Nadir Khan, Naila Mushtaq, Muhammad Zohair Durrani, S.M. Nabeel Ul Haq · 5 authors
The topic of Cryptocurrencies is emerging rapidly. Many investors and public want to invest in digital currencies. So, the nature of cryptocurrency and its theoretical understanding is essential currently. The aim of this research is to study major Cryptocurrencies having capitalization above $1bn and construct directed networks. Eleven major Cryptocurrencies are Bitcoin (BTC), Ethereum (ETH), Cardano (ADA), Binance Coin (BNB), Tether (USDT), Ripple (XRP), Doge Coin (DOGE), USD Coin (USDC), Bitcoin Cash (BCH), Chainlink (Link) and Litecoin (LTC). By using returns Granger Causality test was conducted. This test help in concluding that whether change in one price of cryptocurrency cause a change in other Cryptocurrencies or not. After analysis of results, it was concluded that there is a variation in the Cryptocurrencies relation. Some shows a direct cause and effect relation, while some have a unidirectional relation. However, some of them also showed no meaningful relationship. The relationship among these Cryptocurrencies was then showed using directed networks.
Giulia Rafaiani, Paolo Santini, Marco Baldi, Franco Chiaraluce
The growing interest in Internet of Things (IoT) and Industrial IoT (IIoT) poses the challenge of finding robust solutions for the certification and notarization of data produced and collected by embedded devices. The blockchain and distributed ledger technologies represent a promising solution to address these issues, but rise other questions, for example regarding their practical feasibility. In fact, IoT devices have limited resources and, consequently, may not be able to easily perform all the operations required to participate in a blockchain. In this paper we propose a minimal architecture to allow IoT devices performing data certification and notarization on the Ethereum blockchain. We develop a hardware-software platform through which a lightweight device (e.g., an IoT sensor), holding a secret key and the associated public address, produces signed transactions, which are then submitted to the blockchain network. This guarantees data integrity and authenticity and, on the other hand, minimizes the computational burden on the lightweight device. To show the practicality of the proposed approach, we report and discuss the results of benchmarks performed on ARM Cortex-M4 hardware architectures, sending transactions over the Ropsten testnet. Our results show that all the necessary operations can be performed with small latency, thus proving that an IoT device can directly interact with the blockchain, without apparent bottlenecks.
Antonio J. Di Scala, Andrea Gangemi, Giuliano Romeo, Gabriele Vernetti
In 2020, Sala, Sogiorno and Taufer were able to find the private keys of some Bitcoin addresses, thus being able to spend the cryptocurrency linked to them. This was unexpected since the recovery of non-trivial private keys for blockchain addresses is deemed to be an infeasible problem. In this paper, we widen this analysis by mounting a similar attack on other small subsets of the set of private keys. We then apply it to other blockchains as well, examining Ethereum, Dogecoin, Litecoin, Dash, Zcash and Bitcoin Cash. In addition to the results, we also explain the techniques we have used to perform this exhaustive search for all the addresses that have ever appeared in these blockchains, and we give an estimate of the time needed to perform all the computations. Finally, we also examine the possibility of mounting a similar attack on other elliptic curves used in blockchains, i.e., Curve25519 and NIST P-256.
The coronavirus pandemic occurred in 2019 and caused an impact on cryptocurrencies. This paper focuses on the relation between the return of cryptocurrencies and the new daily confirmed cases of COVID-19 worldwide, taking Bitcoin, Ethereum, and Tether as three examples. It is shown that the new daily cases have a significant influence on Bitcoin and Ethereum. And the short-term impact of new global confirmed cases on Bitcoin is positive, then remains volatile and eventually disappears. The different phenomena show that different cryptocurrencies have reacted differently to the pandemic impact.
Blockchain technology, which includes cryptocurrencies such as Bitcoin, Ethereum,…etc [1,2] which has been evaluated as an investment tool by many people all over the world in recent years, needs to be examined in details, both mathematically and conceptually [8,9]. In fact, it can be said that blockchain technology, which is characterized as an accounting system and database based on distributed ledgers in its most basic form, is extremely secure in terms of copying data or attacking. For this reason, we can say that technology has a more effective security mechanism than any central state-of-the-art authoritative system used today. However, as it is almost impossible to bring all of the security, speed and cost parameters to their full extend in a system at the same time, as in any cryptosystem, the security parameter from the distributed ledger structure in blockchain technology adversely affects the speed and cost parameters. In this article, we discuss the cryptographic working principles of cryptocurrencies, which is an application field of blockchain technology, together with blockchain technology and the features and structures of the blocks contained.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Sandi Rahmadika, Philip Virgil Astillo, Gaurav Choudhary, Daniel Gerbi Duguma · 6 authors
The Internet of Medical Things (IoMT) has risen to prominence as a possible backbone in the health sector, with the ability to improve quality of life by broadening user experience while enabling crucial solutions such as near real-time remote diagnostics. However, privacy and security problems remain largely unresolved in the safety area. Various rule-based methods have been considered to recognize aberrant behaviors in IoMT and have demonstrated high accuracy of misbehavior detection appropriate for lightweight IoT devices. However, most of these solutions have privacy concerns, especially when giving context during misbehavior analysis. Moreover, falsified or modified context generates a high percentage of false positives and sometimes causes a by-pass in misbehavior detection. Relying on the recent powerful consolidation of blockchain and federated learning (FL), we propose an efficient privacy-preserving framework for secure misbehavior detection in lightweight IoMT devices, particularly in the artificial pancreas system (APS). The proposed approach employs privacy-preserving bidirectional long-short term memory (BiLSTM) and augments the security through integrating blockchain technology based on Ethereum smart contract environment. The effectiveness of the proposed model is bench-marked empirically in terms of sustainable privacy preservation, commensurate incentive scheme with an untraceability feature, exhaustiveness, and the compact results of a variant neural network approach. As a result, the proposed model has a 99.93% recall rate, showing that it can detect virtually all possible malicious events in the targeted use case. Furthermore, given an initial ether value of 100, the solution's average gas consumption and Ether spent are 84,456.5 and 0.03157625, respectively.
Background: In the current advancement of communication, anyone can create digital content. Emerging digital marketplaces provides an environment to share digital data with customers who are interested in content, from other digital sources. Digital marketplaces provide a location for both providers and consumers to connect to meet the increased demand. All of this leads to challenges in content protection, copyright protection, contract creation and work trading. Objectives: To address these issues, this scheme suggests a blockchain based approach for managing digital rights to garment design works. This system uses the blockchain, digital copyright management techniques and off-chain computation for garment design work. The visibility of design effects, the secrecy of design details and compliance with applicable regulations are all considered. The data delivery is also assured with the help of the proof-of-delivery concept. Methods: The proposed system has three steps. They are (i) Creating digital copyright documents using key generation and verification of digital signature (ii) Smart contract creation (iii) Certificate generation for confirmed smart contracts. A Smart contract is defined as computerized transaction protocols that execute the terms of a contract. Findings: Smart contracts are created between the designer and customer using Ethereum which is a blockchain based software platform. The interplanetary file system is used to store digital documents. Ethereum blockchain is used to create the smart contract digitally. Ethereum smart contract provides unchangeable, transparent, tamper-proof logs, traceability and responsibility. Finally, E-certificate is generated by the designer for the confirmed contracts and it is uploaded into the IPFS. Novelty and applications: The trusted, decentralized and proof of delivery frameworks are included for digital design work with the key features of IPFS, blockchain and Ethereum smart contract. The proposed work is also compared with the existing works based on several criteria such as blockchain, IPFS, PoD, etc. Keywords: Blockchain; Design work; Copyright Protection; Digital Signature; Ethereum
This study aims to analyze the return and risk of Cryptocurrency assets in order to find out which crypto assets have small risks and large returns. In this research, the test procedures used were the Kruskal Wallis test and paired sample t-test. The research time span was obtained from January 1, 2019 to December 31, 2021 as well as the time span for data collection for price comparisons before and during the COVID-19 pandemic for 2 months from march 11, 2020. The results of this research are that bitcoin, ethereum, and dogecoin do not have a significant return comparison, for the results of risk research also have the result that there is no significant risk comparison between bitcoin, ethereum, and dogecoin. After that, for the results of the price comparison of bitcoin, ethereum, and dogecoin before the covid-19 pandemic and after the announcement of the covid-19 pandemic, the result is bitcoin and ethereum has a significant comparison between the time before the covid-19 pandemic and after the announcement of covid-19. On the contrary, dogecoin did not face a significant price comparison before the covid-19 pandemic as well as after the announcement of covid-19. Before starting an investment, it is better to look at the ability of Cryptocurrency assets to minimize risks and make sure whether the investment objectives are for the long and short term.
Heralded as revolutionary in their potential to improve efficiency, transparency, and sustainability, blockchain technologies promise new forms of large-scale coordination between actors that do not necessarily trust each other. This paper examines blockchain imaginaries and associated metaphors. Our analysis focuses on bitcoin and ethereum, today’s most prominent blockchains that use the proof-of-work consensus mechanism. We identify three principles that organise blockchain imaginaries: substantial, morphological, and structural. These principles position blockchain as an enabler of economic, political and epistemological practices, respectively. Blockchain infrastructure and protocols rely on substantial metaphors (e.g. gold, gas) to govern resource allocation, morphological metaphors (e.g. work, trust) to generate consensus and structural metaphors (e.g. chain, transaction) to establish shared knowledge. Those imaginaries rely on metaphorical displacements of meaning that make blockchain technology relevant and intelligible while simultaneously shaping the direction of technological development and positing these technologies as new forms of economic, political and epistemological organisation. They are not merely descriptive but performative. We conclude by showing how these principles partially overlap with three symbolically generalized media: money, power and truth. Money organises scarcity within the economic system, power organises consensus within the political system, and truth organises knowledge within the science system.
In Smart Grid (SG), Transactive Energy Management (TEM) is one of the most promising approaches to boost consumer participation in energy generation, energy management, and establishing decentralized energy market models using Peer-to-Peer (P2P). In P2P, a prosumer produces electric energy at their place using Renewable Energy Resources (RES) such as solar energy, wind energy, etc. Then, this generated energy is traded with consumers (who need the energy) in a nearby locality. P2P facilitates energy exchange in localized micro-energy markets of the TEM system. Such decentralized P2P energy management could cater to diverse prosumers and utility business models. However, the existing P2P approaches suffer from several issues such as single-point-of-failure, network bandwidth, scalability, trust, and security issues. To handle the aforementioned issues, this paper proposes a Decentralized and Transparent P2P Energy Trading (DT-P2PET) scheme using blockchain. The proposed DT-P2PET scheme aims to reduce the grid’s energy generation and management burden while also increasing profit for both consumers and prosumers through a dynamic pricing mechanism. The DT-P2PET scheme uses Ethereum-blockchain-based Smart Contracts (SCs) and InterPlanetary File System (IPFS) for the P2P energy trading. Furthermore, a recommender mechanism is also introduced in this study to increase the number of prosumers. The Ethereum SCs are designed and deployed to perform P2P in real time in the proposed DT-P2PET scheme. The DT-P2PET scheme is evaluated based on the various parameters such as profit generation (for prosumer and consumer both), data storage cost, network bandwidth, and data transfer rate in contrast to the existing approaches.
Los NFT están superando a la cadena de bloques y a las criptomonedas en popularidad. Se trata de certificados de propiedad almacenados en una cadena de bloques y respaldados por la tecnología blockchain (p. ej., Ethereum) que suelen estar asociados a un activo digital, como las artes visuales, los vídeos, la música o los objetos de colección. Los NFT parecen estar llamados a jugar un papel clave en el denominado metaverso, un entorno digital que opera en la cadena de bloques, donde tecnologías como la realidad virtual y la realidad aumentada actúan como proveedores de componentes visuales, y que ofrece oportunidades de negocio e interacción social ilimitadas. El arte es solo una parte del mundo virtual basado en blockchain donde los avatares, la tierra, los edificios, los nombres, etc., se pueden vender y comprar como NFT. Este fenómeno crea obviamente una serie de implicaciones legales novedosas. La creación, la distribución, la propiedad y el comercio de los NFT son fenómenos nuevos que plantean multitud de cuestiones jurídicas, muchas de las cuales son ambiguas o no están resueltas. En este contexto, el presente trabajo analiza la competencia judicial internacional en controversias relativas a tokens no fungibles, con especial atención al Derecho europeo, haciendo asimismo referencia a la jurisprudencia reciente de terceros Estados en materia de criptoactivos.
Cryptocurrency adalah sebagai aset yang dibuat untuk beroperasi sebagai cara pertukaran yang dilakukan secara digital. Nilainya akan mengalami kenaikan karena berlakunya hukum demand dan supply, di mana jumlah uang digital ini terbatas sedang peminatnya terus bertambah. Pada tahun 2021 di Indonesia mengalami perkembangan investor cryptocurrency yang signifikan, dimana pada akhir tahun tercatat jumlah investor telah mecapai 11,2 juta. Perkembangan tersebut dipicu akibat adanya anggapan perbedaan return yang dihasilkan lebih tinggi dibandingkan instrumen investasi lainnya. Penelitian ini bertujuan untuk mengukur perbedaan return, risk dan kinerja diantara cryptocurrency, IHSG dan Emas, dimana kinerja diukur menggunakan metode Index Sharpe, Index Treynor dan Index Jensen. Populasi yang digunakan pada penelitian adalah sebanyak 5 populasi yaitu; Bitcoin (BTC), Ethereum (ETH), Ripplecoin (XRP), IHSG dan Emas. Metode penelitian yang digunakan pada penelitian ini adalah analisis perbandingan menggunakan pengujian parametrik One-way ANOVA dan pengujian non-parametrik Kruskall-Wallis. Hasil penelitian menunjukan terdapat perbedaan yang signifikan pada variabel risk, Index Sharpe, dan Index Jensen. Sementara pada return dan Index Treynor tidak terdapat perbedaan yang signifikan. Bagi para investor hal yang perlu diperhatikan adalah tidak adanya perbedaan return yang signifikan pada ketiga instrumen penelitian, sementara pada risk cryptocurrency memiliki tingkatan yang paling tinggi. Penelitian yang akan datang diharapkan dapat menambahkan jenis cryptocurrency lainnya dengan periode penelitian yang lebih panjang.
Yeni finansal varlıklar ile klasik yatırım enstrümanları arasındaki ilişkilerin önemi artmaktadır. Çalışmada Diks ve Panchenko Doğrusal Olmayan Nedensellik Testi kullanarak Bitcoin, Ethereum fiyatları ve borsa endeksleri arasındaki nedensellik ilişkileri incelenmektedir. Çalışma dönemi covid-19 pandemisinin Türkiye’de ilan edildiği tarihten başlayarak 11/03/2020-06/04/2022 arasındaki günlük frekanstaki verileri kapsamaktadır. Böylece pandemi süreciyle birlikte küresel çaplı krizlerde kripto para birimleri ile küresel finans piyasaları arasındaki ilişkinin incelenmesi hedeflenmiştir. Çalışma literatürde özellikle Ethereum ile ilgili yapılmış çalışmaların kısıtlı olması sebebi ile diğer çalışmalardan ayrılmaktadır. Kullanılan doğrusal olmayan nedensellik analizi sonuçlarına bakıldığında, dünya borsa endeksi ile Bitcoin fiyatı arasında ve Asya borsa endeksi ile Ethereum fiyatı arasında çift yönlü nedensellik ilişkisi olduğu tespit edilmiştir. Ayrıca Bitcoin fiyatına Avrupa ve ABD borsa endekslerinden tek yönlü nedensellik olduğu görülmektedir. Aynı zamanda Bitcoin fiyatından da Asya borsa endeksine tek yönlü nedensellik ilişkisi mevcuttur. Ethereum fiyatından ise Avrupa borsa endeksine doğru tek yönlü nedensellik ilişkisi söz konusudur.
Abstract - The whole concept of self-sovereign identity (SSI) is gaining a lot of optimism, with the emerging Blockchain Technology in the current tech-scenario. It is a major change in how online interactions will take place in the future considering the identity of each user. The different aspects of SSI are examined by various works in the literature This paper surveys the origin of identity, various digital identity models and how it leads to self-sovereign identity. It then goes on to discuss related research, as well as the SSI's building blocks, which include decentralized IDs, verifiable credentials, a distributed ledger, and a variety of privacy mechanisms. Finally, it proposes a solution for self-sovereign identity by using the Ethereum platform for blockchain and other technologies
The dynamic nature of competitive electricity markets means that participants often resort to some form of derivative financial instrument. One such instrument is a contract-for-difference (CFD), usually available to renewable generators in certain electricity markets to enable them to hedge their price risk. Embracing CFD presents new risks such as counterparty credit, margining, third-party, legal, and process risks. Derivative instruments existing on blockchains have recently demonstrated potential as suitable hedging tools for minimizing the risks of renewable generators. This article applies this concept for the first time to hedge the price risk of renewable generators by implementing a novel decentralized finance instrument, an Ethereum blockchain marketplace governed by a smart contract to mediate between stakeholders mutually enrolled in bilateral CFD arrangements. The employed structure mitigates the underlying risks of traditional arrangements, underpinned by a suite of autonomous mechanisms.
Distributed Ledger Technology is a powerful tool to support direct collaboration between organisations, without requiring full trust into a centralised infrastructure. By defining a program logic and access policies with smart contracts, all interactions are verified in the distributed network and the history of the data is recorded on the ledger. Blockchain implementations targeting enterprise use cases also provide means for private transactions, where the content of the transaction is only readable by authorized participants. Direct access to the ledger requires a node with reliable connection to the network and sufficient computational resources, which usually cannot be fulfilled with lightweight Internet of Things devices and mobile applications. We present an advanced system for accessing an enterprise Blockchain through dedicated gateway nodes, while preserving the functionality of private transactions. A hybrid approach is used to allow computation- and storage restricted clients to send private transactions through a central gateway, and use Light Ethereum Subprotocol to verify the data integrity based on proofs from distributed nodes. To increase the client-side security level, we introduce a dedicated Hardware Security Module for key management and efficient execution of the cryptographic primitives. A proof-of-concept implementation, using the Quorum Blockchain client and an extension for the Tessera transaction manager, validates the feasibility of the approach and can be used for further research in this field.
Retail energy markets are increasingly consumer-oriented, thanks to a growing number of energy plans offered by a plethora of energy suppliers, retailers and intermediaries. To maximize the benefits of competitive retail energy markets, group purchasing is an emerging paradigm that aggregates consumers' purchasing power by coordinating switch decisions to specific energy providers for discounted energy plans. Traditionally, group purchasing is mediated by a trusted third-party, which suffers from the lack of privacy and transparency. In this paper, we introduce a novel paradigm of decentralized privacy-preserving group purchasing, empowered by privacy-preserving blockchain and secure multi-party computation, to enable users to form a coalition for coordinated switch decisions in a decentralized manner, without a trusted third-party. The coordinated switch decisions are determined by a competitive online algorithm, based on users' private consumption data and current energy plan tariffs. Remarkably, no private user consumption data will be revealed to others in the online decision-making process, which is carried out in a transparently verifiable manner to eliminate frauds from dishonest users and supports fair mutual compensations by sharing the switching costs to incentivize group purchasing. We implemented our decentralized group purchasing solution as a smart contract on Solidity-supported blockchain platform (e.g., Ethereum), and provide extensive empirical evaluation.
Pedro Henrique F. S. Oliveira, Daniel Muller Rezende, Heder S. Bernardino, Saulo Moraes Villela · 5 authors
One of the main events that involve the world economy in 2022 is the conflict between Russia and Ukraine. This event offers a rare opportunity to analyze how events of this magnitude can reflect the use of cryptocurrencies. This work aims to investigate the behavior of accounts and their transactions on the Ethereum cryptocurrency during this event. To this end, we collected all transactions that occurred two weeks before and two weeks after the beginning of the conflict, organized into two groups: the collection of the accounts involved in these transactions and the subset of these ones that interacted with a service in Ethereum, called Flashbots Auction. We modeled temporal graphs where each node represents an account, and each edge represents a transaction between two accounts. Then, we analyzed the behavior of these accounts with graph metrics for both groups during each observed week. The results showed changes in the behavior and activity of users and their accounts, as well as variations in the daily volume of transactions.
Abstract— Years of heavy regulation and bureaucratic ineffificiency have slowed innovation for electronic medical records (EMRs). We employ a security risk management (SRM) domain model and a methodology to investigate two security risks – Sybil and Double-spending – that have been identified and are regarded the most significant security issues in blockchain systems. We tested a newly developed framework by looking at the hazards of Sybil and Double-spending in Ethereum-based healthcare apps. MedRec thus enables the emergence of data economics, supplying big data to empower researchers while engaging patients and providers in the choice to release metadata. Finally, we deploy the MIStore on the Ethererum blockchain and give the corresponding performance evaluation. We wrap off the study by laying out our plans for developing an ontology-based blockchain security reference model. Keywords— Sybil risk, Double-spending risk, Ethereum-based healthcare apps, Electronic medical records, big data
Ruzita Abdul‐Rahim, Airil Khalid, Zulkefly Abdul Karim, Mamunur Rashid
This paper estimates the comovement between two leading cryptocurrencies and the G7 stock markets. It then attempts to explain the comovement with the rational investment theory by examining whether it is driven by market uncertainty measures, public attention to COVID-19, and the government’s containment and health responses to COVID-19. Wavelet Coherence heatmaps show that the stock-cryptocurrency comovements increase significantly and positively during the pandemic, indicating that cryptocurrencies lose their safe haven properties against stocks during the heightened market uncertainties. Over the longer investment horizons, Bitcoin reemerges as a safe haven or strong hedger while Ethereum’s properties weaken. Seemingly Unrelated Regression results reveal that the stock-cryptocurrency comovements are rationally explained by market uncertainties, government responses to COVID-19, and market fundamentals. However, the comovements are also driven by the fear of COVID-19 to a certain extent. Our findings offer valuable insights for investors considering cryptocurrencies to rebalance their equity portfolios during market distress. For policymakers, the Economic Policy Uncertainty (EPU) results suggest that government policies and regulatory frameworks can be used to regulate speculation and investment activities in the cryptocurrency market.
Michael Pacheco, Gustavo A. Oliva, Gopi Krishnan Rajbahadur, Ahmed E. Hassan
The Ethereum platform allows developers to implement and deploy applications called Dapps onto the blockchain for public use through the use of smart contracts. To execute code within a smart contract, a paid transaction must be issued towards one of the functions that are exposed in the interface of a contract. However, such a transaction is only processed once one of the miners in the peer-to-peer network selects it, adds it to a block, and appends that block to the blockchain This creates a delay between transaction submission and code execution. It is crucial for Dapp developers to be able to precisely estimate when transactions will be processed, since this allows them to define and provide a certain Quality of Service (QoS) level (e.g., 95% of the transactions processed within 1 minute). However, the impact that different factors have on these times have not yet been studied. Processing time estimation services are used by Dapp developers to achieve predefined QoS. Yet, these services offer minimal insights into what factors impact processing times. Considering the vast amount of data that surrounds the Ethereum blockchain, changes in processing times are hard for Dapp developers to predict, making it difficult to maintain said QoS. In our study, we build random forest models to understand the factors that are associated with transaction processing times. We engineer several features that capture blockchain internal factors, as well as gas pricing behaviors of transaction issuers. By interpreting our models, we conclude that features surrounding gas pricing behaviors are very strongly associated with transaction processing times. Based on our empirical results, we provide Dapp developers with concrete insights that can help them provide and maintain high levels of QoS.
Michael Pacheco, Gustavo A. Oliva, Gopi Krishnan Rajbahadur, Ahmed E. Hassan
Ethereum is one of the most popular platforms for the development of blockchain-powered applications. These applications are known as ÐApps. When engineering ÐApps, developers need to translate requests captured in the front-end of their application into one or more smart contract transactions. Developers need to pay for these transactions and, the more they pay (i.e., the higher the gas price), the faster the transaction is likely to be processed. Developing cost-effective ÐApps is far from trivial, as developers need to optimize the balance between cost (transaction fees) and user experience (transaction processing times). Online services have been developed to provide transaction issuers (e.g., ÐApp developers) with an estimate of how long transactions will take to be processed given a certain gas price. These estimation services are crucial in the Ethereum domain and several popular wallets such as Metamask rely on them. However, despite their key role, their accuracy has not been empirically investigated so far. In this article, we quantify the transaction processing times in Ethereum, investigate the relationship between processing times and gas prices, and determine the accuracy of state-of-the-practice estimation services. Our results indicate that transactions are processed in a median of 57 seconds and that 90% of the transactions are processed within 8 minutes. We also show that higher gas prices result in faster transaction processing times with diminishing returns. In particular, we observe no practical difference in processing time between expensive and very expensive transactions. With regards to the accuracy of processing time estimation services, we observe that they are equivalent. However, when stratifying transactions by gas prices, we observe that Etherscan’s Gas Tracker is the most accurate estimation service for the very cheap and cheap transactions. EthGasStation’s Gas Price API, in turn, is the most accurate estimation service for regular, expensive, and very expensive transactions. In a post-hoc study, we design a simple linear regression model with only one feature that outperforms the Gas Tracker for very cheap and cheap transactions and that performs as accurately as the EthGasStation model for the remaining categories. Based on our findings, ÐApp developers can make more informed decisions concerning the choice of the gas price of their application-issued transactions.
In this paper, we present a model of a multi-client framework for access control to datasets put away in an untrusted cloud climate. Distributed storage like some other untrusted climate needs the capacity to get share data. Our methodology gives an entrance command over the information put away in the cloud the supplier investment. The fundamental device of the access control instrument is a ciphertext-strategy trait-based encryption plot with dynamic credits. Utilizing a blockchain-based decentralized record, our framework gives a permanent log of all significant security occasions, for example, key age, access strategy task, change or repudiation, and access demand. We propose a bunch of cryptographic conventions guaranteeing the security of cryptographic tasks requiring mystery or private keys. Just ciphertexts of hash codes are moved through the blockchain record. The model of our framework is executed utilizing shrewd agreements and tried on the Ethereum blockchain stage. Keywords- cloud storage; attribute-based access control; ciphertext-policy attribute-based encryption; blockchain
Cryptocurrency is an innovative concept of virtual and decentralised currency which has become the new investment option like gold in India. Since there is a lack of a regulatory framework or law about cryptocurrency transactions and trading in India, the buying and selling of Bitcoin, Bitcoin, Ethereum, and other cryptocurrencies are restricted by the government. There are several restrictions on the existence of cryptocurrencies in India. This study is based on understanding cryptocurrency and its effect on the economy. The study is also based on existing scenarios and future prospects. With the rapid growth of information and communication technologies, a lot of daily activities have been digitised and become more time-saving and flexible. A lot of online users have switched to the virtual world and cryptocurrency has created a new business phenomenon to promote buying, trading, and selling digital assets. Cryptocurrency represents intangible and valuable objects used online in various networks and applications like online games, social networks, P2P networks, and virtual worlds. Virtual currency has been used widely in different systems over the years