Smart contract (SC) platforms form blocks of transactions into a chain and execute them via user-defined smart contracts. In conventional platforms like Bitcoin and Ethereum, the transactions within a block are executed \emph{sequentially} by the miner and are then validated \emph{sequentially} by the validators to reach consensus about the final state of the block. In order to leverage the advances of multicores, this paper explores the next generation of smart contract platforms that enables concurrent execution of such contracts. Reasoning about the validity of the object states is challenging in concurrent smart contracts. We examine a programming model to support \emph{optimistic} execution of SCTs. We introduce a novel programming language, so-called OV, and a Solidity API to ease programing of optimistic smart contracts. OV language together with static checking will help reasoning about a crucial property of optimistically executed smart contracts -- the validity of object states in trustless systems.
In recent years blockchain technology has become mainstream research topic because of its decentralized, peer to peer transaction and anonymity properties. There are several applications of blockchain which are secure and easy as compare to the current techniques. One of the applications is a smart contract. Smart contracts are lines of code which are stored on a blockchain and automatically executed when the conditions defined by the it (developer) are met. This smart contract with the addition of blockchain technology can do task fast and with high security. In this paper we have developed a smart contract for a generalized notary application on solidity, Ethereum and the application is tested using the truffle suite. Furthermore, applications and their methodology for notary applications are also mentioned.
Designing an efficient difficulty control algorithm is an essential problem in Proof-of-Work (PoW) based blockchains because the network hash rate is randomly changing. This paper proposes a general difficulty control algorithm and provides insights for difficulty adjustment rules for PoW based blockchains. The proposed algorithm consists a two-layer neural network. It has low memory cost, meanwhile satisfying the fast-updating and low volatility requirements for difficulty adjustment. Real data from Ethereum are used in the simulations to prove that the proposed algorithm has better performance for the control of the block difficulty.
Long before the creation of blockchain platforms, the rise of personal computing and Internet connectivity brought with it a digital, online dimension of the material world, leading to the socio-technical construct known as ‘digital identity’. After the online discussion boards and emailing lists of the early 90s, individuals started socializing via the Internet more predominantly using social networks. One specific type of platform links this online socializing and transacting to blockchain-based spaces: dark web marketplaces. Identified as second-generation cryptocommunities, dark web marketplaces deployed cryptography for the use of pseudonymous identity, for communication, but also currency. This paper explores two questions in this fascinating space: what was the role of identity on the Silk Road, and what governance lessons can be drawn from this illustration for the purpose of applying them to more recent cybercommunities such as Ethereum? The paper is structured as follows. The first part describes the Silk Road and sketches its essential characteristics. The second part looks at how individuals could become platform users on the Silk Road, by analyzing the contractual relationship between the Silk Road and an individual user based on the rights and obligations enshrined in the Silk Road Terms of Service (ToS). The third part critically reflects on arbitrariness as the main pitfall arising out of the private regulatory framework created by the Silk Road, and contributes to existing narratives surrounding the regulatory nature of code by proposing a code-as-procedure perspective for analyzing this regulatory framework. Part four concludes.
of-ethereum-92b543594e84 [https://perma.cc/BWZ2-6PJE].2 In terms of reporting and withholding, the same problems arise in the cash economy, which is responsible for a significant amount of noncompliance with tax laws around the world.But in terms of the identification of reportable transactions, there may be base defining issues.The
Muhammed Siraj, Mohd Izuan Hafez Ninggal, Nur Izura Udzir, Muhammad Daniel Hafiz Abdullah · 5 authors
Sensitive records stored in the cloud such as healthcare records, private conversation and credit card information are targets of hackers and privacy abuse. Current information and record management systems have difficulties achieving privacy protection of such sensitive records in a secure, transparent, decentralized and trustless environment. The Blockchain technology is a nascent and a promising technology that facilitates data sharing and access in a secure, decentralized and trustless environment. The technology enables the use of smart contracts that can be leveraged to complement existing traditional systems to achieve security objectives that were never possible before. In this paper, we propose a framework based on Blockchain technology to enable privacy-preservation in a secured, decentralized, transparent and trustless environment. We name our framework SmartCoAuth. It is based on Ethereum Smart Contract functions as the secure, decentralized, transparent authentication and authorization mechanism in the framework. It also enables tamper-proof auditing of access to the protected records. We analysed how SmartCoAuth could be integrated into a cloud application to provide reliable privacy-preservation among stakeholders of healthcare records stored in the cloud. The proposed framework provides a satisfactory level of data utility and privacy preservation.
Badr Eddine Sabir, Mohamed Youssfi, Omar Bouattane, Hakim Allali
The Internet of Things (IoT) is becoming an indispensable part of the actual Internet and continues to extend deeper into the daily lives of people, offering distributed and critical services. Mobile agents are widely used in the context of IoT and due to the possibility of transmitting their execution status from one device to another in an IoT network, they offer many advantages such as reducing network load, encapsulating protocols, exceeding network latency, etc. Also, Blockchain Technology is growing rapidly allowing for the addition of an approved security layer in many areas. Security issues related to mobile agent migration can be resolved with the use of Blockchain. This paper aims to demonstrate how Blockchain Technology can be used to secure mobile agents in the context of the IoT using Ethereum and a Smart Contract. The transactions within the Blockchain are used to detect the malevolent mobile agents that could infiltrate the IoT systems. The proposed model aims to provide a secure migration of mobile agents to ensure security and protect the IoT applications against malevolent agents. The case of a smart home with multiple applications is applied to verify the proposed solution. The model presented in this paper could be extended to a wider selection of IoT systems outside of the smart home.
Francesco Buccafurri, Vincenzo De Angelis, Roberto Nardone
The Internet of Things is constantly capturing interest from modern applications, changing our everyday life and empowering industrial applications. Interaction and the collaboration among smart devices offer new challenges to security since they conflict with economic and energy consumption requirement constraints. On the other hand, the lack of security measures could negatively impact the concrete adoption of this paradigm. This paper focuses on the Message Queuing Telemetry Transport (MQTT) protocol, widely adopted in the Internet of Things. This protocol does not implement natively secure authentication mechanisms, which are demanded to developers. Hence, this paper proposes a novel OTP (one-time password)-authentication schema for MQTT, which uses the Ethereum blockchain to implement a second-factor out-of-band channel. The proposal enables the authentication of both local and remote devices preserving user privacy and guaranteeing trust and accountability via Ethereum smart contracts.
Roy Cerqueti, Massimiliano Giacalone, Raffaele Mattera
Recently, cryptocurrencies have attracted a growing interest from investors, practitioners and researchers. Nevertheless, few studies have focused on the predictability of them. In this paper we propose a new and comprehensive study about cryptocurrency market, evaluating the forecasting performance for three of the most important cryptocurrencies (Bitcoin, Ethereum and Litecoin) in terms of market capitalization. At this aim, we consider non-Gaussian GARCH volatility models, which form a class of stochastic recursive systems commonly adopted for financial predictions. Results show that the best specification and forecasting accuracy are achieved under the Skewed Generalized Error Distribution when Bitcoin/USD and Litecoin/USD exchange rates are considered, while the best performances are obtained for skewed Distribution in the case of Ethereum/USD exchange rate. The obtain findings state the effectiveness -- in terms of prediction performance -- of relaxing the normality assumption and considering skewed distributions.
Vinicius Branco, Bruno Lippert, Roben Castagna Lunardi, Henry C. Nunes · 9 authors
Após a introdução do Bitcoin, a tecnologia de \textit{blockchain} evoluiu como uma solução para fornecer integridade, não repúdio e disponibilidade de dados para diferentes sistemas. Cenários sensíveis a dados, como Health Care, também podem se beneficiar dessas propriedades da blockchain. Assim, diferentes propostas, tanto da Academia quanto da Indústria, foram implantadas para permitir a adoção de blockchain em aplicativos de assistência médica. No entanto, existem poucas discussões sobre métodos de incentivo para ajudar a motivar novos usuários a adotar sistemas de saúde. Além disso, pouco se discute sobre o desempenho para executar códigos em blockchains públicos e privados. Para resolver esses problemas, este trabalho apresenta uma avaliação do TokenHealth, um aplicativo para monitoramento colaborativo de práticas de saúde com gamificação e incentivos baseados em tokens, em diferentes redes da Ethereum. A solução proposta é implementada por meio de smart contracts usando a linguagem Solidity e executada em máquinas virtuais da Ethereum (EVM). Avaliamos o desempenho da rede de teste Ropsten e de uma instância privada da Ethereum. Os resultados preliminares mostram que a execução de smart contracts leva menos de um minuto para um ciclo completo de diferentes smart contracts. Além disso, apresentamos uma discussão sobre os custos do uso de uma instância privada e da rede principal pública do Ethereum.
I P S P Wardhana, Gede Rasben Dantes, Kadek Yota Ernanda Aryanto
Abstract The falsification and embezzlement of personal data are still found in several cases in the past year. The reason is personal data in physical form are easily manipulated and difficult to be distinguished from the original. The most detrimental impact is if a person’s personal data is used for credit application fraud in the banking industry. Implementation of blockchain technologies, one of which is Ethereum, allows the use of contracts as a rule that must be fulfilled by the parties involved. All stored transactions are perpetual (cannot be deleted or changed), easy to be audited, transparent, and distributed at each participating node. This study aimed to develop a smart contract for personal data transactions with a case study of credit submission at the Bank. The authors developed a trial application using the prototype method in the process of assessment. Assessment was done by black box testing method in the scope of the lab with 10 credit submission data to be transacted. It is resulting in all credit submission data can be transacted and stored in the smart contract. The interview resulted in an opinion that blockchain technology can be used to store personal data and submit credit submissions at the Bank. The results of the analysis on assessments and interviews conclude that blockchain technology can be used as a medium to store personal data and secure credit applications. For future research, testing transactions can be done on Testnet networks with changing several blocks of data.
Ahmed Taha, Ahmed Zakaria, Dong‐Seong Kim, Neeraj Suri
Cloud computing offers a model where resources (storage, applications, etc.) are abstracted and provided “as-a- service” in a remotely accessible manner. Although there are numerous claimed benefits of the Cloud to ensure confidentiality, integrity, and availability of the stored data, the number of security breaches is still on the rise. The lack of security assurance and transparency prevented customers/enterprises from trusting the Cloud Service Providers (CSPs). Unless the customer’s security requirements are identified and documented by the CSPs, customers can not be assured that the CSPs will satisfy their requirements. Furthermore, the customer’s compensation upon a violation is a manual time intensive process. In this paper we address the aforementioned challenges by proposing a decentralized customer-based monitoring approach running over Ethereum blockchain. The proposed approach allows the customer(s) to validate the compliance of CSP(s) to the contracted services in the Service Level Agreements (SLAs) and “autonomsly” compensate customers in case of security breaches. At the same time, the proposed approach prevents customers from misreporting for financial gain. The approach builds upon the Ethereum blockchain infrastructure in order to securely store monitoring logs and incorporate SLAs as smart contracts. The compliance validation framework is implemented and its functionality is evaluated on Amazon EC2 and Ethereum Blockchain.
The paper bill of lading remains pervasive despite numerous problems associated with its form. Blockchain heralds change as it allows unique tokens to be possessed and traded peer-to-peer instantaneously over the internet without the need for a trusted central administrator. Blockchain furthermore promises to ease processes thanks to its applicability in smart contracting procedures. The Model Law on Electronic Transferable Records (MLETR), passed by UNCITRAL in 2017, provides the relevant legal framework for legal protection of the blockchain bill of lading. This paper proposes Ethereum as a viable smart contract-enabled blockchain platform for a bill of lading system and examines said system’s compatibility with the MLETR. The analysis also shows that blockchain technology may have significant consequences for the ‘control’ approach for establishing possession of an electronic transferable record.
This paper compares a number of stochastic volatility (SV) models for modeling and predicting the volatility of the four most capitalized cryptocurrencies (Bitcoin, Ethereum, Ripple, and Litecoin). The standard SV model, models with heavy-tails and moving average innovations, models with jumps, leverage effects and volatility in mean were considered. The Bayes factor for model fit was largely in favor of the heavy-tailed SV model. The forecasting performance of this model was also found superior than the other competing models. Overall, the findings of this study suggest using the heavy-tailed stochastic volatility model for modeling and forecasting the volatility of cryptocurrencies.
Institut Teknologi Bandung Bandung, Indonesia, Intan Muchtadi-Alamsyah, Muhammad Thufaili Imdad, Institut Teknologi Bandung Bandung, Indonesia · 6 authors
In the next few years, Blockchain will play a 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.
В роботі розглянуто проект з відкритим кодом Ethereum Blockchain, що є одним з найпопулярніших представників блокчейн-технологій. В своїй канонічній реалізації Ethereum працює як відкрита публічна децентралізована система, що базується на алгоритмі консенсусу PoW та дозволяє користувачам керувати власною криптовалютою, розробляти та розгортати розумні контракти на базі EVM (Ethereum Virtual Machine), взаємодіяти з розумними контрактами інших користувачів. Оскільки такий алгоритм не задовольняє вимогам більшості корпоративних проектів на базі Ethereum Blockchain, був проведений порівняльний аналіз найпопулярніших алгоритмів консенсусу і на основі результатів цього аналізу проведена оптимізація роботи приватного блокчейн за допомогою вибору алгоритму консенсусу.
M.E in Computer Engineering from SVBIT, GTU, Gandhinagar, India., Pratik Patel, Pinkal Chauhan, M.E in Computer Engineering from LDRP, Gandhinagar, India.
In our everyday lives, IoT plays a vital role. It is crucial to sense, capture and share data from connected devices via internet. Existing system proposed centralized client/server approach where central authority keeps a record of all the activities. Failure of such centralized authority makes the whole system fail. A decentralized / distributed approach is therefore needed if a single failure point is avoided. In this paper contains information to integrating Blockchain in IoT ecosystem in order to achieve access control. We proposed smart contract based architecture which consist multiple permission contract, one decision contract and one entry contract, to achieve distributed and secure IoT device access control. To conclude system framework, we provide a case study in an IoT system with two laptops and one Raspberry Pi single-board computers, where the PCs, DC and EC are implemented based on the Ethereum smart contract platform to achieve the access control.
Pemilihan Suara Secara Elektronis Menggunakan Sistem Terdesentralisasi Berbasis Blockchain Ethereum merupakan suatu sistem yang dibuat dalam bentuk aplikasi yang dapat digunakan dalam pemilihan umum. Hal ini dilakukan untuk menyelesaikan masalah yang dimiliki oleh sistem pemilihan suara secara elektronis yang konvensional dimana integritas data belum terjamin dan data hasil suara kemungkinan dapat dirubah oleh pihak tertentu. Masalah ini dapat diselesaikan dengan membuat sistem pemilihan suara secara elektronik yang menyimpan data hasil suara pada blockchain agar integritas data dapat terjamin. Pembuatan sistem ini dilakukan menggunakan bahasa Solidity, bahasa pemrograman yang sudah Turing Complete pada Ethereum. Source code yang dijalankan akan di kompilasi menjadi Bytecode yang kemudian dijalankan pada Ethereum Virtual Machine. Program yang dibuat tersebut kemudian akan di desentralisasi kan menggunakan Blockchain. Hasil nya adalah sistem Electronic Voting yang terdesentralisasi. Sistem ini dapat diakses melalui website https://pemilurt.herokuapp.com/. Abstract Electronic Voting Using Decentralised System Based On Ethereum’s Blockchain is a system made in the form of application used for Electronic Voting. This is done to solve the current problem on conventional electronic voting system where the integrity of the data can’t be ascertain and the result of the vote can be tampered malicious actors. To solve this problem, an electronic voting system will be built that store the data of election results on blockchain to ensure the integrity of the data. The creation of the system involves using the Solidity language, a Turing Complete programming language used on Ethereum. Source code that will be run will first need to be compiled into Bytecode, which will then in turn run on Ethereum Virtual Machine. The finished program will then be decentralised using Blockchain. The result will be a decentralised Electronic Voting system that can be accessed from the website https://pemilurt.herokuapp.com/.
This paper studies three existing technical solutions for a self-sovereign identity on blockchains and analyzes the arising issues related to the General Data Protection Regulation (GDPR) of the European Union (EU). In particular, the paper provides an overview of the existing Sovrin self-sovereign identity on the Hyperledger Indy public permissioned blockchain as well as uPort and Jolocom on the Ethereum public permissionless blockchain. The paper then concludes with a discussion on the GDPR-compliance of the blockchain-based identity concepts.
In recent years we have seen a great deal of attention to the topic of security analysis in smart contracts, especially those developed for the Ethereum blockchain. As a result, there seems to be an evergrowing demand for secure smart contracts to protect what could potentially be worth billions. In this paper, we introduce Etherolic as a robust, scalable and efficient fuzzing tool based on concolic testing for performing security analysis on smart contracts. Our approach works based on a successful combination of dynamic taint tracking (DTA) and concolic testing that allows users to analyze the bytecode of smart contracts being run on the Ethereum Virtual Machine. Moreover, Etherolic is not only able to identify a wide spectrum of recent vulnerabilities in smart contracts, but also it generates exploits to trigger unknown errors in the code. In order to demonstrate the usefulness of our approach, we evaluated Etherolic on a crafted benchmark suite, comprising several real-world and synthetic smart contracts along with 98 safety features. The result of our preliminary evaluation reveals 204 security violations in the benchmarks.
Cilj ovog rada je otkriti i proširiti moje znanje o distribuiranim mrežama i teoriji aukcija izradom koncept aplikacije za aukcije na Ethereum mreži koristeći pametne ugovore. Nezamjenjivi tokeni koriste se za stvaranje digitalne povjerljivosti, a prvi put bili su implementirani koristeći Ethereum ERC721 token standard. NFT-Auction-dapp je aplikacija bazirana na Ethereumu koja omogućuje korisnicima da kreiraju i sudjeluju u aukcijama NFT tokena u stvarnom vremenu, na globalnoj i distribuiranoj mreži, zadržavajući garancije plaćanja i dostave. U radu ću se služiti znanjima koja sam stekao tijekom studija na Visokom učilištu Algebra i znanjima koja sam stekao samostalno kako bih izgradio aplikaciju, objavio ju na javnu Ethereum mrežu i testirao njezinu funkcionalnost.
Blockchain-based cryptocurrencies and applications have flourished in blockchain research community. Massive data generated from diverse blockchain systems bring not only huge business values but also technological challenges in data analytics of heterogeneous blockchain data. Different from Bitcoin and Ethereum, EOSIO has richer diversity and a higher volume of blockchain data due to its unique architectural design in resource management, consensus scheme and high throughput. Despite its popularity (e.g., 89,800,000 blocks generated till November 14, 2019 since its launch on June 8, 2018), few studies have been made on data analysis of EOSIO. To fill this gap, we collect and process the up-to-date on-chain data from EOSIO. We name these well-processed EOSIO datasets as XBlock-EOS, which consists of 7 well-processed datasets: 1) Block, Transaction and Action, 2) Internal and External EOS Transfer Action, 3) Contract Information, 4) Contract Invocation, 5) Token Action, 6) Account Creation, 7) Resource Management. It is challenging to process and analyze a high volume of raw EOSIO data and establish the mapping from original raw data to the well-grained datasets since it requires substantial efforts in extracting various types of data as well as sophisticated knowledge on software engineering and data analytics. Meanwhile, we present statistics and exploration on these datasets. Moreover, we also outline the possible research opportunities based on XBlock-EOS.
Yuta Nakamura, Yuanyu Zhang, Masahiro Sasabe, Shoji Kasahara
Due to the rapid penetration of the Internet of Things (IoT) into human life, illegal access to IoT resources (e.g., data and actuators) has greatly threatened our safety. Access control, which specifies who (i.e., subjects) can access what resources (i.e., objects) under what conditions, has been recognized as an effective solution to address this issue. To cope with the distributed and trust-less nature of IoT systems, we propose a decentralized and trustworthy Capability-Based Access Control (CapBAC) scheme by using the Ethereum smart contract technology. In this scheme, a smart contract is created for each object to store and manage the capability tokens (i.e., data structures recording granted access rights) assigned to the related subjects, and also to verify the ownership and validity of the tokens for access control. Different from previous schemes which manage the tokens in units of subjects, i.e., one token per subject, our scheme manages the tokens in units of access rights or actions, i.e., one token per action. Such novel management achieves more fine-grained and flexible capability delegation and also ensures the consistency between the delegation information and the information stored in the tokens. We implemented the proposed CapBAC scheme in a locally constructed Ethereum blockchain network to demonstrate its feasibility. In addition, we measured the monetary cost of our scheme in terms of gas consumption to compare our scheme with the existing Blockchain-Enabled Decentralized Capability-Based Access Control (BlendCAC) scheme proposed by other researchers. The experimental results show that the proposed scheme outperforms the BlendCAC scheme in terms of the flexibility, granularity, and consistency of capability delegation at almost the same monetary cost.