In this work, we perform a comprehensive empirical study of smart contracts deployed on the ethereum blockchain. The objective of the analysis is to provide empirical results on smart contracts features, smart contract transactions within the blockchain, the role of the development community, and the source code characteristics. We collected a set of more than 10000 smart contracts source codes and a dataset of meta-data regarding their interaction with the blockchain from etherscan.io. We examined the collected data computing different statistics on naming policies, smart contract ether balance, number of smart contract transactions, functions, and other quantities characterizing the use and purpose of smart contracts. We found that the number of transactions and the balances follow power-law distributions and the software code metrics display, on average, values lower than corresponding metrics in standard software but have high variances. Focusing the attention on the 20 smart contracts with the topmost number of transactions, we found that most of them represent financial smart contracts and some of them have peculiar software development stories behind them. The results show that blockchain software is rapidly changing and evolving and it is no longer devoted only to cryptovalues applications but to general purpose computation.
Stefan Geißler, Thomas Prantl, Stanislav Lange, Florian Wamser · 5 authors
Blockchain and distributed ledger technologies have become more and more popular and widespread during recent years. After the initial hype about the technology and many cryptocurrency related use cases, the technology slowly starts to make its way into other domains like food tracking and document management. In order to further contribute to the search of what this technology can be used for, more detailed performance evaluations are required in order to investigate key performance indicators and general limits of the technology. To this end, we develop a discrete-time queueing model that allows a detailed evaluation of the characteristics of a blockchain system, such as the transaction waiting time distribution. Furthermore, we validate the model by comparing the results to values obtained from measurements in a closed lab environment based on the Ethereum blockchain.
Blockchain technology becomes increasingly popular. It also attracts scams, for example, a Ponzi scheme, a classic fraud, has been found making a notable amount of money on Blockchain, which has a very negative impact. To help to deal with this issue and to provide reusable research data sets for future research, this paper collects real-world samples and proposes an approach to detect Ponzi schemes implemented as smart contracts (i.e., smart Ponzi schemes) on the blockchain. First, 200 smart Ponzi schemes are obtained by manually checking more than 3,000 open source smart contracts on the Ethereum platform. Then, two kinds of features are extracted from the transaction history and operation codes of the smart contracts. Finally, a classification model is presented to detect smart Ponzi schemes. The extensive experiments show that the proposed model performs better than many traditional classification models and can achieve high accuracy for practical use. By using the proposed approach, we estimate that there are more than 500 smart Ponzi schemes running on Ethereum. Based on these results, we propose to build a uniform platform to evaluate and monitor every created smart contract for early warning of scams.
With the rise of artificial intelligence (AI) and deep learning techniques, fake digital contents have proliferated in recent years. Fake footage, images, audios, and videos (known as deepfakes) can be a scary and dangerous phenomenon and can have the potential of altering the truth and eroding trust by giving false reality. Proof of authenticity (PoA) of digital media is critical to help eradicate the epidemic of forged content. Current solutions lack the ability to provide history tracking and provenance of digital media. In this paper, we provide a solution and a general framework using Ethereum smart contracts to trace and track the provenance and history of digital content to its original source even if the digital content is copied multiple times. The smart contract utilizes the hashes of the interplanetary file system (IPFS) used to store digital content and its metadata. Our solution focuses on video content, but the solution framework provided in this paper is generic enough and can be applied to any other form of digital content. Our solution relies on the principle that if the content can be credibly traced to a trusted or reputable source, the content can then be real and authentic. The full code of the smart contract has been made publicly available at Github.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
In recent years, food safety issues have drawn growing concerns from society. In order to efficiently detect and prevent food safety problems and trace the accountability, building a reliable traceability system is indispensable. It is especially essential to accurately record, share, and trace the specific data within the whole food supply chain, including the process of production, processing, warehousing, transportation, and retail. The traditional traceability systems have issues, such as data invisibility, tampering, and sensitive information disclosure. The blockchain is a promising technology for the food safety traceability system because of the characteristics, such as the irreversible time vector, smart contract, and consensus algorithm. This paper proposes a food safety traceability system based on the blockchain and the EPC Information Services and develops a prototype system. The management architecture of on-chain & off-chain data is proposed as well, through which the traceability system can alleviate the data explosion issue of the blockchain for the Internet of Things. Furthermore, the enterprise-level smart contract is designed to prevent data tampering and sensitive information disclosure during information interaction among participants. The prototype system was implemented based on the Ethereum. According to the test results, the average time of information query response is around 2 ms, while the amount of on-chain data and query counts are 1 GB and 1000 times/s, respectively.
Dinh C. Nguyen, Pubudu N. Pathirana, Ming Ding, Aruna Seneviratne
Recent years have witnessed a paradigm shift in the storage of Electronic Health Records (EHRs) on mobile cloud environments, where mobile devices are integrated with cloud computing to facilitate medical data exchanges among patients and healthcare providers. This advanced model enables healthcare services with low operational cost, high flexibility, and EHRs availability. However, this new paradigm also raises concerns about data privacy and network security for e-health systems. How to reliably share EHRs among mobile users while guaranteeing high-security levels in the mobile cloud is a challenging issue. In this paper, we propose a novel EHRs sharing framework that combines blockchain and the decentralized interplanetary file system (IPFS) on a mobile cloud platform. Particularly, we design a trustworthy access control mechanism using smart contracts to achieve secure EHRs sharing among different patients and medical providers. We present a prototype implementation using Ethereum blockchain in a real data sharing scenario on a mobile app with Amazon cloud computing. The empirical results show that our proposal provides an effective solution for reliable data exchanges on mobile clouds while preserving sensitive health information against potential threats. The system evaluation and security analysis also demonstrate the performance improvements in lightweight access control design, minimum network latency with high security and data privacy levels, compared to the existing data sharing models.
Jorge Bernal Bernabé, José Luis Cánovas, José L. Hernández-Ramos, Rafael Torres Moreno · 5 authors
Blockchains offer a decentralized, immutable and verifiable ledger that can record transactions of digital assets, provoking a radical change in several innovative scenarios, such as smart cities, eHealth or eGovernment. However, blockchains are subject to different scalability, security and potential privacy issues, such as transaction linkability, crypto-keys management (e.g. recovery), on-chain data privacy, or compliance with privacy regulations (e.g. GDPR). To deal with these challenges, novel privacy-preserving solutions for blockchain based on crypto-privacy techniques are emerging to empower users with mechanisms to become anonymous and take control of their personal data during their digital transactions of any kind in the ledger, following a Self-Sovereign Identity (SSI) model. In this sense, this paper performs a systematic review of the current state of the art on privacy-preserving research solutions and mechanisms in blockchain, as well as the main associated privacy challenges in this promising and disrupting technology. The survey covers privacy techniques in public and permissionless blockchains, e.g. Bitcoin and Ethereum, as well as privacy-preserving research proposals and solutions in permissioned and private blockchains. Diverse blockchain scenarios are analyzed, encompassing, eGovernment, eHealth, cryptocurrencies, Smart cities, and Cooperative ITS.
Khaled Salah, Nishara Nizamuddin, Raja Jayaraman, M. S. Omar
The globalized production and the distribution of agriculture production bring a renewed focus on the safety, quality, and the validation of several important criteria in agriculture and food supply chains. The growing number of issues related to food safety and contamination risks has established an immense need for effective traceability solution that acts as an essential quality management tool ensuring adequate safety of products in the agricultural supply chain. Blockchain is a disruptive technology that can provide an innovative solution for product traceability in agriculture and food supply chains. Today's agricultural supply chains are complex ecosystem involving several stakeholders making it cumbersome to validate several important criteria such as country of origin, stages in crop development, conformance to quality standards, and monitor yields. In this paper, we propose an approach that leverages the Ethereum blockchain and smart contracts efficiently perform business transactions for soybean tracking and traceability across the agricultural supply chain. Our proposed solution eliminates the need for a trusted centralized authority, intermediaries and provides transactions records, enhancing efficiency and safety with high integrity, reliability, and security. The proposed solution focuses on the utilization of smart contracts to govern and control all interactions and transactions among all the participants involved within the supply chain ecosystem. All transactions are recorded and stored in the blockchain's immutable ledger with links to a decentralized file system (IPFS) and thus providing to all a high level of transparency and traceability into the supply chain ecosystem in a secure, trusted, reliable, and efficient manner.
Blockchain is a network-based technical solution for a set of distributed ledgers that are collectively maintained through decentralization and trustlessness. A smart contract is the most representative application of the blockchain from the 1.0 stage to the 2.0 stage, and it plays an important role in the construction of decentralized applications. According to the characteristics of blockchain without center and trustlessness, this article designs a commodity transaction smart contract based on blockchain technology. The release and execution of the smart contract in this article is implemented on the Ethereum private chain, and the transfer and payment functions of Ethereum are executed through the lightweight wallet plug-in Metamask of the Chrome browser. The execution of the smart contract is tested in the test network, and the operation of the smart contract is completed in the form of gas payment. Gas is the calculation work measurement for executing transactions in Ethereum, and there is a conversion relationship with Ether. The more Gas is paid when each contract is executed, the higher the chance of being packaged and stored first. The transaction model proposed in this paper realizes the decentralization of the system, the transaction and contact information is open, transparent, and non-tamperable, and the contract is automatically stored and executed. This design can greatly increase the transaction speed and gradually reach the performance of a centralized network. And providing an enterprise-level blockchain operating system makes application development and deployment easier.
신뢰하는 중앙기관 없이 노드간 합의를 통해 신뢰성 있는 데이터 공유를 지원하는 블록체인은 비트코인을 시작으로 다양한 분야에서 활용되고 있다. 다양한 블록체인 플랫폼 중 스마트 컨트랙트를 지원하는 이더리움은 다양한 블록체인 서비스 구축에 활발히 활용되고 있지만 아직까지 이더리움 네트워크의 동작 방식이나 특징을 분석한 연구는 미비하다. 본 논문에서는 이더리움 네트워크 구성시 반드시 필요한 노드 탐색 과정을 분석한다. 이더리움 네트워크의 특징과 주요 프로토콜 및 노드 탐색 과정을 설명하고, Go언어로 작성된 이더리움 구현물인 geth의 네트워크 동작에 따른 함수 콜 그래프 분석 결과를 제공한다.
Matteo Franceschi, Davide Morelli, David Plans, Alan Brown · 7 authors
The problem of protecting sensitive data like medical records, and enabling the access only to authorized entities is currently a challenge. Current solutions often require trusting some centralized entity which is in charge of managing the data. The disruptive technology of blockchains may offer the possibility to change the current scenario and give to the users the control on their personal data. In this paper we propose ComeHere, a system able to store medical records and to exploit the blockchain technology to control and track the access right transfer on the blockchain. The paper shows the current status of the project, presents a preliminary proof-of-concept implementation and discusses the future improvements of the system, and some critical issues which are still open.
In this paper, we present the most extensive evaluation of blockchain system to date. To achieve scalability across servers in more than 10 countries located on 4 different continents, we drastically revisited Byzantine fault tolerant blockchains and verification of signatures. The resulting blockchain, called the Red Belly Blockchain (RBBC), commits more than a hundred thousand transactions issued by permissionless nodes. These transactions are grouped into blocks within few seconds through a partially synchronous consensus run by permissioned nodes. It prevents double spending by guaranteeing that a unique block is decided at any given index of the chain in a deterministic way by all participants. We compared the performance of RBBC against traditional Byzantine fault tolerant alternatives and more recent randomized solutions. In the same geo-distributed environment with low-end machines, we noticed two interesting comparisons: (i) the RBBC throughput scales to hundreds of machines whereas the classic 3-step leader-based BFT state machine used by consortium blockchains cannot scale to 40 identically configured nodes; (ii) RBBC guarantees transaction finality in 3 seconds and experiences a third of the latency that randomized-based solutions like HoneyBadgerBFT can offer. This empirical evaluation demonstrates that blockchain scalability can be achieved without sacrificing security.
Bitcoin soaks up most of the hype and the opprobrium heaped on cryptocurrencies, leaving its younger and smaller sibling Ethereum in the shadows. But Ethereum is anything but small. Its market capitalization was roughly US $10 billion at press time, and it has an equally whopping energy footprint.
У статті на основі аналізу причин стрімкого падіння цінності криптовалют у 2018 р. і особливостей 17 альткоїнів з найбільшою ринковою капіталізацією зроблено висновки про вектори розвитку криптовалют і перспективи цього феномену. Виявлено вектори розвитку криптовалют: 1) валюти платформ для створення і функціонування децентралізованих додатків (Ethereum та альтернативні платформи: Eos (позиціонується як швидша, простіша, дешевша); Cardano (для фінансових додатків, що використовуються у щоденній діяльності); Neo (валюта платформи, дружньої до регуляторів (зокрема, китайських); Ehereum Classic – більш децентралізована, з більш строгою незворотністю транзакцій, ніж у Ethereum); 2) платформи для більш ефективних транскордонних платежів (Ripple та більш децентралізована альтернатива – Stellar); 3) вирішення технічних проблем біткоїна (Litecoin – більш зручна для дрібних трансакцій, Bitcoin Cash – альтернативне вирішення проблеми масштабування трансакцій); 4) полегшення торгівлі криптовалютами і вирішення проблеми їхньої волатильності – Tether; 5) внутрішні валюти криптовалютних бірж (Binance Coin); 6) збільшення анонімності трансакцій: Monero, Dash; 7) забезпечення транзакцій в Інтернеті Речей – IOTA; 8) універсальна валюта для віртуальних розваг – TRON. Обґрунтовано гіпотезу, що, не впоравшись з амбітною роллю альтернативи суверенним грошам ієрархічної природи, криптовалюти частково зійдуть до ролі віртуальних валют для локальних віртуальних просторів, а частково перенесуть частину своїх властивостей у традиційні платіжні системи, аби полегшити, скажімо, транскордонні транзакції. Загалом, процес поширення криптовалют синхронізується з процесом поширення інформаційно-мережевої економіки.
With the rapid development of smart mobile terminals (MTs), various industrial Internet of things (IIoT) applications can fully leverage them to collect and share data for providing certain services. However, two key challenges still remain. One is how to achieve high-quality data collection with limited MT energy resource and sensing range. Another is how to ensure security when sharing and exchanging data among MTs, to prevent possible device failure, network communication failure, malicious users or attackers, etc. To this end, we propose a blockchain-enabled efficient data collection and secure sharing scheme combining Ethereum blockchain and deep reinforcement learning (DRL) to create a reliable and safe environment. In this scheme, DRL is used to achieve the maximum amount of collected data, and the blockchain technology is used to ensure security and reliability of data sharing. Extensive simulation results demonstrate that the proposed scheme can provide higher security level and stronger resistance to attack than a traditional database based data sharing scheme for different levels/types of attacks.
The article is dedicated to the actual problems of creation, intervention and introduction of electronic money crypto-currency and blockchain technology at the modern stage. Rather narrow description is given to essence, the history of invention and the types of crypto currency (bit coin, ethereum, etc.,), advantages and defects of their use, the electronic wallet and its types, situation of the electronic money introduc tion in Georgia, the global crypto currency spread and the tendencies and prospective of its possible recognition, assessed is significance of the electronic money in manufacturing, based on the modern technical-technological achievements, money-reporting field, maximally just relations creation and by this - further growth of the economic development and accordingly the permanent enhancement of the living standards of the populations.
Yu Rang Park, Eunsol Lee, Wonjun Na, Sung-Jun Park · 6 authors
BACKGROUND: There are many perspectives on the advantages of introducing blockchain in the medical field, but there are no published feasibility studies regarding the storage, propagation, and management of personal health records (PHRs) using blockchain technology. OBJECTIVE: The purpose of this study was to investigate the usefulness of blockchains in the medical field in relation to transactions with and propagation of PHRs in a private blockchain. METHODS: We constructed a private blockchain network using Ethereum version 1.8.4 and conducted verification using the de-identified PHRs of 300 patients. The private blockchain network consisted of one hospital node and 300 patient nodes. In order to verify the effectiveness of blockchain-based PHR management, PHRs at a time were loaded in a transaction between the hospital and patient nodes and propagated to the whole network. We obtained and analyzed the time and gas required for data transaction and propagation on the blockchain network. For reproducibility, these processes were repeated 100 times. RESULTS: Of 300 patient records, 74 (24.7%) were not loaded in the private blockchain due to the data block size of the transaction block. The remaining 226 individual health records were classified into groups A (80 patients with outpatient visit data less than 1 year old), B (84 patients with outpatient data from between 1 and 3 years before data collection), and C (62 patients with outpatient data 3 to 5 years old). With respect to mean transaction time in the blockchain, C (128.7 seconds) had the shortest time, followed by A (132.2 seconds) and then B (159.0 seconds). The mean propagation times for groups A, B, and C were 1494.2 seconds, 2138.9 seconds, and 4111.4 seconds, respectively; mean file sizes were 5.6 KB, 18.6 KB, and 45.38 KB, respectively. The mean gas consumption values were 1,900,767; 4,224,341; and 4,112,784 for groups A, B, and C, respectively. CONCLUSIONS: This study confirms that it is possible to exchange PHR data in a private blockchain network. However, to develop a blockchain-based PHR platform that can be used in practice, many improvements are required, including reductions in data size, improved personal information protection, and reduced operating costs.