponzi schemes at deployment time with improved performance, and thus can avoid the loss of investors originally.

Dong‐Her Shih, Feng-Chuan Huang, Chia-Yi Chieh, Ming‐Hung Shih · 5 authors

With the rapid development of e-commerce services, online retail has evolved from multi-channel to omni-channel in order to provide customers with more services. However, reverse logistics services (returns and exchanges) have become the target of many fraudulent activities, causing a lot of economic losses for many online retail companies. The current challenge of the traditional countermeasure is it requires a lot of manpower and training resources. In this study, we propose ESPRES, a system that adopts blockchain technology to prevent fraudulent behavior in the process of returns and exchanges with the smart contract and multi-attribute decision-support method to help consumers choose a suitable payment program. A practical implication of this study is that by adopting blockchain technology, a great amount of manpower used on determining whether each return or exchange is fraudulent can be reduced since merchants can check the product ownership. In addition, due to the fact that the footprint of goods cannot be forged, it can also prevent counterfeit or parallel imports of goods.

Nikolay Ivanov, Qiben Yan

Hardware wallets are designed to withstand malware attacks by isolating their private keys from the cyberspace, but they are vulnerable to the attacks that fake an address stored in a clipboard. To prevent such attacks, a hardware wallet asks the user to verify the recipient address shown on the wallet display. Since crypto addresses are long sequences of random symbols, their manual verification becomes a difficult task. Consequently, many users of hardware wallets elect to verify only a few symbols in the address, and this can be exploited by an attacker. In this work, we introduce EthClipper, an attack that targets owners of hardware wallets on the Ethereum platform. EthClipper malware queries a distributed database of pre-mined accounts in order to select the address with maximum visual similarity to the original one. We design and implement a EthClipper malware, which we test on Trezor, Ledger, and KeepKey wallets. To deliver computation and storage resources for the attack, we implement a distributed service, ClipperCloud, and test it on different deployment environments. Our evaluation shows that with off-the-shelf PCs and NAS storage, an attacker would be able to mine a database capable of matching 25% of the digits in an address to achieve a 50% chance of finding a fitting fake address. For responsible disclosure, we have contacted the manufactures of the hardware wallets used in the attack evaluation, and they all confirm the danger of EthClipper.

Yulfitno Wingga Pratama, Denny Kurniadi

Elections are a democratic activity in Indonesia which are carried out every five years to elect leaders, but in the process of manual election calculations, the results are leaked and can cause data security problems. Through this research, we can provide solutions by implementing blockchain technology in election applications that will provide security for election results data stored on the blockchain. Blockchain technology is a chain of data blocks that are connected to each other by peer to peer. This application uses the Solidity programming language and uses a local ethereum blockchain database (Ganache). The method used in making this application is the waterfall method with Unified Modeling Language (UML) modeling where the visual modeling method is in object-oriented system design. From the results of testing the blockchain system for this application, it is found that blockchain can help secure election results very securely, where every result data will be stored in every block in a decentralized blockchain network.

J. Sudeep, S. C. Girish, Karthik A. Ganapathi, K. Raghavendra · 6 authors

No abstract is available for this record.

Arman Kolahan, Seyed Reza Maadi, Zahra Teymouri, Corrado Schenone

Smart homes, connected through a network, can optimize the energy consumption and general load shape of their area. In this work, a blockchain-based smart solution is presented for demand-side management of residential buildings in a neighborhood to improve Peaks to Average Ratios (PAR) of power load, reduce energy consumption, and increase the thermal comfort of occupants by modeling heating, illumination, and appliance systems. For real-time power and temperature monitoring of the neighborhood, a transient numerical physical model has been developed. The simulator has been validated with data measured from a building in Northern Italy. Then, a neighborhood with 2,000 households has been modeled for different occupancy patterns, initial values, and boundary conditions. Two different control scenarios, namely basic and smart, have been considered. In the basic scenario, everything is managed by occupants except the boiler, which is controlled by the indoor temperature of the home. Instead, in the smart scenario, a blockchain-based network has been introduced for buildings to exchange a parameter called the Probability of the Next Hour (PNH). Ethereum Solidity has been deployed for smart contract development in the blockchain. The results show that using blockchain-connected smart controllers aimed at demand-side management can improve PAR, comfort level, and energy efficiency of buildings, which can bring about CO2 reduction on an urban and even global scale.

Damien Graux, Sina Mahmoodi

The growing web of data warrants better data management strategies. Data silos are single points of failure and they face availability problems which lead to broken links. Furthermore the dynamic nature of some datasets increases the need for a versioning scheme. In this work, we propose a novel architecture for a linked open data infrastructure, built on open decentralized technologies. IPFS is used for storage and retrieval of data, and the public Ethereum blockchain is used for naming, versioning and storing metadata of datasets. We furthermore exploit two mechanisms for maintaining a collection of relevant, high-quality datasets in a distributed manner in which participants are incentivized. The platform is shown to have a low barrier to entry and censorship-resistance. It benefits from the fault-tolerance of its underlying technologies. Furthermore, we validate the approach by implementing our solution.

G. Divya, P. Supraja

Smart grid is an innovation in a communication network, interconnected power framework, advanced control technology, and smart metering has been applied to work on the usage of renewable energy resources and alleviate the energy emergency somehow. Blockchain is basically a decentralized accounting ledger with the potential to enable, manage, track and verify thousands of energy transactions per second. The blockchain energy market is proposed to be utilized by networks that share a nanogrid. The application permits nanogrid participants that have an abundance of electrical energy, to offer that energy to different clients of the nanogrid. The application gives a decentralized marketplace for executing electrical energy. Since this blockchain energy market is implemented by Ethereum smart contract, it suffers from the high operating costs that result from the contract's high gas consumption. Ethereum smart contracts are implemented by reworking on acceptoffer function to verifies its validity and withdraw function which uses a single function call for multiple energy transfer contracts to decrease the operation cost.