espanolEn este trabajo el autor propone la implementacion de un nuevo modelo de Registro de la Propiedad que funcionaria exclusivamente mediante procedimientos automaticos de naturaleza algoritmica, y sin necesidad de ningun tipo de intervencion humana. El sistema propuesto requiere la existencia de un sistema contractual de naturaleza abstracta y de un ordenamiento juridico-real basado en el numerus clausus. La implementacion de este sistema tendria lugar dentro de una blockchain privada regida por el protocolo Ethereum, o una version modificada del mismo. EnglishIn this paper the author proposes the implementation of a new model of Land Registry, which would run through automatic procedures of algorithmic character exclusively, and without any kind of human intervention. The system requires a property law based on an exhaustive list of rights in rem (numerus clausus) and an abstract system of title transfer, like the German one. The system would be implemented within a private blockchain governed by the Ethereum protocol, or a modified version of the same.
A blockchain is a distributed hierarchical data structure. Widely-used applications of blockchain include digital currencies such as Bitcoin and Ethereum. This paper proposes an algorithmic approach to analyze the efficiency of a blockchain as a function of the number of blocks and the average synchronization delay. The proposed algorithms consider a random network model that characterizes the growth of a tree of blocks by adhering to a standard protocol. The model is parametric on two probability distribution functions governing block production and communication delay. Both distributions determine the synchronization efficiency of the distributed copies of the blockchain among the so- called workers and, therefore, are key for capturing the overall stochastic growth. Moreover, the algorithms consider scenarios with a fixed or an unbounded number of workers in the network. The main result illustrates how the algorithms can be used to evaluate different types of blockchain designs, e.g., systems in which the average time of block production can match the average time of message broadcasting required for synchronization. In particular, this algorithmic approach provides insight into efficiency criteria for identifying conditions under which increasing block production has a negative impact on the stability of a blockchain. The model and algorithms are agnostic of the blockchain’s final use, and they serve as a formal framework for specifying and analyzing a variety of non-functional properties of current and future blockchains.
Abstract This paper proposes a Bayesian estimation algorithm to estimate Generalized Partition of Unity Copulas (GPUC), a class of nonparametric copulas recently introduced by [18]. The first approach is a random walk Metropolis-Hastings (RW-MH) algorithm, the second one is a random blocking random walk Metropolis-Hastings algorithm (RBRW-MH). Both approaches are Markov chain Monte Carlo methods and can cope with ˛at priors. We carry out simulation studies to determine and compare the efficiency of the algorithms. We present an empirical illustration where GPUCs are used to nonparametrically describe the dependence of exchange rate changes of the crypto-currencies Bitcoin and Ethereum.
Banking is considered only one of many industries that could benefit from using blockchain technology. A promising area in blockchain technology is so-called smart contracts, which is automated, decentralized and programmable contract solutions. Smart contracts can control the transfer of currencies or assets between parties under given conditions. The thesis work shows how blockchain technology could be applied to real estate transactions and minimize the need for third party involvement. The purpose of this paper is to provide an overview of the blockchain technology and its possible applications in the real estate market. The focus was on exploring the process of real estate transactions and problems that could be resolved by using smart contracts and blockchain technology. Witha qualitative research approach and a case study analysis, a proposition of a solution was made and discussed with its benefits and drawbacks. The goal was to in the process find the answers for the research questions such as: How can real estate transactions benefit from blockchain technology? What would it cost to store the necessary data on the main chain of Ethereum? How could blockchain technology be used for managing the transaction of the down payment? Even though a collaboration of systems and smart contracts could handle almost every aspect of a real estate transaction, there are still legal boundaries to it being legally enforceable. The blockchain technology could contribute to more efficient and transparent systems compared to traditional centralized solutions.
The phenomenon of isolated value in each blockchain system has become adistinct issue of the blockchain field. To address this problem, the demandof cross-chain intercommunication came up. In a narrow sense, cross-chainrefers to the process of asset interoperability between relatively independentblockchains. In this thesis, we mainly analyze the design principles, technicaldifficulties, and solutions of cross-chain intercommunication in this narrowsense. With the introduction of distributed ledger technology(DLT), we describethe interaction with other ledgers as the fundamental problem of currentblockchain technology.The implementation of cross-chain is mainly manifested as asset swap and assettransfer. So far, there are many existing application scenarios and projectsadopted from these manifestation. This paper will focus on these two implementations,illustrate their principles, locate the realization difficulties, andput forward corresponding possible solutions. Then we elaborated on eightpopular cross-chain projects underlying mechanism listed with three maincategories. A detailed comparison according to their interoperability level,consensus algorithm and application scenarios of the overall overview of 20cross-chain projects is presented as a table in the Appendix A.During the implementation process, we performed a simple atomic swap crosschainframework based on Hash Time Lock Contract between Bitshares andEthereum, then compare the performance with a wallet application presentby Ripple using Interledger Protocol. These two applications are representedthe two different use case of cross-chain realization.With limited number of projects to test out, our conclusion was reached aftera discussion with the relative merits of the two approaches. Interledger protocolhas a better solution from the aspects of the decentralization, scalability,and whether it supports traditional ledgers.
Callbacks are an effective programming discipline for implementing event-driven programming, especially in environments like Ethereum which forbid shared global state and concurrency. Callbacks allow a callee to delegate the execution back to the caller. Though effective, they can lead to subtle mistakes principally in open environments where callbacks can be added in a new code. Indeed, several high profile bugs in smart contracts exploit callbacks. This work presents the first static technique ensuring modularity in the presence of callbacks and apply it to verify prominent smart contracts. Modularity ensures that external calls to other contracts cannot affect the behavior of the contract. Importantly, modularity is guaranteed without restricting programming. In general, checking modularity is undecidable– even for programs without loops. This work describes an effective technique for soundly ensuring modularity harnessing SMT solvers. The main idea is to define a constructive version of modularity using commutativity and projection operations on program segments. We implemented our approach in order to demonstrate the precision of the modularity analysis and applied it to real smart contracts (including a subset of the 150 most queried contracts in Ethereum). Our implementation decompiles bytecode programs into an intermediate representation and then implements the modularity checking using SMT queries. Our experimental results indicate that the method can be applied to many realistic contracts, and that it is able to prove modularity where other methods fail. The main results in this project have been submitted to the ACM SIGPLAN conference on Systems, Programming, Languages, and Applications: Software for Humanity (OOPSLA 2020).
Maruf Monem, Alif Ahmad, Jumana, Rashad Ahmed · 5 authors
The use of Blockchain in cryptocurrency introduces a technology that acts as an unswervingly growing ledger with the capability to keep an everlasting record of all the transactions in a secure, chronological and immutable system. It removes dependency on central financial services, essentially removing the middle-man from the transaction. Bitcoin holds the highest share in the cryptocurrency market. However, Bitcoin has three major problems which are excessive power consumption, confirmation time, and fair reward distribution. Hence, we propose a system (FaircoinBD) where we focus on reducing energy consumption by limiting participation, increasing propagation speed and fair reward distribution. We have also compared our proposed system with Bitcoin and Ether in terms of energy consumption and have reached the conclusion, that if Bitcoin and Ethereum network used our proposed model there would be a 83.33% and 80.0012% reduction of energy consumption respectively.
Having recently celebrated its ten-year anniversary, Bitcoin should be considered a qualified success. In October 2020, each unit1 was worth about $10,700, and the entire market capitalization was approximately $200 billion.2 Bitcoin is a significant economic force with sizable market value. Despite this success, however, Bitcoin has not been widely adopted as a method of payment, which was its intended use.3 By providing a template for a durable cryptocurrency, Bitcoin also blazed a path for other cryptocurrency projects. In terms of market capitalization and current importance, Ethereum is comfortably in second place.4 In October 2020, it had a market capitalization of approximately $40 billion.5 Unlike Bitcoin, however, Ethereum was not designed primarily to serve as a method of payment. Ethereum supports a system of sophisticated “smart contracts” that would not work on the Bitcoin system. Smart contracts and cryptocurrencies have sparked considerable interest among legal scholars in recent years, and a growing body of scholarship focuses on whether smart contracts and cryptocurrencies can sidestep law and regulation altogether.6 Bitcoin is famously decentralized, without any central actor controlling the system. Its users remain largely anonymous, using alphanumeric addresses instead of legal names. Ethereum shares these traits and also supports smart contracts that can automate the transfer of the Ethereum cryptocurrency (known as ether). Ethereum also supports specialized “tokens” that can be tied to the ownership of assets, goods, and services that exist completely outside of the Ethereum blockchain. The goal of this Article is to evaluate the degree to which cryptocurrencies and smart contracts can operate outside the reach of law and regulation. By some accounts, cryptocurrencies and smart contracts will revolutionize private law.7 Some argue they have the potential to displace contract and property law. For example, in a previous article, I argued that Bitcoin represents a system of private property that exists wholly outside of traditional legal structures.8 In this Article, I will argue that a complete revolution is not inexorable.9 Facing the technical and complicated nature of this subject, we should keep in mind a simple fact: cryptocurrencies and smart contracts are computer data and computer programs. To a large extent, they will have legal force only if given force by judges, regulators, and legislators. Part II describes Bitcoin and how it creates a system of property that exists outside of legal structures. Bitcoin is special because it controls no external assets (like securities, dollars, or gold). It is purely “notional” property that exists only on a computer file. Part III describes Ethereum and how it builds upon the principles of Bitcoin. The primary innovation of Ethereum is smart contracts, which allow for variable and conditional transfers of cryptocurrency. To be of commercial value, however, smart contracts must incorporate economic or financial information (e.g., interest rates or exchange rates). Ethereum allows users to incorporate this information using third party “oracles.” While oracles allow for sophisticated transactions, their presence illustrates some of the limits of smart contracts. Part IV extends the discussion of Ethereum and explains how many developers use it as a way to effectuate property transactions. Tokens are specialized smart contracts used to represent ownership of assets or certain privileges. Conceivably, ownership in any asset— homes, cars, etc.—could be represented by Ethereum tokens. Rather than using a deed of transfer, owners could simply transfer the representative tokens. Part V develops what this Article calls a “remote-computer model” of Bitcoin and Ethereum. Because Bitcoin and Ethereum are computer programs and computer data, we can view each as constituting a single computer. This hypothetical computer is remote in the sense that judges, regulators, and legislators can exercise little control over it directly. The remote computer controls ownership of cryptocurrency units, leaving direct cryptocurrency transactions outside the scope of traditional legal institutions. That being said, smart contracts often purport to control external resources and rights. For example, a smart contract might purport to control the transfer of land or stock in a corporation. These transactions have effects outside the hypothetical remote computer and can potentially be subject to control by legal institutions.
The emergence of e-commerce has changed the way people trade. However, merchants are charged high fees for their use of the platform and for payment services. These costs are passed on to customers in the form of higher prices. Blockchain technology can provide lower transaction fees with high security and privacy level but is incapable of delivering the number of transactions per second demanded by real e-commerce. Establishing a layer above the blockchain to manage transactions which we called Blockchain Layer2 technology, has the potential to solve these issues. In this article, we focus on the effect that layer2 technology can provide in reducing fee costs and improving transaction volumes. We introduce the problems that the e-commerce industry is facing currently and how blockchain layer2 technology can help to address these issues. We list and describe the main layer2 mechanisms based on the Bitcoin and Ethereum blockchains. We discuss issues that arise when applying layer 2 technology to e-commerce. We analyse the costs associated with difference e-commerce payment network topologies and investigate the funds-capacity needed to support high levels of value transfer.
Open access
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques