Xue Ling Woo, Kar Kei Boon, Pei Jin Chee, Zing Yi Ngee · 5 authors
This study examines the relationship between the determinants that will affect on the price formation of Bitcoin from period year 2016 Aug 2 to 2018 May 30, which consist of daily data of 239 observations. A theoretical framework is constructed to test on the relationship between the Bitcoin Price determinants with the independent variables which are computational power of Bitcoin miners (hash rate), gold prices, velocity of Bitcoin in circulation (demand-supply fundamentals) and the price of Ethereum as a substitution coin. Autoregressive Distributed Lag (ARDL) is adapted to test on the long run relationship between the determinants. Besides, causality direction, dynamic stability and shocks of the empirical model are examined in this study.
In this study, we investigate the existence of chaos in the global cryptocurrency market. Specifically, we analyze parameters of chaotic order, nonlinearity, sensitivity to the initial conditions, monofractality, and multifractality. For this purpose, we conduct a comprehensive series of tests, including Brock–Dechert–Scheinkman (BDS) test, largest Lyapunov exponent, box-counting, and monogram analysis for fractal dimension, and multiple tests for long-range dependence (Aggregated Variances, Peng, Higuchi, R/S Analysis, and Multifractal Detrended Fluctuation Analysis (MFDFA)). All tests are performed over a variety of major cryptocurrencies: Bitcoin, Litecoin, Ethereum, and Ripple. The empirical results support the existence of chaos in the cryptocurrency market. Accordingly, cryptocurrency returns are not random and follow a chaotic order. Therefore, long term predictions are not possible, contrary to most of the discussions ongoing in the media and the public.
Adrià Rodríguez-Pérez, Pol Valletbó-Montfort, Jordi Cucurull
The transmission and tabulation of results are critical steps in the election process. If election results are provided quickly and transparently, they may inspire trust and confidence in the overall management of the contest. On the contrary, the late and questionable delivery of results might raise concerns and suspicion. In some cases, improper counting and tabulation procedures have brought candidates to question election results and even spurred long periods of violence. In this paper, we explore the potential of blockchain technology to enhance the counting and tabulation procedures during elections. Blockchains are distributed ledgers technologies whose transactions are protected cryptographically. It means that their contents cannot be tampered with nor modified in the long term. We argue that blockchain technology meets the requirements for electronic transmission and consolidation of election results. To prove so, we have implemented a proof of concept with a smart contract running on an Ethereum blockchain that registers the address of several polling stations and records the tally sheets that these submit at the end of the election. We also resort to the smart contract for the automatic and accurate consolidation of the election results once they have been submitted.
We performed the first systematic study of a new attack on Ethereum that steals cryptocurrencies. The attack is due to the unprotected JSON-RPC endpoints existed in Ethereum nodes that could be exploited by attackers to transfer the Ether and ERC20 tokens to attackers-controlled accounts. This study aims to shed light on the attack, including malicious behaviors and profits of attackers. Specifically, we first designed and implemented a honeypot that could capture real attacks in the wild. We then deployed the honeypot and reported results of the collected data in a period of six months. In total, our system captured more than 308 million requests from 1,072 distinct IP addresses. We further grouped attackers into 36 groups with 59 distinct Ethereum accounts. Among them, attackers of 34 groups were stealing the Ether, while other 2 groups were targeting ERC20 tokens. The further behavior analysis showed that attackers were following a three-steps pattern to steal the Ether. Moreover, we observed an interesting type of transaction called zero gas transaction, which has been leveraged by attackers to steal ERC20 tokens. At last, we estimated the overall profits of attackers. To engage the whole community, the dataset of captured attacks is released on https://github.com/zjuicsr/eth-honey.
A. Timofeev, O. Lebedinskaya, Roman Veynberg, A. A. Grigorev
This article presents prospects of the development of cryptocurrency in Russia, examines the principles of the operation of Bitcoin as main currency nowadays and its application in the real economic sector. Identifies and substantiates the advantages and disadvantages of this technology, as a result, the degree of influence of cryptocurrency and the consequences of its usage in the Russian economy. At present, over 1000 types of cryptocurrencies exist. In this paper, two of them are analyzed: the first cryptocurrency, the leader with the stabilized volatility and price: Bitcoin, and rather a new application for cryptocurrency which was skyrocketed as the second world popular: Ethereum. In this research paper we set an objective to compare Bitcoin and Ethereum, determine problems of cryptocurrency market in Russia and the prospects for development of their usage. In addition, authors are describing history of the research subject and trends to develop: from Bitcoin to Ethereum evolution.
Mining is one of the core elements of the proof-of-work based cryptocurrency economy. In this paper we investigate the generic landscape and hierarchy of miners on the example of Ethereum and Zcash, two blockchains that are among the top 5 in terms of USD value of created coins. Both chains used ASIC resistant proofs-of-work which favors GPU mining in order to keep mining decentralized. This however has changed with recent introduction of ASIC miners for these chains. This transition allows us to develop methods that might detect hidden ASIC mining in a chain (if it exists), and to study how the introduction of ASICs effects the decentralization of mining power. Finally, we describe how an attacker might use public blockchain information to invalidate the privacy of miners, deducing the mining hardware of individual miners and their mining rewards.
Paul Ezhilchelvan, Amjad Aldweesh, Aad van Moorsel
Summary The two‐phase commit (2PC) protocol has long been known to have a provably inevitable vulnerability to blocking or non‐progress amidst server crashes, even when the distributed database system guarantees the most demanding timing‐related or “synchrony” requirements. Our aim here is to eliminate this vulnerability by using a blockchain for coordinating 2PC execution. We present the impossibilities, the possibilities, the cost, and the trade‐offs in this blockchain‐based approach to blocking‐free management of distributed transactions. We prove that a non‐blocking and blockchain‐coordinated 2PC protocol can exist only if both the blockchain and distributed database systems meet synchrony requirements; otherwise, although blocking remains eliminated, transactions can unnecessarily abort. We present a blockchain‐coordinated 2PC protocol and provide rigorous arguments for its correctness under the synchrony requirements. We then implement this protocol on the Ethereum Testnet and demonstrate, through our experiments, that the monetary cost of executing smart contracts is quite small, that the protocol performance slows down when using a public blockchain like Ethereum, and that even major violations of synchrony requirements lead only to relatively small increases in unnecessary aborts. We thus identify a trade‐off between improving protocol performance and admitting a risk that transactions could occasionally abort unnecessarily.
Paul Merrill, Thomas H. Austin, Jenil Thakker, Younghee Park · 5 authors
Bitcoin introduced the world to blockchain-based cryptocurrencies, and Ethereum highlighted their value in building distributed applications (dApps). However, the development of blockchain-based applications has been held back by high transaction fees. In this paper, we introduce a model for free transactions on the blockchain. Rather than spending tokens for transaction fees, a token owner (known as a client) locks tokens to generate new tokens as a reward for the miner who includes the transaction in a block. This token-locking reward model eases congestion on the blockchain in the same manner as fees do in protocols like Bitcoin, but without forcing clients to sacrifice their tokens. This same design can be used to incentivize service providers. We show how a client can lock their tokens to generate new tokens for storage providers, and how this reward mechanism can help to facilitate an audit of the storage provider.
Over the past few years, blockchain technology has attracted much attention. The smart contract is a computer program that implements and executes transactions and business logic on the blockchain. Unlike traditional general-purpose programming languages, the modularization techniques of programming languages for the smart contracts are still immature. Specifically, a suitable modularization mechanism for cross-cutting concerns is still not available. From a software engineering perspective, the modularization of cross-cutting concerns is a fundamental issue that can dramatically affect the contracts' maintainability and readability. As a result, reducing the redundant cross-cutting logic is still a challenging task. This paper proposes a practically viable approach that supports Aspect-Oriented Programming (AOP) for smart contract development on Ethereum-based blockchains. We suggest a set of extension to Solidity, a programming language that runs on the Ethereum-based blockchains, that facilitates AOP semantics and behaviors. As a proof of concept, we also realize the weaving module for the extension. The feasibility of the proposed approach is demonstrated by a case study.
Kota Dharma Teja, M Shravani, Chintarlapallireddy Yaswanth Simha, Manjunath R Kounte
Voting is the primary factor to change the country's future. The manual voting got replaced with the electronic machines called Electronic Voting Machines(EVM). Even after replacement, the issues continue to trouble voters. Issues like missing names in voter list, misplaced votes and so on. That is why we suggest a decentralised system to be integrated with the voting system to make it error-free. One of those decentralised systems are blockchain technology. Our project is developed on Ethereum platform using solidity language. Estonia, the blockchain country uses blockchain for almost all services. The voting procedure is presented in the paper as a case study. We summarise the tools used for the project along with its features. We also appraise the working of the our project in the further sections. Finally, we include the source smart contract code in the appendix. This project open up many possibilities to secure the voting system and help for the welfare of the nations.
As of today, web-based social communication platforms, such as WhatsApp, Twitter, or Facebook, are almost exclusively realized via centralized platforms, based on proprietary interfaces, protocols, and data formats. In consequence, even though social communication being a decentralized, peer-to-peer phenomenon, web-based communication today is implemented via closed, proprietary data silos, which not only lock-in users into their service platforms, but also control and own exchange information and data, including personal and sensitive data such as photos, messages, or contact information. In this paper we present Tawki, a decentralized service architecture for social communication. Using Tawki, users remain in full control of their personal data, which is stored and managed by personal data storages. Each data storage is accessible via a unified Tawki API, which allows users to send and request data to and from other users' personal data storages. Following this approach, social communication is again peer-to-peer without involving a third party controlling and monitoring the process. Tawki uses the Ethereum Name Service (ENS) for both the management of user identities and resolving identifiers to the respective user's personal storage location. Leveraging the immutability of the Ethereum Blockchain, identity management and discovery of personal data storages is secured against censorship and control through any third party.
Khalid AlJemy, Mohammed Alanazi, Mohammed AlSofiry, Adeel Baig
Internet of Things (IoT) is the new technology that will change the Internet era in the coming years. IoT can be used in many fields, such as digitally connected factories, facility management, production flow management inventory management, safety, security, health care, logistics, supply chain optimization, and so on. However, due to limited capabilities in IoT, it is impractical to implement extensive security solutions. Also, security standards for IoT are not mature enough. As a result, many security incidents affect IoT reliability. In this paper, we propose an effective security mechanisms that can be implemented to ensure data accuracy and integrity of IoT devices along with considering its limited hardware resources. We implement Blockchain in IoT to enhance IoT security. We apply our approach using the Ethereum protocol by having multiple Raspberry Pi devices connected as peers to the Blockchain. Also, we discuss the implementation and the expected outcome of this project, which is to implement the Access Control List mechanism using Blockchain to improve the overall IoT security and to connect IoT devices to Ethereum as light nodes.
Abdullah Bin Masood, Hassaan Khaliq Qureshi, Syed Muhammad Danish, Marios Lestas
Cyber-physical Systems (CPS) comprise of a network of physically distributed embedded sensors and actuators equipped with computational and communication capability. In CPS, Internet of Things (IoT) devices communicate in a trustless environment as the data can be compromised due to the centralized database, limited power and computational constraints. At the same time, reliability and resiliency are key concerns in CPS in the face of unforeseen circumstances, often emanating from disaster based failures. In this paper, critical issues of centralized database security in CPS are addressed via a distributed blockchain based solution. The proposed system encompasses a smart contract based framework in Ethereum blockchain. It further explores the potential of blockchain in securing and offering a distributed network for the CPS in a closed loop manner. To demonstrate the realizability of the proposed framework, a testbed implementation for the proposed idea is provided. A desktop computer, a laptop, a simple temperature sensor and a Light Emitting Diode (LED) are interfaced in a Peer-to-Peer (P2P) network using Ethereum. The speedy transaction of sensor data in the blockchain at various difficulty levels and actuation through smart contracts enhance the usability of the platform for CPS and various IoT applications.
Mauro C. Argañaraz, Mario Berón, Miguel Alfredo Bustos, Pedro Rangel Henriques · 5 authors
Ethereum es el principal ecosistema basado en blockchain que proporciona un entorno para codificar y ejecutar contratos inteligentes, propiedad que en estos últimos años recibió gran atención por las nuevas aplicaciones comerciales y, también, por la comunidad científica. El proceso de escritura de contratos seguros y de buen desempeño en la plataforma Ethereum es un gran desafío para los desarrolladores. Implica la aplicación de paradigmas de programación no convencionales debido a las características inherentes de la ejecución de programas de computación distribuida. Además, los errores en los contratos desplegados pueden tener graves consecuencias debido al acoplamiento inmediato del código del contrato y las transacciones financieras. El manejo directo de los activos significa que las fallas tienen más probabilidades de ser relevantes para la seguridad y tienen mayores consecuencias económicas que los errores en las aplicaciones típicas. Una serie de reportes de incidentes muestran que los problemas de seguridad se han utilizado con propósitos fraudulentos. En este artículo, se describe una línea de investigación que se enfoca en fortalecer los aspectos de seguridad, basado en una base sólida de diseño, patrones de código establecidos y probados que faciliten el proceso de escritura de código funcional y libre de errores, para proporcionar una herramienta que permita analizar y detectar falencias de manera automática.
Today's online review systems (used largely by hospitality services, internet retailers, government services, etc.) are highly centralized and subject to tampering and manipulation. Implementing a decentralized, trustworthy, unbiased and transparent review system is a major challenge. In this paper, we present a solution that utilizes Ethereum Blockchain, Smart Contracts, and IPFS to provide a secure, transparent and trusted platform for an online review system with high integrity and resiliency. We discuss key aspects related to architectural design, interactions between system components, algorithms and logic flow. We also show how we implemented and tested the overall system functionalities. Furthermore, we provide vulnerability analysis of the smart contract code. The full smart contract code was made publicly available at Github.
The great market success of Blockchain makes it an extremely valuable target for attackers. A well-known attack in Blockchain is the forking attack, where divergent blockchains are produced for inserting some new features to facilitate security breaches. The state-of-the-art works mostly focus on how to detect attacks in real-time transactions, which is in hindsight and cannot deter the forking attack from the root. To take precautions, we employ the large deviation theory to study the vulnerability of blockchain networks incurred by intentional forks from a micro point of view, boosting forward-looking and strategic planning mechanisms for resisting the forking attack. Our study is fine-grained, because it offers not only the vulnerability probability of a blockchain network but also its decay speed, through which we find setting the parameter related to the robust level has more power than enhancing the computer power in speeding up the failure of attacks. This finding is valuable since it renders an opportunity to improve the robustness of a blockchain network in a cost-efficient way. Our analysis is complementary, since it studies both the impacts of the computational power as well as the number of confirmations on the vulnerability of a blockchain network, providing a theoretical basis to design reasonable schemes for invigorating a blockchain network from technical as well as managerial levels. Extensive experiments carried out on a large-scale cloud platform running the Ethereum protocol show the experimental and analytical results match well, verifying the effectiveness of our analysis.
Cryptocurrencies are developed as a decentralized and trustless payment system, in which participants should be able to conduct payments across borders with acceptable latency. However, the fluctuation of the exchange rate between crypto and fiat currencies has raised significant concerns and thwarted the prevalence of cryptocurrency payment adoption. Existing solutions require merchants to liquidate the received cryptocurrency on an exchange platform. To compensate for the exchange rate risk, merchants tend to charge a higher price in cryptocurrencies compare to in fiat currency, which dampens the incentive of customers to choose cryptocurrencies as the means of payment. This paper proposes an architecture bolstered by smart contracts to transfer the risk from the merchants to the cryptocurrency issuer. This narrows the gap between prices denominated in cryptocurrencies and fiat currencies, and thus increases the adoption of cryptocurrencies as a payment method. The Ethereum blockchain is chosen as the experimental environment in this work, yet the architecture can be migrated to other decentralized systems without additional efforts. This work devises a novel ERC1standard to resolve the payment at a predetermined exchange rate that can be employed by any existing cryptocurrency. Immutable events on the blockchain will be generated upon the issuance and settlement of a payment, which are considered as the receipts for granting rights to the merchants to settle the payment at a regular basis. The architecture demonstrates a notable reduction on the exchange rate risk for the merchants, solving the primary problem of cryptocurrency payment adoptions nowadays.
Blockchain, as the underlying technique of cryptocurrency, has triggered a wave of innovation in decentralized computing. Despite some research on blockchain data query, a primary concern for blockchain to be fully practical is to combat the data query inefficiency and query result authenticity. To provide both efficient and verifiable data query services for blockchain-based systems, we propose a Verifiable Query Layer (VQL). The middleware layer extracts transactions stored in the underlying blockchain system and efficiently reorganizes them in databases to provide various query services for public users. To prevent falsified data being stored in the middleware, a cryptographic hash value is calculated for each constructed database. The database fingerprint including the hash value and some database properties will be first verified by miners and then stored in the blockchain. We implement VQL and conduct extensive experiments based on a practical blockchain system Ethereum. The evaluation results demonstrate that VQL can effectively support various data query services and guarantee the authenticity of query results for the blockchain system.
Traditional cloud Service Level Agreement (SLA) suffers from lacking a trustworthy platform for automatic enforcement. The emerging blockchain technique brings in an immutable solution for tracking transactions among business partners. However, it is still very challenging to prove the credibility of possible violations in the SLA before recording them onto the blockchain. To tackle this challenge, we propose a witness model using game theory and the smart contract techniques. The proposed model extends the existing service model with a new role called “witness” for detecting and reporting service violations. Witnesses gain revenue as an incentive for performing these duties, and the payoff function is carefully designed in a way that trustworthiness is guaranteed: in order to get the maximum profit, the witness has to always tell the truth. This is analyzed and proved through game theory using the Nash equilibrium principle. In addition, an unbiased sortition algorithm is proposed to ensure the randomness of the independent witnesses selection from the decentralized witness pool, to avoid possible unfairness or collusion. An auditing mechanism is also introduced in the paper to detect potential irrational or malicious witnesses. We have prototyped the system leveraging the smart contracts of Ethereum blockchain. Experimental results demonstrate the feasibility of the proposed model and indicate good performance in accordance with the design expectations.
We present models that utilize smart contracts and interledger mechanisms to provide decentralized authorization for constrained IoT devices. The models involve different tradeoffs in terms of cost, delay, complexity, and privacy, while exploiting key advantages of smart contracts and multiple blockchains that communicate with interledger mechanisms. These include immutably recording hashes of authorization information and policies in smart contracts, resilience through the execution of smart contract code on all blockchain nodes, and cryptographically linking transactions and IoT events recorded on different blockchains using hash and time-lock mechanisms. The proposed models are evaluated on the public Ethereum testnets Rinkeby and Ropsten, in terms of execution cost (gas), delay, and reduction of data that needs to be sent to the constrained IoT devices.
Distributed Ledger Technologies and particularly Blockchain-based Decentralized Applications entail transaction data from various use cases and usage behaviors in a decentralized manner. In this context, we propose to apply Process Mining as a means to understand and quantify how a Distributed Ledger is de facto utilized. This paper introduces a heuristic Process Mining approach for extracting high level process structures from Distributed Ledgers and Decentralized Applications, which can also represent changes over time. The universal approach is demonstrated on the basis of the complete set of all transactions that happened on the Ethereum Blockchain during its first three years. Events, cases, and activities allow to compile an evolutionary time line, which shows the Blockchain evolving from its early stages to broader adoption. Furthermore, measures of activity significance, confidence, and process complexity are used to compile dependency graphs, which represent process transitions.
Blockchain is the core technology underlying the first decentralized cryptocurrency, Bitcoin, introduced by Nakamoto in 2008. Since then, blockchain technology has many more advancements that are being developed and experimented. In particular, recent blockchain platforms such as Ethereum offer general and executable scripts, namely smart contracts, that can be employed to develop decentralized applications (DApps) in many domains beyond payment. However, the transparency of blockchain data raises concerns for many applications that require high privacy level. Therefore, many privacy enhancing technologies have been applied to DApp development, including zero knowledge proof (ZKP). This paper focuses on a particular kind of ZKP, called zero knowledge range proof (ZKRP), that has been applied in blockchain-based payments for banks. ZKRP allows a user to convince other people that a secret value actually lies within an interval without revealing any information about the secret. Here we introduce a new ZKRP which has the following remarkable features: (1) Non-interactive: No communication is required between a user and a verifier during the proof. (2) Range-flexibility: There is no limitation on the lower bound and the upper bound of the range except that they are natural numbers. (3) Efficiency: Our scheme is modified from that of Pang et al. (2010), yet achieves better security and is more efficient than their scheme. We believe our new ZKRP can be beneficial to the development of DApps and can extend the application scope to more scenarios.
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Smart Contracts bring Ethereum transactions great convenience, meanwhile they can have potentially devastating financial consequences. To address the lack of security guarantee, we investigate state-of-art bug detection tools and conduct experiments to analyze their pros and cons. Finally, we conduct research to answer why they have false positives and a convincing bug benchmark is provided.