Cryptocurrencies are more than a decade old and several issues have been discovered since their then. One of these issues is a partial negation of the intent to “democratize” money by decentralizing control of the infrastructure that creates, transmits, and stores monetary data. The Programmatic Proof of Work (ProgPoW) algorithm is intended as a possible solution to this problem for the Ethereum cryptocurrency. This paper examines ProgPow’s claim to be Application Specific Integrated Circuit (ASIC) resistant. This is achieved by isolating the proof-of-work code from the Ethereum blockchain, inserting the ProgPoW algorithm, and measuring the performance of the new implementation as a multithread CPU program, as well as a GPU implementation. The most remarkable difference between the ProgPoW algorithm and the currently implemented Ethereum Proof-of Work is the addition of a random sequence of math operations in the main loop that require increased memory bandwidth. Analyzing and comparing the performance of the CPU and GPU implementations should provide an insight into how the ProgPoW algorithm might perform on an ASIC.
This paper examines the market efficiency of three key cryptocurrency markets namely: Bitcoin, Ethereum and Monero, before and during the COVID-19 pandemic. This research makes use of a Durbin-Watson test and a non-parametric runs test to test for weak-form efficiency, and two comprehensive event studies to test for semi-strong form and strong form efficiency. We conclude neither market can be considered efficient due to the presence of strong positive correlation, and inefficient reactions to our event studies. Despite this, each market became more efficient during the COVID-19 pandemic than before, due to the presence of weaker positive correlation during this timeframe, but inefficient, nonetheless. Thus, the study finds that of the tested cryptocurrency markets, none can be consider wholly efficient. This conclusion is consistent with the vast majority of existing literature.
Abstract Blockchain technology has rapidly emerged as a decentralized trusted network to replace the traditional centralized intermediator. Especially, the smart contracts that are based on blockchain allow users to define the agreed behaviour among them, the execution of which will be enforced by the smart contracts. Based on this, we propose a decentralized booking system that uses the blockchain as the intermediator between hoteliers and travellers. The system enjoys the trustworthiness of blockchain, improves efficiency and reduces the cost of the traditional booking agencies. The design of the system has been formally modelled using the CSP# language and verified using the model checker Process Analysis Toolkit. We have implemented a prototype decentralized booking system based on the Ethereum ecosystem.
Mahmoud El-Gayyar, Hany F. ElYamany, Katarina Grolinger, Miriam A. M. Capretz · 5 authors
A federated identity is a single identity that enables users to access multiple services across a network of business parties. Such identities are subject to various threats and attacks and face diverse challenges including identity leaks, centralised management, auditing limitations, and long breach investigation processes. This paper proposes a framework aimed at automating and decentralising the generation and auditing of a robust and secured blockchain-based federated identity in a marketplace. Business parties participating in the marketplace form the nodes of a distributed blockchain network and participate in the creation of federated identities. Users of this network can access services provided by any one of the participating parties using a single federated identity. All transactions are fully audited in the blockchain, meaning that participating parties can monitor access to their service and users can trace the use of their identities. The proposed framework has been evaluated using two blockchain technologies (Ethereum and Hyperledger Fabric) to measure its performance in public and permissioned blockchain environments.
With the greater availability and reduced dimensions of complex electronics, an Internet of Things (IoT) will emerge in the future, in which machines use sensors to collect and evaluate information about the physical world and share it with other machines without having to rely on human interaction. Blockchain technology encompasses features such as trustworthiness and decentralization and these features can be advantageous in the IoT context, as they can help to ensure data integrity in an Internet of Things unmonitored by humans. In the course of this paper, we investigate to what extent the use of blockchain technology is feasible for autonomous devices in IoT. For this purpose, a prototypical client blockchain component is built using the single-board computer Raspberry Pi and a simulated Ethereum blockchain. This prototype will be examined for aspects like proper functionality, response times and performance.
Mazin Debe, Khaled Salah, Raja Jayaraman, Junaid Arshad
An enormous amount of drug supply is regularly wasted due to several reasons related to incorrect prescription, purchase of unnecessary quantities, drug intolerance, allergy, or interactions. On the other hand, these medicines may be needed by patients who cannot afford to purchase them. To address this challenge, we propose a fully decentralized solution that governs the return and redistribution of unused drugs that are fit for usage. Our approach exploits the decentralized blockchain technology, smart contracts, and decentralized storage systems such as the Interplanetary File Systems (IPFS). We develop a system that provides the ability for customers as well as pharmacies to return re-usable, resellable drugs for donation or resale at a lower price. The proposed scheme tracks the production of drugs from manufacturers to traders that subsequently sell them to customers. Unused drugs can be returned after approval by specialized entities and then redistributed. In particular, we present the decentralized system architecture and implement a prototype on a test Ethereum blockchain platform to present the suggested workflow. Further, we provide system evaluation focused on assessing system functionality, performance, execution cost, and security of smart contracts and their robustness. We have also made our smart contracts code publicly available on Github.
Jorge Eterovic, Jonatan Uran Acevedo, Alejandro Rusticcini, Nora Gigante
Blockchain Federal Argentina (BFA) es la primera plataforma multiservicios abierta y participativa de Argentina pensada para integrar servicios y aplicaciones sobre la Blockchain de Ethereum. Las organizaciones, tanto públicas como privadas, pueden formar parte de Blockchain Federal Argentina, ejerciendo distintos roles de control dentro de la organización. También pueden desplegar aplicaciones sobre la plataforma. El proyecto de investigación consiste en implementar un nodo Minero (en adelante nodo Sellador) en la Universidad Nacional de La Matanza, dentro de la red Blockchain Federal Argentina, para lo cual se celebrará un contrato de colaboración público-privada entre la UNLaM, representada por el Departamento de Ingeniería e Investigaciones Tecnológicas (DIIT) y el consorcio Blockchain Federal Argentina. Este contrato hará a la UNLaM parte del mencionado consorcio y permitirá montar un nodo Sellador dentro de la infraestructura Blockchain-BFA. En el marco de este proyecto, se desarrollará e implementará una dApp (Aplicación Distribuida) que quedará disponible para su uso libre para toda la comunidad académica. La relevancia de este trabajo radica en la importancia que tiene para una institución formar parte de una red con las características de BFA. Hasta el momento, la UNLaM, no forma parte de BFA ni de otras plataformas similares.
The frequent occurrence of food safety accidents at the global level has triggered consumer sensitivity. Establishing a food traceability system can effectively guarantee food safety and increase consumer confidence and satisfaction. Existing food traceability systems often ignore environmental factors that affect food quality at all stages of the supply chain, and the authenticity of the information obtained through traceability is difficult to guarantee. In this study, a food supply chain traceability model was established based on blockchain and radio frequency identification (RFID) technologies. The model focused on the traceability of environmental data during the various stages of the food supply chain and combined a centralized database and blockchain for data storage. The lot identification data of the various supply chain stages were stored in a centralized database, while the environmental data were stored in a blockchain. Thereby, the authenticity and accuracy of the traceability data were ensured. The blockchain part of the model has been simulated in the Ethereum test environment, and the experiment has achieved traceability of temperature data.
In this article, we present the first solution for multi-party certified email that achieves fairness and confidentiality without the intervention of a TTP but with blockchain support when problems arise. Our solution preserves the confidentiality of the mail exchanged between the sender and the recipients even when the blockchain is involved. We provide a proof of concept implementation based on Ethereum smart contracts that shows it is feasible from a practical point of view. Because the functions of a smart contract are only executed on the blockchain in the case of conflict, costs are minimised compared to solutions that execute the functions on the blockchain in all cases (on-chain solutions). Moreover, the solution can be integrated into the existing email infrastructure.
Bitcoin, Ethereum and Ripple are the three major cryptocurrencies with market capitalisation exceeding 70% of all the cryptos. The covid-19 threats since the beginning of the 2020 are disturbing the financial markets all around the world. This study is an enquiry to model the fluctuations among the three cryptocurrencies with the hypothesis that whether a combination of two coins could explain the changes in the other coin. The study found that Bitcoin and Ripple are better explaining the Ethereum returns in the short-run. The negative error correction coefficient found in the regression indicates that if the daily log returns of ETH is above that of the daily log return of BTC by one point, the daily log return of ETH fall by 1.11 point. On the other hand, the positive error correction coefficient indicates that if the daily log return of ETH is above that of the daily log return of XRP by one point, the daily log return of ETH increases by 0.14 point.
In order to solve the problem that most of the existing blockchain-based searchable encryption schemes only support exact keyword search and mutual distrust between the cloud server and the user, a searchable encryption scheme based on blockchain, that has functions such as file update dynamically, search results verification, fuzzy keyword search, and fair payment, is proposed. We use edit distance to generate the fuzzy keywords set. According to the un-modification characteristic of Ethereum blockchain and the security of the RSA accumulator, our scheme can verify the search results by the smart contract and realize the service-payment fairness between the user and the cloud server. The security analysis shows that the proposed scheme achieves non-adaptive semantic security. Performance analysis and experiment show that our scheme is efficient and meets the demand of search application in the cloud environment.
Background: Due to the rising popularity of autonomous unmanned vehicles, and the lack of well-defined rules to follow, a solution is needed when the physical space is crowded to a point where it becomes a hazard. Partitioning space discretely is currently done in some cases, allowing vehicles to reserve partitions to operate within. This idea is expanded upon to ultimately propose a blockchain-based solution to the inefficiency of safety margins. Objectives: The main objective was to explore whether a blockchain-based system can be used by vehicles to automatically reserve the volumes of space they need for a limited time. The solution to congestion becomes a method for vehicles to communicate between each other to exchange the remainder of their reservations once they are no longer needed, even while disconnected from the main blockchain network, in exchange for the same currency used to reserve the volumes. Methods: An Ethereum private blockchain network is set up, and a smart contract is developed and deployed onto this blockchain. An emulation program used the smart contract functions to reserve and exchange volumes to evaluate the functionality, several isolated tests evaluated the network performance, and aspects that could not be tested were theoretically analyzed. Results: The system functions as intended, although a level of trust is required during exchanges. There is no risk of two vehicles reserving the same volume at the same time. The results indicate that some performance aspects will be affected by an increasing number of users, although the entire effect can be placed on synchronization time if the network parameters are adjusted. This likely affects the overall efficiency but not as much as it would with the original parameters. Conclusions: The proposed solution is viable to use, although further development is necessary before it is ready for release. The necessity currently is not evident, although projections suggest that this solution, or a similar one, will be necessary in the future.
El presente trabajo ofrece soluciones a los problemas juridicos que plantean los smart contracts, por tratarse de clausulas contractuales autoimplementadas en un codigo informatico que autoejecuta su contenido. Estos versan sobre su discutida naturaleza juridica, la adhesion del consumidor 2.0 mediante Blockchain, su personalizacion con Ethereum, los errores de programacion y la responsabilidad civil, la proteccion y encriptacion de datos de caracter personal, y la formacion y ejecucion del contrato. Las dificultades que plantean los smart contracts requieren de una regulacion europea, inspirada en las legislaciones existentes en algunos territorios de los Estados Unidos y Francia, asi como en los estudios formulados en el ambito de UNIDROIT y la CNUDMI.
EBELOGU Christopher U, ORIAKHI Joseph E, OJO Samuel D, AGU Edward O
Cryptocurrency is generally known to be a digital record of ownership of nominal balance which can be used to pay for transactions. Thus, for any transaction, the buyer gives instructions to transfer ownership of a certain amount of his balances tothe seller. The use of cryptocurrencies such as Bitcoin and Ethereum in performing online transactions has been on the rise andalmost accepted generally in the world. Africa as a continent is not left out in the adoption of blockchain and cryptocurrencies.Today, in 2019, the question of whether or not digital money can actually become a useful and secure part of the Nigerianeconomy is being seriously debated. This paper explores how cryptocurrency technology can be a means of leveraging theNigeria economy and its extremely large population.
Affaf Shahid, Umair Sarfraz, Muhammad Waseem Malik, Muhammad Sohaib Iftikhar · 6 authors
Supply chains are evolving into automated and highly complex networks and are becoming an important source of potential benefits in the modern world. However, it is challenging to track the provenance of data and maintain traceability throughout the network. The traditional supply chains are centralized and dependent on third party for trading. Centralized systems lack transparency, accountability and auditability. In our proposed solution, we have presented a blockchain-based reputation system in Agriculture and Food (Agri-Food) supply chain. It leverages the key features of blockchain and smart contract deployed over ethereum blockchain network. Although blockchain provides an immutable network for supply chain events, it still fails to solve the problem of trust among entities. Therefore, a reputation system is required that logs reviews of sellers and maintains the trust between trading entities.
Open access
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques
Ferdınando Chıacchıo, Lucio Compagno, Diego D’Urso, Luca Velardita · 5 authors
With the growth of a global market, new regulations aiming at preventing the fraud of counterfeiting drugs have been released all over the world. In the pharma industry, an innovative technology named serialization is becoming more and more popular as it allows to implement a packaging process based on a hierarchical aggregation. This guarantees that each box entering in the distribution network is marked with a unique identifier for an easy traceability by a central regulatory in charge to follow the life cycle of the product until given to the final patient. In this scenario, the blockchain might offer a breakthrough proposing a decentralized and immutable traceability mechanism able to increase the security of the data and to reduce the success of a fraud attempt. To demonstrate the effectiveness of this technology, in this paper, a DAPP based on the Ethereum blockchain has been coded and tested as prototype in a pharma industry.
Open access
Blockchain Technology Applications and Security
Innovative Microfluidic and Catalytic Techniques Innovation
Physical Unclonable Functions (PUFs) and Hardware Security
Finansal zaman serilerinde görülen değişen varyans sorununun (ARCH etkisi) sonucu olarak otoregresif koşullu değişen varyans modelleri bulunmuştur. Çalışmamızda, piyasa değeri en yüksek üç kripto paranın [Bitcoin (BTC), Ethereum (ETH) ve Ripple (XRP)] getirileri incelenmiş ve söz konusu getirilerde finansal zaman serilerine benzer şekilde ARCH etkisi bulunmuştur. Söz konusu üç kripto paranın volatiliteleri için en iyi modelin hesaplanmasında altı GARCH modelini karşılaştırılmıştır. Bu modeller sırasıyla GARCH (1,1), EGARCH (1,1), TGARCH (1,1), APARCH (1,1), CGARCH (1,1) ve ACGARCH (1,1) modellerinden oluşmaktadır. Çalışma kapsamında 01.10.2015 - 01.10.2018 tarihleri arasında Bitcoin (BTC), Ethereum (ETH) ve Ripple (XRP) kripto paralarının günlük kapanış verilerinden elde edilen getiriler kullanılmıştır. Volatilite tahminlerinde Bitcoin (BTC) ve Ethereum (ETH) için en iyi model EGARCH (1,1), Ripple (XRP) için ise APARCH (1,1) modeli bulunmuştur. Çalışma kapsamında bu modeller kullanılarak volatiliteler üzerinde negatif şokların pozitif şoklardan daha fazla etkisinin bulunduğunu gösteren kaldıraç etkisi incelenmiştir. Bitcoin (BTC) ve Ethereum (ETH) modellerinde kaldıraç etkisi bulunmamış, bununla birlikte pozitif şoklar negatif şoklara göre daha fazla volatiliteye neden olmuştur. Ancak, Ripple (XRP) volatilite modelinde kaldıraç etkisi belirlenmiştir.