Blockchain Papers

Marc Gillaizeau, Ranadeva Jayasekera, Ahmad Maaitah, Tapas Mishra · 6 authors

No abstract is available for this record.

Andrew Cullen, Pietro Ferraro, Christopher King, Robert Shorten

Directed Acyclic Graph (DAG) based Distributed Ledgers can be useful in a number of applications in the IoT domain. A distributed ledger should serve as an immutable and irreversible record of transactions, however, a DAG structure is a more complicated mathematical object than its blockchain counterparts, and as a result, providing guarantees of immutability and irreversibility is more involved. In this paper, we analyse a commonly discussed attack scenario known as a parasite chain attack for the IOTA Foundation DAG based ledger. We analyse the efficacy of IOTA core MCMC algorithm using a matrix model and present an extension which improves the ledger resistance to these attacks.

Ying Fu, Meng Ren, Fuchen Ma, Xin Yang · 7 authors

Ethereum Virtual Machine (EVM) is the run-time environment for smart contracts and its vulnerabilities may lead to serious problems to the Ethereum ecology. With lots of techniques being developed for the validation of smart contracts, the security problems of EVM have not been well-studied. In this paper, we propose EVMFuzz, aiming to detect vulnerabilities of EVMs with differential fuzz testing. The core idea of EVMFuzz is to continuously generate seed contracts for different EVMs' execution, so as to find as many inconsistencies among execution results as possible, eventually discover vulnerabilities with output cross-referencing. First, we present the evaluation metric for the internal inconsistency indicator, such as the opcode sequence executed and gas used. Then, we construct seed contracts via a set of predefined mutators and employ dynamic priority scheduling algorithm to guide seed contracts selection and maximize the inconsistency. Finally, we leverage different EVMs as crossreferencing oracles to avoid manual checking of the execution output. For evaluation, we conducted large-scale mutation on 36,295 real-world smart contracts and generated 253,153 smart contracts. Among them, 66.2% showed differential performance, including 1,596 variant contracts triggered inconsistent output among EVMs. Accompanied by manual root cause analysis, we found 5 previously unknown security bugs in four widely used EVMs, and all had been included in Common Vulnerabilities and Exposures (CVE) database.

Arif GÜMÜŞ, Hakan Erkuş

Blockchain teknolojisi, resmi kurumların katkısı olmadan bir ağa bağlı bilgisayarlar aracılığı ile çeşitli onaylama ve doğrulama işlemlerinin gerçekleştirildiği bir sistemdir. 21. yy’da ortaya çıkan blockchain teknolojisi ve kripto paraların hızla yatırım aracına dönüştüğü görülmektedir. Bu çalışmada blockchain teknolojisinin kullanımı sonucu ortaya çıkan kripto paralar, paranın tarihinden yola çıkılarak incelenmeye çalışılmıştır. Kripto paralar sahip olduğu gücü insanların güveninden alırken, geleneksel para gücünü kendisini piyasaya süren devletten almaktadır. Bu çalışmada kripto paraların güçlü ve zayıf yönleri anlatılarak gelecekte geleneksel para birimi gibi kullanılıp kullanılamayacağı incelenmiştir. Kripto paraların bir para birimi olmaktan çok bir yatırım aracı olarak kullanıldığı görülmektedir. İnsanların bu paralara güveni devam ettiği sürece kripto paraların varlığını koruyacağı, değerinde artış ve azalışlar olacağı gözlemlenmiş, güvenin yok olması durumunda ise etkinliklerini devam ettiremeyeceği tespit edilmiştir.

Farrukh Arslan

Data security and privacy are one of the key concerns in the Internet of Things (IoT). Usage of IOT is increasing in the society day-by-day, and security challenges are becoming more and more severe. From a data perspective, IOT data security plays a major role. Some of the sensitive data such as criminal record, military information, the medical record of the patients, etc. Due to the size and other features of IOT, it is almost impossible to create an efficient centralized authentication system. The proposed system focused on IoT security for distributed medical record to provide perimeter security to the patient. Building trust in distributed environments without the need for authorities is a technological advance that has the potential to change many industries, the IOT is one among them. Furthermore, it protects data integrity and availability. It improves the accessibility of data by using the indexing method along with the blockchain. Moreover, it facilitate the utility of tracking the previous history of the patient record using the hyper ledger with authorization.

B.V. BURKINSKY, V.F. GORIACHYK, G.M. MURZANOVSKIY

Topicality. It is caused by excessive centralization of powers and financial and material resources by the executive authorities, the inability of the territorial communities of the basic level to fulfill their powers, the deterioration of the quality and availability of public services due to the lack of financial and material provision. Aim and tasks. To investigate the economic aspects of administrative-territorial reform in Ukraine, to identify the main problems of financial provision of territorial communities of the baseline level. Research results. The model of budget relations implemented is aligned not by expenditures, but by income. Such a mechanism has a motivational component regarding the interest in increasing the revenue base of local budgets. At that time, the transition to equalization of local budgets by income led to an increase in the differentiation of communities. Most benefit was given to cities of regional significance whose incomes have increased significantly. Local government revenues consist of own revenues and transfers from the central level. Over the past 20 years, the tendency towards a decrease in the share of local budget revenues and the increase in the share of state budget revenues in the consolidated budget of Ukraine (without intergovernmental transfers) has been observed. The share of local budget revenues without transfers (own revenues) decreased by 1,5 times from 31,4 % in 2002 to 20,9 % in 2018. In the financing system of local self-government, during the study period, the share of transfers increased. The share of own revenues decreased almost 2 times, from 78,4 % in 2002 to 42,1 % in 2018, and the share of transfers increased from 21,6 % to 57,9 %, respectively. This dependence on transfers is of a serious scale: in 45 % of the united territorial communities (UTC) transfers in 2016 amounted to 75 % of revenues. The increase in the share of transfers in the budgets of local self-government, the dependence of the amount of transfers from central authorities and the inability to plan them, as well as the transfer of powers without adequate financial support, pose significant risks to the economic self-sufficiency of local communities. In 2016, 76 % of expenditures of local self-government bodies were performed on behalf of central authorities as financing of "delegated powers" (health care, education, social protection). At the same time, transfers from the central level accounted for only 57,9 % of local budget revenues. That is, a considerable part of delegated powers of local self-government bodies are forced to finance at the expense of their own income. As a result, they have little resources to fulfill their "own authority", namely the construction and repair of local roads and housing, the provision of utilities (water supply and sewerage, waste collection, heating, etc.), as well as local transport and development of " objects of culture and rest. Under the burden of current expenditures, the investment capacity of local self-government bodies is small. The authorities at the oblast and rayon level are not entirely self-governing, as regional and district levels act as local self-government bodies (regional and district councils), as well as executive bodies (oblast and rayon state administrations). The first few have very few powers, and their executive bodies are not created, although this is provided by the Concept. The latter are subordinate to the central authorities and they have a dominant role. All this complicates the assessment of changes at the regional and district levels in the context of financial decentralization. A prerequisite for the normal functioning and development of UTC is their economic self-sufficiency. This implies that the UTC revenues correspond to the expenditures necessary for the exercise of their own and delegated powers. An appropriate methodology is needed to carry out an assessment of the economic self-sufficiency of the communities. More than 4 years of decentralization reform have taken place, but there is no corresponding methodology. The lack of a methodology for assessing the economic self-sufficiency of the combined territorial is due to objective reasons. First, this is the lack of a clear and legally-established division of powers between the executive and local self-government bodies, as well as between the levels of the latter. Secondly, the lack of standards and norms of financial and infrastructural provision of public services (schools, kindergartens, paramedical outpatient departments, out-patient departments, engineering networks, etc.). Conclusions. The conducted study shows that Ukraine has a centralized system of incomes and expenditures, and the reform of financial decentralization has led to the opposite result, namely, to increase the dependence of local self-government on central authorities. The reform of financial decentralization in Ukraine tends to support a model that is more based on transfers than on its own revenue.

Andreas Rahmatian

Electronic currencies and cryptocurrencies, like Bitcoin, are technological innovations but not novelties from a legal-conceptual perspective. This article seeks to provide definitions for "electronic currencies" and "cryptocurrencies" alongside the traditional forms of money. It becomes apparent that Bitcoin is not real "money" but relies on existing currency. At present, its actual role is rather to enable speculation and to circumvent fiscal regulations.

Damiano Di Francesco Maesa, Paolo Mori, Laura Ricci

This work proposes to exploit blockchain technology to define Access Control systems that guarantee the auditability of access control policies evaluation. The key idea of our proposal is to codify attribute-based Access Control policies as smart contracts and deploy them on a blockchain, hence transforming the policy evaluation process into a completely distributed smart contract execution. Not only the policies, but also the attributes required for their evaluation are managed by smart contracts deployed on the blockchain. The auditability property derives from the immutability and transparency properties of blockchain technology. This paper not only presents the proposed Access Control system in general, but also its application to the innovative reference scenario where the resources to be protected are themselves smart contracts. To prove the feasibility of our approach, we present a reference implementation exploiting XACML policies and Solidity written smart contracts deployed on the Ethereum blockchain. Finally, we evaluate the system performances through a set of experimental results, and we discuss the advantages and drawbacks of our proposal.

Pierluigi Siano, Giuseppe De Marco, Alejandro Rolán, Vincenzo Loia

The unpredictability and intermittency introduced by Renewable Energy Sources (RESs) in power systems may lead to unforeseen peaks of energy production, which might differ from energy demand. To manage these mismatches, a proper communication between prosumers (i.e., users with RESs that can either inject or absorb energy) and active users (i.e., users that agree to have their loads changed according to the system needs) is required. To achieve this goal, the centralized approach used in traditional power systems is no longer possible because both prosumers and active users would like to take part in energy transactions, and a decentralized approach based on transactive energy systems (TESs) and Peer-to-Peer (P2P) energy transactions should be adopted. In this context, the Distributed Ledger Technology (DLT), based on the blockchain concept arises as the most promising solution to enable smart contracts between prosumers and active users, which are safely guarded in blocks with cryptographic hashes. The aim of this paper is to provide a review about the deployment of decentralized TESs and to propose and discuss a transactive management infrastructure. In this context, the concept of Proof of Energy is proposed as a novel consensus protocol for P2P energy exchanges managed by DLT. An application of the proposed infrastructure considering a Virtual Power Plant (VPP) aggregator and residential prosumers endowed with a new transactive controller to manage the electrical storage system is discussed.

Bojan Marinković, Paola Glavan, Zoran Ognjanović, Thomas Studer

Abstract In this paper we provide a strongly complete axiomatization of a temporal epistemic logic in which non-rigid sets of agents are allowed. Using this framework, we prove a number of properties of the blockchain protocol with respect to the given set of axioms and premises.

Yan Luo, Hao Jin, Peilong Li

In the digital healthcare era, it is utmost important to harness medical information scattered across healthcare institutions to support in-depth data analysis. However, the boundaries of cyberinfrastructure of healthcare providers place obstacles on data sharing. In this position paper, we firstly identify the challenges of medical data sharing and management. Then we introduce the background and give a brief survey on the state-of-the-art. Finally, we conclude the paper by discussing a few possible research directions to cope with the challenges in current medical information sharing.

Holger Kinkelin, Heiko Niedermayer, Marc Müller, Georg Carle

Configuration management in networks with highest security demands must not depend on just one administrator and her device. Otherwise, problems can be caused by mistakes or malicious behavior of this admin, or when her computer got compromised, which allows an attacker to abuse the administrator's far-reaching permissions. Instead, we propose to use a reliable and resilient configuration management process orchestrated by a configuration management system (CMS). This can be achieved by separation of concerns (proposing a configuration vs. authorizing it), employing multi-party authorization (MPA), and enforcing that only authorized configurations can be deployed. This results in a configuration management process that is decentralized on a human, decision-making level, and a technical, device level. However, due to different opinions or adversarial interference, the result of an MPA process can end in a conflict. This raises the question how such conflicts can be mediated in a better way than just employing majority voting, which is insufficient in certain situations. As an alternative, this paper introduces building blocks of customizable conflict mediation strategies which we integrated into our CMS TANCS . The conflict mediation functionality as well as the initial TANCS implementation run on top of the distributed ledger and smart contract framework Hyperledger Fabric which makes all processes resilient and tamper-resistant.

Yujing Lin, Po-Wei Wu, Cheng-Han Hsu, I‐Ping Tu · 5 authors

Bitcoin is a cryptocurrency that features a distributed, decentralized and trustworthy mechanism, which has made Bitcoin a popular global transaction platform. The transaction efficiency among nations and the privacy benefiting from address anonymity of the Bitcoin network have attracted many activities such as payments, investments, gambling, and even money laundering in the past decade. Unfortunately, some criminal behaviors which took advantage of this platform were not identified. This has discouraged many governments to support cryptocurrency. Thus, the capability to identify criminal addresses becomes an important issue in the cryptocurrency network. In this paper, we propose new features in addition to those commonly used in the literature to build a classification model for detecting abnormality of Bitcoin network addresses. These features include various high orders of moments of transaction time (represented by block height) which summarizes the transaction history in an efficient way. The extracted features are trained by supervised machine learning methods on a labeling category data set. The experimental evaluation shows that these features have improved the performance of Bitcoin address classification significantly. We evaluate the results under eight classifiers and achieve the highest Micro-Fl /Macro-F1 of 87% /86% with LightGBM.

Yuqing Kong, Yiping Ma, Yifan Wu

In future, information may become one of the most important assets in economy. However, unlike common goods (e.g. clothing), information is troublesome in trading since the information commodities are \emph{vulnerable}, as they lose their values immediately after revelation, and possibly unverifiable, as they can be subjective. By authorizing a trusted center (e.g. Amazon) to help manage the information trade, traders are ``forced'' to give the trusted center the ability to become an information monopolist. To this end, we need a trust-free (i.e. without a trusted center and with only strategic traders) unverifiable information trade protocol such that it 1) motivates the sellers to provide high quality information, and the buyer to pay for the information with a fair price (truthful); 2) except the owner, the information is known only to its buyer if the trade is executed (secure). In an unverifiable information trade scenario (e.g. a medical company wants to buy experts' opinions on multiple difficult medical images with unknown pathological truth from several hospitals), we design a trust-free, truthful, and secure protocol, Smart Info-Dealer (SMind), for information trading, by borrowing three cutting-edge tools that include peer prediction, secure multi-party computation, and smart contract. With SMind, without a trusted center, a seller with high-quality information is able to sell her information securely at a fair price and those with low-quality information cannot earn extra money with poor information or steal information from other sellers. We believe SMind will help describe a free and secure information trade scenario in the future.

Gudmundur Sigurdsson, Alberto Giaretta, Nicola Dragoni

No abstract is available for this record.

Francesco Restuccia, Kanhere, Salvatore D'Oro andSalil S., Tommaso Melodia, Sajal Kanta Das

One of the key challenges to the IoT's success is how to secure and anonymize billions of IoT transactions and devices per day, an issue that still lingers despite significant research efforts over the last few years. On the other hand, technologies based on blockchain algorithms are disrupting today's cryptocurrency markets and showing tremendous potential, since they provide a distributed transaction ledger that cannot be tampered with or controlled by a single entity. Although the blockchain may present itself as a cure-all for the IoT's security and privacy challenges, significant research efforts still need to be put forth to adapt the computation-intensive blockchain algorithms to the stringent energy and processing constraints of today's IoT devices. In this paper, we provide an overview of existing literature on the topic of blockchain for IoT, and present a roadmap of research challenges that will need to be addressed to enable the usage of blockchain technologies in the IoT.

Yao Sun, Lei Zhang, Gang Feng, Bowen Yang · 6 authors

Blockchain has shown a great potential in Internet of Things (IoT) ecosystems for establishing trust and consensus mechanisms without involvement of any third party. Understanding the relationship between communication and blockchain as well as the performance constraints posing on the counterparts can facilitate designing a dedicated blockchain-enabled IoT systems. In this paper, we establish an analytical model for the blockchain-enabled wireless IoT system. By considering spatio-temporal domain Poisson distribution, i.e., node geographical distribution in spatial domain and transaction arrival rate in time domain are both modeled as Poisson point process (PPP), we first derive the distribution of signal-to-interference-plus-noise ratio (SINR), blockchain transaction successful rate as well as overall throughput. Based on the system model and performance analysis, we design an algorithm to determine the optimal full function node deployment for blockchain system under the criterion of maximizing transaction throughput. Finally, the security performance is analyzed in the proposed networks with three typical attacks. Solutions such as physical layer security are presented and discussed to keep the system secure under these attacks. Numerical results validate the accuracy of our theoretical analysis and optimal node deployment algorithm.

Mario Arias-Oliva, Jorge Pelegrín Borondo, Gustavo Matías-Clavero

The first commercial transaction with the first cryptocurrency in 2010 marked the start of a revolution in transactions. Blockchain and cryptocurrencies will dramatically transform how we do transactions, just as the Internet revolutionized how we communicate. Currently, more than 2,000 cryptocurrencies are quoted on the market, and many more are being launched in initial coin offerings for use as an exchange method in a specific business ecosystem or as rights to assets or liabilities. As an emerging fintech, cryptocurrencies open up many opportunities, but they also pose significant challenges and limitations. This paper analyzes the key factors for the successful development of a cryptocurrency from a consumer-behavior perspective. Using a technology acceptance theoretical framework, we test a model able to explain almost 85% of the intention to use cryptocurrencies. Surprisingly, risk was not a significant factor. This could be because most of the respondents considered operating with cryptocurrencies to be risky; the lack of variability in their responses to the questions about perceived risk would explain this lack of explanatory power. However, willingness to manage cryptocurrency risk could be a precondition for adoption. The performance expectancy for a given cryptocurrency was the most important factor for its success. The research was conducted in Spain with college-educated adults with basic knowledge of the Internet.

Rui Zhang, Rui Xue, Ling Liu

Blockchain offers an innovative approach to storing information, executing transactions, performing functions, and establishing trust in an open environment. Many consider blockchain as a technology breakthrough for cryptography and cybersecurity, with use cases ranging from globally deployed cryptocurrency systems like Bitcoin, to smart contracts, smart grids over the Internet of Things, and so forth. Although blockchain has received growing interests in both academia and industry in the recent years, the security and privacy of blockchains continue to be at the center of the debate when deploying blockchain in different applications. This article presents a comprehensive overview of the security and privacy of blockchain. To facilitate the discussion, we first introduce the notion of blockchains and its utility in the context of Bitcoin-like online transactions. Then, we describe the basic security properties that are supported as the essential requirements and building blocks for Bitcoin-like cryptocurrency systems, followed by presenting the additional security and privacy properties that are desired in many blockchain applications. Finally, we review the security and privacy techniques for achieving these security properties in blockchain-based systems, including representative consensus algorithms, hash chained storage, mixing protocols, anonymous signatures, non-interactive zero-knowledge proof, and so forth. We conjecture that this survey can help readers to gain an in-depth understanding of the security and privacy of blockchain with respect to concept, attributes, techniques, and systems.

Jamal Bouoiyour, Refk Selmi

International audience

Robert Campbell

This paper evaluates the current cybersecurity vulnerability of the prolific use of Elliptical Curve Digital Signature Algorithm (**ECDSA**) cryptography in use by the Bitcoin Core, Ethereum, Bitcoin Cash, and enterprise blockchains such as Multi-Chain and Hyperledger projects Fabric, and Sawtooth Lake. These blockchains are being used in media, health, finance, transportation and government with little understanding, acknowledgment of the risk and no known plans for mitigation and migration to safer public-key cryptography. The second aim is to evaluate ECDSA against the threat of **Quantum Computing** and propose the most practical National Institute of Standards and Technology (NIST) Post-Quantum Cryptography candidate algorithm lattice-based cryptography countermeasure that can be implemented near-term and provide a basis for a coordinated industry-wide lattice-based public-key implementation. Commercial quantum computing research and development is rapid and unpredictable, and it is difficult to predict the arrival of fault-tolerant quantum computing. The current state of covert and classified quantum computing research and advancement is unknown and therefore, it would be a significant risk to blockchain and Internet technologies to delay or wait for the publication of draft standards. Since there are many hurdles Post-Quantum Cryptography (PQC) must overcome for standardisation, coordinated large-scale testing and evaluation should commence promptly.

Eko Yunianto, Yudi Prayudi, Bambang Sugiantoro

Digital evidence handling and preservation are one stage of digital forensic process. This part is very crucial because digital evidence is the basis of digital forensic process. The credibility of digital evidence must be maintaned for law and court process. Process of preservation of digital evidence known as chain of custody (CoC). CoC is a document that used to ensure that digital evidence remains and does not change. Both during the investigation process until the completion of the forensic process. Electronic evidence documentation is different from digital evidence documentatation. The different are character and the metadata. Some adjustments need to be accomodated on system for digital evidence. Digital evidence is easy to change as well as its CoC document. It needs to be protected. A new technology is needed that can ensure integrity of digital evidence and CoC Document like the blockchain. In this study, digital evidence management will be built on the CoC concept with blockchain technology. More precisely, this design combines the framework of the Digital Evidence Bag (DEC) with blockchain technology. This prototype is known as the Blockchain Digital Evidence Bag (B-DEC). B-DEC utilizes the data storage integrity to accommodate digital evidence management that refers to DEC. In this case, the prototype will build on a smart contract based on Ethereum. The development of the DEC framework also will be adjusted to accommodate DEC applications in the blockchain.

Karan Bhatia, Jivesh Vij, H R Prashanth Kumar, Yogesh Sharma

Blockchain is an evolving technology providing us the ability to design and develop decentralized distributed solutions. It has yields wide-scale impact on finance industry with reducing intermediate authorities. By building digital currency tracking of the transaction has become much easier and immutable nature of block not only give credibility but also is a cheap storage mechanism. So, we decided to explore its feasibility in the real estate industry. Real estate is one of the biggest sectors all across the world and is known to have millions of transactions every day. By making a digital system we can not only reduce redundant paperwork but also increase robustness in the system. It would also help investigating agencies to track transaction like many incidents came where terrorists bought or leased land with fake identities. By developing a system efficient enough to validate citizen and property and provide quick fetching of the transaction would be a revolutionary change for the industry as at present date all transaction are offline at it is impossible to collect data all across the country. This research paper explores one possible model of blockchain in the real estate market particularly rules and regulation followed in India with authentication using AADHAR.

Sebastian Lawrenz, Priyanka Sharma, Andreas Rausch

In the digital Economy 'Data is the new oil. In the last decade technology has disrupted every filed imaginable. One such booming technology is Blockchain. A blockchain is essentially a distributed database of records or public ledger of all transactions or digital events that have been executed and shared among participating parties. And once entered, the information is immutable. Ongoing projects and prior work in the fields of big data, data mining and data science has revealed how relevant data can be used to enhance products and services. There are uncountable applications and advantages of relevant data. The most valuable companies of today treat data as a commodity, which they trade and earn revenues.