Heather Leigh Flannery, Avinash Burra, Combiz Richard Abdolrahimi, Jim Kyung-Soo Liew
Session Description: The session will address what and who the stakeholders are in healthcare, and how smart contracts can be deployed in decentralized payment system in healthcare, types of platforms that can be deployed, the structure of private blockchains, what the best public platforms for smart contracts with payments are, and if scalable, technological limitations. In addition, best case implementations ,where smart contracts are deployed , specifically, with healthcare payments and reimbursements.
Thomas Hepp, Matthew Sharinghousen, Philip Ehret, Alexander Schoenhals · 5 authors
Abstract Supply chains are the basis of most everyday life products. Both data integrity and authenticity of related information have severe implications for quality and safety of end-products. Hence, tamper-proof storage is necessary that prevents unauthorized modifications. We examine peer-reviewed blockchain technologies according to four criteria relevant to supply chains: On-chain storage, off-chain storage, verification cost and secure data sharing. Our evaluation yields an overview of concepts for modeling supply chain processes and points out that on-chain storage is currently not practical.
Token Curated Registries (TCR) are decentralized recommendation systems that can be implemented using Blockchain smart contracts. They allow participants to vote for or against adding items to a list through a process that involves staking tokens intrinsic to the registry, with winners receiving the staked tokens for each vote. A TCR aims to provide incentives to create a well-curated list. In this work, we consider a challenge for these systems - incentivizing token-holders to actually engage and participate in the voting process. We propose a novel token-inflation mechanism for enhancing engagement, whereby only voting participants see their token supply increased by a pre-defined multiple after each round of voting. To evaluate this proposal, we propose a simple 4-class model of voters that captures all possible combinations of two key dimensions: whether they are engaged (likely to vote at all for a given item) or disengaged, and whether they are informed (likely to vote in a way that increases the quality of the list) or uninformed, and a simple metric to evaluate the quality of the list as a function of the vote outcomes. We conduct simulations using this model of voters and show that implementing token-inflation results in greater wealth accumulation for engaged voters. In particular, when the number of informed voters is sufficiently high, our simulations show that voters that are both informed and engaged see the greatest benefits from participating in the registry when our proposed token-inflation mechanism is employed. We further validate this finding using a simplified mathematical analysis.
Compact E-cash achieves an efficient system by withdrawing 2n coins within O(1) operations and storing the coins in O(n) bits. For preventing a double-spender from cheating again, it is necessary to trace his e-coins. So full-tracing in compact E-cash system means tracing double-spender and tracing his coins. However, the efficiency problem caused by coin-tracing without TTP (trusted third party) has not been solved. For solving this problem, we introduce a non-standard construction into zero-knowledge proof of payment protocol, which leaks coin information when double-spending but is proven to be perfect zero-knowledge to verifier when spending a coin only once. Therefore, it achieves tracing dishonest users' coins and preserving the anonymity of honest users. Comparing with the existing most efficient method of coin-tracing without TTP, we improve computational complexity from O(k) to O(1) with less storage space. In addition, to improve efficiency and practicality further, batch-spending (spending any number of coins in one operation) and compact-spending (spending all coins in one operation) had been proposed. Based on the non-standard zero-knowledge proof, our scheme provides more efficient batch/compact-spending. Moreover, we also make a comparison with Bitcoin and Bitcoin Lightning Network, which have attracted considerable attention.
The obligatory features of the unit of account are formulated. Distinctive characteristic properties of a set of cryptocalculation units, in particular, subsets of x-type (coin) and y-type (token) calculation units, are revealed. It is proved that these sets do not intersect. It is proposed to allocate a subset of C 2 in the set of coins, which has an additional characteristic property — functioning on the basis of a smart contract. The thesis that any settlement unit carries the cost of a resource is proved. Even for units of account with the so-called “intrinsic value” (bitcoin), the presence of a resource in its functions was found. Four characteristic properties inherent in the set of “money” (M = {money}) are disclosed and a subset DM = {digital money} is allocated, containing a set of digital Fiat money secured by the state (sets F = {fat}) and a subset P = {private}, which is actually an addition to the set F). It is proved that cryptocurrencies have characteristic properties of the set M = {money} only within their own community. The paradox of the algorithmic guarantor, reflecting the absence of the need for formalization of algorithmic informal institutions, is formulated. Disclosed defnitions of such concepts as “cryptocurrency”, “token economy” and “tokenization economy”. Euler circles are used to visualize the relationship between different sets of calculation units. A coherent classifcation of calculation units based on the characteristic properties of the identifed sets is formed. The results of the study can be used to form the basis of legal regulation of the circulation of digital units of account.
We compute the revenue ratio of the Trail Stubborn mining strategy in the Bitcoin network and compare its profitability to other block-withholding strategies. We use for this martingale techniques and a classical analysis of the hiker problem. In this strategy the attacker could find himself mining in a shorter fork, but we prove that for some parameter values it is still profitable to not give up. This confirms previous numerical studies.
Blockchain menawarkan berbagai dobrakan di bidang teknologi, mulai dari bidang keuangan hingga kesehatan. Beberapa usulan juga menerapkan blockchain pada teknologi IoT untuk meningkatkan unjuk kerja dan scalability. Namun, tipikal penerapan teknologi IoT dalam skala masif masih memiliki beberapa kendala, terlebih dalam hal manajemen akses dan identitas peranti yang terkoneksi. Makalah ini mengusulkan kombinasi dari permissioned blockchain dan teknologi Keyless Signature Infrastructure (KSI) sebagai metode untuk mengatur hak akses dan identitas peranti IoT. KSI dikenal mampu untuk memberikan layanan tanda tangan digital tanpa tergantung pada kunci privat maupun publik dengan menggunakan teknik pohon hash. Dengan karakteristik dari blockchain yang terdistribusi, teknologi KSI dapat dipadukan secara lebih efisien. Hasil yang diperoleh memberikan manajemen akses dan identitas dengan scalability yang tinggi.
Ralph Kwadwo Osei, Maurizio Canavari, Martin Hingley
Blockchain is a data management innovation that allows the linkage of successive records regarding a digital entity, and to store them into a shared, decentralized, distributed and retroactively unchangeable data structure. Each bit of information related to the recorded events contains the public key of the owner, therefore, the whole record is formed by a chain of transactions with blocks of information identifying where the transaction was generated from and its current destination (Nakamoto, 2008). Blockchain is the technology behind Bitcoin, an online currency that was first introduced in 2009. The technology makes it possible to conduct business between members within the network without relying on third parties as guarantors to prove transaction integrity, thus increasing speed and reducing cost of transaction. Moreover, the transparency posed by the technology makes it possible to trace goods and services through all stages, making the technology a unique tool that can be assimilated by, for example, the Agro-food supply chain systems. Specifically, Blockchain is being tested in a pilot project in the UK meat (Beef) industry by the FSA (Food Standards Agency) and the slaughterhouses, with IBM Blockchain platform to ensure full transparency and compliance with regulations, (Evenstad, 2018). However, the uptake of Blockchain in the fresh produce (fresh and fresh, short-life processed fruit, vegetables, salads) supply chain is lagging, in the United Kingdom, and remains untested and limited to literature, models and specific case studies in the United States of America and France. The study aims at understanding how prepared stakeholders are in adopting Blockchain for their operations. An inductive qualitative method was employed through non-structured interviews with three companies and one consumer focus group. The interviews were guided by seven (7) open-ended questions, which were unstructured. The collected data was analyzed with axial coding through constant comparative methods. Seven (7) themes were identified as factors influencing the adoption of Blockchain in the fresh produce supply chain in the UK. These are, novelty of the technology, complexity of the fresh produce supply chain in UK, level of product transformation, technological compatibility with operations, cost and value, Customer (retailer) push for adoption, and public/consumers opinion. The adaptation of Blockchain by the current fresh produce supply chain in the UK and the EU at large will come about when concerns on Novelty, and complexity of supply chain systems are fully addressed.
La tecnologa ha marcado un claro punto de inflexin en todos los mbitos del entorno actual, suscitando un cambio en el know how de las actividades empresariales, estableciendo nuevas pautas de actuacin en el mercado.Dentro de las tecnologas disruptivas que, de forma notable, estn incidiendo en estas ltimas podemos citar la cadena de bloques.Una de las obras de referencia en materia de Blockchain es, precisamente, la presente monografa.Como es conocido, el Blockchain es un anglicismo que se traduce como cadena de bloques.Representa un procedimiento informtico -protocolo-inicialmente creado con el objetivo de soportar las criptomonedas cuyo paradigma es Bitcoin.Esta ltima presenta dos caracteres diferenciadores bsicos, respecto a la moneda tradicional o decimonnica, a saber: la voluntariedad y su naturaleza descentralizada.La disrupcin que suscita en los medios de pago, en el espacio mercantil, estriba en que las criptomonedas, con carcter general, han operado al margen de las monedas fiduciarias.Podemos manifestar que los valores en los que las mismas oscilan se encuentran fuertemente condicionadas por la ley de la oferta y de la demanda.Blockchain es el soporte de Bitcoin, es decir es el protocolo informtico que sirve de base a la criptomoneda ms notable en la actualidad.La cadena de bloques constituye una combinacin de distintas tecnologas con un fin acreditativo.Es, en definitiva, una novedosa manifestacin de lo que se ha llamado economa colaborativa.Constituye, adems, una herramienta de carcter acreditativo que fomenta la aportacin/invocacin del procedimiento con el fin de sustentar las pretensiones de las partes frente a una posible controversia.Se ha dicho, con acierto, que la figura que analizamos es como un libro pblico de contabilidad.Ms bien, puede decirse que se erige en un instrumento registral o tabular que cuenta con una tabla indeleble o compartida como
This article departs from the post 2008 financial crisis context, from its intersection with technological developments, and from the socio-technical arrangements configured by this conjuncture. It explores plans and actions – of mainstream financial institutions, and of a community seeking for alternatives to centralised economy and governance – for the use of digital platforms supported by blockchain infrastructure. In particular, it explores how such plans and actions relate to conceptions of public and peer trust and how they appear to produce, or reinforce, reputational imaginaries and quantification practices within added value philosophies. By illuminating a tension between the two identified case examples, I seek to render alternative communities’ and financial institutions’ conceptions, imaginaries and practices (more) visible and to analyse their organisational marketing strategies – where there is a pragmatic and discursive operationalisation of technology as well as of trust as means to gain more self-sovereignty in action, while navigating markets and regulated actual world contexts.
Elvira Albert, Pablo Gordillo, Albert Rubio, Ilya Sergey
Gas is a measurement unit of the computational effort that it will take to execute every single operation that takes part in the Ethereum blockchain platform. Each instruction executed by the Ethereum Virtual Machine (EVM) has an associated gas consumption specified by Ethereum. If a transaction exceeds the amount of gas allotted by the user (known as gas limit), an out-of-gas exception is raised. There is a wide family of contract vulnerabilities due to out-of-gas behaviours. We report on the design and implementation of GASTAP, a Gas-Aware Smart contracT Analysis Platform, which takes as input a smart contract (either in EVM, disassembled EVM, or in Solidity source code) and automatically infers sound gas upper bounds for all its public functions. Our bounds ensure that if the gas limit paid by the user is higher than our inferred gas bounds, the contract is free of out-of-gas vulnerabilities.
Elvira Albert, Pablo Gordillo, Albert Rubio, Ilya Sergey
Gas is a measurement unit of the computational effort that it will take to execute every single operation that takes part in the Ethereum blockchain platform. Each instruction executed by the Ethereum Virtual Machine (EVM) has an associated gas consumption specified by Ethereum. If a transaction exceeds the amount of gas allotted by the user (known as gas limit), an out-of-gas exception is raised. There is a wide family of contract vulnerabilities due to out-of-gas behaviours. We report on the design and implementation of GASTAP, a Gas-Aware Smart contracT Analysis Platform, which takes as input a smart contract (either in EVM, disassembled EVM, or in Solidity source code) and automatically infers sound gas upper bounds for all its public functions. Our bounds ensure that if the gas limit paid by the user is higher than our inferred gas bounds, the contract is free of out-of-gas vulnerabilities.
There has been much debate about whether returns on financial assets, such as stock returns or commodity returns, are predictable; however, few studies have investigated cryptocurrency return predictability. In this article we examine whether bitcoin returns are predictable by a large set of bitcoin price-based technical indicators. Specifically, we construct a classification tree-based model for return prediction using 124 technical indicators. We provide evidence that the proposed model has strong out-of-sample predictive power for narrow ranges of daily returns on bitcoin. This finding indicates that using big data and technical analysis can help predict bitcoin returns that are hardly driven by fundamentals.
Blockchain, as one of the crypto-intensive creatures, has become a very hot topic recently. Although many surveys have recently been dedicated to the security and privacy issues of blockchains, there still lacks a systematic examination on the cryptographic primitives in blockchains. To this end, we in this paper conduct a systematic study on the cryptographic primitives in blockchains by comprehensive analysis on top-30 mainstream cryptocurrencies, in terms of the usages, functionalities, and evolutions of these primitives. We hope that it would be helpful for cryptographers who are going to devote themselves to the blockchain research, and the financial engineers/managers who want to evaluate cryptographic solutions for blockchain-based projects.
Open access
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Can securities be settled on a blockchain, and, if so, what are the gains relative to existing settlement systems? The main benefit of a blockchain is faster and more flexible settlement, whereas settlement fails need to be ruled out where participants fork the chain to cancel trading losses. With a proof-of-work protocol, the blockchain needs to restrict settlement speed through block size and time in order to generate transaction fees, which finance costly mining. Despite mining being a deadweight cost, our estimates for the U.S. corporate debt market yield net gains from a blockchain in the range of 1–4 bps. Received May 31, 2017; editorial decision May 29, 2018 by Editor Itay Goldstein. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.
Fran Casino, Thomas K. Dasaklis, Constantinos Patsakis
This work provides a systematic literature review of blockchain-based applications across multiple domains. The aim is to investigate the current state of blockchain technology and its applications and to highlight how specific characteristics of this disruptive technology can revolutionise “business-as-usual” practices. To this end, the theoretical underpinnings of numerous research papers published in high ranked scientific journals during the last decade, along with several reports from grey literature as a means of streamlining our assessment and capturing the continuously expanding blockchain domain, are included in this review. Based on a structured, systematic review and thematic content analysis of the discovered literature, we present a comprehensive classification of blockchain-enabled applications across diverse sectors such as supply chain, business, healthcare, IoT, privacy, and data management, and we establish key themes, trends and emerging areas for research. We also point to the shortcomings identified in the relevant literature, particularly limitations the blockchain technology presents and how these limitations spawn across different sectors and industries. Building on these findings, we identify various research gaps and future exploratory directions that are anticipated to be of significant value both for academics and practitioners.
Tetris is an Asynchronous Byzantine Fault Tolerance consensus algorithm designed for next generation high-throughput permission and permissionless blockchain. The core concept of Tetris is derived from Reasoning About Knowledge, which we believe to be the most appropriate tools for revealing and analyzing the fundamental complexity of distributed systems. By analyzing the states of knowledge that each participant attained in an unreliable system, we can capture some of the basis underlying structure of the system, then help us designing effective & efficient protocols. Plus the adoption of Full Information Protocol (FIP) with the optimized message traffic model, Tetris has finally got high performance, with proved safety. Tetris achieve consensus finality in seconds, means transactions can be confirmed greatly faster than other scheme like Pow/Dpos. Tetris also achieve fairness, which is critically important in some areas such as stock market etc.