Because of the popularity of the Internet, the integration services have gradually changed people daily life, such as e-commerce activities on transactions, transportation and so on. The E-auction, one of the popular e-commerce activities, allows bidders to directly bid the products over the Internet. As for sealed bid, the extra transaction cost is required for the intermediaries because the third-party is the important role between the buyers and the sellers help to trade both during the auction. In addition, it never guarantees whether the third-party is trust. To resolve the problems, the blockchain technology with low transaction cost is used to develop the smart contract of public bid and sealed bid. The smart contract, proposed in 1990 and implements via Ethereum platform, can ensure the bill secure, private, non-reputability and inalterability owing to all the transactions are recorded in the same but decentralized ledgers. The smart contract is composed of the address of Auctioneer, the start auction time, deadline, the address of current winner, the current highest price. In the experiments, the accounts are created through Ethereum wallet. In miner stage, the MinerGate is used in miner stage for obtaining money to pay the transaction fee. At recorder stage, the nodes of blockchain are synchronized to generate smart contract.
Blockchain is a highly popular paradigm for non-centralized applications, especially in finance and trade. Performance is a major challenge for blockchains, since consensus approaches are known not to scale. In this presentation we address blockchain performance, from the perspective of model-based prediction as well as benchmark-based assessment. We present research results about smart contracts in the Ethereum blockchain and discuss the requirements for generic benchmarks for blockchain performance. Benchmarking is a common approach to compare industry-class systems. As blockchain technologies mature, the role of reliable benchmarks will become increasingly important. However, definitions of benchmarks for blockchains are still in their infancy. We argue that there is a clear need for benchmarks, and that benchmarks should be based on the sound scientific principles of metrology [1]. A variety of important performance issues should be addressed, including the performance of the proof (be it work, stake, or other), transaction processing and block creation. Moreover, in all these situations, establishing energy consumption benchmarks is critical in determining if incentives are in place for miners to operate the blockchain system. A particularly interesting element in some blockchains is the mechanism of smart contracts. For instance, in Ethereum, the fees associated with executing contracts depend on the benchmarked performance of the operation code. In [2] it was demonstrated that uncertainty with respect to the correctness of the anticipated execution time impacts the decisions miners will take. We will discuss improved benchmarking approaches for operational code.
The design of a successful distributed system for enabling payments and small transactions among Internet users has long been a major challenge in applied computer science. Bitcoin, the first cryptocurrency having reached world-wide popularity, suffers from sustainability problems such as inefficient energy expenditure for its network operation and from perverse incentives that foster speculative hoarding behavior. We propose a digital transfer system based on a variant of the Bitcoin ledger that is meant to support deterministic small payments with enforced proportional transaction fees: to achieve this property, we renounce the persistence of balances expected of a cryptocurrency, thus mitigating currency hoarding. We introduce at the same time a novel external incentive mechanism based on a verifiable third party with the goal of promoting long-term sustainability, adjusting the margins of profitability for contributors to the proof-of-work scheme without stifling the transaction rate.
Smart contracts gain rapid exposure since the inception of blockchain<br/>technology. Today's smart contracts are coded in non-mainstream<br/>procedural programming languages (e.g. Solidity for Ethereum),<br/>which lifts the requirement to draft enterprise ready smart contract to<br/>both a legal professional and a programmer instead of only the former.<br/>In search for a smart contract language that reduces the threshold to<br/>draft one, this conceptual paper elaborates how business logic can be<br/>converted to executable code for commitment-based smart contracts.<br/>Hereby, a contract is viewed as a set of reciprocal commitments. The<br/>smart contract ensures the automated execution of all or most of these<br/>commitments. In order to leverage its event processing capabilities,<br/>Reaction RuleML has been used to appropriately represent the<br/>elements and working of passive and active rules within a<br/>commitment based smart.
The political regime allowed economic liberalization after 1960; nevertheless, its impact did not change the regional disparities between the less and more developed regions of Spain. In spite of all that, the Spanish economy became quite modem on the eve of the death of Franco on 20 November 1975. In the Article 131.2 of the Spanish Constitution, it clearly enshrines the foundation of a committee for the participation of the trade unions and other professional, entrepreneurial, and economic organizations. In the 1990s, the autonomous communities developed their own systems of interest intermediation, which were working well in certain regions and less so in others. The decentralization and regionalization of industrial relations is being complemented by national indicative pacts, which shape the bargaining boundaries at the regional level. The integration into the European Union was a major factor in stabilizing the political economy of Spain, particularly in view of decentralizing production and economic processes.
The increasing popularity of Bitcoin, Ethereum and other cryptocurrencies has led to a rising interest in its underlying blockchain technology. Blockchains serve as distributed ledgers, and are fundamentally different from traditional distributed databases. In view of this large scale adoption of blockchain technology, it is of interest to analyze the performance of the underlying mechanisms in peer-to-peer blockchain networks.
I consider a developer working on an open-source blockchain-based software that can be used only in conjunction with a specific crypto-token. This token can be sold in an Initial Coin Offering (ICO) to raise funds, but can also be sold later on a frictionless financial market to earn a profit. I show that, if the developer raises funds in an ICO, in each post-ICO period there is a positive probability that the developer sells all of his tokens on the market and, as a consequence, no development occurs. If the developer does not need to raise funds via an ICO, the equilibrium will nonetheless be inefficient because the developer's payoff depends on the surplus generated by the protocol in a given period (when he expects to sell his tokens). He therefore fails to internalize that the protocol will be used (and generate surplus) over multiple periods.
We develop a dynamic asset-pricing model of cryptocurrencies/tokens that allow users to conduct peer-to-peer transactions on digital platforms. The equilibrium value of tokens is determined by aggregating heterogeneous users' transactional demand rather than discounting cashflows as in standard valuation models. Endogenous platform adoption builds upon user network externality and exhibits an S-curve-it starts slow, becomes volatile, and eventually tapers off. Introducing tokens lowers users' transaction costs on the platform by allowing users to capitalize on platform growth. The resulting intertemporal feedback between user adoption and token price accelerates adoption and dampens user-base volatility.
The rise of centralized mining pools for risk sharing does not necessarily undermine the decentralization required for permissionless blockchains: Each individual miner's cross-pool diversification and endogenous fees charged by pools generally sustain decentralization, because larger pools better internalize their externality on global hash rates, charge higher fees, attract disproportionately fewer miners, and thus grow more slowly. Instead, mining pools as a financial innovation escalate the arms race among competing miners and thus significantly increase the energy consumption of proof-of-work-based consensus mechanisms. Empirical evidence from Bitcoin mining supports our model predictions. The economic insights inform many other blockchain protocols as well as the industrial organization of mainstream sectors with similar characteristics but ambiguous prior findings.
We introduce FairSwap -- an efficient protocol for fair exchange of digital goods using smart contracts. A fair exchange protocol allows a sender S to sell a digital commodity x for a fixed price p to a receiver R. The protocol is said to be secure if R only pays if he receives the correct x. Our solution guarantees fairness by relying on smart contracts executed over decentralized cryptocurrencies, where the contract takes the role of an external judge that completes the exchange in case of disagreement. While in the past there have been several proposals for building fair exchange protocols over cryptocurrencies, our solution has two distinctive features that makes it particular attractive when users deal with large commodities. These advantages are: (1) minimizing the cost for running the smart contract on the blockchain, and (2) avoiding expensive cryptographic tools such as zero-knowledge proofs. In addition to our new protocols, we provide formal security definitions for smart contract based fair exchange, and prove security of our construction. Finally, we illustrate several applications of our basic protocol and evaluate practicality of our approach via a prototype implementation for fairly selling large files over the cryptocurrency Ethereum.
We propose a design for philanthropic or publicly-funded seeding to allow (near) optimal provision of a decentralized, self-organizing ecosystem of public goods. The concept extends ideas from Quadratic Voting to a funding mechanism for endogenous community formation. Individuals make public goods contributions to projects of value to them. The amount received by the project is (proportional to) the square of the sum of the square roots of contributions received. Under the standard model this yields first best public goods provision. Variations can limit the cost, help protect against collusion and aid coordination. We discuss applications to campaign finance, open source software ecosystems, news media finance and urban public projects. More broadly, we offer a resolution to the classic liberal-communitarian debate in political philosophy by providing neutral and non-authoritarian rules that nonetheless support collective organization.
Distributed Ledger Technology (DLT) creates a decentralized system for trust and transaction validation using executable smart contracts to update information across a distributed database. This type of ecosystem can be applied to Commodity Trade Finance to alleviate critical issues of information asymmetry and the cost of transacting which are the leading causes of the Trade Finance Gap (ie. the lack of supply of capital to meet total trade finance demand). The possibility of scaling up such ecosystems with a number of Institutional Investors and micro small medium enterprises (MSME) would be advantageous, however, it brings up its own set of challenges including the stability of the system design. Agent-based modeling (ABM) is a powerful method to assess the financial ecosystem dynamics. DLT ecosystems model well under ABM, as the agents present a clearly defined taxonomy. In this study, we use ABM to assess the Aquifer Institute Platform - a DLT-based Commodity Trade Finance system, in which a growing number of participating parties is closely related to the circulation of utility tokens and transaction flows. We study the system dynamics of the platform and propose an appropriate setup for different transaction loads.