Blockchain Papers

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No abstract is available for this record.

Keltoum Bendiab, Nicholas Kolokotronis, Stavros Shiaeles, Samia Boucherkha

Secure and reliable management of identities has become one of the greatest challenges facing cloud computing today, mainly due to the huge number of new cloud-based applications generated by this model, which means more user accounts, passwords, and personal information to provision, monitor, and secure. Currently, identity federation is the most useful solution to overcome the aforementioned issues and simplify the user experience by allowing efficient authentication mechanisms and use of identity information from data distributed across multiple domains. However, this approach creates considerable complexity in managing trust relationships for both the cloud service providers and their clients. Poor management of trust in federated identity management systems brings with it many security, privacy and interoperability issues, which contributes to the reluctance of organizations to move their critical identity data to the cloud. In this paper, we aim to address these issues by introducing a novel trust and identity management model based on the Blockchain for cloud identity management with security and privacy improvements.

Ubaidullah Rajput, Fizza Abbas, Heekuck Oh

Bitcoin is a decentralized crypto-currency, which is based on the peer-to-peer network, and was introduced by Satoshi Nakamoto in 2008. Bitcoin transactions are written by using a scripting language. The hash value of a transaction’s script is used to identify the transaction over the network. In February 2014, a Bitcoin exchange company, Mt. Gox, claimed that they had lost hundreds of millions US dollars worth of Bitcoins in an attack known as transaction malleability. Although known about since 2011, this was the first known attack that resulted in a company loosing multi-millions of US dollars in Bitcoins. Our reason for writing this paper is to understand Bitcoin transaction malleability and to propose an efficient solution. Our solution is a softfork (i.e., it can be gradually implemented). Towards the end of the paper we present a detailed analysis of our scheme with respect to various transaction malleability-based attack scenarios to show that our simple solution can prevent future incidents involving transaction malleability from occurring. We compare our scheme with existing approaches and present an analysis regarding the computational cost and storage requirements of our proposed solution, which shows the feasibility of our proposed scheme.

Nisha Malik, Priyadarsi Nanda, Arushi Arora, Xiangjian He · 5 authors

Authentication and revocation of users in Vehicular Adhoc Networks (VANETS) are two vital security aspects. It is extremely important to perform these actions promptly and efficiently. The past works addressing these issues lack in mitigating the reliance on the centralized trusted authority and therefore do not provide distributed and decentralized security. This paper proposes a blockchain based authentication and revocation framework for vehicular networks, which not only reduces the computation and communication overhead by mitigating dependency on a trusted authority for identity verification, but also speedily updates the status of revocated vehicles in the shared blockchain ledger. In the proposed framework, vehicles obtain their Pseudo IDs from the Certificate Authority (CA), which are stored along with their certificate in the immutable authentication blockchain and the pointer corresponding to the entry in blockchain, enables the Road Side Units (RSUs) to verify the identity of a vehicle on road. The efficiency and performance of the framework has been validated using the Omnet++ simulation environment.

Petr Novotny, Qi Zhang, Richard Hull, Salman Baset · 8 authors

Academic publishing is continuously evolving with the gradual adoption of new technologies. Blockchain is a new technology that promises to change how individuals and organizations interact across various boundaries. The adoption of blockchains is beginning to transform diverse industries such as finance, supply chain, international trade, as well as energy and resource management and many others. Through trust, data immutability, decentralized distribution of data, and facilitation of collaboration without the need for centralized management and authority, blockchains have the potential to transform the academic publishing domain and to address some of the current problems such as productivity and reputation management, predatory publishing, transparent peer-review processes and many others. In this paper, we outline the technologies available in the domain of permissioned blockchains with focus on Hyperledger Fabric and discuss how they can be leveraged in the domain of academic publishing.

Hao Guo, Ehsan Meamari, Chien‐Chung Shen

Autonomous vehicles are capable of sensing their environment and navigating without any human inputs. However, when autonomous vehicles are involved in accidents between themselves or with human subjects, liability must be indubitably decided based on accident forensics. This paper proposes a blockchain-inspired event recording system for autonomous vehicles. Due to the inefficiency and limited usage of certain blockchain features designed for the traditional cryptocurrency applications, we design a new "proof of event" mechanism to achieve indisputable accident forensics by ensuring that event information is trustable and verifiable. Specifically, we propose a dynamic federation consensus scheme to verify and confirm the new block of event data in an efficient way without any central authority. The security capability of the proposed scheme is also analyzed against different threat and attack models.

Nasr Al-Zaben, Md. Mehedi Hassan Onik, Jinhong Yang, Nam Yong Lee · 5 authors

Surveillance and secrecy breaching incidents of users' privacy questioned the current third-parties data collection procedure. Massive amounts of Personally Identifiable Information (PII) are being exploited due to malpractice, identity theft, spamming, phishing and cyber-espionage. A large amount of data flow from users to enterprises for data-driven market analysis and prediction. Consequently, it is tough to track the flow and genuineness of PII. Blockchain technology, an ‘immutable’ distributed ledger which can efficaciously track PII exchange, store, and distribution. In contrast, ongoing EU General Data Protection Regulation (GDPR) demands ‘right to forget’ and ‘should be erasable’ rights. However, this paper proposes an off-chain Blockchain architecture which uses both local database and distributed ledgers to preserve a trustable PII life cycle. Considering the key factors of GDPR, prevailing Blockchain architecture were modified and a prototype was created to validate our proposed architecture using multichain 2.0. Proposed architecture stores PII and Non-PII physically separated location. Finally, with proposed architecture user will realm privacy and rigidity of Blockchain along with the privacy regulation of GDPR. Validation is done by comparing proposed system with existing methodology from technical aspects, future research scopes is also well advocated.

Richard Ford Burley

Current citation indexes such as Scopus and the Web of Science rely on centralized curation to function. This creates a series of potentially negative incentives, both financial and academic, which could be addressed through the creation of an unpermissioned, distributed ledger of citations. This paper explores this possibility using Bitcoin as a model.

Saqib Ali, Guojun Wang, Bebo White, Roger Leslie Cottrell

The blockchain is an innovative technology which opened doors to new applications for solving numerous problems in distributed environments. In this work, we design a blockchain-based data storage and access framework for PingER (worldwide end-to-end Internet performance measurement project) to remove its total dependence on a centralized repository. We use the permissioned blockchain and Distributed Hash Tables (DHT) for this purpose. In the proposed framework, metadata of the files are stored on the blockchain whereas the actual files are stored off-chain through DHT at multiple locations using a peer-to-peer network of PingER Monitoring Agents. This will provide decentralized storage, distributed processing, and efficient lookup capabilities to the PingER framework.

Jia Kan, Shangzhe Chen, Xin Huang

Blockchain technology is ushering in another break-out year, the challenge of blockchain still remains to be solved. This paper analyzes the features of Bitcoin and Bitcoin-NG system based on blockchain, proposes an improved method of implementing blockchain systems by replacing the structure of the original chain with the graph data structure. It was named GraphChain. Each block represents a transaction and contains the balance status of the traders. Additionally, as everyone knows all the transactions in Bitcoin system will be baled by only one miner that will result in a lot of wasted effort, so another way to improve resource utilization is to change the original way to compete for miner to election and parallel mining. Researchers simulated blockchain with graph structure and parallel mining through python, and suggested the conceptual new graph model which can improve both capacity and performance.

Νικόλαος Αλεξόπουλος, Sheikh Mahbub Habib, Max Mühlhäuser

Authorization, and more generally Trust Management (TM), is an indispensable part of the correct operation of most IT systems. The advent of the Internet of Things (IoT), with its cyber-physical and distributed nature, creates new challenges, that existing TM systems cannot adequately address, such as for example the need for non-interactive exclusive access enforcement. In the meantime, a line of thought in the research community is that Distributed Ledgers (DLs), like the one implemented by the Ethereum blockchain, can provide strong security guarantees for distributed access control. However, this approach has not yet been examined in a scientific, systematic manner, and has many pitfalls, with arguably the most important one being scalability.

Sagwadi Mabunda

Virtual currencies are on the rise and so is money laundering. While there are efforts to combat money laundering through various intergovernmental bodies, many have expressed concern over the rise of virtual currencies. Some cryptocurrencies such as Bitcoin have played a major role in the proliferation of online money laundering as it possesses characteristics that criminals are fond of. Bitcoin and other cryptocurrencies are decentralised, anonymous/pseudonymous and irreversible. They provide the means to skirt the Anti-Money laundering safeguards that have been put in place.
\nThis paper discusses the intersection between Anti-Money Laundering efforts and the challenges that are introduced by cryptocurrencies such as Bitcoin. It also looks at the case of Liberty Reserve to highlight these challenges.

Jianwen Chen, Kai Duan, Rumin Zhang, Liaoyuan Zeng · 5 authors

In blockchain systems, especially cryptographic currencies such as Bitcoin, the double-spending and Byzantine-general-like problem are solved by reaching consensus protocols among all nodes. The state-of-the-art protocols include Proof-of-Work, Proof-of-Stake and Delegated-Proof-of-Stake. Proof-of-Work urges nodes to prove their computing power measured in hash rate in a crypto-puzzle solving competition. The other two take into account the amount of stake of each nodes and even design a vote in Delegated-Proof-of-Stake. However, these frameworks have several drawbacks, such as consuming a large number of electricity, leading the whole blockchain to a centralized system and so on. In this paper, we propose the conceptual framework, fundamental theory and research methodology, based on artificial intelligence technology that exploits nearly complementary information of each nodes. And we designed a particular convolutional neural network and a dynamic threshold, which obtained the super nodes and the random nodes, to reach the consensus. Experimental results demonstrate that our framework combines the advantages of Proof-of-Work, Proof-of-Stake and Delegated-Proof-of-Stake by avoiding complicated hash operation and monopoly. Furthermore, it compares favorably to the three state-of-the-art consensus frameworks, in terms of security and the speed of transaction confirmation.

Dan McGinn, Douglas McIlwraith, Yuwei Guo

Bitcoin is the first implementation of a technology that has become known as a 'public permissionless' blockchain. Such systems allow public read/write access to an append-only blockchain database without the need for any mediating central authority. Instead, they guarantee access, security and protocol conformity through an elegant combination of cryptographic assurances and game theoretic economic incentives. Not until the advent of the Bitcoin blockchain has such a trusted, transparent, comprehensive and granular dataset of digital economic behaviours been available for public network analysis. In this article, by translating the cumbersome binary data structure of the Bitcoin blockchain into a high fidelity graph model, we demonstrate through various analyses the often overlooked social and econometric benefits of employing such a novel open data architecture. Specifically, we show: (i) how repeated patterns of transaction behaviours can be revealed to link user activity across the blockchain; (ii) how newly mined bitcoin can be associated to demonstrate individual accumulations of wealth; (iii) through application of the naïve quantity theory of money that Bitcoin's disinflationary properties can be revealed and measured; and (iv) how the user community can develop coordinated defences against repeated denial of service attacks on the network. Such public analyses of this open data are exemplary benefits unavailable to the closed data models of the 'private permissioned' distributed ledger architectures currently dominating enterprise-level blockchain development owing to existing issues of scalability, confidentiality and governance.

Nyane Ezekiel Macdonald Mofokeng, Thapeli Kenny Matima

The era of transformation powered by digitization, improvements in information and communication technology, machine learning, robotics and artificial intelligence is upon us. Today, we are able to solve complex problems with the aid of technology. That notwithstanding, animal populations globally are under threat, with the extinction of species taking place at a far accelerated pace than can be reversed, thus making wildlife conservation a critical issue of our time. Along with wildlife extinction currently underway, there remains a chronic financial shortage for wildlife conservation and the funding shortfall is expanding annually. This research contends that blockchain, the technology underpinning cryptocurrencies such as Bitcoin can be utilized as a catalyst by the development of cryptowildlife nonfungible tokens (NFTs), which are provably scarce, unique and programmable digital wildlife collectible assets. These could be used to finance wildlife conservation as a supplementary source of revenue.

Michael C. Urban, Danielle M. Pineda

Produced by the Mowat Centre at the School of Public Policy and Governance, University of Toronto.

Dianhui Mao, Fan Wang, Zhihao Hao, Haisheng Li

The food supply chain is a complex system that involves a multitude of "stakeholders" such as farmers, production factories, distributors, retailers and consumers. "Information asymmetry" between stakeholders is one of the major factors that lead to food fraud. Some current researches have shown that applying blockchain can help ensure food safety. However, they tend to study the traceability of food but not its supervision. This paper provides a blockchain-based credit evaluation system to strengthen the effectiveness of supervision and management in the food supply chain. The system gathers credit evaluation text from traders by smart contracts on the blockchain. Then the gathered text is analyzed directly by a deep learning network named Long Short Term Memory (LSTM). Finally traders' credit results are used as a reference for the supervision and management of regulators. By applying blockchain, traders can be held accountable for their actions in the process of transaction and credit evaluation. Regulators can gather more reliable, authentic and sufficient information about traders. The results of experiments show that adopting LSTM results in better performance than traditional machine learning methods such as Support Vector Machine (SVM) and Navie Bayes (NB) to analyze the credit evaluation text. The system provides a friendly interface for the convenience of users.

Johannes Krupp, Christian Rossow

Cryptocurrencies like Bitcoin not only provide a decentralized currency, but also provide a programmatic way to process transactions. Ethereum, the second largest cryptocurrency next to Bitcoin, is the first to provide a Turing-complete language to specify transaction processing, thereby enabling so-called smart contracts. This provides an opportune setting for attackers, as security vulnerabilities are tightly intertwined with financial gain. In this paper, we consider the problem of automatic vulnerability identification and exploit generation for smart contracts. We develop a generic definition of vulnerable contracts and use this to build TEE THER, a tool that allows creating an exploit for a contract given only its binary bytecode. We perform a large-scale analysis of all 38,757 unique Ethereum contracts, 815 out of which our tool finds working exploits for—completely automated.

Ping-Heng Kuo, Alain Mourad, Jae-Hyun Ahn

The decentralized nature of existing and future wireless network topologies has opened some unique opportunities for DLT to play a role in communications. In this column, we have reviewed the basic operation of a consensus mechanism, as well as the current trend of a DLT-based security model that is particularly important for loT. We further point out that, beyond application layer and security, DLT also has potential in other aspects of wireless networking such as computing and radio connectivity. Specifically, we see DLT as a perfect tool that should be leveraged to realize fog -RAN, as the consensus mechanism of DLT may be used to maintain tight synchronization among computing and networking resources in different locations. On the other hand, DLT could also be employed to avoid potential collision that may occur in grant -free uplink access. In summary, we believe that DLT will gradually become a key tool to reshape communication systems in a wide range of aspects, covering not just applications and security, but also connectivity and computing.

Eda Yalçın Kayacan, Aygül Anavatan

Bitcoin açık kaynaklı bir kod olarak yayınlanan ve blok zinciri (blockchain) teknolojisine dayanan ilk kriptopara birimidir. Kriptopara birimlerinin avantajı, merkezi olmayan yapılar olması ve bu sayede merkez bankalarına ihtiyaç duymayıp işlem maliyetlerinin az olmasıdır. Bu çalışmanın amacı, son zamanlarda popülerliği artan ve en köklü kriptopara birimi olan Bitcoin getirilerinin kaotik yapıya sahip olup olmadığını tespit etmektir. Başlangıç koşullarına aşırı duyarlı olan seriler kaotik dinamiklere sahiptir. Eğer seriler kaotik özelliklere sahipse, geleneksel yöntemlerle incelenmeleri yanıltıcı sonuçlar verebilmektedir. Bu amaçla, 19.12.2011-29.01.2018 dönemine ait Bitcoin getiri serisi kullanılarak ilk olarak BDS (Brock, Dechert ve Scheinkman) testi ile doğrusal olmayan bağımlılık test edilmiş, ardından serideki uzun dönemli bellek yapısını belirlemek için dönüştürülmüş genişlik (rescaled range-R/S) yöntemi uygulanarak Hurst üsteli elde edilmiştir. Ardından, yanlış en yakın komşular yöntemi ile uygun gömme boyutu belirlenmiştir. Serideki kaotik davranışı tespit etmek için korelasyon boyutu hesaplanmış ve Lyapunov üsteli değeri pozitif bulunmuştur. Sonuç olarak, serinin doğrusal olmayan dinamikler içerdiği, uzun belleğe sahip olduğu ve serinin kaotik özellikler taşıdığı bulgusu elde edilmiştir.

Koji Takahashi

Cryptocurrency exchanges, i.e. online platforms where customers exchange their cryptocurrencies for other cryptocurrencies or fiat currencies, are routinely targeted by hackers, which often result in a massive drain of cryptocurrencies. The heists can be large enough to bring down the exchanges to their knees. The customers of an exchange who have entrusted it with cryptocurrencies would have a contractual right to claim their return. If the exchange is wound up, however, personal claims (such as a contractual claim) brought in bankruptcy proceedings would not yield to them a full recovery. It is, therefore, practically important to examine whether the cryptocurrencies entrusted to an exchange are shielded from the bankruptcy of the exchange provider, so that the customers can obtain a full recovery. Under most, if not all, legal systems, the answer to this question would be unclear because cryptocurrencies are a novel asset and because the legal relationships between an exchange provider and its customers have not been sufficiently scrutinised. This article will seek to improve legal clarity by presenting an analytical framework, identifying issues, and pointing to possible solutions. It will begin by examining the law of Japan, possibly the only country in the world where the matter has been litigated. Following a hacking attack, Mt Gox, the world’s biggest operator of a Bitcoin exchange at that time, became insolvent. After the opening of bankruptcy proceedings, one of its former customers filed a suit against the bankruptcy trustee in Japan, seeking a full recovery of the Bitcoins he had entrusted to the exchange. Rather than relying on a personal claim, the plaintiff asserted ownership over what he saw as “his Bitcoins”. His claim was, however, dismissed by the Tokyo District Court for reasons to be examined in this article. More recently, other customers filed a suit in Japan by trying another legal avenue to obtain a full recovery. They are arguing that their Bitcoins had been held by the exchange on trust for them. After presenting an analysis under Japanese law, this article will explore its relevance to other legal systems. Since Japanese law belongs to the family of civil law systems, the analysis concerning the ownership of cryptocurrencies would have direct relevance to other civil law systems in the context of rei vindicatio (vindication of property). It would also inform the debate whether cryptocurrencies are “property” in terms of the tort of conversion in common law systems. The analysis concerning whether an exchange holds cryptocurrencies on trust for its customers would be useful to all the common law systems of which the law of trusts forms an integral part as well as any civil law systems which, like Japanese law, have introduced the concept of trusts.

А. А. Новиков

Cryptocurrencies – a new, but quickly developing concept within the sphere of finance. Opinions regarding it still differ, not only on a personal level, but also when it comes to governments. Overall the legal regulation regarding cryptocurrencies in the world is still in the formation stage. Currently the legal norms that do exist, are primarily directed towards the minimization of existing risks, especially in the field of money laundering. Though there is already no reason to doubt, that during the coming years the regulation will become stricter. In some countries cryptocurrencies are outright forbidden. For example, in China, in February 2018 additions to the legislation were issues, that broadened the cryptocurrencies ban. In other countries cryptocurrencies shall be strictly regulated. For example, in Estonia, a member of EU, cryptocurrencies are fully legal. Estonia can be reviewed as a country that independently developed its own regulation in this field. Though there is no guarantee that the legislators will keep up with the quickly developing technologies. One way or another cryptocurrencies exist and are not going anywhere. The legislation that regulates them shall be developed further and they shall become a important part of the modern financial system. The level of their influence is hard to predict, things are changing too quickly, but their existence is a fact. It is necessary to remember, that that cryptocurrencies are not a magical solution or means of profit. It is a financial instrument, new, in many ways unique, with its own special drawbacks and benefits. It is important to know and understand them, also to keep an eye on the developing technologies.

Clara, Siti Nurbaiti

Nowadays people rely on many things in order to do daily activity. As time goes by, global economy has changed and has had significant growth. The form of money has also changed, from only being available in the physical form, such as coins and banknotes, now we have the digital form of money, otherwise known as virtual currency. This paper discusses about the legal status of Bitcoin as virtual currency in Indonesia according to Law Number 7 of 2011 regarding Currency Law. The author examines the problem by using normative legal research methods with descriptive approach. The data was collected from secondary and primary data and is used as supportive research data. The collected data is analysed using qualitative method. The result of this research is the legal status of Bitcoin as virtual currency in Indonesia according to Law Number 7 of 2011 regarding Currency Law has not been regulated yet. Therefore, the government of Indonesia needs to make a specific regulation to regulate Bitcoin in Indonesia.

Zübeyir Turan

Kripto paralar günümüzde sıklıkla karşımıza çıkan para teriminden biridir. Ülkelerarasında ticaret sınırının kalkması ile birlikte ulusal paralara alternatif para birimi olan kripto para, mal ve hizmet ticaretinde kullanılabildiği gibi, aksi durumlarda da kullanımı yıllar geçtikçe artmaktadır. Kripto kelime anlamıyla cyripto ve currency kelimelerinin bir araya getirilmesi ile oluşmuş, ana teması şifre olan kelimedir. Şifreleme yöntemi ile alışveriş ve alım-satımlar gerçekleştirilmektedir. Bu şifreleme sisteminin güvenilirliği konusunda her ne kadar tartışma olsa da, kullanım alanı gün geçtikçe yaygınlaşma göstermektedir. Çalışmada kripto paranın en yaygın kullanım şekli olan bitcoin incelenmiş, ortaya çıkışı ve sistemi hakkında bilgi verilmiştir. Türkiye ve diğer ülkelerdeki kullanımı her ne kadar sınırlayıcı olsa da muhatap bir kurum olmadığı sürece kullanım alanının genişleyeceği aşikârdır.