We present a static analysis approach that combines concrete values and symbolic expressions. This symbolic value-flow (“symvalic”) analysis models program behavior with high precision, e.g., full path sensitivity. To achieve deep modeling of program semantics, the analysis relies on a symbiotic relationship between a traditional static analysis fixpoint computation and a symbolic solver: the solver does not merely receive a complex “path condition” to solve, but is instead invoked repeatedly (often tens or hundreds of thousands of times), in close cooperation with the flow computation of the analysis. The result of the symvalic analysis architecture is a static modeling of program behavior that is much more complete than symbolic execution, much more precise than conventional static analysis, and domain-agnostic: no special-purpose definition of anti-patterns is necessary in order to compute violations of safety conditions with high precision. We apply the analysis to the domain of Ethereum smart contracts. This domain represents a fundamental challenge for program analysis approaches: despite numerous publications, research work has not been effective at uncovering vulnerabilities of high real-world value. In systematic comparison of symvalic analysis with past tools, we find significantly increased completeness (shown as 83-96% statement coverage and more true error reports) combined with much higher precision, as measured by rate of true positive reports. In terms of real-world impact, since the beginning of 2021, the analysis has resulted in the discovery and disclosure of several critical vulnerabilities, over funds in the many millions of dollars. Six separate bug bounties totaling over $350K have been awarded for these disclosures.
<sec> <title>BACKGROUND</title> Recent advancements in digital pathology resulting from advances in imaging and digitization have increased the convenience and usability of pathology for disease diagnosis, especially in oncology, urology, and gastroenteric diagnosis. However, despite the possibilities to include low-cost diagnosis and viable telemedicine, digital pathology is not yet accessible owing to expensive storage, data security requirements, and network bandwidth limitations to transfer high-resolution images and associated data. The increase in storage, transmission, and security complexity concerning data collection and diagnosis makes it even more challenging to use artificial intelligence algorithms for machine-assisted disease diagnosis. We designed and prototyped a digital pathology system that uses blockchain-based smart contracts using the nonfungible token (NFT) standard and the Interplanetary File System for data storage. Our design remediates shortcomings in the existing digital pathology systems infrastructure, which is centralized. The proposed design is extendable to other fields of medicine that require high-fidelity image and data storage. Our solution is implemented in data systems that can improve access quality of care and reduce the cost of access to specialized pathological diagnosis, reducing cycle times for diagnosis. </sec> <sec> <title>OBJECTIVE</title> The main objectives of this study are to highlight the issues in digital pathology and suggest that a software architecture–based blockchain and the Interplanetary File System create a low-cost data storage and transmission technology. </sec> <sec> <title>METHODS</title> We used the design science research method consisting of 6 stages to inform our design overall. We innovated over existing public-private designs for blockchains but using a 2-layered approach that separates actual file storage from metadata and data persistence. </sec> <sec> <title>RESULTS</title> Here, we identified key challenges to adopting digital pathology, including challenges concerning long-term storage and the transmission of information. Next, using accepted frameworks in NFT-based intelligent contracts and recent innovations in distributed secure storage, we proposed a decentralized, secure, and privacy-preserving digital pathology system. Our design and prototype implementation using Solidity, web3.js, Ethereum, and node.js helped us address several challenges facing digital pathology. We demonstrated how our solution, which combines NFT smart contract standard with persistent decentralized file storage, solves most of the challenges of digital pathology and sets the stage for reducing costs and improving patient care and speed of diagnosis. </sec> <sec> <title>CONCLUSIONS</title> We identified technical limitations that increase costs and reduce the mass adoption of digital pathology. We presented several design innovations using NFT decentralized storage standards to prototype a system. We also presented the implementation details of a unique security architecture for a digital pathology system. We illustrated how this design can overcome privacy, security, network-based storage, and data transmission limitations. We illustrated how improving these factors sets the stage for improving data quality and standardized application of machine learning and artificial intelligence to such data. </sec>
Ningyu He, Weihang Su, Zhou Yu, Xinyu Liu · 10 authors
The continuing expansion of the blockchain ecosystems has attracted much attention from the research community. However, although a large number of research studies have been proposed to understand the diverse characteristics of individual blockchain systems (e.g., Bitcoin or Ethereum), little is known at a comprehensive level on the evolution of blockchain ecosystems at scale, longitudinally, and across multiple blockchains. We argue that understanding the dynamics of blockchain ecosystems could provide unique insights that cannot be achieved through studying a single static snapshot or a single blockchain network alone. Based on billions of transaction records collected from three representative and popular blockchain systems (Bitcoin, Ethereum and EOSIO) over 10 years, we conduct the first study on the evolution of multiple blockchain ecosystems from different perspectives. Our exploration suggests that, although the overall blockchain ecosystem shows promising growth over the last decade, a number of worrying outliers exist that have disrupted its evolution.
Do Hai Son, Tran Thi Thuy Quynh, Tran Viet Khoa, Dinh Thai Hoang · 9 authors
A smart grid is an important application in Industry 4.0 with a lot of new technologies and equipment working together. Hence, sensitive data stored in the smart grid is vulnerable to malicious modification and theft. This paper proposes a framework to build a smart grid based on a highly effective private Ethereum network. Our framework provides a real smart grid that includes modern hardware and a smart contract to secure data in the blockchain network. To obtain high throughput but a low uncle rate, the difficulty calculation method used in the mining process of the Ethereum consensus mechanism is modified to adapt to the practical smart grid setup. The performance in terms of throughput and latency are evaluated by simulation and verified by the real smart grid setup. The enhanced private Ethereum-based smart grid has significantly better performance than the public one. Moreover, this framework can be applied to any system used to store data in the Ethereum network.
Wouter van Groesen, Pieter; id_orcid 0000-0001-8020-4609 Pauwels
Construction supply chains (CSC) are converging chains in which intransparency, risks and trust issues between parties occur. To increase transparency and efficiency by means of automation, physical asset tracking (PAT), digital asset management (DAM) and distributed ledger technology (DLT) can be combined. We therefore investigate here to what extent geospatial sensors, a jointly managed information system, a private permissioned Ethereum blockchain network and several smart contracts can be combined to aid towards this purpose. A framework is developed and incremented into several interacting prototypes. These prototypes consist of: (1) a QR-code mobile application for asset tracking, (2) a Revit model for parameter centralization, (3) several smart contracts deployed on the Ethereum Goërli network and (4) a dashboard WebApp. Four distinct test scenarios are developed to verify the functionalities of these applications. Test results indicated achievement of desired post-conditions. Hence, (semi) automation of compliance checking activities and tokenized payments is realized. <br/>
Wei Yan Ng, Tien-En Tan, Prasanth V H Movva, Andrew Hao Sen Fang · 12 authors
The COVID-19 pandemic has had a substantial and global impact on health care, and has greatly accelerated the adoption of digital technology. One of these emerging digital technologies, blockchain, has unique characteristics (eg, immutability, decentralisation, and transparency) that can be useful in multiple domains (eg, management of electronic medical records and access rights, and mobile health). We conducted a systematic review of COVID-19-related and non-COVID-19-related applications of blockchain in health care. We identified relevant reports published in MEDLINE, SpringerLink, Institute of Electrical and Electronics Engineers Xplore, ScienceDirect, arXiv, and Google Scholar up to July 29, 2021. Articles that included both clinical and technical designs, with or without prototype development, were included. A total of 85 375 articles were evaluated, with 415 full length reports (37 related to COVID-19 and 378 not related to COVID-19) eventually included in the final analysis. The main COVID-19-related applications reported were pandemic control and surveillance, immunity or vaccine passport monitoring, and contact tracing. The top three non-COVID-19-related applications were management of electronic medical records, internet of things (eg, remote monitoring or mobile health), and supply chain monitoring. Most reports detailed technical performance of the blockchain prototype platforms (277 [66·7%] of 415), whereas nine (2·2%) studies showed real-world clinical application and adoption. The remaining studies (129 [31·1%] of 415) were themselves of a technical design only. The most common platforms used were Ethereum and Hyperledger. Blockchain technology has numerous potential COVID-19-related and non-COVID-19-related applications in health care. However, much of the current research remains at the technical stage, with few providing actual clinical applications, highlighting the need to translate foundational blockchain technology into clinical use.
Cryptocurrency is a new sort of asset that has emerged as a result of the advancement of financial technology and it has created a big opportunity for researches. Cryptocurrency price forecasting is difficult due to price volatility and dynamism. Around the world, there are hundreds of cryptocurrencies that are used. This paper proposes three types of recurrent neural network (RNN) algorithms used to predict the prices of three types of cryptocurrencies, namely Bitcoin (BTC), Litecoin (LTC), and Ethereum (ETH). The models show excellent predictions depending on the mean absolute percentage error (MAPE). Results obtained from these models show that the gated recurrent unit (GRU) performed better in prediction for all types of cryptocurrency than the long short-term memory (LSTM) and bidirectional LSTM (bi-LSTM) models. Therefore, it can be considered the best algorithm. GRU presents the most accurate prediction for LTC with MAPE percentages of 0.2454%, 0.8267%, and 0.2116% for BTC, ETH, and LTC, respectively. The bi-LSTM algorithm presents the lowest prediction result compared with the other two algorithms as the MAPE percentages are: 5.990%, 6.85%, and 2.332% for BTC, ETH, and LTC, respectively. Overall, the prediction models in this paper represent accurate results close to the actual prices of cryptocurrencies. The importance of having these models is that they can have significant economic ramifications by helping investors and traders to pinpoint cryptocurrency sales and purchasing. As a plan for future work, a recommendation is made to investigate other factors that might affect the prices of cryptocurrency market such as social media, tweets, and trading volume.
Mwrwan Abubakar, Zakwan Jaroucheh, Ahmed Al Dubai, Bill Buchanan
The Session Initiation Protocol (SIP) is the principal signalling protocol in Voice over IP (VoIP) systems, responsible for initialising, terminating, and maintaining sessions amongst call parties. However, the problem with the SIP protocol is that it was not designed to be secure by nature as the HTTP digest authentication used in SIP is insecure, making it vulnerable to a variety of attacks. The current solutions rely on several standardised encryption protocols, such as TLS and IPsec, to protect SIP registration messages. However, the current centralised solutions do not scale well and cause algorithm overload when encoding and decoding SIP messages. In trying to rectify this issue, we propose in this paper a blockchain-based lightweight authentication mechanism, which involves a decentralised identity model to authenticate the SIP client to the SIP server. Our mechanism uses a smart contract on the Ethereum blockchain to ensure trust, accountability and preserves user privacy. We provided a proof-of-concept implementation to demonstrate our work. Further analysis of this approach's usability, mainly CPU and memory usage, was conducted comparing to IPsec and TLS. Then we discussed our system's security and presented a security analysis. Our analysis proves that our approach satisfies the SIP protocol security requirements.
Technological advancements of Blockchain and other Distributed Ledger Techniques (DLTs) promise to provide significant advantages to applications seeking transparency, redundancy, and accountability. Actual adoption of these emerging technologies requires incorporating cost-effective, fast, QoS-enabled, secure, and scalable design. With the recent advent of quantum computing, the security of current blockchain cryptosystems can be compromised to a greater extent. Quantum algorithms like Shor's large integer factorization algorithm and Grover's unstructured database search algorithm can provide exponential and quadratic speedup, respectively, in contrast to their classical counterpart. This can put threats on both public-key cryptosystems and hash functions, which necessarily demands to migrate from classical cryptography to quantum-secure cryptography. Moreover, the computational latency of blockchain platforms causes slow transaction speed, so quantum computing principles might provide significant speedup and scalability in transaction processing and accelerating the mining process. For such purpose, this article first studies current and future classical state-of-the-art blockchain scalability and security primitives. The relevant quantum-safe blockchain cryptosystem initiatives which have been taken by Bitcoin, Ethereum, Corda, etc. are stated and compared with respect to key sizes, hash length, execution time, computational overhead, and energy efficiency. Post Quantum Cryptographic algorithms like Code-based, Lattice-based, Multivariate-based, and other schemes are not well suited for classical blockchain technology due to several disadvantages in practical implementation. Decryption latency, massive consumption of computational resources, and increased key size are few challenges that can hinder blockchain performance.
Ethereum Improvement Proposal (EIP) 1559 was recently implemented to transform Ethereum's transaction fee market. EIP-1559 utilizes an algorithmic update rule with a constant learning rate to estimate a base fee. The base fee reflects prevailing network conditions and hence provides a more reliable oracle for current gas prices. Using on-chain data from the period after its launch, we evaluate the impact of EIP-1559 on the user experience and market performance. Our empirical findings suggest that although EIP-1559 achieves its goals on average, short-term behavior is marked by intense, chaotic oscillations in block sizes (as predicted by our recent theoretical dynamical system analysis [1]) and slow adjustments during periods of demand bursts (e.g., NFT drops). Both phenomena lead to unwanted inter-block variability in mining rewards. To address this issue, we propose an alternative base fee adjustment rule in which the learning rate varies according to an additive increase, multiplicative decrease (AIMD) update scheme. Our simulations show that the latter robustly outperforms the EIP-1559 protocol under various demand scenarios. These results provide evidence that variable learning rate mechanisms may constitute a promising alternative to the default EIP-1559-based format and contribute to the ongoing discussion on the design of more efficient transaction fee markets.
Isaac Adjei-Mensah, Isaac Osei Agyemang, Collins Sey, Linda Delali Fiasam · 5 authors
From online education and trading, all aspects of our lives are affected by digital technology. Among them, the storage of music has also entered the digital era. Music productions created by artists have brought great joy to people. However, when artists upload their works, they are most downloaded and reprinted by others, and copyright information and the issue associated with the sharing of music arise. This will have a significant negative impact on the enthusiasm and motivation of artists. This paper provides an internet database platform for artists, which uses the distributed and tamper-proof technology of the Ethereum blockchain to store music works, and protect the copyright information of each album or music produced by artists in the music industry. Design and implementation of the system model and data storage are proposed and data storage processes based on the Ethereum smart contract are demonstrated in detail. The system stores music information on the blockchain network, using the smart contract to provide artists with a fast and efficient royalty payment. Node.js is applied to carry out the experiments of our system, and we test Remote Procedure Calls (RPC) with available account and private keys for contract development and use block explorer to track music information on the blockchain. Our system enables copyright revenue to be attributed to music creators that will help to eliminate the illegal uploading of music on other websites.
Bitcoin is an innovative and path-breaking technology that has influenced numerous industries across the globe. It is a form of digital currency (cryptocurrency) that can be used for trading and has the potential to replace fiat money, where the underlying infrastructure is called Blockchain. The Blockchain is an open ledger that provides decentralization, transparency, immutability, and confidentiality. Blockchain can be used in enormous applications, such as healthcare, logistics, supply chain management, the IoT, and so forth. Most of the industrial applications rely on the permissioned blockchain. However, the permissioned blockchain fails in some aspects, such as interoperability among different platforms. This paper suggests a sustainable system to solve the interoperability issue of the permissioned blockchain by designing a new infrastructure. This work has been tested in ethereum and hyperledger frameworks, which obtained a success rate of 100 percent.
Blockchain technology is fast becoming the most transformative technology of recent times and has created hype and optimism, gaining much attention from the public and private sectors. It has been widely deployed in decentralized crypto currencies such as Bitcoin and Ethereum. Bitcoin is the success story of a public blockchain application that propelled intense research and development into blockchain technology. However, scalability remains a crucial challenge. Both Bitcoin and Ethereum are encountering low-efficiency issues with low throughput, high transaction latency, and huge energy consumption. The scalability issue in public Blockchains is hindering the provision of optimal solutions to businesses and industries. This paper presents a systematic literature review (SLR) on the public blockchain scalability issue and challenges. The scope of this SLR includes an in-depth investigation into the scalability problem of public blockchain, associated fundamental factors, and state-of-art solutions. This project managed to extract 121 primary papers from major scientific databases such as Scopus, IEEE explores, Science Direct, and Web of Science. The synthesis of these 121 articles revealed that scalability in public blockchain is not a singular term. A variety of factors are allied to it, with transaction throughput being the most discussed factor. In addition, other interdependent vita factors include storages, block size, number of nodes, energy consumption, latency, and cost. Generally, each term is somehow directly or indirectly reliant on the consensus model embraced by the blockchain nodes. It is also noticed that the contemporary available consensus models are not efficient in scalability and thus often fail to provide good QoS (throughput and latency) for practical industrial applications. Our findings exemplify that the Internet of Things (IoT) would be the leading application of blockchain in industries such as energy, finance, resource management, healthcare, education, and agriculture. These applications are, however, yet to achieve much-desired outcomes due to scalability issues. Moreover, Onchain and offchain are the two major categories of scalability solutions. Sagwit, block size expansion, sharding, and consensus mechanisms are examples of onchain solutions. Offchain, on the other hand, is a lighting network.
Since its inception in the late 2000s, blockchain has emerged as a powerful tool for creating trust without intermediaries to incentivize global communities for working for a common goal, such as the improvement of its very ecosystem, its applications and community adoption. While first blockchains were mainly devised for confirming transactions of their innate cryptocurrencies like Bitcoin, smart-contract blockchains like Ethereum can interface with the real-world through so-called &ldquo;oracles&rdquo;, which feed trustful off-chain information. This paper introduces digital twins of physical objects and processes as computational oracles to effectively unleash the tremendous opportunity offered by blockchain to the realm of fundamental science, research and technology development (RTD). The crowdsourcing concept is illustrated with the example of centrifugal flow control in microfluidic &ldquo;Lab-on-a-Disc&rdquo; (LoaD) systems.
Open access
Innovative Microfluidic and Catalytic Techniques Innovation
K. S. Arikumar, Deepak Kumar A, GowthamC, Sahaya Beni Prathiba
The most shocking events were was the recent discovery of the fraudulent activities in the Punjab National Bank. This is due to frequent systemic failures that detect human errors. Blockchain technology is the greatest solution for this issue. It is surprisingly common for the information settlement mechanism like SWIFT to be on a isolated ledger from the payment settlement mechanism. If the banks uses a ledger that stores information settlement distributed across all the participants, then the fraudulent user may reflect on all the available participants in the transactions, auditors and regulators. Our Paper is a Decentralised Loan Management Web Application (DApp) built on Ethereum blockchain which targets on preventing such fraudulent attacks on Loans sanctions by decentralising the processes. The security features authentication of the user identity, authentication of bank officials and multiple levels of verification of details are implemented using Public Key Infrastructure (PKI).
Open access
User Authentication and Security Systems
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Niclas Kannengieser, Sebastian Lins, Christian Sander, Klaus Winter · 6 authors
Smart contracts are a promising means of formalizing and reliably enforcing agreements between entities using distributed ledger technology (DLT). Research has revealed that a significant number of smart contracts are subject to programming flaws, making them vulnerable to attacks and leading to detrimental effects, such as asset loss. Researchers and developers call for a thorough analysis of challenges to identify their causes and propose solutions. To respond to these calls, we conducted two literature reviews and diverse expert interviews and synthesized scattered knowledge on challenges and solutions. We identified 29 challenges (e.g., code visibility, code updateability, and encapsulation) and 60 solutions (e.g., gas limit specification, off-ledger computations, and shadowing). Moreover, we developed 20 software design patterns (SDPs) in collaboration with smart contract developers. The SDPs help developers adjust their programming habits and thus support them in their daily development practices. Our results provide actionable knowledge for smart contract developers to overcome the identified challenges and offer support for comparing smart contract integration concepts across three fundamentally different DLT protocols (i.e., Ethereum, EOSIO, and Hyperledger Fabric). Moreover, we support developers in becoming aware of peculiarities in smart contract development and the resulting benefits and drawbacks.
RICARDO CARREÑO AGUILERA, Miguel Patiño-Ortiz, Julián Patiño-Ortiz, Erick Velázquez Lozada
Due to the exponential growth in the use of systems with applications of blockchain technology, this paper develops a funding system, with donations and offers of shares, through the Ethereum platform with blockchain technology. Given the benefits that blockchain provides data protection and has high security, this paper offers a decentralized donation expert system using smart contracts that makes fully reliable donation systems to attract more funds to this urgent global health issue. Smart contracts provide faithful donations and meet the characteristics of being versatile, accessible, and sustainable to combat the COVID-19 pandemic. This expert system found the Merkle grid as an optimum method to work efficiently on the blockchain. The expert system proved to be steady and efficient by using an essential test dataset. A reliable donation system expects more donors and investors since a sustainable and reliable approach is always a milestone. The primary purpose of developing this system is to attract donors to bring down the COVID-19 pandemic by providing a faithful donation system.
The process of educational informatization in the digital era of big data is one of the significant changes in the transformation of the educational model from traditional classrooms (face to face) to online teaching and learning based, which brings innovations from various e-learning. E-Learning is distance learning that uses computer technology, computer networks and the internet. The E-Learning system in higher education in Indonesia which is still centralized is a problem in developing E-Learning in this research in implementing the Independent Campus Policy, one of the manifestations of student-centered and decentralized learning launched by the Ministry of Education and Culture (Kemdikbud). This research takes advantage of blockchain technology to achieve breakthrough E-Learning in Higher Education that is not centralized or decentralized. Blockchain technology provides the advantages of decentralized digital certificate issuance as well as secure storage using the Ethereum blockchain. The results show blockchain technology to solve weaknesses in the field of online education based on Merdeka Campus, namely the issuance of certificates as evidence of student learning outcomes in the form of a formal digital certificate in decentralized E-Learning and insecurity in storage for verification using the Ethereum blockchain. The digital certificate from the transaction will identify block hash, gas usage, block number and block time as different private keys.\n\nKeywords: E-Learning, Independent Campus, Blockchain, Digital Certificate Verification Abstrak \n\nProses informatisasi pendidikan di era digital data besar (big data) merupakan salah satu perubahan signifikan transformasi model pendidikan dari kelas trandisional (tatap muka) menjadi berbasis belajar-mengajar secara online, yang membawa inovasi dari berbagai e-learning. E-Learning adalah pembelajaran jarak jauh yang menggunakan teknologi komputer, jaringan komputer, dan internet. Sistem E-Learning pada Pendidikan tinggi di Indonesia yang masih terpusat menjadi permasalahan pengembangan E-Learning penelitian ini dalam menerapkan Kebijakan Kampus Merdeka salah satu perwujudan pembelajaran berpusat pada mahasiswa (student centered learning) dan terdesentralisasi yang diluncurkan oleh Kementerian Pendidikan dan Kebudayaan (Kemdikbud). Penelitian ini mengambil keunggulan teknologi blockchain agar dicapai terobosan E-Learning pada Pendidikan Tinggi yang tidak terpusat atau terdesentralisasi. Teknologi blockchain memberikan keunggulan penerbitan sertifikat digital terdesentralisasi serta penyimpanan aman menggunakan Ethereum blockchain. Hasil penelitian menunjukkan teknologi blockchain menyelesaikan kelemahan di bidang pendidikan online berbasis Kampus Merdeka yaitu penerbitan sertifikat digital sebagai bukti hasil belajar mahasiswa berupa sertifikat digital secara legal formal pada E-Learning secara terdesentralisasi dan ketidakamanan dalam penyimpanan untuk verifikasi sertifikat digital menggunakan Ethereum blockchain. Sertifikat digital hasil transaksi tersebut akan teridentifikasi block hash, gas usage, block number dan block time sebagai private key yang berbeda satu dengan lainnya.\n\nKata kunci: E-Learning, Kampus Merdeka, Blockchain, Verifikasi Sertifikat Digital
WAN ATIQAH WAN JAMARUL IMRAN, Mohamed Hisham Yahya, Muhammad Hafiz Ali, MOHD AKBAL QAMAS ABDUL BASIR .
This research studies the factors that affect volatility in cryptocurrency markets. The relationship between information asymmetry and cybercriminal risks are studied against the volatility and return of cryptocurrencies, namely, Bitcoin (BTC), Ethereum (ETH), Bitcoin Cash (BCH) dan Ripple (XRP). These cryptocurrencies are selected as they are cryptocurrencies that are being traded by Luno, Sinergy and Tokenzie (the exchange companies regulated by the Securities Commissions of Malaysia). 730 observations were collected for each cryptocurrency via the CoinMarketCap website, from 1 January 2019 to 30 December 2020. The ADF test and the Kolmogorov-Smirnov test have been conducted before the analysis of the data. The results show the stationarity and non-normality of the data collected. The EGARCH-GED model is used to analyse the relationship between information asymmetry and volatility. The findings indicate a significant relationship between information asymmetry and volatility in BTC, ETH ad XRP. The Event Study Method (ESM) is used to analyse the effect of cybercriminal risks on returns. The result shows that all four cryptocurrencies show a significant relationship between cybercriminal risks and returns.
Fátima Leal, Bruno Veloso, Benedita Malheiro, Juan C. Burguillo · 6 authors
Explainable recommendations enable users to understand why certain items are suggested and, ultimately, nurture system transparency, trustworthiness, and confidence. Large crowdsourcing recommendation systems ought to crucially promote authenticity and transparency of recommendations. To address such challenge, this paper proposes the use of stream-based explainable recommendations via blockchain profiling. Our contribution relies on chained historical data to improve the quality and transparency of online collaborative recommendation filters – Memory-based and Model-based – using, as use cases, data streamed from two large tourism crowdsourcing platforms, namely Expedia and TripAdvisor. Building historical trust-based models of raters, our method is implemented as an external module and integrated with the collaborative filter through a post-recommendation component. The inter-user trust profiling history, traceability and authenticity are ensured by blockchain, since these profiles are stored as a smart contract in a private Ethereum network. Our empirical evaluation with HotelExpedia and Tripadvisor has consistently shown the positive impact of blockchain-based profiling on the quality (measured as recall) and transparency (determined via explanations) of recommendations.
Muhammad Danil Muis, Muhammad Rifki Fauzan, Parman Sukarno, Aulia Arif Wardana
This reserach build access control and file distribution management system for electronic diploma and transcript using ethereum smart contract and InterPlanetary File System (IPFS). The falsification of diplomas/transcripts is one of the problems in education. In Indonesia, falsification of diplomas/transcripts is a form of criminal act of falsifying letters. In addition, diplomas/transcripts that have not been digitalized make them easily damaged, lost, and difficult to manage. Therefore, this research developed digital diploma/transcript as digital twin from the hardcopy of diploma/tramscript. This research used IPFS to store data in a distributed system and Smart Contracts Blockchain to store and protect the digital diploma/transcript. The system also comes with access control to create and give approval for diplomas or transcripts to be published and saved into the system. Access control settings will be saved using the blockchain. This research using Quality of Service test method for measurethroughput, packet loss, and delay. Beside that, tis research also analysis the usage of Central Processing Unit and Random Access Memory from the system. Based on the test that has been done, the fake diploma/transcript detection system can be run properly by using 1 node to 5 nodes. The best throughput value during the process of making and validating the diploma/transcript is to use 1 node. The value of packet loss in the process of making and validating the certificate/transcript has a very good category. The value of delay in the process of making and validating the diploma/transcript has a very good category.
We present CELESTIAL, a framework for formally verifying smart contracts written in the Solidity language for the Ethereum blockchain. CELESTIAL allows programmers to write expressive functional specifications for their contracts. It translates the contracts and the specifications to F⋆ to formally verify, against an F⋆ model of the blockchain semantics, that the contracts meet their specifications. Once the verification succeeds, CELESTIAL performs an erasure of the specifications to generate Solidity code for execution on the Ethereum blockchain. We use CELESTIAL to verify several real-world smart contracts from different application domains. Our experience shows that CELESTIAL is a valuable tool for writing high-assurance smart contracts.
Current advances in information technology have brought about significant changes, including ways to carry out elections using computer technology known as e-voting. Blockchain underlies the popularity of the digital currency Bitcoin and some other digital money, sparking the start of a new era of Internet use, including electronic voting (e-voting) system. In this work, we proposed designing and implementing an evoting system powered by the Ethereum blockchain. We used real-world data from the Indonesian Election Commission (KPU) with 26 candidates and 15,725 voters from the Jelupang sub-district. The testing and evaluation results using three miners in the blockchain show that the system could commit around 23 transactions per second. All 15,725 votes are committed to the blockchain successfully within 12.75 minutes. The total time required for creating all blockchain accounts is 13.4 hours.
Youssef Faqir-Rhazoui, Javier Arroyo, Samer Hassan
Abstract Blockchain technology has enabled a new kind of distributed systems. Beyond its early applications in Finance, it has also allowed the emergence of novel new ways of governance and coordination. The most relevant of these are the so-called Decentralized Autonomous Organizations (DAOs). DAOs typically implement decision-making systems to make it possible for their online community to reach agreements. As a result of these agreements, the DAO operates automatically by executing the appropriate portion of code on the blockchain network (e.g., hire people, delivers payments, invests in financial products, etc). In the last few years, several platforms such as Aragon, DAOstack and DAOhaus, have emerged to facilitate the creation of DAOs. As a result, hundreds of these new organizations have appeared, with their communities interacting mediated by blockchain. However, the literature has yet to appropriately explore empirically this phenomena. In this paper, we aim to shed light on the current state of the DAO ecosystem. We review the three main platforms nowadays (Aragon, DAOstack, DAOhaus) which facilitate the creation and management of DAOs. Thus, we introduce their main differences, and compare them using quantitative metrics. For such comparison, we retrieve data from both the main Ethereum network ( mainnet ) and a parallel Ethereum network ( xDai ). We analyze data from 72,320 users and 2,353 DAO communities in order to study the three ecosystems across four dimensions: growth, activity, voting system and funds. Our results show that there are notable differences among the DAO platforms in terms of growth and activity, and also in terms of voting results. Still, we consider that our work is only a first step and that further research is needed to better understand these communities, and evaluate their level of accomplishment in reaching decentralized governance.