Sam Goundar, Rahul Chand, Fariha Tafsil, Reema Mala · 5 authors
The emergence of the Internet has opened a world of possibilities to connect and interact through web portals and to exchange information over the network. In the past decade, buying and selling of goods and services online has become more common through e-commerce. With the advent of Cryptocurrencies, the possibilities of e-commerce have reached new heights for all web users who see potential in this technology. Cryptocurrencies have opened new dimensions based on a Blockchain technology for e-commerce through decentralization; increased privacy and digitalization of coins allow users to anonymously trade online. This has become more common in the Darknet, which is simply the unindexed side of the Internet. This chapter compares the three Cryptocurrencies, namely bitcoin, ethereum and monero, used for e-commerce in the Darknet.
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 više od 10 godina, u posljednje vrijeme riječ blockchain se može čuti gotovo svakodnevno. Razlog tome su njegova revolucionarna svojstva i primjene, koje predvode internet u novu eru. Svjedoci smo nastajanju decentraliziranih aplikacija čiji je temelj upravo blockchain. Decentralizirane aplikacije još su u ranoj fazi, ali postoji sve veća i veća potreba za spremanjem podatka na blockchain. U ovom diplomskom radu objašnjeno je funkcioniranje blockchaina te nastajanje blokova. Na praktičnom primjeru uspješno je prikazano rješenje spremanja i čitanja podataka u i iz Ethereum blockchaina kroz igru za više igrača. Trenutno postoji nekolicina ideja kojima bi se poboljšalo spremanje podataka u blockchain, ali svaka ideja ima svoje prednosti i mane te je na korisniku da odluči koja mu platforma najviše odgovara. Uz sve pozitivne primjere blockchaina, postoji i velika negativna strana, a to je velik utrošak energije na rudarenje, odnosno spremanje podataka. Kako blockchain konstantno napreduje, ovaj problem se namjerava riješiti u bliskoj budućnosti, prelaskom s "proof of work" načinom rudarenja, na "proof of stake" način, gdje će manje ljudi sudjelovati u rudarenju, što će se pozitivno odraziti na okoliš.
Although it originated more than 10 years ago, the word blockchain has been around lately can hear almost daily. The reason for this is its revolutionary properties and applications, leading the internet into a new era. We are witnessing the emergence of decentralized an application whose foundation is precisely blockchain. Decentralized applications are still at an early stage, but there is a growing need to store data on the blockchain. In this diploma thesis, the functioning of the blockchain and its origin are explained blocks. The save and read solution was successfully demonstrated on a practical example data to and from the Ethereum blockchain through a multiplayer game. There are currently a few ideas that would improve the storage of data in the blockchain, but each idea has its own advantages and disadvantages and it is up to the user to decide which platform suits him best.
With all the positive examples of blockchain, there is also a big downside, and that is a big one energy consumption for ie data storage. How to blockchain constantly As it progresses, this problem is intended to be solved in the near future, by switching from “proof of work way of mining, in the proof of stake way, where fewer people will participate in which will have a positive impact on the environment.
Prabhat Kumar, Randhir Kumar, Govind P. Gupta, Rakesh Tripathi
Abstract With the advancement of blockchain technology, and the proliferation of Internet of things (IoT)‐driven devices, the blockchain‐IoT applications is changing the perception and working infrastructure of smart networks. Blockchain supports decentralized architecture and provides secure management, authentication, and access to IoT systems by deploying smart contracts provided by Ethereum. The growing demand and expansion of blockchain‐IoT systems is generating large volume of sensitive data. Moreover, distributed denial‐of‐service (DDoS) attacks are the most challenging threats to smart contracts in blockchain‐IoT systems. The 2016 decentralized autonomous organization and 2017 parity wallet attacks exposed the critical fault‐lines among Ethereum smart contracts. Currently, there is no security mechanism available for smart contracts after its deployment in blockchain‐IoT systems. In order to address these challenges, first we use two artificial intelligence techniques, random forest (RF) and XGBoost that gives full autonomy in decision making capabilities in the proposed security framework. Second, for data load balancing and distributed file storage of IoT data, interplanetary file system is suggested. Finally, we are the first to propose a distributed framework based on fog computing to detect DDoS attacks in smart contracts. The performance of the detection system is evaluated using actual IoT dataset, namely, BoT‐IoT. The proposed system is evaluated in terms of accuracy (AC), detection rate (DR), and false alarm rate (FAR). The results confirms the superiority of the proposed framework over some of the recent state‐of‐art techniques in detecting rare attacks. The proposed framework has achieved DR up to 99.99% using RF by using 10 features of BoT‐IoT dataset.
Alexander Leid, Brink van der Merwe, Willem Visser
Ethereum smart contract exploits have inflicted enormous monetary damage due to vulnerabilities introduced accidentally by the contract authors. Many of these errors can now be detected automatically by a growing number of security analysis tools that specifically target the most common vulnerabilities present in the Ethereum smart contract ecosystem. The aim of this work is to identify state-of-the-art security analysis tools that assist auditors in automatically testing and verifying real-world contracts. We compare two such symbolic executioners, Manticore (which we also extend) and Mythril, and one fuzz tester, Echidna, to evaluate their effectiveness when analysing a set of challenge contracts hosted online, as well as twenty of the most popular ERC-20 tokens found on the main Ethereum network. Our results showed that the tools were able to solve 24 of the 39 challenge contracts and both symbolic tools achieved on average more than 80% code coverage on successful evaluations of the popular ERC-20 token data. Code coverage plateaued after the second symbolic transaction, suggesting a good performance target for continuous integration environments.
Permissioned and private blockchain platforms are increasingly used in today’s 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.
The trade of electricity on the free market is realized through energy exchanges. This article describes the Electricity Trading Web Platform, which stores information about Ethereum Blockchain transactions and the rest of the information in a relational database.
Sreenivas Sudarshan Seshadri, David Rodriguez, Mukunda Subedi, Kim‐Kwang Raymond Choo · 7 authors
Unlike conventional servers housed in a centralized and secured indoor environment (e.g., data centers), Internet-of-Things (IoT) devices such as sensor/actuator are geographically distributed and may be closely located to the physical systems where IoT devices are utilized. However, the resource-constrained nature of IoT devices limits their capacity to deploy sophisticated security solutions. The proposed approach assumes that a device can be compromised and hence, the need to be able to automatically isolate the compromised device(s). In order to enforce security policies even when devices are compromised, we propose using blockchain in the monitoring framework. Unlike existing centralized or distributed security solutions (which do not consider the possibility that the solutions themselves can be compromised), the proposed blockchain-based framework can enforce the security policies as long as a majority of the devices are not compromised. By employing the permissioned blockchain (Hyperledger Fabric) and add-on hardware modules, the proposed framework offers significantly lower latency and overhead compared to permissionless blockchain frameworks (e.g., Ethereum) and allows existing IoT devices to join the framework without modification.
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.
This study explores the connectedness between cryptocurrencies (Bitcoin, Ethereum, Ripple, Bitcoin cash and Ethereum Operating System) and major stock markets (NYSE composite index, NASDAQ composite index, Shanghai Stock Exchange, Nikkei 225 and Euronext NV). Using the asymmetric dynamic conditional correlation (ADCC) and wavelet coherence approaches, we document a significant time-varying conditional correlation between the majority of the cryptocurrencies and stock market indices and that the negative shocks play a more prominent role than the positive shocks of the same magnitude. Overall, our findings explore potential avenues for diversification for investors across cryptocurrencies and major stock markets.
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 contracts’ 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.
João Henrique Faes Battisti, Maurício 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 describes the Distributed Ledger Network Analyzer (DiLeNA), a new software tool for the analysis of the transactions network recorded in Distributed Ledger Technologies (DLTs). The set of transactions in a DLT forms a complex network. Studying its characteristics and peculiarities is of paramount importance, in order to understand how users interact in the distributed ledger system. The tool design and implementation is introduced and some results are provided. In particular, the Bitcoin and Ethereum blockchains, i.e. the most famous and used DLTs at the time of writing, have been analyzed and compared.