This paper proposes a comprehensive framework using blockchain architecture to create a decentralized applications store, in order to reduce the approval time for apps that are to be deployed on deployment systems i.e. applications stores, and specially for mobile platforms e.g. Apple and Google play stores. This work potentially can solve some of the existing challenges with the current centralized application approval process by Apple and Google. These companies currently charge a flat commission rate of 30% [1] of the total applications revenues from the applications owners. This commission is considered to be very high, especially for applications with revenues in the order of few million dollars. In addition, the length of the review period prior to deployment for any new or revised apps delays the release to the marketplace hence costing economic losses to the app owners. Currently, Apple and Google stores takes around two days and two hours respectively to review and approve the apps on their stores. However, by using decentralized technologies such as the blockchain, the time to review and publish a new or a revised app can be significantly reduced from few days to few minutesIn this paper a novel framework is proposed based on the blockchain architecture incorporating the Ethereum network, Interplanetary Files System (IPFS), VueJS, and a backend database. The framework is experimentally validated, and the results show the reduction in terms of the number of minutes to approve apps by the app stores.
Elizabeth C. Crites, Mary Maller, Sarah Meiklejohn, Rebekah Mercer
Token-curated registries (TCRs) are a mechanism by which a set of users are able to jointly curate a reputable list about real-world information. Entries in the registry may have any form, so this primitive has been proposed for use—and deployed—in a variety of decentralized applications, ranging from the simple joint creation of lists to helping to prevent the spread of misinformation online. Despite this interest, the security of this primitive is not well understood, and indeed existing constructions do not achieve strong or provable notions of security or privacy. In this paper, we provide a formal cryptographic treatment of TCRs as well as a construction that provably hides the votes cast by individual curators. Along the way, we provide a model and proof of security for an underlying voting scheme, which may be of independent interest. We also demonstrate, via an implementation and evaluation, that our construction is practical enough to be deployed even on a constrained decentralized platform like Ethereum.
Blockchain is a kind of technology which comprehensively uses cryptography, distributed databases, P2P communication, smart contracts and other technologies. In a decentralized and trustless network, it uses encryption algorithms to verify and store data in a chained data structure. Blockchain technology is a universal low-level technical architecture that generates and synchronizes data on distributed nodes through a consensus mechanism, and implements automatic execution of contract terms and data operations with the help of programmable scripts. This paper systematically sorts out the blockchain and deconstructs its key technical elements. Under this premise, the basic architecture of the blockchain system is analyzed starting from the architecture and the implementation protocol. Taking the application development of blockchain technology as the context and combining with the application scenarios of Bitcoin, Ethereum and Super Ledger, the technical principles, implementation paths, app-lication status and existing challenges are expounded. This paper seeks to provide readers with help and reference in the systematic learning and in-depth research of blockchain technology.
During the Coincheck incident, which recorded the largest damages in cryptocurrency history in 2018, it was demonstrated that using Mosaic token can have a certain effect. Although it seems attractive to employ tokens as countermeasures for cryptocurrency leakage, Mosaic is a specific token for the New Economy Movement (NEM) cryptocurrency and is not employed for other blockchain systems or cryptocurrencies. Moreover, although some volunteers tracked leaked NEM using Mosaic in the CoinCheck incident, it would be better to verify that the volunteers can be trusted. Simultaneously, if someone (e.g., who stole cryptocurrencies) can identify the volunteers, then that person or organization may be targets of them. In this paper, we propose an anonymous trust-marking scheme on blockchain systems that is universally applicable to any cryptocurrency. In our scheme, entities called token admitters are allowed to generate tokens adding trustworthiness or untrustworthiness to addresses. Anyone can anonymously verify whether these tokens were issued by a token admitter. Simultaneously, only the designated auditor and no one else, including nondesignated auditors, can identify the token admitters. Our scheme is based on accountable ring signatures and commitment, and is implemented on an elliptic curve called Curve25519, and we confirm that both cryptographic tools are efficient. Moreover, we also confirm that our scheme is applicable to Bitcoin, Ethereum, and NEM.
Compared with traditional insurance schemes, usage-based insurance (UBI) for vehicles is more economic and accurate for drivers since its insurance premium calculation depends on how vehicles are driven. However, UBI requires sensitive driving data to determine insurance premiums, and this could result in serious privacy breach for drivers. Meanwhile, existing UBI solutions rely on a centralized entity (i.e., the insurance company) to manage insurances. In this article, we design a decentralized and privacy-preserving UBI scheme, called DUBI, based on the blockchain technology and zero-knowledge proof. In our scheme, a smart contract running over the blockchain serves as a “decentralized” insurance company, while drivers continuously upload their committed driving data to the blockchain. Periodically, the driver submits accumulated driving statistics with a zero-knowledge proof to the smart contract, which verifies the proof and calculates the insurance premium from the submitted statistics. We formulate an ideal functionality for DUBI under the universal composability framework, and then provide a formal security proof for DUBI. Furthermore, we give in-depth analysis and performance evaluation for DUBI with an implementation based on Ethereum. It shows that DUBI is highly efficient in processing UBI insurances in both storage and computation: DUBI is about seven times more efficient than existing schemes in storage, and proof generation and verification take only 7 and 30 ms, respectively.
Smart Contracts (SC for short) are gaining momentum as a suitable technology for ensuring trusted execution of Business Processes (BP for short) in open environment. Nevertheless, the transactional semantics of SC which follow ACID transactions are not appropriate for BP characteristics. Indeed, it is admitted that ACID transactions are limited to cope with complex control structure and long running execution of BP. Transactional Business Processes (TBP for short) have emerged as an extension to ACID models to overcome these limits. A TBP ensures transactional reliability of advanced transactions having a control structure as complex as for BP. In this paper, we propose an approach that builds on SC and extends them to implement TBP. We extend Caterpillar, an existing BP execution engine developed on top of Ethereum, to implement our approach and support the execution of TBP.
The statistical concept of gambler’s ruin suggests that gambling has a large amount of risk. Nevertheless, gambling at casinos and gambling on the Internet are both hugely popular activities. In recent years, both prospect theory and laboratory-controlled experiments have been used to improve our understanding of risk attitudes associated with gambling. Despite theoretical progress, collecting real-life gambling data, which is essential to validate predictions and experimental findings, remains a challenge. To address this issue, we collect publicly available betting data from a DApp (decentralized application) on the Ethereum blockchain, which instantly publishes the outcome of every single bet (consisting of each bet’s timestamp, wager, probability of winning, userID and profit). This online casino is a simple dice game that allows gamblers to tune their own winning probabilities. Thus the dataset is well suited for studying gambling strategies and the complex dynamic of risk attitudes involved in betting decisions. We analyse the dataset through the lens of current probability-theoretic models and discover empirical examples of gambling systems. Our results shed light on understanding the role of risk preferences in human financial behaviour and decision-makings beyond gambling.
Blockchain technology has evolved into many applications and it has many advantages, especially in insurance business, because the Blockchain solutions minimize the time to process claims for losses and operational expenses. This paper compares the application of private and public Blockchain for insurance services through the experimental implementation of smart contracts based on Hyperledger Fabric and Ethereum. The results from the experiments are presented.
Previous studies have shown that cryptocurrencies could hedge equities. However, most of those studies did not take into account the recent cryptocurrencies bubbles in 2018 and domestic currencies. Therefore, this research aimed to study whether the hedge effectiveness of cryptocurrencies still exists. This research used five cryptocurrencies (bitcoin, ethereum, monero, ripple, and litecoin), equity indices (Indonesia, Malaysia, Vietnam, Thailand, and the Philippines), and iShares ETF MSCI World (developed world). Commodities-based hedging using iShares S&P GSCI Commodity-Indexed Trust was also analyzed as a comparison. The asymmetric generalized dynamic conditional correlation (AG-DCC) GARCH showed that one cryptocurrency could not significantly and consistently hedge equities while five equally weighted cryptocurrencies could marginally hedge equities. Meanwhile, the classical minimum variance model also showed that the hedge effectiveness of cryptocurrencies was insignificantly positive. Equity traders could add cryptocurrencies into portfolios when the purpose was to maximize the Sharpe ratio instead of hedging. Overall, commodities were the better hedge for Southeast Asia emerging markets.
Yassin M. Thibodeau Hafid, Dimitrios Makrakis, Etienne Elie
Nowadays, the proportion of the global supply of green energy sources (e.g., solar and wind) is increasing dramatically. Integrating these sources into the current smart grid is very challenging, given that the smart grid has centralized topology which is costly and inefficient. In particular, the current procedures used in the wholesale energy market are slow, time-consuming and thus expensive for small-scale energy sources (e.g., small-scale solar energy farms). Indeed, these sources are excluded in practice from the energy market. Thus, to integrate the increasing number of small-scale energy sources, there is a need to transform the smart grid into a decentralized system. A promising technology to realize this decentralization is Blockchain. With its characteristics like immutability, security, and decentralization, we believe that Blockchain will be the core technology for the future decentralized smart grid. In this paper, we propose a peer-to-peer (P2P) energy trading system based on Ethereum. The objective is to allow any participant (e.g., big/small producers and consumers) to securely trade energy with minimum cost. The proposed approach moves most of the processing and storage off-chain, with the objective to minimize the cost of on-chain (i.e., smart contract) processing and storage while guaranteeing the security of the trading process. Stable coins are used to pay for the trade so as to overcome the problem of the instability regarding cryptocurrency exchange rates. Our proposal has been implemented, tested and deployed on the Ethereum official test network Ropsten. The results show that the proposed approach implements the P2P trading process with very small cost, making it an affordable solution for all participants, including small-scale sources.
Fáber D. Giraldo, Barbosa Milton C., Carlos E. Gamboa
Blockchain technology has been presented as a support for trust needs between transactions in electronic information systems. Its successful use in cryptocurrencies has allowed it to explore its capabilities in commercial, industrial, and service systems, backed by the operational alternatives offered by Ethereum Smart Contracts and the cryptographic security of public and private key. These keys are used as a way to make online transactions anonymously, with the guarantee offered by the Blockchain network that they are executed safely. With the above in mind, this concept can be extended to the electoral processes, thus allowing its application in electronic voting systems, especially when the protocols currently used lack the trust factor between the different social actors. This document presents a proof of concept in which Blockchain and other technologies are applied, to allow interaction as an electronic voting system for the election of unique candidates. This has been achieved through the specification of an architecture designed especially for electoral processes, from which it is implemented and a simulation is carried out in order to obtain data that generates value, when evaluating Blockchain technology as an alternative to current voting systems.
The development of the Internet has increased the amount of data exponentially, and the reliable transmission, sharing, and storage of data have become the primary problems of data sharing. This article combines the decentralized and irreversible characteristics of the Ethereum blockchain, integrates IPFS distributed storage technology, and proposes a data sharing platform under a new technology environment to ensure data security, user rights protection, and high-speed data processing. Provide a new technology application environment for current data sharing.
Michael Rodler, Wenting Li, Ghassan Karame, Lucas Davi
Recent attacks exploiting errors in smart contract code had devastating consequences thereby questioning the benefits of this technology. It is currently highly challenging to fix errors and deploy a patched contract in time. Instant patching is especially important since smart contracts are always online due to the distributed nature of blockchain systems. They also manage considerable amounts of assets, which are at risk and often beyond recovery after an attack. Existing solutions to upgrade smart contracts depend on manual and error-prone processes. This paper presents a framework, called EVMPatch, to instantly and automatically patch faulty smart contracts. EVMPatch features a bytecode rewriting engine for the popular Ethereum blockchain, and transparently/automatically rewrites common off-the-shelf contracts to upgradable contracts. The proof-of-concept implementation of EVMPatch automatically hardens smart contracts that are vulnerable to integer over/underflows and access control errors, but can be easily extended to cover more bug classes. Our extensive evaluation on 14,000 real-world (vulnerable) contracts demonstrate that our approach successfully blocks attack transactions launched on these contracts, while keeping the intended functionality of the contract intact. We perform a study with experienced software developers, showing that EVMPatch is practical, and reduces the time for converting a given Solidity smart contract to an upgradable contract by 97.6 %, while ensuring functional equivalence to the original contract.
In this research, the evolution of Distributed Ledger Technology (DLT) in\nsupply chains has been mapped from the inception of the technology until June\n2020, utilising primarily public data sources. Two hundred seventy-one\nblockchain projects operating in the supply chain have been analysed on\nparameters such as their inception dates, types of blockchain, stages reached,\nsectors applied to and type of organisation that founded the project. We\nconfirm generally understood trends in the blockchain market with the creation\nof projects following the general hype and funding levels in the industry. We\nobserve most activity in the Agriculture/Grocery sector and the\nFreight/Logistics sector. We see the shift of market interest from primarily\nprivate companies (startups) to public companies and consortia and the change\nin blockchain adoption from Ethereum to Hyperledger. Finally, we observe higher\nsuccess and lower failure rates for Hyperledger-based projects in comparison to\nEthereum-based projects.\n
Distributed ledger technologies, the most famous of which are blockchains, emerged in 2009. as consensus solutions in the byzantine environment. In this thesis, the functionality of the most popular public blockchains is explained. The development of blockchains can be divided according to their functionalities. Bitcoin as the first public blockchain to solve the problem of double spending has the main functionality of digital money, ie. recording and transferring value. Ethereum as an innovation introduces smart contracts which significantly expand the functionality of the hitherto rather primitive Bitcoin’s scripting language. Currently, Ethereum is facing a problem of scalability, however, remedies arise naturally, without decreases of decentralization and network security. One of them is Telegram Open Network, a network that, with all the functionality of Ethereum, introduces instant hypercube routing and ”self-healing” vertical blockchain mechanism, thus improving scalability by several orders of magnitude. Due to the popularity of the field of blockchains and generally distributed ledgers, new decentralized platforms develop on a daily basis, hence, the possibility of interoperability among them is gaining in importance.
Abstract This research explores blockchain as a competitive advantage (CA) for higher education institutions (HEIs) in the Philippines. The respondents’ awareness of the relevance of blockchain use was also tested. The researcher aims to verify if blockchain is a foundational technology to be implemented in academe. Theoretical framework was formulated based on the knowledge procurement cycle and distributed learning ledger. The researcher proposes that conceptual framework, centered on blockchain (Ethereum), will enhance recordkeeping in education. Frequency, percentage, and weighted mean determined the degree of relevance of blockchain as CA of Philippine HEIs. One-way ANOVA determined respondents’ significant relationship (SR) with regard to blockchain awareness and identified SR of blockchain as CA over other colleges in terms of cost and differentiation. The results showed that students were most aware of the relevance of blockchain while professors were least aware. Both null hypotheses were accepted. There is no SR on the respondents’ awareness on the use of blockchain. Respondents considered technology relevant and a foundational technology in recordkeeping. The research proposes EduChain Activity Flow Model to enhance recordkeeping in the academe. It will offer ample job opportunities to students in the field of blockchain. Also, the researcher suggests that administrators may incorporate blockchain training as part of faculty development. This research will pave the way for future researchers to study other aspects of blockchain in education. Keywords: blockchain, blockchain technology, EduChain Activity Flow Model
Pamateni ugovori kao vrsta digitalnog i računalnog izvršavanja neke njemu specificirane programske logike mogu poslužiti u raznim primjenama gdje sudionici ne vjeruju jedan drugome i potreban im je posrednik ili decentralizirani medij kao blockchain gdje nitko neće imati kontrolu, a pametni ugovor će se svejedno moći izvršiti. Pametni ugovori imaju usku funkcionalnost ako se samo bave onim što se događa na blockchainu, ali ako ih želimo povezati sa vanjskim svijetom potreban je entitet imena Oracle, koji služi kao poveznica sa informacijama iz vanjskog svijeta i operacijama koje se jedino mogu izvršavati izvan blockchaina (npr. slanje novca preko bankarskog sustava itd.). Mi smo koristili Chainlink decentraliziranu Oracle mrežu i njihovu tehnologiju da bi povezali pametne ugovore sa vanjskim svijetom. Kreirali smo mobilnu i web aplikaciju te ih povezali sa pametnim ugovorom kreiranim na testnom Kovan Ethereum blockchainu. Funkcionalnost tog pametnog ugovora je bila a registrirani korisnici mogu prelaziti zadane rute te biti sigurni da će njihovi lokacijski podaci nastali prilikom izvršavanja rute na siguran način obraditi i biti upisani na blockchain pomoću Chainlink čvorova tj. operatora koji su uz pomoć dodatkovnog programa (eng. Data Adapter) procesirali i obradili te lokacijske podatke.
In the era of big data, modern data marketplaces have received much attention as they allow not only large enterprises but also individuals to trade their data. This new paradigm makes the data prone to various threats, including piracy, illegal reselling, tampering, illegal redistribution, ownership claiming, forgery, theft, misappropriation, etc. Although digital watermarking is a promising technique to address the above-mentioned challenges, the existing solutions in the literature are deemed to be incompetent in big data scenarios due to the following factors: V's of big data, involvement of multiple owners, incremental watermarking, large cover-size and limited watermark-capacity, non-interference, etc. In this paper, we propose a novel big data watermarking technique that leverages the power of blockchain technology and provides a transparent immutable audit trail for data movement in big data monetizing scenarios. In this context, we address all the crucial challenges mentioned above. We present a prototype implementation of the system as a proof of concept using Solidity on Ethereum platform, and we perform experimental evaluation to demonstrate its feasibility and effectiveness in terms of execution gas costs. To the best of our knowledge, this is the first proposal which deals with watermarking issues in the context of big data.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Akhmad Ridho Ashariansyah, Nur Iriawan, Adatul Mukarromah
Perdagangan merupakan sebuah kegiatan tukar menukar barang atau jasa yang dilakukan manusia untuk memenuhi kebutuhan hidup. Perkembangan sistem pembayaran yang dilakukan umat manusia dimulai dari sistem pertukaran barang atau barter, logam mulia seperti emas dan perak, koin, uang kartal, uang giral, dan uang elektronik (e-money). Selain itu, muncul cryptocurrency yaitu mata uang digital dengan sistem kriptografi dalam setiap proses transaksi datanya tanpa melalui pihak ketiga. Namun cryptocurrency memiliki kelemahan perubahan harga yang sangat besar dalam waktu yang sangat cepat. Pergerakan harga yang berfluktuasi sangat tinggi tersebut menyebabkan kekhawatiran pemilik aset kripto mengalami kerugian, maka pemodelan harga cryptocurrency sangat penting untuk dilakukan agar meminimalisir risiko kerugi-an. Berdasarkan pola pergerakan harga yang berfluktuasi sangat tinggi yang berbeda tiap periodenya maka dilakukanlah pemodelan harga cryptocurrency mengguna-kan Markov Switching Autoregressive (MSAR) dengan algoritma Expectation Maximization. Selain meminimkan risiko kerugian, penelitian ini juga ingin mengetahui model MSAR mana yang mampu mengklasifikasikan state dengan baik. Data yang digunakan yaitu harga harian cryptocurrency dengan nilai kapitalisasi pasar terbesar dari September 2015 hingga Januari 2020. Hasil penelitian menunjukkan bahwa bitcoin dan ripple menggunakan model MS(8)AR(1), sedangkan ethereum menggunakan model MS(9)AR(1). Selain itu model MS(8)AR(1) pada data ripple menjadi model dengan nilai akurasi tertinggi dibandingkan model lainnya dalam hal klasifikasi state.
Pedro Caetano Diniz Siqueira, José Walmir Gonçalves Duque
A evolucao da tecnologia e cada vez mais rapida e tem impacto direto na sociedade - o modo como as pessoas veem o dinheiro mudou drasticamente e a tecnologia comecou a afetar a economia com o nascimento do Bitcoin, a primeira Criptomoeda do mundo, que foi inicialmente proposta em 2008 e em 2018 inspirou este artigo. Em face ao cenario das Criptomoedas, este trabalho tem por objetivo desenvolver um prototipo de aplicacao de Crowdfunding, fazendo uso da Blockchain e que possa ser capaz de processar Smart Contracts dentro da Ethereum Network, a fim de demonstrar a efetividade da aplicacao de metodos, tecnicas e ferramentas adequadas a esse contexto moderno de tecnologia. Para o desenvolvimento da solucao, foi admitida a Criptomoeda Ethereum, totalmente digital e descentralizada. Fazendo uso de uma API disponibilizada pela Ethereum, a web3, foi possivel escrever as transacoes na Blockchain e, para uma interface amigavel, foi utilizada a biblioteca React.js. Em paralelo, para viabilizar a escrita dos contratos, foi utilizada a linguagem Solidity, baseada em Javascript. Como resultado do trabalho, obteve-se um sistema eletronico de transacao descentralizado que nao necessita de um intermediario, que conta com assinaturas digitais que permitem forte controle sobre propriedade prevencao de gasto duplo, tudo isso por meio de uma rede peer-to-peer que utiliza prova de trabalho para criar um registro publico, que e impraticavel para fraudadores modificarem. Portanto, o artigo oferece uma visao atual sobre aplicacoes envolvendo Criptomoedas e mostra o quao eficazes sao essas solucoes modernas referentes a transacoes de capital.
Current cryptocurrencies, such as Bitcoin and Ethereum, enable anonymity by using public keys to represent user accounts. On the other hand, inferring blockchain account types (i.e., miners, smart contracts or exchanges), which are also referred to as blockchain identities, is significant in many scenarios, such as risk assessment and trade regulation. Existing work on blockchain deanonymization mainly focuses on Bitcoin that supports simple transactions of cryptocurrencies. As the popularity of decentralized application (DApp) platform blockchains with Turing-complete smart contracts, represented by Ethereum, identity inference in blockchain faces new challenges because of user diversity and complexity of activities enabled by smart contracts. In this paper, we propose I$^2$GL, an identify inference approach based on big graph analytics and learning to address these challenges. Specifically, I$^2$GL constructs a transaction graph and aims to infer the identity of nodes using the graph learning technique based on Graph Convolutional Networks. Furthermore, a series of enhancement has been proposed by exploiting unique features of blockchain transaction graph. The experimental results on Ethereum transaction records show that I$^2$GL significantly outperforms other state-of-the-art methods.
With the increasing popularity of blockchain technology, it has also become a hotbed of various cybercrimes. As a traditional way of scam, the phishing scam has new means of scam in the blockchain scenario and swindles a lot of money from users. In order to create a safe environment for investors, an efficient method for phishing detection is urgently needed. In this paper, we propose a three steps framework to detect phishing scams on Ethereum by mining Ethereum transaction records. First, we obtain the labeled phishing accounts and corresponding transaction records from two authorized websites. According to the collected transaction records we build an Ethereum transaction network. Then, a network embedding method node2vec which can extract the latent features of accounts is used for subsequent phishing classification. Finally, to distinguish whether the account is a phishing account, we adopt the one-class support vector machine (SVM) to classify. The experimental result demonstrates that F-score of our phishing detection method can achieve 0.846, which verifies the validity of our model. To the best of our knowledge, this is the first work that investigates the phishing scams on Ethereum based on transaction records.