A. Timofeev, O. Lebedinskaya, Roman Veynberg, A. A. Grigorev
This article presents prospects of the development of cryptocurrency in Russia, examines the principles of the operation of Bitcoin as main currency nowadays and its application in the real economic sector. Identifies and substantiates the advantages and disadvantages of this technology, as a result, the degree of influence of cryptocurrency and the consequences of its usage in the Russian economy. At present, over 1000 types of cryptocurrencies exist. In this paper, two of them are analyzed: the first cryptocurrency, the leader with the stabilized volatility and price: Bitcoin, and rather a new application for cryptocurrency which was skyrocketed as the second world popular: Ethereum. In this research paper we set an objective to compare Bitcoin and Ethereum, determine problems of cryptocurrency market in Russia and the prospects for development of their usage. In addition, authors are describing history of the research subject and trends to develop: from Bitcoin to Ethereum evolution.
Mining is one of the core elements of the proof-of-work based cryptocurrency economy. In this paper we investigate the generic landscape and hierarchy of miners on the example of Ethereum and Zcash, two blockchains that are among the top 5 in terms of USD value of created coins. Both chains used ASIC resistant proofs-of-work which favors GPU mining in order to keep mining decentralized. This however has changed with recent introduction of ASIC miners for these chains. This transition allows us to develop methods that might detect hidden ASIC mining in a chain (if it exists), and to study how the introduction of ASICs effects the decentralization of mining power. Finally, we describe how an attacker might use public blockchain information to invalidate the privacy of miners, deducing the mining hardware of individual miners and their mining rewards.
Mauro C. Argañaraz, Mario Berón, Miguel Alfredo Bustos, Pedro Rangel Henriques · 5 authors
Ethereum es el principal ecosistema basado en blockchain que proporciona un entorno para codificar y ejecutar contratos inteligentes, propiedad que en estos últimos años recibió gran atención por las nuevas aplicaciones comerciales y, también, por la comunidad científica. El proceso de escritura de contratos seguros y de buen desempeño en la plataforma Ethereum es un gran desafío para los desarrolladores. Implica la aplicación de paradigmas de programación no convencionales debido a las características inherentes de la ejecución de programas de computación distribuida. Además, los errores en los contratos desplegados pueden tener graves consecuencias debido al acoplamiento inmediato del código del contrato y las transacciones financieras. El manejo directo de los activos significa que las fallas tienen más probabilidades de ser relevantes para la seguridad y tienen mayores consecuencias económicas que los errores en las aplicaciones típicas. Una serie de reportes de incidentes muestran que los problemas de seguridad se han utilizado con propósitos fraudulentos. En este artículo, se describe una línea de investigación que se enfoca en fortalecer los aspectos de seguridad, basado en una base sólida de diseño, patrones de código establecidos y probados que faciliten el proceso de escritura de código funcional y libre de errores, para proporcionar una herramienta que permita analizar y detectar falencias de manera automática.
Traditional cloud Service Level Agreement (SLA) suffers from lacking a trustworthy platform for automatic enforcement. The emerging blockchain technique brings in an immutable solution for tracking transactions among business partners. However, it is still very challenging to prove the credibility of possible violations in the SLA before recording them onto the blockchain. To tackle this challenge, we propose a witness model using game theory and the smart contract techniques. The proposed model extends the existing service model with a new role called “witness” for detecting and reporting service violations. Witnesses gain revenue as an incentive for performing these duties, and the payoff function is carefully designed in a way that trustworthiness is guaranteed: in order to get the maximum profit, the witness has to always tell the truth. This is analyzed and proved through game theory using the Nash equilibrium principle. In addition, an unbiased sortition algorithm is proposed to ensure the randomness of the independent witnesses selection from the decentralized witness pool, to avoid possible unfairness or collusion. An auditing mechanism is also introduced in the paper to detect potential irrational or malicious witnesses. We have prototyped the system leveraging the smart contracts of Ethereum blockchain. Experimental results demonstrate the feasibility of the proposed model and indicate good performance in accordance with the design expectations.
We present models that utilize smart contracts and interledger mechanisms to provide decentralized authorization for constrained IoT devices. The models involve different tradeoffs in terms of cost, delay, complexity, and privacy, while exploiting key advantages of smart contracts and multiple blockchains that communicate with interledger mechanisms. These include immutably recording hashes of authorization information and policies in smart contracts, resilience through the execution of smart contract code on all blockchain nodes, and cryptographically linking transactions and IoT events recorded on different blockchains using hash and time-lock mechanisms. The proposed models are evaluated on the public Ethereum testnets Rinkeby and Ropsten, in terms of execution cost (gas), delay, and reduction of data that needs to be sent to the constrained IoT devices.
Transaction privacy is a hard problem on an account-based blockchain such as Ethereum. While Ben-Sasson et al. presented the Zerocash protocol [BCG+14] as a decentralized anonymous payment (DAP) scheme standing on top of Bitcoin, no study about the integration of such DAP on top of a ledger defined in the account model was provided. In this paper we aim to fill this gap and propose ZETH, an adaptation of Zerocash that can be deployed on top of Ethereum without making any change to the base layer. Our study shows that not only ZETH could be used to transfer Ether, the base currency of Ethereum, but it could also be used to transfer other types of smart contract-based digital assets. We propose an analysis of ZETH's privacy promises and argue that information leakages intrinsic to the use of this protocol are controlled and well-defined, which makes it a viable solution to support private transactions in the context of public and permissioned chains.
Crowdfunding has become a popular form of collective funding, in which small donations or investments, made by groups of people, support the development of new projects in exchange of free products or different types of recognition. Social network sites, on the other hand, promote user cooperation and currently are at the basis of any individuals cyber-interactions. In this paper, we present LikeStarter, a blockchain-based decentralized platform that combines social interactions with crowdfunding mechanisms, allowing any user to raise funds while becoming popular in the social network. Being built over the Ethereum blockchain, LikeStarter is structured as a Decentralized Autonomous Organization (DAO), that fosters crowdfunding without the intervention of any central authority, and recognizes the active role of donors, enabling them to support artists or projects, while making profits.
This paper contributes a shred of quantitative evidence to the embryonic literature as well as existing empirical evidence regarding spillover risks among cryptocurrency markets. By using VAR (Vector Autoregressive Model)-SVAR (Structural Vector Autoregressive Model) Granger causality and Student’s-t Copulas, we find that Ethereum is likely to be the independent coin in this market, while Bitcoin tends to be the spillover effect recipient. Our study sheds further light on investigating the contagion risks among cryptocurrencies by employing Student’s-t Copulas for joint distribution. This result suggests that all coins negatively change in terms of extreme value. The investors are advised to pay more attention to ‘bad news’ and moving patterns in order to make timely decisions on three types (buy, hold, and sell).
Popular blockchain such as Ethereum and several others execute complex transactions in blocks through user defined scripts known as smart contracts. Normally, a block of the chain consists of multiple transactions of smart contracts which are added by a miner. To append a correct block into blockchain, miners execute these smart contract transactions (SCT) sequentially. Later the validators serially re-execute the SCT of the block. In the current era of multi-core processors, by employing serial execution of the transactions, the miners and validators fail to utilize the cores properly and as a result have poor throughput. By adding concurrency using object semantics to smart contracts execution, we can achieve the better efficiency and higher throughput. Some authors have used read-write STMs (RWSTMs) for the concurrent execution of SCT. Working with higher level operations provide greater concurrency, better throughput and reduces the number of aborts than RWSTMs. In this paper, we develop an efficient framework to execute the SCT concurrently by miner using optimistic Object-Based Software Transactional Memory systems (OSTMs) and Multi-Version OSTMs (MV-OSTM). A proposed block includes SCT, final states of the shared data-items, hash of the previous block and a block graph (BG). BG captures the conflicting relations among the transactions. Later, the validators re-execute the same SCT concurrently and deterministically with the help of BG given by miner to verify the final state. If the validation is successful then proposed block appended into the blockchain and miner gets incentive otherwise discard the proposed block. MV-OSTM and OSTM miner performs 4.5x and 3.86x average speedups over serial miner. Along with, MV-OSTM and OSTM validator outperforms average 32.81x and 29.76x than serial validator.
As an append-only distributed database, blockchain is utilized in a vast variety of applications including the cryptocurrency and Internet-of-Things (IoT). The existing blockchain solutions have downsides in communication and storage efficiency, convergence to centralization, and consistency problems. In this paper, we propose LightChain, which is the first blockchain architecture that operates over a Distributed Hash Table (DHT) of participating peers. LightChain is a permissionless blockchain that provides addressable blocks and transactions within the network, which makes them efficiently accessible by all the peers. Each block and transaction is replicated within the DHT of peers and is retrieved in an on-demand manner. Hence, peers in LightChain are not required to retrieve or keep the entire blockchain. LightChain is fair as all of the participating peers have a uniform chance of being involved in the consensus regardless of their influence such as hashing power or stake. LightChain provides a deterministic fork-resolving strategy as well as a blacklisting mechanism, and it is secure against colluding adversarial peers attacking the availability and integrity of the system. We provide mathematical analysis and experimental results on scenarios involving 10K nodes to demonstrate the security and fairness of LightChain. As we experimentally show in this paper, compared to the mainstream blockchains like Bitcoin and Ethereum, LightChain requires around 66 times less per node storage, and is around 380 times faster on bootstrapping a new node to the system, while each LightChain node is rewarded equally likely for participating in the protocol.
This thesis work is aimed at developing understanding of the hash functions and algorithms being used in blockchain technologies Bitcoin in comparison to Ethereum and private blockchain hash functions. This study attempts to answer one fundamental research question: “What considerations are important in assessing blockchain cryptographic security, with an emphasis on hash functions”. \n \nThe study was carried out qualitatively using a desk research approach and combining this approach with using two public blockchains-based cryptocurrencies; Ethereum and Bitcoin as case studies. The research aims to provide a holistic view of blockchain cryptographic security comparing Bitcoin and Ethereum as use cases, and thus providing a consolidated document which students studying cryptography can access to obtain a better understanding of what is involved in blockchain security. From an academic perspective, the research aims at providing a model which can be used in assessing what is important to consider in the cryptographic security of blockchains. \n \nThree main categories of factors considered were presented in the proposed model which were strategical factors, complexity attributes and technical drivers. This results in a base crucial metrics such as absence of secret seeds, efficiency of verification, preimage collision resistance, fixed output size, low collision probability, and even distribution of preimages in output.
Internet of Things (IoT) and blockchain are two technologies which are pioneer nowadays and in the future. IoT become pioneer because our goverment sets Industrial Revolution 4.0 which signifies the IoT technology. For blockchain, it is a technology which has a significant development. These two technologies have a good future. The innovation in this design is combining these two technologies. IoT has a problem in securitization, but blockchain has an advantage in security. So, by combining these technologies, the problem could be resolved. This design used microcontroller ESP32. It will collect three data sets, i.e. altitude, pressure and temperature. The data will be sent through Internet to Ethereum blockchain network in Ropsten TestNet. The Data will store in state variables. Twenty data have been sent and tested. The data has been verified to be stored in Ethereum Virtual Machine because the data could be verified through etherscan.io. So, the conclusion is this design could prove that blockchain could be used to data securitization in IoT. Internet of Things (IoT) dan blockchain merupakan dua teknologi yang akan menjadi pioneer saat ini dan di masa mendatang. Pioneer saat ini karena pemerintah menetapkan Revolusi Industri 4.0 yang salah satu titik beratnya adalah IoT. Untuk blockchain, saat ini merupakan teknologi yang mengalami perkembangan signifikan. Kedua teknologi ini menjanjikan. Salah satu hal yang dapat menjadi inovasi adalah menggabungkan keduanya. IoT memiliki permasalahan pada sekuriti, sedangkan blockchain memiliki keunggulan dalam hal sekuriti. Dengan demikian, menggunakan teknologi blockchain untuk aplikasi IoT akan menjadi solusi. Alat yang dirancang menggunakan mikrokontroler ESP32. Alat ini akan mengakuisis data dari tiga buah sensor, yaitu sensor ketinggian, tekanan dan suhu. Data-data ini dikirim melalui Internet ke jaringan blockchain Ethereum di TestNet Ropsten. Data tersebut akan disimpan di state variables. Dua puluh data dikirim dan berhasil disimpan di Ethereum Virtual Machine. Ini terbukti dengan setiap data yang dikirim dapat divalidasi dan terekam di etherscan.io. Dengan demikian, perancangan alat ini berhasil membuktikan bahwa IoT dapat menggunakan blockchain untuk sekuritisasi data.
The paper presents the use of states of explosionproof method for analyzing the behavior of systems that provide smart contract technology. The selected example system is ShadowEth, whose main task is to ensure sufficient confidentiality of information stored in the Ethereum blockchain currency. The Petri network model for the ShadowEth system has been presented. The system
Ethereum Virtual Machine (EVM) is the run-time environment for smart contracts and its vulnerabilities may lead to serious problems to the Ethereum ecology. With lots of techniques being developed for the validation of smart contracts, the security problems of EVM have not been well-studied. In this paper, we propose EVMFuzz, aiming to detect vulnerabilities of EVMs with differential fuzz testing. The core idea of EVMFuzz is to continuously generate seed contracts for different EVMs' execution, so as to find as many inconsistencies among execution results as possible, eventually discover vulnerabilities with output cross-referencing. First, we present the evaluation metric for the internal inconsistency indicator, such as the opcode sequence executed and gas used. Then, we construct seed contracts via a set of predefined mutators and employ dynamic priority scheduling algorithm to guide seed contracts selection and maximize the inconsistency. Finally, we leverage different EVMs as crossreferencing oracles to avoid manual checking of the execution output. For evaluation, we conducted large-scale mutation on 36,295 real-world smart contracts and generated 253,153 smart contracts. Among them, 66.2% showed differential performance, including 1,596 variant contracts triggered inconsistent output among EVMs. Accompanied by manual root cause analysis, we found 5 previously unknown security bugs in four widely used EVMs, and all had been included in Common Vulnerabilities and Exposures (CVE) database.
Damiano Di Francesco Maesa, Paolo Mori, Laura Ricci
This work proposes to exploit blockchain technology to define Access Control systems that guarantee the auditability of access control policies evaluation. The key idea of our proposal is to codify attribute-based Access Control policies as smart contracts and deploy them on a blockchain, hence transforming the policy evaluation process into a completely distributed smart contract execution. Not only the policies, but also the attributes required for their evaluation are managed by smart contracts deployed on the blockchain. The auditability property derives from the immutability and transparency properties of blockchain technology. This paper not only presents the proposed Access Control system in general, but also its application to the innovative reference scenario where the resources to be protected are themselves smart contracts. To prove the feasibility of our approach, we present a reference implementation exploiting XACML policies and Solidity written smart contracts deployed on the Ethereum blockchain. Finally, we evaluate the system performances through a set of experimental results, and we discuss the advantages and drawbacks of our proposal.
This paper evaluates the current cybersecurity vulnerability of the prolific use of Elliptical Curve Digital Signature Algorithm (**ECDSA**) cryptography in use by the Bitcoin Core, Ethereum, Bitcoin Cash, and enterprise blockchains such as Multi-Chain and Hyperledger projects Fabric, and Sawtooth Lake. These blockchains are being used in media, health, finance, transportation and government with little understanding, acknowledgment of the risk and no known plans for mitigation and migration to safer public-key cryptography. The second aim is to evaluate ECDSA against the threat of **Quantum Computing** and propose the most practical National Institute of Standards and Technology (NIST) Post-Quantum Cryptography candidate algorithm lattice-based cryptography countermeasure that can be implemented near-term and provide a basis for a coordinated industry-wide lattice-based public-key implementation. Commercial quantum computing research and development is rapid and unpredictable, and it is difficult to predict the arrival of fault-tolerant quantum computing. The current state of covert and classified quantum computing research and advancement is unknown and therefore, it would be a significant risk to blockchain and Internet technologies to delay or wait for the publication of draft standards. Since there are many hurdles Post-Quantum Cryptography (PQC) must overcome for standardisation, coordinated large-scale testing and evaluation should commence promptly.
Digital evidence handling and preservation are one stage of digital forensic process. This part is very crucial because digital evidence is the basis of digital forensic process. The credibility of digital evidence must be maintaned for law and court process. Process of preservation of digital evidence known as chain of custody (CoC). CoC is a document that used to ensure that digital evidence remains and does not change. Both during the investigation process until the completion of the forensic process. Electronic evidence documentation is different from digital evidence documentatation. The different are character and the metadata. Some adjustments need to be accomodated on system for digital evidence. Digital evidence is easy to change as well as its CoC document. It needs to be protected. A new technology is needed that can ensure integrity of digital evidence and CoC Document like the blockchain. In this study, digital evidence management will be built on the CoC concept with blockchain technology. More precisely, this design combines the framework of the Digital Evidence Bag (DEC) with blockchain technology. This prototype is known as the Blockchain Digital Evidence Bag (B-DEC). B-DEC utilizes the data storage integrity to accommodate digital evidence management that refers to DEC. In this case, the prototype will build on a smart contract based on Ethereum. The development of the DEC framework also will be adjusted to accommodate DEC applications in the blockchain.
Open access
Artificial Intelligence in Healthcare and Education
Attribute-based access control makes access control decisions based on the assigned attributes of subjects and the access policies to protect objects by mediating operations from the subjects. Authority, which validates attributes of subjects, is one key component to facilitate attribute-based access control. In an increasingly decentralized society, multiple attributes possessed by subjects may need to be validated by multiple different authorities. This paper proposes a multi-authority attribute-based access control scheme by using Ethereum's smart contracts. In the proposed scheme, Ethereum smart contracts are created to define the interactions between data owner, data user, and multiple attribute authorities. A data user presents its attributes to different attribute authorities, and after successful validation of attributes, obtains attribute tokens from respective attribute authorities. After collecting enough attribute tokens, a smart contract will be executed to issue secret key to the data user to access the requested object. The smart contracts for multi-authority attribute-based access control have been prototyped in Solidity, and their performance has been evaluated on the Rinkeby Ethereum Testnet.
D. Nagarajan, M. Lathamaheswari, Said Broumi, J. Kavikumar
Blockchain Technology (BCT) is a growing and reliable technology in various fields such as developing business<br> deals, economic environments, social and politics as well. Without having a trusted central party this technology, gives the<br> guarantee for safe and reliable transactions using Bitcoin or Ethereum. In this paper BCT has been considered using Bitcoins.<br> Also Blockchain Single and Interval Valued Neutrosophic Graphs have been proposed and applied in transaction of Bitcoins.<br> Also degree, total degree, minimum and maximum degree have been found for the proposed graphs. Further, comparative<br> analysis is done with advantages and limitations of different types of Blockchain graphs.
Michel Zadé, Jonas Myklebost, Peter Tzscheutschler, Ulrich Wagner
\begin{abstract} When an author under the pseudonym Satoshi Nakamoto published the paper `Bitcoin: A Peer-to-Peer Electronic Cash System' in 2008, the first cryptocurrency using the new blockchain technology was introduced. Over the last decade, more than 1000 different cryptocurrencies, such as Ethereum, Ripple, and Litecoin were developed and Bitcoin's currency had almost reached an equivalent value of \SI{20000}{\$\per BTC}. After recognizing the disrupting momentum that the blockchain technology generated, scientists started to develop blockchain use cases for the energy sector. However, the scientific literature so far offers only rough and incomplete estimations when questions about the current and future energy consumption of the Bitcoin network are raised. This paper introduces a new scenario model to estimate the mining power demand of the Bitcoin and Ethereum network. Six scenarios are developed on the basis of mining hardware efficiency and network parameter data. The results show that an increase of the mining hardware efficiency will only have a limited impact on the overall power demand of blockchain networks. Furthermore, the current power demand of the Ethereum network is in the range from \SIrange{0.6}{3}{\giga\watt} and therefore, is similar to the one of Bitcoin. In case of linear growth of the block difficulty and sigmoidal increase of the hardware efficiency until the year of 2025, the mining power demand for the Bitcoin blockchain will be approximately \SI{3}{\giga\watt}. Furthermore, the model and the scenarios are adaptable to other cryptocurrencies that use the proof-of-work consensus algorithm to create scenarios for their future power demand.
Muhannad Abdul Moneim Uday, P. Devi Prasad, N. Jagadeesh Sai
Energy Trading through Blockchain is an innovative way to trade solar energy across different places. It enables the owners of solar plants to trade the solar energy that is been produced by their plants in an easy and utmost secure manner using Blockchain technology. The core point of the project is to pay for what is being served. The source and destination stations will be abiding to a smart contract which allows them to pay for exactly the served amount of energy. Each and every transaction is stored in a ledger. Operating the entire system in Ethereum platform provides transparency, security and credibility to the process. The process entirely runs on the transfer of cryptocurrencies and not any other mode of money.
The aim of this work is to study the use of decentralization and smart contracts on blockchain networks. We investigate the implementation and use of smart contracts on the platforms Bitcoin, Ethereum and Hyperledger Fabric. Additionally, we have researched consensus algorithms and their respective uses, mentioning both advantages and disadvantages where necessary. To conclude, there is an example contract that is meant to be a close to direct translation of a generic legal house rental contract to show how a legal contract can be translated.
Summary We present an overview of hybrid Casper the Friendly Finality Gadget (FFG), a proof‐of‐stake checkpointing protocol overlaid onto Ethereum's proof‐of‐work blockchain. We describe its core functionalities and reward scheme and explore its properties. Our findings indicate that Casper's implemented incentives mechanism ensures liveness, while providing safety guarantees that improve over standard proof‐of‐work protocols. On the basis of a minimal impact implementation of the protocol as a smart contract on the blockchain, we discuss additional issues related to parametrization, funding, throughput, and network overhead and detect potential limitations.