Οι υπηρεσίες ονοματοδοσίας παρέχουν τα απαραίτητα θεμέλια για την ανάπτυξη ποικίλων και σημαντικών εφαρμογών, όπως το ηλεκτρονικό εμπόριο και η ηλεκτρονική τραπεζική. Επί του παρόντος, αυτές οι υπηρεσίες ονοματοδοσίας βρίσκονται υπό τον έλεγχο κεντρικοποιημένων οντοτήτων, τις οποίες πρέπει να εμπιστευόμαστε ότι λειτουργούν σωστά. Δυστυχώς, η κεντρικοποίηση (εμπιστοσύνης) επιφέρει πολλά μειονεκτήματα όσον αφορά την ασφάλεια, τη διαθεσιμότητα και την ανοχή σφαλμάτων,όπως φαίνεται από μία πληθώρα περιστατικών ασφάλειας κατά τη διάρκεια των ετών όπου τέτοιες οντότητες έχουν παραβιαστεί. Η αποκέντρωση έχει προταθεί ως εναλλακτική λύση για την αντιμετώπιση αυτών των ζητημάτων. Παρ 'όλα αυτά,η αποκέντρωση εγείρει άλλα προβλήματα όπως, π.χ., η αντιμετώπιση της μη ανταποδοτικότητας και οι Σιβυλλικές επιθέσεις. Σε αυτή τη διατριβή, αξιοποιούμε την επεκτασιμότητα, την ασφάλεια, καθώς και τον ενσωματωμένο μηχανισμό παροχής κινήτρων των συστημάτων blockchain και προτείνουμε τον σχεδιασμό μιας αποκεντρωμένης υπηρεσίας ονοματοδοσίας βασισμένη σε έξυπνα συμβόλαια. Πιο συγκεκριμένα, είμαστε οι πρώτοι που παρουσιάζουμε τον πλήρη φορμαλισμό του προβλήματος σχεδιασμού υπηρεσιών ονοματοδοσίας στο πλαίσιο τoυ μοντέλου Γενικής Σύνθεσης και αποδεικνύουμε την ασφάλεια της κατασκευής μας υπό την ισχυρή υπόθεση RSA στο μοντέλο του Τυχαίου Μαντείου και την ύπαρξη μιας ιδεατής λειτουργικότητας έξυπνου συμβολαίου.Το κύριο εμπόδιο στην πραγματοποίηση μιας υπηρεσίας ονοματοδοσίας βασισμένη σε έξυπνα συμβόλαια είναι το μέγεθος της αποθηκευμένης πληροφορίας σε αυτά η οποία,όντας η πιο δαπανηρή πηγή πρόσβασης και τροποποίησης, θα πρέπει να ελαχιστοποιηθεί για να θεωρηθεί μια κατασκευή βιώσιμη. Επιλύουμε αυτό το ζήτημα ορίζοντας και χρησιμοποιώντας στην υπηρεσία ονοματοδοσίας μας έναν προσθετικό, παγκόσμιο κρυπτογραφικό συσσωρευτή δημόσιας κατάστασης σταθερού μεγέθους, ένα κρυπτογραφικό εργαλείο το οποίο μπορεί να είναι ανεξάρτητου ενδιαφέροντος στο πλαίσιο των πρωτοκόλλων blockchain. Αυτός ο συσσωρευτής προκαλεί αποθήκευση σταθερού μεγέθους πληροφορίας εις βάρος υπολογιστικής πολυπλοκότητας. Για να διερευνήσουμε το αντίκτυπο ανάμεσα σε αυτά τα δύο,προτείνουμε και υλοποιούμε μια δεύτερη κατασκευή, η οποία διατηρεί τις ιδιότητες ασφαλείας της πρώτης και, όπως απεικονίζεται μέσα από την αξιολόγησή μας, είναι η μόνη έκδοση με σταθερού μεγέθους αποθηκευμένη πληροφορία που μπορεί να αναπτυχθεί στη βασική αλυσίδα τουEthereum, της πιο αξιοσημείωτης δημόσιας πλατφόρμας έξυπνων συμβολαίων κατά τη στιγμή αυτής της γραφής. Συγκρίνουμε αυτές τις δύο κατασκευές με την απλή προσέγγιση των περισσότερων προηγούμενων υλοποιήσεων, π.χ., του EthereumName Service, όπου όλα τα αρχεία ταυτότητας αποθηκεύονται πάνω στο έξυπνο συμβόλαιο, για να καταδείξουμε αρκετές ελλείψεις του Ethereumκαι του μοντέλου κοστολόγησής του. Για την αντιμετώπιση αυτών των ζητημάτων, καθώς και άλλων,εισαγάγουμε ένα εναλλακτικό παράδειγμα για την ανάπτυξη εφαρμογών βασισμένες σε έξυπνα συμβόλαια στις οποίες το μέθεγος της αποθηκευμένης πληροφορίας σε αυτά είναι σταθερή και διευκολύνει την επαλήθευση των δεδομένων των εφαρμογών, τα οποία αποθηκεύονται σε και αναζητούνται από ένα εξωτερικό, δυνητικά αναξιόπιστο, δίκτυο αποθήκευσης. Αυτή η προσέγγιση είναι σχετική για ένα ευρύ φάσμα εφαρμογών, όπως κάθε σύστημα αποθήκευσης κλειδιών και τιμών.Δείχνουμε την αποτελεσματικότητα της προσέγγιση μας με την παρουσίαση μιας μελέτης όπου προσαρμόζουμε το πιο ευρέως αναπτυγμένο πρότυπο για ανταλλάξιμα νομίσματα, δηλ., το πρότυπο νομισμάτων ERC20.Αντιμετωπίζουμε τη μονοτονικά αυξανόμενη αποθηκευμένη πληροφορία του Ethereum η οποία, αν δεν ελεγχθεί, θα έχει άμεσο αντίκτυπο στην ασφάλεια του Ethereum και, τελικά, στη μακροζωία του. Εισαγάγουμε επαναλαμβανόμενα τέλη που είναι ανάλογα με την αποθηκευμένη πληροφορία στα έξυπνα συμβόλαια και ρυθμιζόμενα από τους κόμβους που διατηρούν το δίκτυο. Προτείνουμε ένα μοντέλο όπου το κόστος των λειτουργιών αποθήκευσης αντικατοπτρίζει την προσπάθεια που πρέπει να καταβάλουν οι κόμβοι για να τις εκτελέσουν. Δείχνουμε ότι κάτω από ένα τέτοιο σύστημα τιμολόγησης που ενθαρρύνει οικονομία στην αποθηκευμένη πληροφορία στα έξυπνα συμβόλαια, οι κατασκευές που παρουσιάζονται σε αυτή τη διατριβή μειώνουν τα τέλη συναλλαγών κατά μία τάξη μεγέθους. Υποστηρίζουμε ότι αυτές οι βελτιώσεις είναι λογικές για κάθε πλατφόρμα έξυπνων συμβολαίων που επιθυμεί να υποστηρίζει την ανάπτυξη αυθαίρετων κατανεμημένων εφαρμογών από τους χρήστες της.
Chinnapong Angsuchotmetee, Pisal Setthawong, Sapjarern Udomviriyalanon
Voting is an essential activity in the modern democracy. To facilitate the voting process, there are several attempts on proposing an electronic voting system such that, the voting and tallying processes can be done efficiently and the results would be accountable to the public. To date, however, an online electronic voting system has been rarely adopted in practice due to the possibility of having the voting result tampered through vote-rigging or cyber-attacking. In 2009, the blockchain algorithm was proposed by Satoshi Nakamoto. Blockchain is a technique for recording transactions between self-auditing ledgers in an open, distributed, permanent, and verifiable manner. Even though blockchain was originally designed for a financial applications, it is possible to apply blockchain to other domains, including in the implementation of an online decentralized-based electronic voting system. In this study, the architecture of a blockchain-based electronic voting system, named \textit{BlockVOTE}, is proposed. The architecture design and all related formal definitions are given. To validate the proposal, two BlockVOTE prototypes were implemented using two different blockchain application frameworks. The performance analysis of both versions of the prototypes are given. The analysis of both technical and management aspects on the possibility of adopting the proposed decentralized voting system in an actual voting scenario is also given at the end of this study.
Mohib Hirani, Malka N. Halgamuge, Pham Duong Thu Hang
This study investigates a range of data security models developed to achieve data security using blockchain technology for different industrial domains. Current industries utilize data-driven mechanisms for decision making with concern focussed on ensuring data security. Blockchain has the potential to secure data by integrating different information systems since data is decentralized, encrypted and validated by the whole network. This study includes an analysis of blockchain security models using data extracted from 30 peer-reviewed scientific publications over two years (2017-2019). This study analyzed three components of the publications, including the process involved in securing data, the stage of development for securing data and in which industry a model is best applied. Results of the research show that the majority of articles (51.11%) cited Blockchain as a key feature of data security for improvising the data sharing process in industries. This study also finds that the stage of implementation most commonly featured is the proposal stage with potential architectures yet to be implemented (30%). Finally, this study shows that models are applied in industrial domains such as enterprises using data analytics, finance, Internet of Things (IoT), healthcare, education, and cloud service providers. This study finds that security models are most often applied to industries and supply chain management models (28.13%). It is recommended that industry professionals conduct further research to customize the data security models in their own domain. This study gives clear guidelines to researchers of suitable frameworks, processes and consensus mechanism to utilize Blockchain in Industries for data security.
This article traces the debates occurring in the music industry where blockchain technology surged as an ideal solution for long-standing disagreements over distribution, publishing, licensing, sales, streaming, and listening. The projections (in conferences, media, opinion pieces, and academic reports) started as techno-utopian, but over time the discourse shifted from “radical” to “incorporative” goals. The technological dreams were scaled back as the scope of social challenges to technological solutions became clearer. Borrowing from Clive Barnett’s theory of convening publics, we argue that the role of the blockchain in this environment was not necessarily as a technological solution, but rather as a “convening” force that brought disparate actors together. Nonetheless, we still have to ask, who is invited to convene, and who is left out?
Smart city is one of the major Internet of Things (IoT) applications and has become an emerging paradigm with the recent advancements of IoT devices and sensors. But the heterogenous nature of a smart city IoT environment makes it vulnerable to many privacy and security concerns and introduces significant challenges for access control of IoT resources especially where access needs to be provided to third parties and external organizations. This paper proposes a new structural relationships-based access control (SRBAC) model that can be used to delegate resource access rights to users in a large scale IoT scenario like smart city while keeping the resource owner in full control. The proposed architecture uses smart contracts and public blockchain for managing access control for external users and a local off-block chain storage for managing access control for organization’s internal users and enforcing fine-grained access control for the resources.
Denis Rangelov, Nikolay Tcholtchev, Philipp Lämmel, Ina Schieferdecker
In recent years the emergence of the Ethereum Blockchain has introduced a new alternative perspective on how web applications can be build. More precisely, the Ethereum Blockchain allows the development of applications, where programming code can be executed in a decentralized manner with no restrictions imposed by a central authority. However, as it is the case with many emerging technologies, there is a fair amount of trade-offs that have to be considered when this technology is used as a platform for implementing decentralized applications. In this work we present two architectural designs for building decentralized applications (DApps) based on the Ethereum Blockchain technology. Within this context, we discuss the inherent strengths and weaknesses of each of the architectural designs as well as the set of challenges that we faced during the development process.
Miloš N. Mladenović, Montasir Abbas, Claudio Roncoli, Sanaz Bozorg Chenani
Development of integrated mobility and traffic management strategies is an important aspect of the ongoing transition of urban mobility systems. Extending from existing credit schemes, this research presents a system design and evaluation of a framework based on the principle of Universal Basic Mobility. In particular, using premises of long-term cooperation and hierarchical self-organization, the system design includes user-based Mobility Credits interrelated with Priority Levels. To complement the cooperation framework, system architecture is formulated in line with the distributed ledger technology. The proposed framework is tested using web-based interaction in the form of stated-preference experiment. Results are analyzed through statistical distributions and a discrete-choice model of user decision-making within the proposed framework. This research concludes that this framework could nudge uses towards reciprocity and altruism in their travelling behavior. In addition, experiment participants have provided a range of comments related to positive features, potential for failure, and further development. Finally, the paper ends by raising several implications for wider citizen participation in the integrated mobility system design and evaluation.
Since the formation of Bitcoin in 2009, various private digital currencies have been presented. Bitcoin is by a long shot the best one. It has been getting a great deal of media consideration, and its all out market worth has arrived at 20 billions USD in March 2017. More importantly, a number of central banks started recently to explore the adoption of cryptocurrency and blockchain technologies for retail and large-value payments. Bitcoin is a digital currency based on a peer-topeer payment system managed by an open source software and characterized by lower transaction costs, greater security and scalability than fiat money and no need of a central bank. In spite of criticisms about illegal uses and social consequences, it is attracting the interest of the scientific as well as economic community. Be that as it may, notwithstanding Bitcoin’s worth, the paper clarified, physical stores have been delayed to acknowledge it as a technique for installment. Subsequently, a few lookers are getting to be critical about whether this tech-trendy person digital money, which everybody has known about however the vast majority don’t genuinely comprehend, will ever supplant conventional cash. Only one exchange can use as much vitality as a whole family unit does in seven days, and there are around 300,000 exchanges each day. That vitality request is usually met through petroleum product vitality sources, which, alongside contaminating air and water, radiate ozone harming substances that reason environmental change. At the end of the day, Bitcoins are adding to the warming of the climate without giving a noteworthy open advantage consequently. Some Bitcoin lovers guarantee that it will in the long run become a standard money, and that the cryptogovernance framework whereupon it’s manufactured could really support the earth. In any case, the Bitcoin market is unstable, its future dinky. Off-the-rack PCs used to be incredible enough to mine Bitcoins. Presently, on the grounds that the math issues are so perplexing, they should utilize particular equipment called Application Specific Integrated Circuit, or ASIC. These mining machines are huge and run hot, and the individuals who use them—either Bitcoin mining organizations or Bitcoin devotees cooperating—utilize a great deal of power to do as such. Organizations and associations that mine bitcoin will once in a while have a huge number of these machines pressed into far reaching distribution centers. Hence, the present study is an attempt to define and evaluate the current trends of the literature concerned with the sustainability of bitcoin, considering the environmental impacts and economic aspects. The study is divided into four parts – first part explains the concept of bitcoin in detail with its history. The second part of the study details the statement of the problem. The third part deals with results and discussions and the last is the concluding part. In the results and discussion part, the data dealing with trends in the value of bitcoin in USD and in Indian markets are exhibited. The main exchanges dealing with bitcoin in India are then given and the number of bitcoins available and their market capitalisation worldwide is shown.
 From the analysis, it is very clear that the value of bitcoin has tremendously increased over the period of time. One of the main allegations against the bitcoin trading is its fluctuating volatility depicted. It’s because of this issue, that bitcoins are considered to be very dangerous commodity to be traded. Also, form the point of sustainability, it emerges that the transition of the whole monetary system in the new cryptocurrency will result in an unacceptable amount of energy consumed to mine new bitcoins and to maintain the entire virtual monetary system, and probably bitcoin will remain a niche currency.
In any registration process, it is a hassle to always bring physical documents. Not only that, the process is elongated if they are lost, and will contribute to identity theft if unauthorized persons have access to those documents. Therefore, the objective of this paper is to generate a decentralized system, similar to the concept of blockchain, to allow registered persons to access user’s personal records. To further elaborate, this system is designed to be used by three consumers, which are: user, authority, and third-party (requester). Nowadays, majority of systems are susceptible to massive data breaches. However, some researches have theorized that blockchain technology may solve this problem, such as one that uses a real-world example, Aadhaar. In conclusion, this project enhances that the area of blockchain identity is vital in helping society gain control of their personal details. Since most of researches are focused on storage system of businesses using blockchain, personal identities of the people should be digitized on the blockchain as well. An identity verification system that is entirely owned by the individual will increase trust that the data is genuine and reliable.
Sina Rafati Niya, Sebastian Allemann, Arik Gabay, Burkhard Stiller
Data leaks and privacy scandals have been a growing concern of the last decade. While most traditional, i.e., centralized, online platforms require users to register with their personal data, they potentially expose the user's identity and data to be used for unintended purposes. This work proposes TradeMap as an integrated architecture, designing and enabling an online end-to-end (e2e) trading market place, while supporting anonymous management features. TradeMap addresses the Swiss Financial Market Supervisory Authority (FINMA) regulations by designing a FINMA-complaint Know Your Customer (KYC) platform. Additionally, TradeMap is based on blockchains and employs Ethereum Smart Contracts (SC). Thus, trust and anonymity between the market place and the KYC system relies on zero knowledge proof-based SCs used for user identification processes. With this management approach proposed, the user authentication is only verified within the KYC platform, providing a legally valid and fully anonymous online trading platform.
The paper highlights why, contrary to frequent claims, cryptocurrencies will not replace the existing monetary system. The reason is that despite its shortcomings the current monetary system is a product of a long evolution which had adjusted it to the needs of the economy. Cryptocurrencies will probably remain what they have been during the last decade, i.e. the popular speculative assets and the means of payment used – due to their anonymity – for illicit operations. The recent monetary system, based on deposit money issued by commercial banks, will not be replaced also by deposit money issued by central banks (Central Bank Digital Currency) as the CBDC would lack a rational mechanism of its allocation and would pose risks to financial stability
Md. Ibrahim Khan, Fahim Faisal, Sami Azam, Asif Karim · 6 authors
Abstract Modern storage technology has shifted from traditional offline state to cloud based technology since some time now. Because of this transition, the present society is now more dependent on the online storage solutions. Synchronization of files and keeping a history of changes are critical parts of any cloud system. Therefore, an implementation of Blockchain Technology with traditional file synchronization and versioning system can be extremely fruitful. Blockchain is not a new technology, but recently its importance has sky-rocketed as the society is moving towards the decentralized World Wide Web. Blockchain is “an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way” [1]. Blockchain provides immutable data storage and access with the combination of Proof-of-Work [2, 3]. Due to such appealing features, the study undertaken here investigates and proposes a Blockchain based resilient cloud storage solution that makes a sound utilization of various properties fundamental to any Blockchain based framework.
Nowadays, blockchain is one of the most popular and innovate technologies over the world. Although this technology appears for first time in the Bitcoin cryptocurrency, in recent years, a lot of researchers and industries from different fields such as banking, financial, supply chain management, etc. have given more involved than ever before. The blockchain is implemented in decentralized and distributed ledgers in peer-to-peer (p2p) networks where non-trusting peers can implement digital asset transactions without the need of central authority. Then, other peers in the network, according specific rules determined by the network, validate these transactions, insert them in the block and append the block in the chain (ledger). The key contribution for the proper operation of the blockchain is the consensus protocols. Through these protocols, all the peers in the network or the majority of them, they have to reach an agreement for a specific block in order to insert it in the chain based on different blockchains rules. In this master thesis, we will analyze in depth the general architecture of the blockchain and various consensus protocols that implemented in different blockchains in order to be able to improve the Delegated Byzantine Fault Tolerance (DBFT) consensus algorithm, which is used in the NEO blockchain technology. Finally, a development of a reputation mechanism is needed based on the improvement of the DBFT algorithm in order to measure the reputation of the peers for a specific day.
Christos Profentzas, Magnus Almgren, Olaf Landsiedel
For any distributed system, and especially for the Internet of Things, recording interactions between devices is essential. At first glance, blockchains seem to be suitable for storing these interactions, as they allow multiple parties to share a distributed ledger. However, at a closer look, blockchains require heavy computations, large memory capacity, and always-on communication to the cloud; these are three properties that are challenging for IoT devices with limited resources. In this paper, we present IoTLogBlock to address these challenges. IoTLogBlock connects resource-constrained IoT devices to the blockchain, and it consists of three building blocks jointly enabling recording transactions: a lightweight contract signing protocol, a blockchain network, and a smart contract. The contract signing protocol allows devices to interact locally to perform transactions, even if no communication to the cloud and the blockchain exists at that moment. At a later time, devices forward the stored transactions to the blockchain, where a smart contract ultimately verifies the transactions. We evaluate our design on low-power devices and quantify the performance in terms of memory, computation, and energy consumption. Our results show that a constrained device can create and sign a transaction within 3 s on average. Finally, we expose the devices to network scenarios with edge connections ranging from 10 s to over 2 h.
Ryan Shivers, Mohammad Ashiqur Rahman, Hossain Shahriar
Ride-hailing and ride-sharing applications have recently gained in popularity as a convenient alternative to traditional modes of travel. Current research into autonomous vehicles is accelerating rapidly and will soon become a critical component of a ride-hailing platform's architecture. Implementing an autonomous vehicle ride-hailing platform proves a difficult challenge due to the centralized nature of traditional ride-hailing architectures. In a traditional ride-hailing environment the drivers operate their own personal vehicles so it follows that a fleet of autonomous vehicles would be required for a centralized ride-hailing platform to succeed. Decentralization of the ride-hailing platform would remove a road block along the way to an autonomous vehicle ride-hailing platform by allowing owners of autonomous vehicles to add their vehicle to a community driven fleet when not in use. Blockchain technology is an attractive choice for this decentralized architecture due to its immutability and fault tolerance. This paper proposes a framework for developing a decentralized ride-hailing architecture implemented on the Hyperledger Fabric blockchain platform. The implementation is evaluated using a static analysis tool and performing a performance analysis under heavy network load.
Matteo Varvello, Iñigo Querejeta Azurmendi, Antonio Nappa, Panagiotis N. Papadopoulos · 6 authors
Distributed Virtual Private Networks (dVPNs) are new VPN solutions aiming to solve the trust-privacy concern of a VPN's central authority by leveraging a distributed architecture. In this paper, we first review the existing dVPN ecosystem and debate on its privacy requirements. Then, we present VPN0, a dVPN with strong privacy guarantees and minimal performance impact on its users. VPN0 guarantees that a dVPN node only carries traffic it has "whitelisted", without revealing its whitelist or knowing the traffic it tunnels. This is achieved via three main innovations. First, an attestation mechanism which leverages TLS to certify a user visit to a specific domain. Second, a zero knowledge proof to certify that some incoming traffic is authorized, e.g., falls in a node's whitelist, without disclosing the target domain. Third, a dynamic chain of VPN tunnels to both increase privacy and guarantee service continuation while traffic certification is in place. The paper demonstrates VPN0 functioning when integrated with several production systems, namely BitTorrent DHT and ProtonVPN.
Electronic Health Records (EHRs) have improved many aspects of healthcare and allowed for easier patient management for medical providers. Blockchains have been proposed as a promising solution for supporting Electronic Health Records (EHRs), but have also been linked to scalability concerns about supporting real-world healthcare systems. This paper quantifies the scalability issues and bottlenecks related to current blockchains and puts into perspective the limitations blockchains have with supporting healthcare systems. Particularly we show that well known blockchains such as Bitcoin, Ethereum, and IOTA cannot support transactions of a large scale hospital system such as the University of Kentucky HealthCare system and leave over 7.5M unsealed transactions per day. We then discuss how bottlenecks of blockchains can be relieved with sidechains, enabling well-known blockchains to support even larger hospital systems of over 30M transactions per day. We then introduce the Patient-Healthchain architecture to provide future direction on how scaling blockchains for EHR systems with sidechains can be achieved.
Purpose – The purpose of this paper was to conduct a systemic review of extant cryptocurrency research in order to identify important features of these studies and to provide directions for future cryptocurrency research. Methodology - The Systematic Quantitative Assessment Technique (SQAT) was used to identify and review relevant peer-reviewed journal articles that investigated various facets of cryptocurrency. \nFindings – 54 journal articles were identified from 12 high-quality databases. The findings of the review revealed that most of the studies took place in Europe, North America and Asia, while Africa has been largely ignored. The main focus of cryptocurrency articles has been on a call for regulation of cryptocurrency without much work done on how to mitigate its vulnerability to the financing of terrorism and as a tool for money laundering. Finally, most cryptocurrency articles adopted a single research method – survey. There is a need for future studies to combine a variety of methods so as to gain additional insight into the issues of cryptocurrency’s vulnerability, risk identification and mitigation, regulation and acceptability. \nResearch limitations - The use of limited but high quality academic databases means that some articles were not considered for this review. \nOriginality/value – This study is one of the few studies to conduct a systematic review on a phenomenon which has the potential to transform the global financial landscape.
Eder J. Scheid, Timo Hegnauer, Bruno Rodrigues, Burkhard Stiller
The blockchain (BC) world is rapidly becoming a universe of several ledgers designed for a specific purpose, holding data previously stored (i.e., siloed) in centralized databases. The use of different BCs for the same purpose could hamper the frictionless exchange of data or value. On one hand, it is natural that there are competing implementations exploring the benefits of BC. On the other hand, the problem of siloed data re-emerges, with respect to isolated chains. In this regard, BC interoperability is necessary to connect different BCs, exchanging information and assets. Moreover, to foster BC employment, developers must be able to interact with such different BCs without knowing the details of each implementation. This paper presents a novel solution, called Bifröst, to store and retrieve data on different BCs. Bifröst employs a notary scheme, which allows for connectivity to different BCs. The presented prototype is highly modular and currently implements seven adapters to popular BC implementations, including Bitcoin, Ethereum, and Stellar. The developed prototype was evaluated concerning performance, security, and data size to verify the feasibility of such an implementation and assess design decisions taken during its development.
Internet of things (IoT), mobile edge computing (MEC), and unmanned aerial vehicle (UAV) have attracted significant attention in both industry and academic research. By consolidating these technologies, IoT can be facilitated with improved connectivity, better data transmission, energy saving, and other advantages. However, the communication between these entities is subject to potential cyber threats. In addition, the integrity of the data must be maintained after storing into local storage. Blockchain is a data structure that supports features like pseudonymity, data integrity etc. This paper represents a blockchain based data acquisition process in which information is gathered from IoTs using UAV as a relay and is securely kept in blockchain at MEC server. In the proposed scheme, data are encrypted prior to transfer to MEC server with the assistance of a UAV. Upon receiving the data, MEC server validates the data and the identity of the sender. Successful validation is followed by stocking of the data into blockchain, subsequent to obtaining consent from the validators. Security analysis is conducted in order to show the feasibility of the proposed secure scheme. Finally, the performance of the proposed scheme is analyzed via simulation and implementation.
Yeray Mezquita, Amin Shokri Gazafroudi, Juan M. Corchado, Miadreza Shafie‐khah · 6 authors
The security of smart grids is put at risk due to their automation and remote access features. Blockchain technology can be used as a distributed ledger where data is stored and all the data transactions between the different entities of a smart grid are signed to protect them from such attacks. This paper proposes a multi-agent system (MAS) that combines smart contracts and blockchain to enable Peer-to-Peer electricity trading in a MicroGrid (MG) scenario, without the need for human intervention. The use of blockchain technology helps reduce transaction costs and allows to make micro transactions in the proposed market. Blockchain also improves the security of the platform because all the involved actors can be certain about the authorship of the information produced in the system. Finally, the use of a MAS and the possibility of negotiating between the agents helps obtain an optimal state in the system in which the costs of energy are minimal and the local production of energy is profitable.
Countries around the world are nowadays actively promoting development in intelligent agriculture. Each of them must develop a specific plan tailored to environmental farming indices of each individual farm, and such information would be both important and sensitive. This is why information in intelligent agriculture requires protection from network security to ensure data privacy and integrity. This study proposes applying dark web technology to ensure the privacy of blockchains and servers. The study will monitor packet transmission frequency in intelligent agriculture to prevent distributed denial-of-service (DDOS) attacks. The main features of system include: (1) An identity authentication mechanism, (2) secure transmission of information, (3) establishment of private blockchains, (4) a faster, improved authentication system for blockchain information, and (5) resistance against DDOS attacks. The proposed scheme can safeguard network security for the IoT as well as the servers by way of applying dark web technology, which can avoid exposure of blockchains and server ID addresses and thus in turn lower the risks of DDOS attack damages. Experiment results indicate that the application of lightweight encryption of proposed scheme does indeed improve the authentication speed while also satisfying requirements of network security.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
We develop a new Data-Driven Phasic Word Identification (DDPWI) methodology to determine which words matter as the bitcoin pricing dynamic changes from one phase to another. With Google search volumes as a baseline, we find that Reddit submissions are both correlated with Google and have a comparable relationship with a variety of bitcoin metrics, using Spearman's rho. Reddit provides complete access to the text of submissions. Rather than associating sentiment with market activity, we describe the DDPWI method for finding specific 'price dynamic' words associated with changes in the bitcoin pricing pattern through 2017 and 2018. We assess the significance of these changes using Wilcoxon Rank-Sum Tests with Bonferroni corrections. These price dynamic words are used to pull out associated words in the submissions thereby providing the context to their use. For example, the price dynamic word 'ban', which became significantly higher in frequency as prices fell, occurred in the context of both government regulation and internet companies banning cryptocurrency adverts. This approach could be used more generally to look at social media and discussion forums at a granular level identifying specific words that impact the metric under investigation rather than overall sentiment.
The widespread recognition of the smart contracts has established their importance in the landscape of next generation blockchain technology. However, writing a correct smart contract is notoriously difficult. Moreover, once a state-changing transaction is confirmed by the network, the result is immutable. For this reason, it is crucial to perform a thorough testing of a smart contract application before its deployment. This paper's focus is on the test coverage criteria for smart contracts, which are objective rules that measure test quality. We analyze the unique characteristics of the Ethereum smart contract program model as compared to the conventional program model. To capture essential control flow behaviors of smart contracts, we propose the notions of whole transaction basis path set and bounded transaction interaction. The former is a limited set of linearly independent inter-procedural paths from which the potentially infinite paths of Ethereum transactions can be constructed by linear combination, while the latter is the permutations of transactions within a certain bound. Based on these two notions, we define a family of path-based test coverage criteria. Algorithms are given to the generation of coverage requirements. A case study is conducted to compare the effectiveness of the proposed test coverage criteria with random testing and statement coverage testing.