Çalışmada gün geçtikçe popülerliği ve buna bağlı olarak toplam piyasa değerleri ve işlem hacimleri artan, çok sayıda ve çok çeşitli piyasalarda işlem gören kripto paraların fiyatlarının birbiri üzerindeki etkisi araştırılmıştır. Çalışmada, Bitcoin, Ethereum, Ripple, Bitcoin Cash, Cardano, Litecoin, NEM, NEO, Stellar ve IOTA kripto paralarının seçiminde toplam piyasa değerleri dikkate alınmıştır ve en yüksek toplam piyasa değerine sahip 10 kripto para analize dahil edilmiştir. 15 Aralık 2017 ve 17 Ocak 2018 tarihleri arasında çalışmaya konu olan kripto paraların günlük fiyat hareketleri arasındaki ilişkiyi incelemek için serilere Johansen Eşbütünleşme Testi ve Granger Nedensellik Testi uygulanmıştır. Çalışmanın sonucunda, Cardano’nun NEO’nun Granger nedeni olduğu, Bitcoin’in Bitcoin Cash’in Granger nedeni olduğu, Litecoin’in Bitcoin Cash’in Granger nedeni olduğu, NEM’in Bitcoin Cash’in Granger nedeni olduğu, Ripple’ın Bitcoin’in Granger nedeni olduğu, NEO ve Ethereum’un birbirinin Granger nedeni olduğu, NEO ve Litecoin’in birbirinin Granger nedeni olduğu ve NEM’in Stellar’ın Granger nedeni olduğu tespit edilerek, bu değişkenlerin fiyat hareketlerinin kısa dönemde birbirini etkilediği ortaya konmuştur.
Marco Alessi, Alessio Camillò, Enza Giangreco, Marco Matera · 6 authors
In the times we are living, data protection infringements, at local, national or international level, are a daily occurrence, highlighting how important is the problem of users' awareness and “consent” about what data should or not be shared. A vast number of service providers strives to have access to users' personal data. While users may be aware of sharing their data with services they receive, they may be still unaware if their data is passing in others' hands and unknown third parties. But the sharing of personal data remains unavoidable, in this always connected digital era, contextualized services are not only fancy desires, they could save money, time, and even lives. The problem becomes even more complicate if we try to consider the devices around us: how to share devices we own, so that we can receive pervasive services, based on our contexts and device functionalities. The European Authority has provided regulations about personal data protection, but there are still significant differences in the ways each EU member state would implement the protection of privacy and personal data in national laws, policies, and practices. The tool that should empower users with the personal data protection has to face two problems: data privacy and control. Due to the lack of central authorities, blockchain based technologies would seem fit for the challenge, but such solutions are not fully exploited. One possible reason could be that distributed architectures alone do not achieve privacy of data. In this paper we tackle the challenge of a novel Personal Data Store, by making use of a distributed architecture, based on the Ethereum framework, together with an ontology to model user profile and data/device sharing towards services. Such solution, The Decentralized Identity Manager, solves personal data protection by offering a unique endpoint, without any central authority, where users can manage their data/device access, their privacy levels, and grant or deny sharing consent, every time services ask for personal data.
The Enterprise Ethereum Client Specification by the Enterprise Ethereum Alliance defines the requirements which Ethereum Clients offering private smart contract capabilities should comply with. This specification though ground breaking, misses some important blockchain requirements and does not fully consider the requirements of Ethereum Clients offering Private Sidechain capabilities. This paper presents the case for Private Sidechains and defines requirements to be complied with to deliver this technology. The capabilities of three blockchain clients have been analysed based on the requirements: Quorum, Parity, and Hyperledger Fabric. Quorum and Hyperledger Fabric operate as private consortium blockchains where as Parity delivers private transaction capabilities on top of Ethereum MainNet. These differing approaches has led to different strengths and weaknesses which has resulted in each client not complying with one or more key requirement. In particular, none of the reviewed blockchain clients support the ability to determine bootstrap information to establish on-demand blockchains and none of the clients support secure management and pinning from Ethereum MainNet. This paper presents Ethereum Private Sidechains and a range of technologies which allow it to deliver on complex sidechain requirements. Ethereum Registration Authorities are presented, which allow entities which have not previously interacted to securely obtain information to bootstrap a sidechain, and a Management and Pinning strategy is described which allows the state of a sidechain to be securely pinned to Ethereum MainNet without compromising privacy.
There are several studies that propose identity management that utilizes blockchain technology. In Ethereum, the main programmable blockchain system, data on a blockchain are saved as encoded binaries for executing automatic verification. To decode a binary, users need to know the application binary interfaces (ABI) that describes the data structure of the registered information. However, the manner by which ABI are shared in the current blockchain protocol is opaque. To resolve this problem, we describe a new protocol for embedding the ABI on a blockchain transaction when a registrant registers information. Our method enables users to read registered data with information on the blockchain alone, and it guarantees transparency without requiring users to trust third parties.
Jelena Pajić, José Rivera, Kaiwen Zhang, Hans‐Arno Jacobsen
The recent success of electric vehicles leads to unprecedentedly high peaks of demand on the electric grid at the times when most people charge their cars. In order to avoid unreasonably rising costs due to inefficient utilization of the electricity infrastructure, we propose EVA: a scheduling system to solve the valley filling problem by distributing the electricity demand generated by electric vehicles in a geographically limited area efficiently over time spans in which the electric grid is underutilized. EVA is based on a smart contract running on the Ethereum blockchain in combination with off-chain computational nodes performing the schedule calculation using the Alternating Direction Method of Multipliers (ADMM). This allows for a high degree of transparency and verifiability in the scheduling computation results while maintaining a reasonable level of efficiency. In order to interact with the scheduling system, we developed a decentralized app with a graphical frontend, where the user can enter vehicle information and future energy requirements as well as review upcoming schedules. The calculation of the schedule is performed on a daily basis, continuously providing schedules for participating users for the following day.
Popularly known for powering cryptocurrencies such as Bitcoin and Ethereum, blockchains is seen as a disruptive technology capable of impacting a wide variety of domains, ranging from finance to governance, by offering superior security, reliability, and transparency in a decentralized manner. In this tutorial presentation, we first study the original Bitcoin design, as well as Ethereum and Hyperledger, and reflect on their design from an academic perspective. We provide an overview of potential applications and associated research challenges, as well as a survey of ongoing research projects. We mention opportunities blockchain creates for event-based systems. Finally, we conclude with a walkthrough showing the process of developing a decentralized application (ĐSApp), using a popular Smart Contract language (Solidity) for the blockchain platform of Ethereum.
Bitcoin and Ethereum are novel mechanisms for decentralizing the concept of money and computation. Extending decentralization to the human identity concept, we can think of using blockchain for creating a list of verified human identities with a one-person-one-ID property. UniqueID is a Decentralized Autonomous Organization(DAO) for maintaining human identities such that every physical human entity can have no more that one account. One part of this identity is simply the user's claim on one of his unique, permanent, and measurable characteristics -biometrics. Blockchain has proved its integrity as a platform for storing and performing computations on such claims. The biggest challenge here is to ensure that the user has submitted his own valid biometric data. Human verifiers can check if there is any inconsistency in other users' data, by peer-to-peer checks. For preventing bad behavior and centralization in the verification process, UniqueID benefits from novel governance mechanisms to choose verifiers and punish unjust ones. Also, there are incentives for honest verifiers and users by newly generated tokens. We show how the users' privacy can be preserved by using state-of-the-art cryptographic techniques, and so they can use their identity without any concerns for votings, financial and banking purposes, social media accounts, reputation systems etc.
Jun 18, 2018·Andrew Burnie, 2018. Exploring the Interconnectedness of Cryptocurrencies using Correlation Networks. In Cryptocurrency Research Conference 2018 (Anglia Ruskin University, 2018). Anglia Ruskin University, Cambridge, UK
Correlation networks were used to detect characteristics which, although fixed over time, have an important influence on the evolution of prices over time. Potentially important features were identified using the websites and whitepapers of cryptocurrencies with the largest userbases. These were assessed using two datasets to enhance robustness: one with fourteen cryptocurrencies beginning from 9 November 2017, and a subset with nine cryptocurrencies starting 9 September 2016, both ending 6 March 2018. Separately analysing the subset of cryptocurrencies raised the number of data points from 115 to 537, and improved robustness to changes in relationships over time. Excluding USD Tether, the results showed a positive association between different cryptocurrencies that was statistically significant. Robust, strong positive associations were observed for six cryptocurrencies where one was a fork of the other; Bitcoin / Bitcoin Cash was an exception. There was evidence for the existence of a group of cryptocurrencies particularly associated with Cardano, and a separate group correlated with Ethereum. The data was not consistent with a token's functionality or creation mechanism being the dominant determinants of the evolution of prices over time but did suggest that factors other than speculation contributed to the price.
Correlation networks were used to detect characteristics which, although\nfixed over time, have an important influence on the evolution of prices over\ntime. Potentially important features were identified using the websites and\nwhitepapers of cryptocurrencies with the largest userbases. These were assessed\nusing two datasets to enhance robustness: one with fourteen cryptocurrencies\nbeginning from 9 November 2017, and a subset with nine cryptocurrencies\nstarting 9 September 2016, both ending 6 March 2018. Separately analysing the\nsubset of cryptocurrencies raised the number of data points from 115 to 537,\nand improved robustness to changes in relationships over time. Excluding USD\nTether, the results showed a positive association between different\ncryptocurrencies that was statistically significant. Robust, strong positive\nassociations were observed for six cryptocurrencies where one was a fork of the\nother; Bitcoin / Bitcoin Cash was an exception. There was evidence for the\nexistence of a group of cryptocurrencies particularly associated with Cardano,\nand a separate group correlated with Ethereum. The data was not consistent with\na token's functionality or creation mechanism being the dominant determinants\nof the evolution of prices over time but did suggest that factors other than\nspeculation contributed to the price.\n
The Ethereum blockchain offers two core technical features: an ability to create a tamper-proof distributed ledger of computer code and an ability to design economic incentives to align actors inte...
Message digest algorithms are one of the underlying building blocks of\nblockchain platforms such as Ethereum. This paper analyses situations in which\nthe message digest collision resistance property can be exploited by attackers.\nTwo mitigations for possible attacks are described: longer message digest sizes\nmake attacks more difficult; and, including timeliness properties limits the\namount of time an attacker has to determine a hash collision.\n
By comparing cryptocurrencies with other existing payment methods, including banknotes and bank cards, it is clear that the use of Bitcoin and its competitors (Ethereum, \dots) is almost insignificant in world trade. We may also note that these cryptocurrencies have become tools of speculation, which is the antithesis of their primary purpose. Based essentially on the security of electronic signatures, the Ecash introduced here will put the users back to the center of the game and exclude miners and their enormous waste of power energy. Thus, the purpose of this paper is to show that even a piece of paper can be recycled into a secure Ecash, while remaining environmentally friendly. Hence, we create here a cryptocurrency that would use a slight modification of the current banknotes to set up anonymous electronic transactions. By trading with banknotes, we mechanically transfer ownership of the paper money from one owner to another, hence, in this scheme, we introduce the notion of ownership transfer. It implies that at each transaction the elements allowing to authenticate the Ecash does not change, while the ownership certificate will change since the Ecash is transfer towards someone else.
We analyze the economic incentives generated by the proof-of-stake mechanism discussed in the Ethereum Casper upgrade proposal. Compared with proof-of-work, proof-of-stake has a different cost structure for attackers. In Budish (2018), three equations characterize the limits of Bitcoin, which has a proof-of-work mechanism. We investigate their counterparts and evaluate the risk of double-spending attack and sabotage attack. We argue that PoS is safer than PoW agaisnt double-spending attack because of the tractability of attackers, which implies a large "stock" cost for the attacker. Compared to a PoW system whose mining equipments are repurposable, PoS is also safer against a sabotage attack.
Cryptocurrencies are newly emerging asset class that has received a lot of at- tention recently. Many investors are considering investing in them as a way of portfolio diversification. This thesis examines whether cryptocurrencies are gambling assets which could be important for investors' decision making and also for better understanding of the cryptocurrencies themselves. Gambling asset is understood in terms of stocks and therefore a comparison of crypto- currency and stock lottery characteristics is made. It is shown that in most time periods it cannot be said that cryptocurrencies exhibit larger lottery characteristics. Furthermore, it is shown that Litecoin, Ethereum, Ripple, Dash and Monero would classify as gambling asset, however, Bitcoin would not. JEL classification C12, C38, C55, G11, O33 Keywords cryptocurrencies, Bitcoin, gambling, gambling asset, investment Author's e-mail novotnyf1@gmail.com Supervisor's e-mail ladislav.kristoufek@fsv.cuni.cz 1
Jun 6, 2018·World Academy of Science, Engineering and Technology, International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering
Petar Tsankov, Andrei Dan, Dana Drachsler Cohen, Arthur Gervais · 6 authors
Permissionless blockchains allow the execution of arbitrary programs (called smart contracts), enabling mutually untrusted entities to interact without relying on trusted third parties. Despite their potential, repeated security concerns have shaken the trust in handling billions of USD by smart contracts. To address this problem, we present Securify, a security analyzer for Ethereum smart contracts that is scalable, fully automated, and able to prove contract behaviors as safe/unsafe with respect to a given property. Securify's analysis consists of two steps. First, it symbolically analyzes the contract's dependency graph to extract precise semantic information from the code. Then, it checks compliance and violation patterns that capture sufficient conditions for proving if a property holds or not. To enable extensibility, all patterns are specified in a designated domain-specific language. Securify is publicly released, it has analyzed >18K contracts submitted by its users, and is regularly used to conduct security audits by experts. We present an extensive evaluation of Securify over real-world Ethereum smart contracts and demonstrate that it can effectively prove the correctness of smart contracts and discover critical violations.
Son dönemlerde dünyada olduğu gibi ülkemizde de popülaritesi giderek artan ve başta Bitcoin, Ethereum gibi kripto paraları içinde barındıran kripto para piyasası gerek uluslararası gerekse ulusal yazının ilgisini çekmektedir. Küresel değişimin ağırlıklı olarak finansal bağlamının son halkalarından biri olan bu piyasaya adaptasyon ve gelişim için hem işletmelerin hem de ulusların vizyon sahibi olarak gerekli adımları atmaları gerekmektedir. Bu durum karşısında bir toplumda; bilgi, farkındalık ve kullanım oranlarının ölçülmesi gereken en temel yapı taşları vatandaş ve işletmeler olacaktır. Bu bağlamda yapılmış olan araştırmanın iki temel aşaması bulunmaktadır. İlk aşamada ulaşılmak istenen amaç; Türk toplumunun kripto para piyasası hakkındaki farkındalık ve tutumunu ölçmek iken; ikinci aşamadaki amaç ise Türkiye’deki kripto para kullanan işletmelerin motivasyonlarını incelemektir. Bu temel amaçlar doğrultusunda ilgi sırasıyla 154 kişi ile anket ve 10 işletme ile çevrimiçi mülakat yapılmıştır. Elde edilen bulgular neticesinde tartışma ve sonuç kısmında birey-işletme-toplum üçlü skalasında çeşitli çıkarımlarda ve önerilerde bulunulmuştur
Blockchains have become an integral part of many distributed applications, providing a new platform for interaction between system components. Blockchains are perhaps most known for their use in crypto-currency systems, such as Bitcoin and Ethereum, where pseudo-anonymous parties engage in transactions without a trusted third party. Blockchain systems often struggle to meet performance demands of real-word applications, rendering them inappropriate for performance sensitive applications.\nThere is also concerns regarding the immense amount of electrical energy required to securely run existing public blockchain systems. Bitcoin alone consumes more than small countries. Private systems have higher throughput and avoid excessive energy consumption, but have closed membership and do not scale to the same extent.\n\nBoth public and private blockchains rely on some form of membership mechanism providing peers with a view of other participants. Existing systems often employ partial view protocols due to their natural scalability. However, recent work have shown that full view protocols are feasible in practice, and can scale to thousands of participants. With full membership, applications can send messages directly to their destination without any intermediate hops.\n\nThis thesis presents FireChain, which combines a Byzantine fault-tolerant gossip service and full membership, with a proposal for blockchain systems that does not consume excessive energy. We evaluate FireChain's performance through experiments on PlanetLab, and show that it scales beyond hundreds of members.
The commodity industry, the transaction lifecycle of commodities, its value chain and supply chain are complex systems with many parties involved. Ownership of cargoes are determined by who is holding the physical paper, the Bill of Lading. The participants in the industry require constant verification between parties, and this resultsin cumbersome paper-heavy back-office operations which are exposed to human errors. \nThe entire commodity transaction life-cycle involves the value chain and supply chain, and it creates a complicated and long chain involving several intermediaries, each taking a piece of the pie and adds to transaction costs for producers. The roles of intermediaries in the commodity industry can be financing trades, facilitating trade, managing risk, on-site inspection and verification of cargoes, shipping, and logistics.\nBlockchain technology is the technology underlying bitcoins and most of the cryptocurrencies in existence. Bitcoin enabled people to transfer money, peer-to-peer without an intermediary to establish trust and facilitate transactions. Bitcoin has paved the way for further use-cases of the technology, which has a much broader use-case spectrum than just being the underlying technology of cryptocurrencies.\nBlockchain is a decentralized, distributed ledger, where transactions are stored in blocks and secured with cryptography. It allows anyone to execute trade without an intermediary to establish trust between parties. It allows for one single source of the truth between counterparties through enhancing transparency, visibility and availability of transactions data and information.\nBlockchains can be fully transparent, but a blockchain can also allow for privacy. There are different types of blockchain, public/private/hybrid, and each of these types serves its purpose a little bit differently. In a private or hybrid blockchain, information that is sensitive to a certain trade remains private by only allowing the counterparties of that trade transparency into the transactions of that certain trade.\nThe blockchain technology enhances cyber security through decentralization and cryptography. Digital tokens can replace the Bill of Lading to track ownership of cargoes. Smart contracts that self-execute triggered upon a set of predetermined conditions are among the features of blockchain technology. The convenience of blockchain technology, is that anyone at any time can build its own decentralized application on top of already existing blockchain platforms like Ethereum, Hyperledger and others. These factors create for a unique opportunity to digitalize the commodity industry, gaining security, efficiency and opening up possibilities for new trade models in trade finance.
This paper considers the design, the development and the experimental evaluation, of a blockchain based smart contract specifying the operating rules of a real time, uniform-price double auction energy market. Producers and consumers interact with this contract sending their offers and bids accordingly and the contract clears the market based on a double auction model. We propose four different approaches for implementing, through the Ethereum platform, both the P2P network as well as the smart contract. We systematically compare the above approaches on the basis of their decentralization nature, operating costs, computational costs, effectiveness, security, privacy and beyond. This comparison is achieved through large scale, real time simulations based on the GridLAB-D platform.
Aleksandr Kapitonov, Ivan Berman, Sergey Lonshakov, Aleksandr Krupenkin
The article presents the architecture of communication protocol for modern industrial processes and business based on cyber-physical systems - Industry 4.0. The main attention is paid to one of the key trends of this concept - to economical autonomous agents i.e. to robots or smart things, which are able to make decisions independently about their economic actions. Agents begin to fully participate in business processes, so it is important to automate the processes and ensure formal and secure communication between multiple heterogeneous agents, taking into account the economic component of the industry. The article shows how to organize economic interaction between agents using a peer-to-peer network based on decentralized Blockchain technology and smart contracts. The general concept of protocol work is described and the experience of its implementation on ROS and Ethereum Blockchain is presented in the form of universal software for different agents. As a result, the experience of applying this solution in various projects is described: a business project with unmanned aerial vehicles (UAV) and an educational project of "smart city".
Energy conservation measurements in buildings are more and more popular as they benefit from an intelligent contractual framework called Energy Performance Contracts (EPC), where energy savings are measured as the difference between a predictive baseline model and the actual consumption. While modern predictive models make use of large amounts of data from external sources and increasingly complex algorithms, these two aspects make their use difficult in practice because they need mutual understanding and transparency, requiring the involvement of a third-party for auditing. In this sense, we designed and developed a prototype that overcomes these issues by storing the predictive models and the data in an immutable blockchained data structure using the Ethereum framework. To the best of our knowledge, this is the first working prototype using the blockchain technology applied to EPCs. This paper presents and discusses the technical solutions and best-practice guidelines adopted in this prototype.