Blockchain Papers

A. Priyadharshini, M. Prasad, R. Joshua Samuel Raj, S. Geetha

No abstract is available for this record.

Chun Kwong Koo, Artur Semeyutin, Chi Keung Marco Lau, Jian Fu

We study the tails’ behavior of four major Cryptocurrencies (Bitcoin, Litecoin, Ethereum and Ripple) by employing the Autoregressive Fr´echet model for conditional maxima. Using five-minute-high-frequency data, we report time-evolving tails as well as provide a straightforward measure of tails asymmetry for positive and negative intra-day returns. We find that only Bitcoin has a notable more massive tail for positive returns asymmetry while the remaining three Cryptocurrencies have a general tendency towards more massive negative intra-day tails. All considered Cryptocurrencies depict lighter tails as the market matures.

Shreya Khatal, Jayant Rane, Dhiren Patel, Pearl Patel · 5 authors

No abstract is available for this record.

Jacopo Grecuccio, Edoardo Giusto, Fabio Fiori, Maurizio Rebaudengo

Recently, the interest around the Blockchain concept has grown faster and, as a consequence, several studies about the possibility of exploiting such technology in different application domains have been conducted. Most of these studies highlighted the benefits that the use of the blockchain could bring in those contexts where integrity and authenticity of the data are important, e.g., for reasons linked to regulations about consumers’ healthcare. In such cases, it would be important to collect data, coming in real-time through sensors, and then store them in the blockchain, so that they can become immutable and tamper-proof. In this paper, the design and development of a software framework that allows Internet-of-Things (IoT) devices to interact directly with an Ethereum-based blockchain are reported. The proposed solution represents an alternative way for integrating a wide category of IoT devices without relying on a centralized intermediary and third-party services. The main application scenario for which the project has been conceived regards food-chain traceability in the Industry 4.0 domain. Indeed, the designed system has been integrated into the depiction of a use case for monitoring the temperature of fish products within a warehouse and during the delivery process.

Emre Deniz, Dilek Teker

Purpose-As the cryptocurrency market is beginning to attract investors, a new portfolio of cryptocurrencies has been published in the literature on macro-economic factors affecting these currencies. This research also aimed to identify the interaction between gold, brent oil, Bitcoin, Ethereum and Ripple. Methodology-The database includes the Daily prices of Bitcoin, Ethereum, Ripple, gold and brent oil prices between the period of 03.04.2018-31.12.2020 which consist of 500 daily data. Natural logaritm for each indicator is used. First, the stationarity of the series were analyzed with ADF (Augmented Dickey Fuller) unit root test. Lag lengths are determined. Interactions between the series were analyzed by the Johansen Cointegration test, Granger Causality test, Impulse-Response Function and Variance Decomposition method. Findings-The series are found out to be stationary at first difference. According to the cointegration test result, cointegration could not be found between our data. According to Granger causality analysis, only one-way relationship was found from bitcoin to gold. Impulse response graphs indicate that all variables respond in a reducing way to reducing shocks occurred in each indicator. Shocks have lost their effect on average in 2 days.

Venelina Nikolova, Juan Evangelista Trinidad Segovia, M. Fernández–Martínez, M.A. Sánchez-Granero

One of the main characteristics of cryptocurrencies is the high volatility of their exchange rates. In a previous work, the authors found that a process with volatility clusters displays a volatility series with a high Hurst exponent. In this paper, we provide a novel methodology to calculate the probability of volatility clusters with a special emphasis on cryptocurrencies. With this aim, we calculate the Hurst exponent of a volatility series by means of the FD4 approach. An explicit criterion to computationally determine whether there exist volatility clusters of a fixed size is described. We found that the probabilities of volatility clusters of an index (S&P500) and a stock (Apple) showed a similar profile, whereas the probability of volatility clusters of a forex pair (Euro/USD) became quite lower. On the other hand, a similar profile appeared for Bitcoin/USD, Ethereum/USD, and Ripple/USD cryptocurrencies, with the probabilities of volatility clusters of all such cryptocurrencies being much greater than the ones of the three traditional assets. Our results suggest that the volatility in cryptocurrencies changes faster than in traditional assets, and much faster than in forex pairs.

Zhenghui Li, Yan Wang, Zhehao Huang

This paper examines the risk connectedness across the seven cryptocurrencies, Bitcoin, Ethereum, Ripple, Litecoin, Stellar, Monero and Dash, who admit large capitalizations in the cryptocurrency market. The data sample is from August 7, 2015 to February 15, 2020. We apply the CAViaR model to measure the return risks of the cryptocurrencies, showing their similar risk tendencies with volatility clusterings during the beginning of 2017 and the end of 2018. The net pairwise spillover index developed by Diebold and Yilmaz (2012) is use as the measure for the risk connectedness among the cryptocurrencies. We find that the risk spillover directions are highly correlative with the capitalizations of the cryptocurrencies. The cryptocurrencies with small capitalizations transmit risks to those with large cryptocurrencies. In the risk downward tendency, the risk spillover levels among the cryptocurrencies are stronger than that in the risk upward tendency, while the spillover directions keep the same in both risk tendencies, except the cryptocurrency Monero, which may be due to the trading volume difference from the others. We use the generalized forecast error variance decomposition for the spillover index and explore the risk connectedness across the cryptocurrencies in differen time frequencies, including the short term (0-4 days), medium term (4-30 days) and long term (30-300 days) frequency. The risk spillovers in the short term frequency can be neglected, which implies the delay effects of risk spillovers. The risk spillovers in medium term frequency are mostly stronger than that in long term frequency. The dynamic connectedness result shows the risk spillover mean in the long term frequency is larger than that in the medium term frequency. An inverse result holds for the risk spillover range. The risk spillover fluctuations in the long and medium term frequency admit the coincident comparison for spillover levels in these two frequencies. The findings in this paper provide suggestions for regulators controlling the market stability and investors generating investment strategies.

Silvia Bartolucci, Giuseppe Destefanis, Marco Ortu, Nicola Uras · 6 authors

Abstract The network of developers in distributed ledgers and blockchains open source projects is essential to maintaining the platform: understanding the structure of their exchanges, analysing their activity and its quality (e.g. issues resolution times, politeness in comments) is important to determine how “healthy” and efficient a project is. The quality of a project affects the trust in the platform, and therefore the value of the digital tokens exchanged over it. In this paper, we investigate whether developers’ emotions can effectively provide insights that can improve the prediction of the price of tokens. We consider developers’ comments and activity for two major blockchain projects, namely Ethereum and Bitcoin, extracted from Github. We measure sentiment and emotions (joy, love, anger, etc.) of the developers’ comments over time, and test the corresponding time series (i.e. the affect time series ) for correlations and causality with the Bitcoin/Ethereum time series of prices. Our analysis shows the existence of a Granger-causality between the time series of developers’ emotions and Bitcoin/Ethereum price. Moreover, using an artificial recurrent neural network (LSTM), we can show that the Root Mean Square Error (RMSE)—associated with the prediction of the prices of cryptocurrencies—significantly decreases when including the affect time series.

Hyun-Ji Chu, Byoungju Choi

최근 블록체인 기반의 소프트웨어가 점차 복잡하고 다양하게 개발되고 있다. 이러한 블록체인 기반 소프트웨어의 기능적 측면에서의 신뢰성을 보장하기 위해 개발 단계에서 엄격한 테스트를 거치도록 요구되고 있으며, 이를 지원하는 다양한 정적 분석 도구 및 동적 테스트 도구가 개발되고 있다. 그러나 전자의 경우엔 실제로 런타임 중에 발생 가능한 잠재적인 문제들을 발견하기 어렵다는 문제가 있으며, 후자의 경우엔 여러 이더리움 계정이 얽힌 통합 테스트의 용도로 활용하기 쉽지 않다는 한계가 있다. 이에 본 연구에서는 테스트 항목을 자동으로 정의하여 테스트 데이터로 만들어주고, 스마트 컨트랙트 개발자가 이를 활용해 스마트 컨트랙트 코드가 설계 모델과 같게 동작하는지 확인할 수 있도록 하는 로그 기반의 이더리움 스마트 컨트랙트 동적 테스트 도구 LESTT를 제안하며, 이더리움 지갑 스마트 컨트랙트 시스템 예제를 통해 그 적용 사례를 보인다.

Javad Ghofrani, Kirill Loisha, Dirk Reichelt

In the next few years, Blockchain will playa central role in IoT as a technology. It enables the traceability of processes between multiple parties independent of a central instance. Blockchain allows to make the processes more transparent, cheaper, and safer. This research paper was conducted as systematic literature search. Our aim is to understand current state of implementation in context of Blockchain Technology for digital protection of communication in industrial cyber-physical systems. We have extracted 28 primary papers from scientific databases and classified into different categories using visualizations. The results show that the focus in around 14% papers is on solution proposal and implementation of use cases Secure transfer of order data using Ethereum Blockchain, 7% papers applying Hyperledger Fabric and Multichain. The majority of research (around 43%) is focusing on solution development for supply chain and process traceability.

Alberto García-Martínez, Stefano Angieri, Bingyang Liu, Fei Yang · 5 authors

The current mechanism to secure Border Gateway Protocol relies on the resource public key infrastructure (RPKI) for route origin authorization. The RPKI implements a hierarchical model that intrinsically makes lower layers in the hierarchy susceptible to errors and abuses from entities placed in higher layers. In this article, we present InBlock, a distributed autonomous organization that provides decentralized management of IP addresses based on blockchain, embedding an alternative trust model to the hierarchical one currently implemented by the RPKI. By leveraging on blockchain technology, InBlock requires consensus among the involved parties to change existent prefix allocation information. InBlock also fulfills the same objectives as the current IP address allocation system, i.e., uniqueness, fairness, conservation, aggregation, registration, and minimized overhead. InBlock is implemented as a set of blockchain smart contracts in Ethereum, performing all the functions needed for the management of a global pool of addresses without human intervention. Any entity may request an allocation of addresses to the InBlock registry by solely performing a (crypto) currency transfer to the InBlock. We describe our InBlock implementation and we perform several experiments to show that it enables fast address registering and incurs in very low management costs.

Daniel Liebau, Thomas Lambert, Peter Roosenboom

The years 2017 and 2018 saw an influx of ventures raising substantial amounts of money through initial coin offerings (ICOs). The Ethereum blockchain greatly facilitated the spectacular surge of ICOs, even though utility tokens and cryptocurrencies are not primarily meant for raising external capital for start-up firms. Now that the ICO market bubble ebbed away security token offerings (STOs) have emerged, allowing investment in regulated securities recorded on a blockchain. Blockchain Capital paved the way with its crowd sale of equity tokens on a blockchain in April 2017. In August 2018, tZERO successfully completed the largest STO thus far, raising USD 134 million. More recently, in April 2019, Societe Generale SFH issued and settled covered bonds worth over USD 100 million as a security token. While the literature has succeeded in providing many insights about the gains and losses in both ICO and cryptocurrency markets, much less is known about this nascent STO market.

Yue Wang, Jiguo Yu, Biwei Yan, Guijuan Wang · 5 authors

No abstract is available for this record.

Richard Richard, Yaya Heryadi, Lukas Lukas, Agung Trisetyarso

No abstract is available for this record.

Daojing He, Zhi Wen Deng, Yuxing Zhang, Sammy Chan · 6 authors

Ethereum started the blockchain-based smart contract technology that due to its scalability more and more decentralized applications are now based on. On the downside this has led to the exposure of more and more security issues and challenges, which has gained widespread attention in terms of research in the field of Ethereum smart contract vulnerabilities in both academia and industry. This article presents a survey of the Ethereum smart contract's various vulnerabilities and the corresponding defense mechanisms that have been applied to combat them. In particular, we focus on the random number vulnerability in the Fomo3d-like game contracts, as well as that attack and defense methods applied. Finally, we summarize the existing Ethereum smart contract security audit methods and compare several mainstream audit tools from various perspectives.

Laura Barbera

L'influenza delle criptovalute sull'economia globale sta crescendo anno dopo anno. Anche i piu scettici si sono dovuti ricredere e, in qualche modo, considerare il fenomeno come un vero e proprio cambiamento epocale. Un primo obiettivo di questo studio e cogliere motivazioni storiche, culturali e innovazioni che hanno accompagnato questo nuovo paradigma. Inoltre, lo sviluppo del seguente lavoro di tesi si pone l'obiettivo di indagare da un punto di vista tecnico gli strumenti crittografici (funzione hash, firma digitale, protocollo di Timestamp, meccanismi di consenso, Blockchain) che hanno permesso l'esplosione nel mondo delle criptovalute, mettendoli a confronto. Senza la loro solidita e maturita storica i protocolli sarebbero stati facilmente attaccati e nessuno si sarebbe sentito sicuro ad affidarvi il proprio investimento. Nello specifico si sono analizzate nel dettaglio le Blockchain delle criptovalute che e possibile acquistare e vendere tramite il portale di Young Platform, azienda con cui si e collaborato nella stesura del presente progetto. Da Bitcoin tutto ha avuto origine; ancora oggi e la prima e piu influente valuta sul mercato e come tale ha richiesto una trattazione assestante. Seguono Ethereum, Ripple, Litecoin, Stellar, Algorand, solo alcune delle valute digitali piu capitalizzate e che dunque catturano l'interesse di tanti investitori in tutto il mondo. Nel Capitolo 2 sono state presentate evidenziandone le somiglianze e i punti di distacco da Bitcoin. La seconda parte tratta argomentazioni di tipo statistico/economico cercando di far luce su aspetti interni al mercato delle criptovalute in modo da approcciarsi consapevolmente ad un mercato tanto interessante quanto estremamente rischioso. Relazioni interne ed esterne, confronti di sicurezza e privacy sono alcune delle tematiche affrontate. Nell'ultima sezione si trattano le Stablecoin, una differente prospettiva per l'utilizzo di valute digitali come mezzo di pagamento giornaliero. In particolare USD Coin e PaxGold, valute che e possibile scambiare su Young Platform. Il lavoro si conclude con un accenno alla Decentralized Finance, frontiera della Blockchain 2.0 e dunque basata su crypto-assets, un nuovo modo di gestire le proprie finanze in maniera indipendente, senza intermediari e con grandi benefici.

Runkai Yang, Xiaolin Chang, Jelena Mišić, Vojislav B. Mišić

No abstract is available for this record.

Anum Nawaz, Jorge Peña Queralta, Jixin Guan, Muhammad Awais · 8 authors

With an increasing penetration of ubiquitous connectivity, the amount of data describing the actions of end-users has been increasing dramatically, both within the domain of the Internet of Things (IoT) and other smart devices. This has led to more awareness of users in terms of protecting personal data. Within the IoT, there is a growing number of peer-to-peer (P2P) transactions, increasing the exposure to security vulnerabilities, and the risk of cyberattacks. Blockchain technology has been explored as middleware in P2P transactions, but existing solutions have mainly focused on providing a safe environment for data trade without considering potential changes in interaction topologies. we present EdgeBoT, a proof-of-concept smart contracts based platform for the IoT built on top of the ethereum blockchain. With the Blockchain of Things (BoT) at the edge of the network, EdgeBoT enables a wider variety of interaction topologies between nodes in the network and external services while guaranteeing ownership of data and end users' privacy. in EdgeBoT, edge devices trade their data directly with third parties and without the need of intermediaries. This opens the door to new interaction modalities, in which data producers at the edge grant access to batches of their data to different third parties. Leveraging the immutability properties of blockchains, together with the distributed nature of smart contracts, data owners can audit and are aware of all transactions that have occurred with their data. we report initial results demonstrating the potential of EdgeBoT within the IoT. we show that integrating our solutions on top of existing IoT systems has a relatively small footprint in terms of computational resource usage, but a significant impact on the protection of data ownership and management of data trade.

Suman Mann, Tanya Jain, Aakash Vyas

Perhaps the most advanced application of the distributed ledger technology (DLT), the Blockchain is a decentralized system that is known to store immutable metadata with the use of robust cryptographic hashes and consensus mechanisms. The very foundation of the Blockchain is the establishment of trust-less transactions in peer-to-peer networks. Having been deemed to set off a whirlwind in Industry 4.0 as we know it and starting out with the groundbreaking Bitcoin, this relatively new technology is on the way to prove that it can find applications in almost every imaginable sector. While most people focus only on cryptocurrencies; this disruptive technology, in fact, offers utilities to many administrative operations, fintech procedures, and everyday services which could earlier only be done offline and/or in person, that can now be safely moved to the Internet as Software as a Service (SaaS) models. What makes Blockchain a powerful tool for digitalizing everyday facilities is the introduction of smart contracts, as brought forward foremost by the Ethereum platform. Considering today"s technology, Blockchain may create one of the most prominent alternatives to traditional voting in terms of security, consistency and speed. The Blockchain technology, fortified by Smart Contracts, enables enhanced data verifiability and lowered costs while maintaining the openness and transparency of the voting process. The anonymity of voters, the security of ballot transmission and the veracity of votes during the billing phase are the most fundamental requirements for voting. In this paper, a potential use case of Blockchain, an E-Voting protocol, is proposed, that utilizes the Blockchain as a transparent ballot box to cast votes.

Van-Duy Pham, Canh-Tuan Tran, Thang Trung Nguyen, Tien-Thao Nguyen · 7 authors

In recent years, centralized storage systems have been extensively adopted by many companies, organizations, and individuals for storing and sharing data. These systems, however, make concerns for users of a single point of failure and the involvement of a centralized entity or third party. Therefore, there is a need for developing decentralized storage systems to overcome the drawbacks of traditional approach. In order to enhance secure and transparent characteristics of decentralized storage systems, in this paper, we present a combination of IPFS (InterPlanetary File System), ABE (Attribute-based Encryption), Multi-Authority ABE (MA-ABE), and Ethereum blockchain. In particular, we facilitate the advantages of IPFS network to store user's data in a distributed manner. Furthermore, we make the use of MA-ABE to encrypt a document, which an user needs to share it among multiple organizations. The hash returned by the IPFS network will be stored in the Ethereum blockchain network to provide trustworthy for all users participating in our system. To the best of our knowledge, it is the first storage system using IPFS, ABE, MA-ABE, and blockchain technologies together to ensure decentralized, secure, and transparent characteristics for storing and sharing data.

Xiaodong Qi, Yin Yang, Zhao Zhang, Cheqing Jin · 5 authors

This paper presents LinSBFT, a Byzantine Fault Tolerance (BFT) protocol with the capacity of processing over 2000 smart contract transactions per second in production. LinSBFT applies to a permissionless, public blockchain system, in which there is no public-key infrastructure, based on the classic PBFT with 4 improvements: (\romannumeral1) LinSBFT achieves $O(n)$ worst-case communication volume, in contract to PBFT's $O(n^4)$; (\romannumeral2) LinSBFT rotates the leader of protocol randomly to reduce the risk of denial-of-service attacks on leader; and (\romannumeral3) each run of LinSBFT finalizes one block, which is robust against participants that are honest in one run of the protocol, and dishonest in another, and the set of participants is dynamic, which is update periodically. (\romannumeral4) LinSBFT helps the delayed nodes to catch up via a synchronization mechanism to promise the liveness. Further, in the ordinary case, LinSBFT involves only a single round of voting instead of two in PBFT, which reduces both communication overhead and confirmation time, and employs the \emph{proof-of-stake} scheme to reward all participants. Extensive experiments using data obtained from the Ethereum demonstrate that LinSBFT consistently and significantly outperforms existing in-production BFT protocols for blockchains.

Rateb Jabbar, Mohamed Kharbeche, Khalifa N. Al‐Khalifa, Moez Krichen · 5 authors

The concept of smart cities has become prominent in modern metropolises due to the emergence of embedded and connected smart devices, systems, and technologies. They have enabled the connection of every "thing" to the Internet. Therefore, in the upcoming era of the Internet of Things, the Internet of Vehicles (IoV) will play a crucial role in newly developed smart cities. The IoV has the potential to solve various traffic and road safety problems effectively in order to prevent fatal crashes. However, a particular challenge in the IoV, especially in Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications, is to ensure fast, secure transmission and accurate recording of the data. In order to overcome these challenges, this work is adapting Blockchain technology for real time application (RTA) to solve Vehicle-to-Everything (V2X) communications problems. Therefore, the main novelty of this paper is to develop a Blockchain-based IoT system in order to establish secure communication and create an entirely decentralized cloud computing platform. Moreover, the authors qualitatively tested the performance and resilience of the proposed system against common security attacks. Computational tests showed that the proposed solution solved the main challenges of Vehicle-to-X (V2X) communications such as security, centralization, and lack of privacy. In addition, it guaranteed an easy data exchange between different actors of intelligent transportation systems.

Guoxiong Su, Wenyuan Yang, Zhengding Luo, Yinghong Zhang · 6 authors

The need for data trading promotes the emergence of data market. However, in conventional data markets, both data buyers and data sellers have to use a centralized trading platform which might be dishonest. A dishonest centralized trading platform may steal and resell the data seller's data, or may refuse to send data after receiving payment from the data buyer. It seriously affects the fair data transaction and harm the interests of both parties to the transaction. To address this issue, we propose a novel blockchain-based data trading framework with Trusted Execution Environment (TEE) to provide a trusted decentralized platform for fair data trading. In our design, a blockchain network is proposed to realize the payments from data buyers to data sellers, and a trusted exchange is built by using a TEE for the first time to achieve fair data transmission. With these help, data buyers and data sellers can conduct transactions directly. We implement our proposed framework on Ethereum and Intel SGX, security analysis and experimental results have demonstrated that the framework proposed can effectively guarantee the fair completion of data tradings.

Blaž Bagić

Ovaj rad nadograđuje alat za statičku analizu pametnih ugovora, Slither, sa novim detektorom za ranjivost zvanu umetanje ispred (eng. front running). Rad opisuje provedeno istraživanje potrebno za stvaranje početne hipoteze o načinu kojim će se moći detektirati umetanje ispred. Koraci implementacije novog detektora su dani zajedno sa poglavljem o provedenim eksperimentima i njihovim rezultatima. Implementirano rješenje ima određene mane, za koje postoji poglavlje u kojemu se diskutira o tome što se i kako može unaprijediti da bi se ostvarilo bolje rješenje.