This, together with the related term Bitcoin, was a revolution in blockchain as envisioned by the mystery character Satoshi Nakamoto up to 2008. All this changes the very way the foundations of digital exchange and storage were thought about: decentralized, transparent, immutable, the very fundamentals of Distributed Ledger Technology enabling safe data exchange without an intermediary. The blockchain is fundamentally a chain of blocks carrying information about transactions, including times and cryptographic hashes, each of these connecting to the previous one in one unbroken chain, for which no modification is viable. The whole design of Blockchain has been to solve a number of issues, including double spending, fraud, and inefficient records, with distributed nodes and consensus mechanisms such as Proof of Work and Proof of Stake, facilitated by cryptographic keys. Other areas beyond cryptocurrency where quite a number of innovative uses are cut across include supply chain, healthcare, financial, and real estate sectors. For example, while the supply chain process is being promoted to become effective and transparent in order to ensure the origin and quality of the product, adding to the guarantee that the user's personal health information will not be accessed and tampered with, blockchain uses smart contracts in automating agreement processes within the contract. All of them are expecting cost reduction, operating efficiencies enhancement, enhanced securities of many industries. Anyhow, there exist quite a number of serious obstacles standing in the way of the wide application of blockchain technology. Firstly, the problem of scalability has still been an issue whereby the network performance tends to be problematic when users are increased. Besides, energy wasting cannot be ignored-apparently mostly a challenge from the PoW kind of system proved to be consuming too much energy, standing big on the road to sustainability. Of course, the mere lack of any kind of international rules and standards is already a complication in making them work. It also underlines failures in the adoption of the system or in decentralizing and is still an open technical and organizational challenge on how to combine blockchain with traditional structures. Their solutions require compounding ideas: sharding of blockchain to make it big, off-chain solutions for the blockchain to be many but thin, and provision of amicable solution consensus mechanisms for environmental conservation. Besides coherent policy vision, in addition to the existing cornerstones of regulation besides well-laid-out standards of interoperability, it is important to create confidence and give a road map across different industries. This paper hereby conceptually reviews the literature with respect to how the blockchain technology was designed to show revolutionary capability in the different fields and what keeps on tormenting it with its future.KEYS: Blockchain technology; Distributed Ledger; Decentralization; Cryptographic keys; Consensus mechanisms; Proof of Work; Proof of Stake; Smart contracts; Supply chain management; Data immutability; Transparency; Scalability; Energy consumption; Challenges to regulatory bodies; Security vulnerability; Sharding; off- chain processing; Interoperability; Applications using blockchain; Architecture of blockchain.
Blockchain technology has gained significant prominence in recent years due to its public, distributed, and decentration characteristics, which was widely applied in all walks of life requiring distributed trustless consensus. However, the most cryptographic protocols used in the current blockchain networks are susceptible to the quantum attack with rapid development of a sufficiently large quantum computer. In this paper, we first give an overview of the vulnerabilities of the modern blockchain networks to a quantum adversary and some potential post-quantum mitigation methods. Then, a new lattice-based signature scheme has been proposed, which can be used to secure the blockchain network over existing classical channels. Meanwhile, the public and private keys are generated by the Bonsai Trees technology withRandBasisalgorithm from the root keys, which not only ensure the randomness, but also construct the lightweight nondeterministic wallets. Then, the proposed scheme can be proved secure in random oracle model, and it is also more efficient than similar literatures. In addition, we also give the detailed description of the post-quantum blockchain transaction. Furthermore, this work can help to enrich the research on the future post-quantum blockchain (PQB).
Rafael Ziolkowski, Gianluca Miscione, Gerhard Schwabe
The blockchain technology challenges the view on established modes of governance by offering distributed authentication without the need for a central authority, which is well-exemplified by Bitcoin. While the governance of and through Bitcoin is well- accentuated in research, we spotlight impacts on governance which blockchain-based systems bring to inter-organizational settings as well as their purpose. To build our arguments, we explore those impacts on two contrasting cases from the domains of automotive and public administration and relate them to cryptocurrencies. Relying on interviews with experts from said organizations utilizing blockchain technology, and a content analysis of related grey literature, we discuss established forms of governance as well as platforms and infrastructures against the impacts which blockchain-based systems cause. After referring those to the concepts of markets, hierarchies, networks, and tribes, we critically reflect on their purpose by utilizing the notions of infrastructures and platforms, and conclude blockchain-based systems to possibly alter the way established modes of governance are enacted.
ResumenLa tesis que se defiende en este trabajo es que el complejo modelo institucional y territorial vasco funciona aceptablemente bien, a pesar de sus luces y sombras, y puede ser un ejemplo de la idea ampliamente generalizada de cómo un modelo de organización territorial descentralizada (y sus complejas, pero al mismo tiempo, valiosas formas de interacción entre los distintos niveles de gobierno), pueden mejorar la calidad del gobierno de sus instituciones, ayudar en el desarrollo humano, económico y social, aumentar la transparencia, administrar los recursos disponibles para ofrecer mejores servicios públicos y, en definitiva, mejorar la calidad democrática de la sociedad.Summary1. Introduction. 2. The distribution of competences between the Common Institutions of the Autonomous Community of Euskadi and the Regional Administrative Bodies of the Historical Territories ofBizkaia, Gipuzkoa and Álava. 2.1. The distribution of competences in the Statute of Autonomy of the Basque Country. 2.2. The distribution of competences in the Law of Historical Territories. 3. The competences of the municipal institutions of Euskadi. 4. Conclusion.AbstractThe thesis defended in this paper is that the complex Basque institutional and territorial model works acceptably well, despite its lights and shadows, and can be an example of the widespread idea of how a model of decentralized territorial organization (and their complex, but at the same time valuable forms of interaction between the various levels of government), can enhance the quality of government of their institutions, help in the human, economic and social development, raise transparency and manage available resources to deliver better public services and, in short, improve the democratic quality of society.
Zhao Cai, Fei Liu, Eric T.K. Lim, Chee‐Wee Tan · 5 authors
Although cryptocurrencies have garnered enormous public attention in recent times, extensive fluctuations in their prices have deterred prospective investors. Due to the \n absence of a centralized valuation authority, the credibility of cryptocurrencies as a viable investment vehicle remains elusive. Building on attention theory, this study posits that prospective investors of cryptocurrencies are likely to search online for information before deciding whether to make a commitment. We hence investigate the effects of Google search on the return and risk of 268 cryptocurrencies over 181 trading days. \n Results indicate that the Google Search Volume Index (SVI) of a given cryptocurrency \n exerts significant and positive impact on its price and turnover.
Concurrency, the art of doing many things at the same time is slowly becoming a science. It is very difficult to master, yet it arises all over modern computing systems, both when the communication medium is shared memory and when it is by message passing. Concurrent programming is hard because it requires to cope with many possible, unpredictable behaviors of communicating processes interacting with each other. Right from the start in the 1960s, the main way of dealing with concurrency has been by reduction to sequential reasoning. We trace this history, and illustrate it through several examples, from early ideas based on mutual exclusion, passing through consensus and concurrent objects, until today ledgers and blockchains. We conclude with a discussion on the limits that this approach encounters, related to fault-tolerance, performance, and inherently concurrent problems.
Michael Rodler, Wenting Li, Ghassan Karame, Lucas Davi
Recently, a number of existing blockchain systems have witnessed major bugs and vulnerabilities within smart contracts. Although the literature features a number of proposals for securing smart contracts, these proposals mostly focus on proving the correctness or absence of a certain type of vulnerability within a contract, but cannot protect deployed (legacy) contracts from being exploited. In this paper, we address this problem in the context of re-entrancy exploits and propose a novel smart contract security technology, dubbed Sereum (Secure Ethereum), which protects existing, deployed contracts against re-entrancy attacks in a backwards compatible way based on run-time monitoring and validation. Sereum does neither require any modification nor any semantic knowledge of existing contracts. By means of implementation and evaluation using the Ethereum blockchain, we show that Sereum covers the actual execution flow of a smart contract to accurately detect and prevent attacks with a false positive rate as small as 0.06% and with negligible run-time overhead. As a by-product, we develop three advanced re-entrancy attacks to demonstrate the limitations of existing offline vulnerability analysis tools.
We propose a secure computation solution for blockchain networks. The correctness of computation is verifiable even under malicious majority condition using information-theoretic Message Authentication Code (MAC), and the privacy is preserved using Secret-Sharing. With state-of-the-art multiparty computation protocol and a layer2 solution, our privacy-preserving computation guarantees data security on blockchain, cryptographically, while reducing the heavy-lifting computation job to a few nodes. This breakthrough has several implications on the future of decentralized networks. First, secure computation can be used to support Private Smart Contracts, where consensus is reached without exposing the information in the public contract. Second, it enables data to be shared and used in trustless network, without disclosing the raw data during data-at-use, where data ownership and data usage is safely separated. Last but not least, computation and verification processes are separated, which can be perceived as computational sharding, this effectively makes the transaction processing speed linear to the number of participating nodes. Our objective is to deploy our secure computation network as an layer2 solution to any blockchain system. Smart Contracts\cite{smartcontract} will be used as bridge to link the blockchain and computation networks. Additionally, they will be used as verifier to ensure that outsourced computation is completed correctly. In order to achieve this, we first develop a general MPC network with advanced features, such as: 1) Secure Computation, 2) Off-chain Computation, 3) Verifiable Computation, and 4)Support dApps' needs like privacy-preserving data exchange.
The focus of this chapter concerns the changing balance among three major funding sources to medical care. It examines the trend of growth and decline of franchise funding relative to the two public funding sources (government subsidies and public insurances) during the period of economic reform. An analysis is devoted to the issue of shrinkage of government subsidies that was inadvertently caused by decentralization of managerial powers from the central to the provincial and local level, coupled with the pro-growth policy advocated by the government prior to the early 2000s. The study treats the decline and restoration of public expenditures (government’s subsidies and public insurances) as a long-term process, dictated by the progress of institutional and policy restructuring. In addition, it tries to make a preliminary assessment on the extent medical care is politicized in the process of policymaking.
Blockchain has been widely adopted in the last few years even though it is in its infancy. The first well-known application built on blockchain technology was Bitcoin, which is a decentralized and distributed ledger to record crypto-currency transactions. All of the transactions in Bitcoin are anonymously transferred and validated by participants in the network. Bitcoin protocol and its operations are so reliable that technologists have been inspired to enhance blockchain technologies and deploy it outside of the crypto-currency world. The demand for private and non-crypto-currency solutions have surged among consortiums because of the security and fault tolerant features of blockchain. To introduce blockchain concepts, we survey the three most popular blockchain architectures: Bitcoin, Ethereum, and Hyperledger Fabric. We then build Gradubique, a blockchain network built on top of Hyperledger Fabric. Gradubique allows instructors from any school to post exam and course grades to the Gradubique network. Employers and graduate schools can extract transcripts from Gradubique. Security is guaranteed by the blockchain technology. Standardization and translation of transcripts can be built into the network, and the distributed nature of the network can make it virtually cost-free.
Cryptocurrencies are defined as a digital currency in which encryption techniques are utilized to regulate generation of units of currency and verify the transfer of funds, independent of a central governing body such as a bank. Due to the large number of cryptocurrencies currently available, there inherently exists many price discrepancies due to market inefficiencies. Market inefficiencies occur when the price of assets do not reflect their true value. In fact, these types of pricing discrepancies exist in other financial markets, including fiat currency exchanges and stock exchanges. However, these discrepancies are more significant in the cryptocurrency domain due to the low levels of government regulation, higher amounts of speculation, and human behaviors driven by investors seeking profit. These types of pricing discrepancies can be eliminated to some extent by executing arbitrages, which are defined as a sequences of trades beginning and ending with the same asset which result in more of that asset at the end of the trading sequence. Through executing arbitrages, the market should become more efficient. This project was an attempt to execute intra-exchange arbitrage on the well- known cryptocurrency exchange Binance and generate profit, and as a side effect make the cryptocurrency exchange market more fluid. Although the project did not record phenomenal profits, it did successfully generate several hundred dollars over the course of several months, independent of market fluctuations.
Yuichi Yagawa, H. Kato, Shuichiro Sakikawa, Gaku Suzuki
Due to global changes in social structure, the needs for social infrastructure are diversified and continually changing overtime. To capture the structural changes in the market and to sustainably and continuously improve the quality of life of users, innovative manufacturing is required to flexibly and incrementally innovate their business in finance, organizations, technology, and operations. In this chapter, we explain our incremental expansion of social infrastructure business to the UK railway market using the autonomous decentralized system concept.
This chapter discusses the form of autonomous decentralized software known as the blockchain. It covers the original usage ofblockchain distributed ledger technology, a part of the Bitcoin cryptocurrency. It summarizes the functional software architecture ofblockchain that provides secure and uninterruptible service. It briefly discusses the growth and proliferation of cryptocurrencies throughout the economy. The main focus of the section is the application of blockchain technology beyond currencies, as a disintermediating force in various industries, such as finance, healthcare, publishing, and software, including the potential for widespread distributed, autonomous organizations, based on smart contracts built on the blockchain technology. While the technology is complicated and the word blockchain isn't exactly sonorous, the main idea is simple. Blockchains enable us to send money directly and safely from me to you, without going through a bank, a credit card company, or PayPal. Rather than the Internet of Information, it's the Internet of Value or of Money. It's also a platform for everyone to know what is true-at least with regard to structured recorded information [1].
Consider the following set-up for the plot of a possible future episode of the TV series Black Mirror: human brains can be connected directly to the net and MiningMind Inc. has developed a technology that merges a reward system with a cryptojacking engine that uses the human brain to mine cryptocurrency (or to carry out some other mining activity). Part of our brain will be committed to cryptographic calculations (mining), leaving the remaining part untouched for everyday operations, i.e., for our brain's normal daily activity. In this short paper, we briefly argue why this set-up might not be so far fetched after all, and explore the impact that such a technology could have on our lives and our society.
Directed acyclic graphs (DAGs) are emerging as an attractive alternative to traditional blockchain architectures for distributed ledger technology. In particular, DAG ledgers with stochastic attachment mechanisms potentially offer many advantages over blockchain, including scalability and faster transaction speeds. However, the random nature of the attachment mechanism coupled with the requirement of protection against double-spending transactions might result in an unstable system in which not all transactions get eventually validated. Such transactions are said to be orphaned, and will never be validated. Our principal contribution is to propose a simple modification to the attachment mechanism for the Tangle (the IOTA DAG architecture). This modification ensures that all transactions are validated in finite time, and preserves essential features of the popular Monte Carlo selection algorithm. In order to demonstrate these results, we derive a fluid approximation for the Tangle (in the limit of infinite arrival rate) and prove that this fluid model exhibits the desired behavior. We also present simulations that validate the results for finite arrival rates.
This paper aims to offer new perspectives on the blockchain™s ecological sustainability issue. We introduce a measurement framework that offers a panoramic view of the environmental concerns associated with blockchain technologies in a cryptocurrency cont
ENGLISH: \n \nBitcoin is one of digital currencies by cryptography as the basic system with the highest price in digital marketplace until 2018, so it becomes one of digital asset used to invest and becomes one of the most popular investment tools in society. But this phenomenon still become polemic because it has no explicit regulations yet. So, this research objectives are to know the mechanism of Bitcoin investment in society and the legal expert opinion towards it. \n \nThis research used empirical juridical method with sociological juridical approach. The analytical method is descriptive and concluded in inductive way that explained the result from specific to general. \n \nThis research results are the Bitcoin investment mechanism in society divided into mining and trading activity. In Islamic views, the legal expert opines that mining activity is allowed to do because there are two kinds of akad did in it and has no element of maysîr at all. Whereas, if does not be incompatible with sharia principal, Bitcoin trading is allowed to do. In positive law views, these two types of investment activity still had no explicit regulation yet. Although it can to be associated with some regulations such as Civil Code, The Currency Law, Electronic Information and Transaction Law, and Bank of Indonesia Regulation, it still need to regulate explicitly and written in specific role, either in regulation or fatwa forms, so it gives the legal certainty to society. Hopefully, this research provides the suggestion to government to law the vacuum of norm of Bitcoin. \n \nINDONESIA: \n \nBitcoin merupakan salah satu mata uang digital yang berbasis program kriptografi dengan harga tertinggi hingga tahun 2018 sehingga menjadi salah satu aset digital untuk berinvestasi dan menjadi salah satu sarana investasi paling popular di masyarakat. Namun, fenomena tersebut masih menjadi polemik karena tidak dinaungi oleh payung hukum yang jelas. Penelitian ini bertujuan untuk mengetahui mekanisme investasi Bitcoin yang dilakukan serta pandangan pakar hukum terhadap fenomena tersebut. \n \nPenelitian ini menggunakan metode yuridis empiris, dengan pendekatan yuridis sosiologis. Analisis yang digunakan bersifat deskriptif dan disimpulkan secara induktif yaitu dengan menguraikan kasus yang bersifat khusus dan disimpulkan secara umum. \n \n \nHasil penelitian yang diperoleh adalah mekanisme investasi Bitcoin yang dilakukan dapat berupa mining, dan trading. Dalam perspektif Islam, pakar hukum berpendapat bahwa aktivitas mining boleh untuk dilakukan karena terdapat dua akad yang berbeda selama melakukan prosesnya, dan tidak mengandung unsur maysîr. Sedangkan, trading Bitcoin boleh untuk dilakukan selama tidak bertentangan dengan prinsip syariah. Secara hukum positif, kedua aktivitas tersebut belum memiliki payung hukum yang jelas. Meskipun dapat dikaitkan dengan beberapa peraturan, seperti KUH Perdata, Undang-Undang Mata Uang, Undang-Undang ITE, serta Peraturan Bank Indonesia, investasi Bitcoin perlu untuk diatur secara tertulis dalam peraturan khusus yang berbeda, baik dalam bentuk peraturan perundang-undangan ataupun fatwa. Sehingga akan memberikan kepastian hukum terhadap masyarakat. Dengan adanya penelitian ini diharapkan dapat memberikan masukan pada pemerintah untuk menyikapi kekosongan hukum Bitcoin.
Zusammenfassung Digitale Einheiten auf der Grundlage der Blockchain-Technologie sind derzeit in aller Munde. Manche dieser Einheiten wie ihr prominentester Verterter, der Bitcoin, fungieren als private virtuelle Währung. Andere, die sog. Tokens, sollen dazu dienen, den Handel mit bestimmten Rechtspositionen, die in diesen Tokens repräsentiert werden, zu erleichtern. Der nachfolgende Beitrag klärt zunächst die technologischen und begrifflichen Grundlagen und entwickelt darauf aufbauend das Konzept der digitalen Verbriefung.
Jan Heinrich Beinke, Duc Thanh Nguyen, Frank Teuteberg
In recent years, the blockchain technology has aroused growing interest in science and practice. Particularly the financial sector has high expectations of this technology, as is evidenced by numerous established start-ups and large amounts of venture cap