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
Abstract This research explores blockchain as a competitive advantage (CA) for higher education institutions (HEIs) in the Philippines. The respondentsâ 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 respondentsâ 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 respondentsâ 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 raÄunalnog izvrĆĄavanja neke njemu specificirane programske logike mogu posluĆŸiti u raznim primjenama gdje sudionici ne vjeruju jedan drugome i potreban im je posrednik ili decentralizirani medij kao blockchain gdje nitko neÄe imati kontrolu, a pametni ugovor Äe se svejedno moÄi izvrĆĄiti. Pametni ugovori imaju usku funkcionalnost ako se samo bave onim ĆĄto se dogaÄa na blockchainu, ali ako ih ĆŸelimo povezati sa vanjskim svijetom potreban je entitet imena Oracle, koji sluĆŸi kao poveznica sa informacijama iz vanjskog svijeta i operacijama koje se jedino mogu izvrĆĄavati izvan blockchaina (npr. slanje novca preko bankarskog sustava itd.). Mi smo koristili Chainlink decentraliziranu Oracle mreĆŸu 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 Äe njihovi lokacijski podaci nastali prilikom izvrĆĄavanja rute na siguran naÄin obraditi i biti upisani na blockchain pomoÄu Chainlink Ävorova tj. operatora koji su uz pomoÄ 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.
Internet of Things (IoT) is an advanced computing network where all physical objects are connected to the internet. All these objects are able to communicate and interact with each other using many technologies such as radio-frequency identification (RFID) technology, wireless technologies and other sensors technologies. Security concept is the main concern to ensure the sustainable development in IoT and to achieve confidentiality, Integrity, Availability (CIA) and Privacy. Blockchain (BC) is a technology based on the concept of trust and security that is the base of in the cryptocurrency such as Bitcoin and Ethereum. BC has three main pillars of transparency, immutability and distributed DB. Nowadays, Blockchain is paving the way to provide security and privacy in peer-to-peer networks with similar topologies to IoT. This paper proposes an integrated framework for implementing IoT with blockchain technology to guarantee high level of security and validation process based on the integration between consensus algorithms of blockchain (PBFT and Tangle). In addition, this paper proposes a direction algorithm to direct IoT transactions to appropriate BC algorithm to be validated by PBFT or Tangle. The propose framework ensure security, scalability and high performance by optimizing the data transmission overhead and enhancing the validation process by using the propose direction algorithm with reducing both of the resource utilization and the latency time. The conducted experimental results for the propose framework state that the latency time is reduced by 50% than using each consensus BC algorithm separately and mitigate the apprehensive from Sybil attack because of the load balance between consensus algorithms and the dynamic of validation.
Ashish Rajendra Sai, Jim Buckley, Brian Fitzgerald, Andrew Le Gear
Bitcoin introduced delegation of control over a monetary system from a select few to all who participate in that system. This delegation is known as the decentralization of controlling power and is a powerful security mechanism for the ecosystem. After the introduction of Bitcoin, the field of cryptocurrency has seen widespread attention from industry and academia, so much so that the original novel contribution of Bitcoin, i.e., decentralization, may be overlooked, due to decentralizationsâ assumed fundamental existence for the functioning of such crypto-assets. However, recent studies have observed a trend of increased centralization in cryptocurrencies such as Bitcoin and Ethereum. As this increased centralization has an impact the security of the blockchain, it is crucial that it is measured, towards adequate control. This research derives an initial taxonomy of centralization present in decentralized blockchains through rigorous synthesis using a systematic literature review. This is followed by iterative refinement through expert interviews. We systematically analyzed 89 research papers published between 2009 and 2019. Our study contributes to the existing body of knowledge by highlighting the multiple definitions and measurements of centralization in the literature. We identify different aspects of centralization and propose an encompassing taxonomy of centralization concerns. This taxonomy is based on empirically observable and measurable characteristics. It consists of 13 aspects of centralization, classified over six architectural layers: Governance, Network, Consensus, Incentive, Operational, and Application. We also discuss how the implications of centralization can vary depending on the aspects studied. We believe that this review and taxonomy provides a comprehensive overview of centralization in decentralized blockchains involving various conceptualizations and measures.
Elizabeth Nathania Witanto, Yustus Eko Oktian, Sang-Gon Lee, Jin-Heung Lee
As the usage growth rate of Internet of Things (IoT) devices is increasing, various issues related to these devices need attention. One of them is the distribution of the IoT firmware update. The IoT devicesâ software development does not end when the manufacturer sells the devices to the market. It still needs to be kept updated to prevent cyber-attacks. The commonly used firmware update process, over-the-air (OTA), mostly happens in a centralized way, in which the IoT devices directly download the firmware update from the manufacturerâs server. This central architecture makes the manufacturerâs server vulnerable to single-point-of-failure and latency issues that can delay critical patches from being applied to vulnerable devices. The Open Connectivity Foundation (OCF) is one organization contributing to providing interoperability services for IoT devices. In one of their subject areas, they provide a firmware update protocol for IoT devices. However, their firmware update process does not ensure the integrity and security of the patches. In this paper, we propose a blockchain-based OCF firmware update for IoT devices. Specifically, we introduce two types of firmware update protocol, direct and peer-to-peer updates, integrated into OCF firmware update specifications. In the direct scenario, the device, through the IoT gateway, can download the new firmware update from the manufacturerâs server. Meanwhile, in the peer-to-peer scheme, the device can query the update from the nearby gateways. We implemented our protocol using Raspberry Pi hardware and Ethereum-based blockchain with the smart contracts to record metadata of the manufacturerâs firmware updates. We evaluated the proposed systemâs performance by measuring the average throughput, the latency, and the firmware update distributionâs duration. The analysis results indicate that our proposal can deliver firmware updates in a reasonable duration, with the peer-to-peer version having a faster completion time than the direct one.
Recursive Length Prefix (RLP) is used to encode a wide variety of data in Ethereum, including transactions. The work described in this paper provides a formal specification of RLP encoding and a verified implementation of RLP decoding, developed in the ACL2 theorem prover. This work has led to improvements to the Ethereum documentation and additions to the Ethereum test suite.
William Pourmajidi, Lei Zhang, John Steinbacher, Tony Erwin · 5 authors
Service Level Agreements (SLA) are employed to ensure the performance of Cloud solutions. When a component fails, the importance of logs increases significantly. All departments may turn to logs to determine the cause of the issue and find the party at fault. The party at fault may be motivated to tamper with the logs to hide their role. We argue that the critical nature of Cloud logs calls for immutability and verification mechanism without the presence of a single trusted party. This article proposes such a mechanism by describing a blockchain-based log storage system, called Logchain, which can be integrated with existing private and public blockchain solutions. Logchain uses the immutability feature of blockchain to provide a tamper-resistance platform for log storage. Additionally, we propose a hierarchical structure to address blockchainsâ scalability issues. To validate the mechanism, we integrate Logchain into Ethereum and IBM Blockchain. We show that the solution is scalable and perform the analysis of the cost of ownership to help a reader select an implementation that would address their needs. The Logchain's scalability improvement on a blockchain is achieved without any alteration of blockchainsâ fundamental architecture. As shown in this work, it can function on private and public blockchains and, therefore, can be a suitable alternative for organizations that need a secure, immutable log storage platform.
The land is an immovable property. Tracing the details of property and involvement of third-party is the challenging task. Fraudulent may forge documents and mislead the purchaser and if it's a litigate land it takes many years in the court battle, waste of time and resource. Problems escalate in this current land registration process which is non-transparent. Such demands made to integrate technologies and lead to the blooming of blockchain technology. Blockchain is a decentralized and transparent ledger. The smart contract is the confirmable and permanent document between two parties. This proposed framework is used to develop a registration application system in which new purchaser has to register and continue with the further process. The proposed research work is implemented using SHA256 algorithm which provides unique hash values for the messages getting stored in blocks and ethereum blockchain technology is used to store both smart contract and transaction details.
Tasneem Darwish, Kamalrulnizam Abu Bakar, Gen Matsuda, Ahmed Aliyu · 13 authors
Blockchain provides a distributed digital ledger platform for not only cryptocurrencies but also many other distributed applications. Blockchain platforms work flow and performance are controlled by the used consensus algorithms. Although many studies evaluated cryptocurrency from the Shariah perspective, they focused only on the cryptocurrency concept and did not consider the underlying blockchain technology. However, designing a Shariah compliant application on top of a non Shariah compliant platform does not fulfil the requirements of Shariah. Therefore, it is necessary to use a Shariah compliant blockchain platform in order to produce Shariah compliant blockchain applications. To support the production of Shariah compliant blockchain applications, this study provides a comparative analysis of the most used consensus algorithms in blockchain platforms. In particular, the considered consensus algorithms are evaluated from a Shariah perspective. In conclusion, based on the conducted evaluation some of the widely used blockchain platforms (e.g. Bitcoin and Ethereum) are found to be not compliant with the Shariah rules due to using a consensus algorithm that is not Shariah compliant.
Premda je nastao prije viĆĄe od 10 godina, u posljednje vrijeme rijeÄ blockchain se moĆŸe Äuti gotovo svakodnevno. Razlog tome su njegova revolucionarna svojstva i primjene, koje predvode internet u novu eru. Svjedoci smo nastajanju decentraliziranih aplikacija Äiji je temelj upravo blockchain. Decentralizirane aplikacije joĆĄ su u ranoj fazi, ali postoji sve veÄa i veÄa potreba za spremanjem podatka na blockchain. U ovom diplomskom radu objaĆĄnjeno je funkcioniranje blockchaina te nastajanje blokova. Na praktiÄnom primjeru uspjeĆĄno je prikazano rjeĆĄenje spremanja i Äitanja podataka u i iz Ethereum blockchaina kroz igru za viĆĄe igraÄa. Trenutno postoji nekolicina ideja kojima bi se poboljĆĄalo spremanje podataka u blockchain, ali svaka ideja ima svoje prednosti i mane te je na korisniku da odluÄi koja mu platforma najviĆĄe odgovara. Uz sve pozitivne primjere blockchaina, postoji i velika negativna strana, a to je velik utroĆĄak energije na rudarenje, odnosno spremanje podataka. Kako blockchain konstantno napreduje, ovaj problem se namjerava rijeĆĄiti u bliskoj buduÄnosti, prelaskom s "proof of work" naÄinom rudarenja, na "proof of stake" naÄin, gdje Äe manje ljudi sudjelovati u rudarenju, ĆĄto Äe se pozitivno odraziti na okoliĆĄ.
Permissioned and private blockchain platforms are increasingly used in todayâs industry. This paper provides a comprehensive and comparative study of the 5 major frameworks (Fabric, Ethereum, Quorum, MultiChain and R3 Corda) with regard to the community activities, performance, scalability, privacy and adoption criteria. Based on a literature review, this study shows that even if Fabric is promising, the final selection of a framework for a specific case-study is always a trade-off. Finally, lessons learnt are given for industrial practitioners and researchers.
The CAP theorem says that no blockchain can be live under dynamic participation and safe under temporary network partitions. To resolve this availability-finality dilemma, we formulate a new class of flexible consensus protocols, ebb-and-flow protocols, which support a full dynamically available ledger in conjunction with a finalized prefix ledger. The finalized ledger falls behind the full ledger when the network partitions but catches up when the network heals. Gasper, the current candidate protocol for Ethereum 2.0's beacon chain, combines the finality gadget Casper FFG with the LMD GHOST fork choice rule and aims to achieve this property. However, we discovered an attack in the standard synchronous network model, highlighting a general difficulty with existing finality-gadget-based designs. We present a construction of provably secure ebb-and-flow protocols with optimal resilience. Nodes run an off-the-shelf dynamically available protocol, take snapshots of the growing available ledger, and input them into a separate off-the-shelf BFT protocol to finalize a prefix. We explore connections with flexible BFT and improve upon the state-of-the-art for that problem.
Cryptocurrency like Bitcoin, Ethereum and many others are closely affiliated with the financial technology (fintech) industry. These digital or virtual currencies are encrypted using cryptography and distributed on public ledger (blockchain) across decentralised peer-to-peer (P2P) networks. Since cryptocurrencies are issued by private entities and technically beyond the controls of any states, they may be exploited by criminals for illicit purposes such as money laundering, terrorism financing and many others. Thus, this article will examine whether cryptocurrency amounts to a new form of money under the existing rules on financial services and analyse how it should be regulated. This study is a qualitative research that adopts pure legal research methodology by analysing existing laws on national currency and digital currency. Further, the study analysed other secondary sources including academic books, journal articles, conference papers, and other materials in newspapers or reputable websites. The output of the research is expected to provide an overview on the regulatory framework for cryptocurrency in Malaysia. In conclusion, the government has favoured a minimalist approach so as not to stiffen the innovation and future development of cryptocurrency in the country.
Abstract The explosive epidemic of the coronavirus (COVID-19) has exposed the constraints in health care systems to handle public health emergencies. It's evident that adopting innovative technologies reminiscent of blockchain will facilitate in eective designing operations and resource deployments. Within the health care sector to improve the information management system by reducing delays in regulative approvals, communication between dierent stakeholders of the chain with the help of blockchain technology. To ensure authenticity of the information collected from public and government agencies, blockchain based system plays an important role. This paper tends to review implementation of blockchain application and opportunities in combating the COVID-19 pandemic. To trace according information involving in recent cases, deaths and recovered cases maintaining through blockchain storage system that has been proposed and implemented blockchain system based on Ethereum smart contract. An interactive model and respective algorithm has been explained with detailed analysis on information integrity, security, transparency and traceability.
Ilhaam A. Omar, Raja Jayaraman, Khaled Salah, Mecit Can Emre Simsekler · 6 authors
BACKGROUND: Clinical Trials (CTs) help in testing and validating the safety and efficacy of newly discovered drugs on specific patient population cohorts. However, these trials usually experience many challenges, such as extensive time frames, high financial cost, regulatory and administrative barriers, and insufficient workforce. In addition, CTs face several data management challenges pertaining to protocol compliance, patient enrollment, transparency, traceability, data integrity, and selective reporting. Blockchain can potentially address such challenges because of its intrinsic features and properties. Although existing literature broadly discusses the applicability of blockchain-based solutions for CTs, only a few studies present their working proof-of-concept. METHODS: We propose a blockchain-based framework for CT data management, using Ethereum smart contracts, which employs IPFS as the file storage system to automate processes and information exchange among CT stakeholders. CT documents stored in the IPFS are difficult to tamper with as they are given unique cryptographic hashes. We present algorithms that capture various stages of CT data management. We develop the Ethereum smart contract using Remix IDE that is validated under different scenarios. RESULTS: The proposed framework results are advantageous to all stakeholders ensuring transparency, data integrity, and protocol compliance. Although the proposed solution is tested on the Ethereum blockchain platform, it can be deployed in private blockchain networks using their native smart contract technologies. We make our smart contract code publicly available on Github. CONCLUSIONS: We conclude that the proposed framework can be highly effective in ensuring that the trial abides by the protocol and the functions are executed only by the stakeholders who are given permission. It also assures data integrity and promotes transparency and traceability of information among stakeholders.
Efficient and reliable access control in smart cities is critical for the protection of various resources for decision making and task execution. Existing centralized access control schemes suffer from the limitations of single point of failure, low reliability, and poor scalability. This article, therefore, proposes a distributed and reliable access control framework for smart cities by combining the blockchain smart contract technology and the attribute-based access control (ABAC) model. The framework consists of one policy management contract (PMC) for managing the ABAC policies, one subject attribute management contract (SAMC) for managing the attributes of subjects (i.e., entities accessing resources), one object attribute management contract (OAMC) for managing the attributes of objects (i.e., resources being accessed), and one access control contract (ACC) for performing the access control. To show the feasibility of the proposed framework, we construct a local private Ethereum blockchain system to implement the four smart contracts and also conduct experiments to evaluate the monetary cost as well as to compare the proposed framework with an existing access control list (ACL)-based scheme. The experimental results show that although the proposed scheme consumes more money than the ACL-based scheme at the deployment stage, it introduces less monetary cost during the system running especially for large-scale smart cities.
Jiachi Chen, Xin Xia, David Lo, John Grundy · 6 authors
Smart contracts are Turing-complete programs running on the blockchain. They are immutable and cannot be modified, even when bugs are detected. Therefore, ensuring smart contracts are bug-free and well-designed before deploying them to the blockchain is extremely important. A contract defect is an error, flaw or fault in a smart contract that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. Detecting and removing contract defects can avoid potential bugs and make programs more robust. Our previous work defined 20 contract defects for smart contracts and divided them into five impact levels. According to our classification, contract defects with seriousness level between 1-3 can lead to unwanted behaviors, e.g., a contract being controlled by attackers. In this paper, we proposeDefectChecker, a symbolic execution-based approach and tool to detect eight contract defects that can cause unwanted behaviors of smart contracts on the Ethereum blockchain platform.DefectCheckercan detect contract defects from smart contractsâ bytecode. We verify the performance ofDefectCheckerby applying it to an open-source dataset. Our evaluation results show thatDefectCheckerobtains a high F-score (88.8 percent in the whole dataset) and only requires 0.15s to analyze one smart contract on average. We also appliedDefectCheckerto 165,621 distinct smart contracts on the Ethereum platform. We found that 25,815 of these smart contracts contain at least one of the contract defects that belongs to impact level 1-3, including some real-world attacks.
JoĂŁo Henrique Faes Battisti, MaurĂcio A. Pillon, Guilherme Koslovski, Charles C. Miers
A considerable number of electronic transaction systems employ classicapproaches based on centralized trust mechanisms, not exploitingthe latest technological advances. Alternatively, the concept ofblockchain stands out, elaborated without the need for this centralizedtrust, but rather dependent on securely chained technologies in whichthe elements involved can conduct secure negotiations. Blockchain isdesigned to address security and distributed system issues through theuse of encryption, algorithms, P2P networks, and consensus mechanisms.This paper presents a Denial of Service (DoS) security analysisof the more traditional Practical Byzantine Fault Tolerance (PBFT)and Proof of Work (PoW) consensus mechanisms available onMultichain and Ethereum solutions based on a private / consortiumblockchain scenario. We present our results of a controlled DoSattack, revealing the importance and need for security-relatedanalysis of blockchain implementations of private / consortiumblockchains.
This paper investigates volatility spillovers among six competitor Cryptocurrencies from August 8, 2015 to September 01, 2019. A Generalized VAR framework is used to measure time varying spillovers index. Results provide evidence of (i) a rise in volatility spillovers transmitted among monitored Cryptocurrencies since the second quarter of 2017. (ii) Ethereum acts as the major contributor on spillovers index, contrary to Ripple that presents the main recipient of spillovers. (iii) the pairwise (Monero-Ripple) and (Bitcoin-Ethereum) present a low connectedness level driving consequently beneficial diversification opportunities for cryptocurrency investors.