Distributed key generation (DKG) is widely used in multi-party computation and decentralized applications. DKG has two phases, namely sharing and reconstruction. Most of the prior DKG protocols need at least 2 rounds for the sharing phase, in case some party raises a dispute. The existing 1-round DKG protocol [Fouqueet al., PKC’01], built based on a publicly verifiable secret sharing (PVSS) scheme, assumes a static adversary model and its reconstruction phase requires$O(n^{2})$communication complexity. Motivated by the observation that a ciphertext-policy attribute-based encryption (CP-ABE) scheme hides secret sharing (SS) in ciphertext, we utilize decentralized CP-ABE to achieve the first adaptively secure 1-round DKG protocol. Firstly, a CP-ABE scheme enables the ciphertexts in DKG to be externally decrypted, making our protocol superior to the PVSS-based DKG protocol in reconstruction. The communication and computation complexities are both lowered to$O(n)$thanks to the constant-sized decryption key and the proposed batch decryption. The use of CP-ABE also makes our DKG protocol storage-friendly, i.e., the parties store no ciphertext after the sharing phase. Secondly, we add non-interactive zero-knowledge (NIZK) proofs to make the CP-ABE ciphertext publicly verifiable by leveraging the sigma protocol and the Fiat-Shamir heuristic. Thirdly, we demonstrate our protocol’s feasibility by presenting a proof-of-concept implementation over Ethereum, which is used as a public channel and a trustworthy computation platform. The implementation is a non-trivial task due to Ethereum’s incompatibility with the bilinear mapping group.
Cryptocurrency has become a popular asset in global financial markets, meaning that not only individual investors but also asset management companies around the world are considering this new investment class. The main contribution of this research is to address an intra-day forecasting problem with hourly granularity by comparing deep network architectures, including ones with and attention mechanisms for the Ethereum intrinsic cryptocurrency (ETH). The results showed that the TCN outperformed other architectures considered for a short-term forecast period in terms of processing time and it is amongst the most accurate models using an ARIMA model as a baseline.
Engin Zeydan, Jorge Baranda, Josep Mangues‐Bafalluy
Existing network service provisioning and lifecycle management (LCM) workflows rely on heterogeneous devices from multiple vendors and collaboration between multiple network actors, which can lead to numerous trust management and interoperability issues. Blockchain networks (BCNs) are a revolutionary way to establish trust in untrusted environments. In this complex environment, BCNs can help ensure transparency and security for network service LCM. However, BCNs are also vulnerable to quantum attacks. Advances in quantum computing will challenge the security of existing blockchain technology based on Public Key Infrastructure (PKI) technologies. In this paper, we explore how network services can be managed in a multiple administrative scenario. Our approach uses BCNs to track the operational steps of network service instantiation metrics while benefiting from the security features of post-quantum cryptography (PQC). Together with the use of N-th degree Truncated polynomial Ring Units (NTRU) as an example of a PQC algorithm that relies on the parallelization power of the Toom-Cook computation method with different security levels, we have shown that Quorum can provide a lower average time-to-write value compared to other BCNs considered (Ethereum and Hyperledger). At the end of the paper, we discuss the evaluation results and future directions regarding the coexistence of PQC algorithms and BCNs for network service orchestration and service federation between multiple administrative domains.
Kahlid S. Alqarni, Faris A. Almalki, Ben Othman Soufiene, Obaid Ali · 5 authors
Agriculture is confronted with several significant difficulties, such as rising air temperatures and population growth, causing the implementation of smart farming operations as an optimum solution. This research aims to contribute to the growing knowledge of the potential role of blockchain technology in promoting the concept of smart farming by enhancing the efficiency of farming operations by boosting agricultural production, lowering environmental impact, and automating the work of farmers. It proposes a secure blockchain‐based framework to establish trust among smart farming users. The framework utilizes asymmetric key exchange mechanism using an ECC authentication algorithm and SHA‐256 hash function cryptography to secure communication between sensors and drones in the farm field. The SHA‐256 hashing function ensures data integrity as attempts to tamper with data result in a different hash value, breaking the chain of blocks. To demonstrate the feasibility of the proposed framework, a proof‐of‐concept implementation was developed on the Ethereum blockchain, in which smart contracts were used to model the framework operations. The proof of concept’s performance was examined using Hyperledger Caliper for latency, throughput, and transaction success rate. The findings clearly indicate that blockchain technology can provide an efficient and scalable mechanism to advance smart farming and address some of the barriers that inhibit smart farming, particularly regarding to data integrity and availability.
Know Your Customer (KYC) process plays a vital role for all banks in authenticating the identity of their customers. KYC verification is crucial to prevent banks from being used by illegal elements for money laundering activities such as drug trafficking, terrorism and other crimes. Manual KYC process in mainstream at present is less secure, time consuming and outdated. Since Blockchain offers features like decentralization, immutability and security, these limitations can be eliminated by using Blockchain based KYC verification. In this paper, we have proposed decentralized KYC verification process using Ethereum Blockchain platform. It would allow all the banks in the Blockchain network to verify and vote for legitimacy of the data provided by the customer. Depending on number of votes KYC status of customer gets stored on the Blockchain. Major enhancement in our proposed method is, banks can also vote for other banks if any bank is tampering with the KYC data and it will get removed from the network based on this voting. In this way, Blockchain can be used to improve the efficiency of KYC process with its distinctive features.
In recent years, cloud-based medical record sharing has greatly improved the process of researching the disease and patient diagnosis. However, since cloud systems are centralized, there is serious concern about data security and privacy. Blockchain technology is viewed as a promising method of dealing with privacy issues and data security because of its exclusive features of distributed ledgers, secrecy, verifiability, and enhanced security. The literature review has shown significant works on integrating blockchain technology with cloud system for managing and sharing healthcare data. It has been analyzed that previous works are primarily dependent on the centralized data storage approach, which raises privacy concerns. The previous works also do not emphasize handling big medical data and lack the reliability of the end-to-end security features system. This paper has presented an authorization framework for ensuring data security and privacy preservation using blockchain technology with IPFS as decentralized file storage and sharing system. The proposed study devises a proof of replication algorithm using smart contracts to provide a better access control mechanism. The implementation of the proposed framework is based on the symmetric encryption and Ethereum blockchain platform. The study outcome illustrates the efficiency and availability of the proposed scheme compared to the typical cloud-based blockchain method.
Sara Ait Bennacer, Abdessadek Aaroud, Khadija Sabiri, Mohamed Rguibi · 5 authors
In the context of COVID-19 pandemic, the Moroccan Interior and Health Ministries have proposed to use the health pass with a QR code to identify vaccinated people. Additionally, the government suggested a mobile application to control the health passport authenticity. However, the key problem is the possibility of anyone scanning the QR code and figuring out citizens' private information, causing severe issues about individual privacy. In this work, the main contribution is integrating a private Blockchain-based digital health passport to ensure high protection of sensitive information, security and privacy among all the actors (Government, Ministry of Interior, Ministry of Health, verifiers) that comply with the CNDP (National Commission for the Control of Personal Data Protection) and the Moroccan Law 09-08. In our proposed architectural framework solution, we identify two types of actors: authorized and unauthorized, to limit and control access to the citizens' personal information. Besides, to preserve individuals' privacy, we adopt on-chain and off-chain storage (Interplanetary File Systems IPFS). In our case, smart contracts improve security and privacy in the health passport verification process. Our system implementation describes the proposed solution to grant individual privacy. To verify and validate our approach, we used Remix-IDE and Ethereum Blockchain to build smart contracts.
Identity Management Systems (IdMS) have seemingly evolved in recent years, both in terms of modelling approach and in terms of used technology. The early centralized, later federated and user-centric Identity Management (IdM) was finally replaced by Self-Sovereign Identity (SSI). Solutions based on Distributed Ledger Technology (DLT) appeared, with prominent examples of uPort, Sovrin or ShoCard. In effect, users got more freedom in creation and management of their identities. IdM systems became more distributed, too. However, in the area of interoperability, dynamic and ad-hoc identity management there has been almost no significant progress. Quest for the best IdM system which will be used by all entities and organizations is deemed to fail. The environment of IdM systems is, and in the near future will still be, heterogenous. Therefore a person will have to manage her or his identities in multiple IdM systems. In this article authors argument that future-proof IdM systems should be able to interoperate with each other dynamically, i.e. be able to discover existence of different identities of a person across multiple IdM systems, dynamically build trust relations and be able to translate identity assertions and claims across various IdM domains. Finally, authors introduce identity relationship model and corresponding identity discovery algorithm, propose IdMS-agnostic identity discovery service design and its implementation with use of Ethereum and Smart Contracts.
As the cryptocurrency market dynamically evolves, important financial and economic issues arise. The main focus of the present research is on the price of cryptocurrencies. Following the exploration of the literature base, special emphasis was put on the comparison between the crypto market and markets for different asset classes (gold, stocks, foreign currency) and on the identification of connection points. Next, the article focuses on the period after 2020, and applies the event study methodology in order to establish, how the two cryptocurrencies with the highest market capitalization (Bitcoin and Ethereum) reacted to selected events. These events mainly encompassed hacker attacks aimed at the systems that form the basis of the operation of cryptocurrencies, and also certain steps regarding their regulation and application. Overall, it was established that hacker attacks did not have a significant effect on the exchange rates of the two examined cryptocurrencies. Effects of regulatory action on prices are mixed, however even significant effects can be regarded as short-lived.
Junqin Huang, Linghe Kong, Long Cheng, Hong‐Ning Dai · 8 authors
Mobile crowdsensing (MCS) can promote data acquisition and sharing among mobile devices. Traditional MCS platforms are based on a triangular structure consisting of three roles: data requester, worker (i.e. , sensory data provider) and MCS platform. However, this centralized architecture suffers from poor reliability and difficulties in guaranteeing data quality and privacy, even provides unfair incentives for users. In this paper, we propose a blockchain-based MCS platform, namely BlockSense, to replace the traditional triangular architecture of MCS models by a decentralized paradigm. To achieve the goal of trustworthiness of BlockSense, we present a novel consensus protocol, namely Proof-of-Data (PoD), which leverages miners to conduct useful data quality validation work instead of “useless” hash calculation. Meanwhile, in order to preserve the privacy of the sensory data, we design a homomorphic data perturbation scheme, through which miners can verify data quality without knowing the contents of the data. We have implemented a prototype of BlockSense and conducted case studies on campus, collecting over 7,000 data from workers' mobile phones. Both simulations and real-world experiments show that BlockSense can not only improve system security, preserve data privacy and guarantee incentives fairness, but also achieve at least 5.6x faster than Ethereum smart contracts in verification efficiency.
The emergency of cryptocurrency has caused a shift in the financial markets. Although it was created as a currency for exchange, cryptocurrency has been shown to be an asset, with investors seeking to profit from it rather than using it as a medium of exchange. Despite being a financial asset, cryptocurrency has distinct, stylised facts like any other asset. Studying these stylised facts allows the creation of better-suited models to assist investors in making better data-driven decisions. The data used in this thesis was of three leading cryptocurrencies: Bitcoin, Ethereum, and Dogecoin and the Johannesburg Stock Exchange (JSE) data as a guide for comparison. The sample period was from 18 September 2017 to 27 May 2021. The goal was to research the stylised facts of cryptocurrencies and then create models that capture these stylised facts. The study developed risk-quantifying models for cryptocurrencies. The main findings were that cryptocurrency exhibits stylised facts that are well-known in financial data. However, the magnitude and frequency of these stylised facts tend to differ. For example, cryptocurrency is more volatile than stock returns. The volatility also tends to be more persistent than in stocks. The study also finds that cryptocurrency has a reverse leverage effect as opposed to the normal one, where past negative returns increase volatility more than past positive returns. The study also developed a hybrid GARCH model using the extreme value theorem for quantifying cryptocurrency risk. The results showed that the GJR-GARCH with GDP innovations could be used as an alternative model to calculate the VaR. The volatile nature of cryptocurrency was also compared with that of the JSE while accounting for structural breaks and while not accounting for them. The results showed that the cryptocurrencies’ volatility patterns are similar but differ from those of the JSE. The cryptocurrency was also found to be an inefficient market. This finding means that some investors can take advantage of this inefficiency. The study also revealed that structural breaks affect volatility persistence. However, this persistence measure differs depending on the model used. Markov switching GARCH models were used to strengthen the structural break findings. The results showed that two-regime models outperform single-regime models. The VAR and DCC-GARCH models were also used to test the spillovers amongst the assets used. The results showed short-run spillovers from Bitcoin to Ethereum and long-run spillovers based on the DCC-GARCH. Lastly, factors affecting cryptocurrency adoption were discussed. The main reasons affecting mass adoption are the complexity that comes with the use of cryptocurrency and its high volatility. This study was critical as it gives investors an understanding of the nature and behaviour of cryptocurrency so that they know when and how to invest. It also helps policymakers and financial institutions decide how to treat or use cryptocurrency within the economy.
Distributed Agile Software Development (DASD) is the most important approach for the modern software industry that allows geographically independent software development. In the past, different tools and frameworks were proposed to solve communication and collaboration issues in DASD but they lacked transparency, trust, traceability, and security. These shortcomings resulted in project failure or overdue, customer dissatisfaction, project deal cancellations, and payment clashes between the customers and development teams. This paper addresses and overcomes the major issues of transparency, trust, security, traceability, coordination, and communication in DASD by embedding blockchain technology. We have proposed a novel blockchain-based framework named as AgilePlus which executes the smart contracts on a private ethereum blockchain for acceptance testing, secure payment, verification of developer’s payment requirements, and automatic payment distribution into the digital wallets of development teams. The execution of these smart contracts automatically assign penalties to the customers for late or non-payments and also to the developers for overdue tasks. Moreover, we have also solved the blockchain’s scalability challenge in AgilePlus by utilizing Interplanetary File System (IPFS) as off-chain storage. Lastly, experimental results prove that the proposed framework enhances transparency, communication, coordination, traceability, security and solves trust issues of both customers and developers in DASD.
Mohamed Abdel Kader Mohamed Elgendy, Mohamed Aborizka, Ali Allam
A blockchain is a data structure that is implemented as a distrusted database or digital ledger. The transactions are saved to a block of transactions that is attached in turn to the blockchain after the verification process, in which each block in the chain contains a hash signature of the previous block in addition to the hash signature of the block itself. The blocks on the blockchain are chained as an immutable list using the proof-of-work procedure, where there is no way to alter or delete an attached block due to the strict security policy used for structuring the chain of blocks. Each node holds a copy of the blockchain in which the miners take the responsibility of verifying and attaching blocks to the blockchain. The Ethereum blockchain introduced the smart contract which holds logic to be processed once the contract is established. These smart contracts are developed via the Solidity programming language. This proposed paper exploits the Ethereum blockchain along with smart contracts as the base technology for implementing the proposed blockchain-based model. The paper aims to develop a multilayered blockchain-based model, in which the blockchain model is set up on a private blockchain Ethereum network where the nodes share the electronic medical records (EMR) among the P2P (peer-to-peer) network that will be used to secure the IoT medical transactions. Solidity smart contract, introduced by Ethereum, is deployed to handle the EMR “open-query-transfer” operations on the private network, whereas the miners are responsible to validate the transactions. Finally, the research conducts a performance analysis of the Ethereum network using the Ethereum Caliper, considering several performance factors, which are: Maximum Latency, Minimum Latency, Average Latency, and Throughput.
Wahome E. Wangui, Thomas Ogoro Ombati, Robert Oboko
In the last decade, research and development around distributed ledger technology (DLT) has grown exponentially. The financial services industry has been revolutionized by the explosion of cryptocurrencies like Bitcoin and Ethereum. Researchers have taken the principles used in these cryptocurrencies and are using them to develop other DLTs in various fields. This study explores how blockchain can be used to provide traceability, visibility, and transparency in the Kenyan informal distributed manufacturing industry. SOKO, an aggregator of artisans spread all over Nairobi, was the case study used. Purposive and convenience-based were the sampling methods used. 48 SOKO supply chain employees and active artisans were the sample population. Interviews and observations were data collection methods used. Content analysis, a qualitative data analysis method, was used to capture emerging and predetermined themes. Google sheets and Dovetail were the tools used for this study. This paper finds that the use of the immutability and proof of origin features of blockchain greatly enhances traceability within a supply chain. It is imperative that the granular information collected should be intuitive and accessible to all parties to enhance visibility. Amplified traceability and visibility greatly improved transparency and accountability within the SOKO ecosystem. A pivotal recommendation for future research is the usage of unit-based tagging technologies e.g. barcodes, QR codes, or RFID. The combined use of such technologies and blockchain would achieve the highest level of traceability, especially when working with diverse producers who produce similar products.
Muhammad Imran, Bin Yao, Waqas Ali, Adnan Akhunzada · 7 authors
Blockchain technology in recent years has become potentially pervasive in the cryptocurrency market, thus providing tamper-proof security to decentralized transaction management systems. Structurally, the design foundation is an ideal advancement of the distributed ledger technology that maintains a set of global states across nodes. As technology expands with a higher trend towards mobile computing, the development of new applications demands understanding the current progression, especially concerning performance, data management, and storage prospects. Here, we report the principle design structure of the blockchain technology combined with the state of the arts, thus characterizing their original topological contexts. We depart from the fundamental concepts of the technology and analyze performance of the Ethereum blockchain on two devices having different computing power. Our presentation is tailored to provide a systematic review of the technology, thus facilitating their possible adoption into the new application domains like the Internet of Things (IoT). Further, we developed Debug-Bench, the first VSCode (Visual Studio Code) extension that enables benchmarking and profiling of the blockchain applications. Finally, we demonstrate several critical challenges concerning the design space of the current blockchain platforms for their implementation over resource-constrained devices.
The increasing interest in digital currencies, their exceptional price rise, and the continuous discussions about their benefits raise the question: to what extent can it be an alternative to the traditional currencies in the future? It has become a prominent topic of discussion among several investments and market stakeholders seeking to enhance the growth of their wealth. This paper aims to bring answers to the nature of relationships between four major cryptocurrencies (Bitcoin, Ethereum, Litecoin, and Ripple), and the stock market return (S&P500). This study applies the wavelet method to daily data from 1 June 2017 to 15 November 2021, in COVID-19 sanitary crisis time. According to the results, this study shows a positive co-movement in the medium and long run between the four studied cryptocurrencies and S&P500 during different periods, especially in times of uncertainty. These findings have practical implications as they can be used strategically to make optimal investment decisions and build portfolio diversification strategies with the conventional financial market asset.
The purpose of this study is to examine the synchronism between the US capital markets (DJ, S&P 500), the United Kingdom (FTSE 100), Canada (S&P/TSX), Germany (DAX 30), France (CAC 40), Japan (Nikkei 225), Italy (Italy Ds Market and major cryptocurrencies such as Bitcoin (BTC), Litecoin (LTC), Ethereum (ETH), and the Crypto 10 index, from February 2018 to November 2021. Based on the findings, we found that BTC and ETH cryptocurrencies drastically reduced their level of integration with their peers over the 2020 worldwide pandemic era, whereas LTC maintained. We also discovered that the Dow Jones, S&P 500, and DAX 30 stock indexes lowered their level of integration when compared to the pre-covid subperiod. For the UK capital market (FTSE 100), Canada (S&P/TSX), Japan (Nikkei 225), France (CAC 40), and Italy (Italy Ds Market) the level of integration increased significantly. These findings support, in part, our research question, that during periods of stress and uncertainty in the global economy capital markets tend towards integration, thus calling into question the hypothesis of efficient portfolio diversification.
Based on the VAR model, we use Bitcoin prices as well as the Ethereum price daily data between December 2019 and January 2022 for dynamic identification, and the empirical analysis results show that the Bitcoin price is the granger reason of Ethereum prices, but Ethereum price is not the Bitcoin prices granger reason, namely in the long run the Bitcoin price fluctuation can affect the Ethereum price fluctuations, But Ethereum price fluctuations do not affect bitcoin price fluctuations. Meanwhile, according to the impulse response diagram, when the Bitcoin price is impacted by one unit, the Ehereum price will fluctuate greatly and approach 0 in the 11th phase. Based on the above research conclusions, this paper will put forward corresponding policy suggestions.