Blockchain Papers

Lin Chen, Lei Xu, Nolan Shah, Zhimin Gao · 6 authors

No abstract is available for this record.

Shayan Eskandari, Jeremy Clark, Vignesh Sundaresan, Moe Adham

In this paper, we present Velocity, a decentralized market deployed on Ethereum for trading a custom type of derivative option. To enable the smart contract to work, we also implement a price fetching tool called PriceGeth. We present this as a case study, noting challenges in development of the system that might be of independent interest to whose working on smart contract implementations. We also apply recent academic results on the security of the Solidity smart contract language in validating our codes security. Finally, we discuss more generally the use of smart contracts in modelling financial derivatives.

James Hazard, Helena Haapio

Modern economies are held together by innumerable contracts. However, current contracts are neither machine-readable nor easily human-readable. The Ricardian Contract paradigm of parameters, prose and code posits a hybrid model of automation and conventional legal text. This paper connects recent work on design criteria for 'Smart Contract Templates' with prose objects and prototype inheritance demonstrated at CommonAccord. Templates authored and shared as prose objects can become the basis for automation, codification, commentary, big data analysis and graphic presentations.

Joost de Kruijff, Hans Weigand

No abstract is available for this record.

Henry Kim, Marek Laskowski

The blockchain constitutes a technology-based, rather than social or regulation based, means to lower uncertainty about one another in order to exchange value. However, its use may very well also lead to increased complexity resulting from having to subsume work that displaced intermediary institutions had performed. We present our perspective that smart contracts may be used to mitigate this increased complexity. We further posit that smart contracts can be delineated according to complexity: Smart contracts that can be verified objectively without much uncertainty belong in an inter- organizational context; those that cannot be objectively verified belong in an intra- organizational context. We state that smart contracts that implement a formal (e.g. mathematical or simulation) model are especially beneficial for both contexts: They can be used to express and enforce inter-organizational agreements, and their basis in a common formalism may ensure effective evaluation and comparison between different intra-organizational contracts. Finally, we present a case study of our perspective by describing Intellichain, which implements formal, agent-based simulation model as a smart contract to provide epidemiological decision support.

Daniele Magazzeni, Peter McBurney, William L. Nash

Smart contracts might encode legal contracts written in natural language to represent the contracting parties' shared understandings and intentions. The issues and research challenges involved in the validation and verification of smart contracts, particularly those running over blockchains and distributed ledgers, are explored.

Massimo Bartoletti, Livio Pompianu

Smart contracts are computer programs that can be consistently executed by a network of mutually distrusting nodes, without the arbitration of a trusted authority. Because of their resilience to tampering, smart contracts are appealing in many scenarios, especially in those which require transfers of money to respect certain agreed rules (like in financial services and in games). Over the last few years many platforms for smart contracts have been proposed, and some of them have been actually implemented and used. We study how the notion of smart contract is interpreted in some of these platforms. Focussing on the two most widespread ones, Bitcoin and Ethereum, we quantify the usage of smart contracts in relation to their application domain. We also analyse the most common programming patterns in Ethereum, where the source code of smart contracts is available.

Usman W. Chohan

The aim of this chapter is to situate blockchain-based governance tools within a public value (PV) context, arguing that public governance on the blockchain requires elements of a “public value mindset,” which is comprised of transparency, efficiency, stakeholder salience and participation, innovative thinking, decentralization, and trust. To illustrate this PV mindset, the chapter analogizes the powerful solution put forth by cryptocurrencies towards the “double spending problem,” an issue that had once plagued electronic money, by arguing that the manner in which the double-spending problem was solved by blockchain technology (as best embodied by cryptocurrencies) also offers lessons for public governance on the blockchain, specifically in terms of the PV elements enumerated above. By elucidating the nature of the double-spending problem and the revolutionary solution offered by cryptocurrencies, the chapter advocates for a similar approach in the application of blockchain technologies to public management and governance.

Alex Biryukov, Dmitry Khovratovich, Sergei Tikhomirov

No abstract is available for this record.

Sergi Delgado-Segura, Cristina Pérez‐Solà, Guillermo Navarro‐Arribas, Jordi Herrera‐Joancomartí

On-line commercial transactions involve an inherent mistrust between participant parties since, sometimes, no previous relation exists between them. Such mistrust may be a deadlock point in a trade transaction where the buyer does not want to perform the payment until the seller sends the goods and the seller does not want to do so until the buyer pays for the purchase. In this paper we present a fair protocol for data trading where the commercial deal, in terms of delivering the data and performing the payment, is atomic, since the seller cannot redeem the payment unless the buyer obtains the data and the buyer cannot obtain the data without performing the payment. The protocol is based on Bitcoin scripting language and the fairness of the protocol can be probabilistically enforced.

Okke Schrijvers, Joseph Bonneau, Dan Boneh, Tim Roughgarden

No abstract is available for this record.

Andrew Urquhart

Investor and media attention in Bitcoin has increased substantially in recently years, reflected by the incredible surge in news articles and considerable rise in the price of Bitcoin. Given the increased attention, there little is known about the behaviour of Bitcoin prices and therefore we add to the literature by studying price clustering. We find significant evidence of clustering at round numbers, with over 10% of prices ending with 00 decimals compared to other variations but there is no significant pattern of returns after the round number. We also support the negotiation hypothesis of Harris (1991) by showing that price and volume have a significant positive relationship with price clustering at whole numbers.

Evangelos Benos, Rod Garratt, Pedro Gurrola-Pérez

Distributed ledger technology (DLT) is a database architecture which enables the keeping and sharing of records in a distributed and decentralized way, while ensuring its integrity through the use of consensus-based validation protocols and cryptographic signatures. In principle, DLT has the potential to reduce costs and increase the efficiency of securities settlement, the ultimate step of every security transaction. In this paper, we first examine to what extent DLT could add value and change securities settlement. We then characterize the innovation process in the post-trade industry and finally, we describe the economics of a hypothetical DLT-based security settlement industry. Our main conclusions are that: i) DLT has the potential to improve efficiency and reduce costs in securities settlement, but the technology is still evolving and it is uncertain at this point what form, if any, a DLT-based solution for securities settlement will ultimately take, ii) technological innovation in the post-trade industry is more likely to achieve its potential with some degree of co-ordination which could be facilitated by the relevant authorities, and iii) if DLT-based securities settlement becomes a reality, then it is likely to be concentrated among few providers which, in the absence of regulation, could result in inefficient monopoly pricing or efficient price discrimination with service providers capturing much of the market surplus.

Sinclair Davidson, Primavera De Filippi, Jason Potts

Abstract Blockchains are a new digital technology that combines peer-to-peer network computing and cryptography to create an immutable decentralised public ledger. Where the ledger records money, a blockchain is a cryptocurrency, such as Bitcoin; but ledger entries can record any data structure, including property titles, identity and certification, contracts, and so on. We argue that the economics of blockchains extend beyond analysis of a new general purpose technology and its disruptive Schumpeterian consequences to the broader idea that blockchains are an institutional technology. We consider several examples of blockchain-based economic coordination and governance. We claim that blockchains are an instance of institutional evolution.

Lin William Cong, Zhiguo He, Jingtao Zheng

Blockchain technology provides decentralized consensus and potentially enlarges the contracting space through smart contracts. Meanwhile, generating decentralized consensus entails distributing information that necessarily alters the informational environment. We analyze how decentralization relates to consensus quality and how the quintessential features of blockchain remold the landscape of competition. Smart contracts can mitigate informational asymmetry and improve welfare and consumer surplus through enhanced entry and competition, yet distributing information during consensus generation may encourage greater collusion. In general, blockchains sustain market equilibria with a wider range of economic outcomes. We further discuss the implications for antitrust policies targeted at blockchain applications. Received May 31, 2017; editorial decision May 29, 2018 by Editor Itay Goldstein.

Peter R. Rizun

Orphan risk for large blocks limits Bitcoin’s transactional capacity while the lack of secure instant transactions restricts its usability. Progress on either front would help spur adoption. This paper considers a technique for using fractional-difficulty blocks (weak blocks) to build subchains bridging adjacent pairs of real blocks. Subchains reduce orphan risk by propagating blocks layer-by-layer over the entire block interval, rather than all at once when the proof-of-work is solved. Each new layer of transactions helps to secure the transactions included in lower layers, even though none of the transactions have been con-firmed in a real block. Miners are incentivized to cooperate building subchains in order to process more transactions per second (thereby claiming more fee revenue) without incur-ring additional orphan risk. The use of subchains also diverts fee revenue towards network hash power rather than dripping it out of the system to pay for orphaned blocks. By nesting subchains, weak block verification times approaching the theoretical limits imposed by speed-of-light constraints would become possible with future technology improvements. As subchains are built on top of the existing Bitcoin protocol, their implementation does not require any changes to Bitcoin’s consensus rules.

Biling Zhang, Chunxiao Jiang, Jung-Lang Yu, Zhu Han

Direct trading is a promising approach to simultaneously achieve trading benefits and reduce transmission line losses in smart grid. However, due to the selfish nature, small-scale electricity suppliers (SESs) and electricity consumers (ECs) will not participate direct trading if the trading does not bring them benefits. Therefore, how to provide proper economic incentives for these two parties to take part in direct trading is an essential issue. Nevertheless, the asymmetry trading information between them makes the problem challenging. In this paper, we propose a contract-based direct trading framework to tackle this challenge, in which the decision making process of ECs and SESs in the presence of asymmetric information is modeled as a contract game. In the proposed game, the EC designs a contract which contains its trading strategies toward all types of SESs. Through the contract, the EC not only attracts SESs to sell electricity but also maximizes its own revenue. The SESs, on the other hand, get maximal benefits if they truthfully select the contract items of their own types. We derive theoretically the optimal contract for the short-term market where the supply of SESs is deterministic. Then we extend our study to the long-term market where the supply of SESs is encountering significant uncertainty. Finally, simulation results are shown to verify the effectiveness of the proposed scheme.

Miles Carlsten, Harry Kalodner, S. Matthew Weinberg, Arvind Narayanan

Bitcoin provides two incentives for miners: block rewards and transaction fees. The former accounts for the vast majority of miner revenues at the beginning of the system, but it is expected to transition to the latter as the block rewards dwindle. There has been an implicit belief that whether miners are paid by block rewards or transaction fees does not affect the security of the block chain.

Christopher Frantz, Mariusz Nowostawski

Blockchain technology has emerged as a solution to consistency problems in peer to peer networks. By now, it has matured as a solution to a range of use cases in which it can effectively provide the notion of third party trust without the need for a trusted (physical) third party, which makes it an attractive coordination mechanism for distributed systems. To promote the wide adoption of this technology, we yet lack mechanisms that make the specification and interpretation of smart contracts accessible to a broader audience. In this work, we propose a modeling approach that supports the semi-automated translation of human-readable contract representations into computational equivalents in order to enable the codification of laws into verifiable and enforceable computational structures that reside within a public blockchain. We identify smart contract components that correspond to real world institutions, and propose a mapping that we operationalize using a domain-specific language in order to support the contract modeling process. We explore this capability based on selected examples and plot out directions for future research on smart contracts.

Sungwook Kim

Abstract Bitcoin is a digital cryptocurrency that has generated considerable public interests through a fully decentralised network with an inherently independence from governments or any central authorities. Although its short history has been volatile, the Bitcoin maintains a core group of committed users. In this study, we look at the Bitcoin complex structure and design a new Bitcoin mining protocol while developing a novel incentive payment process. To effectively implement an incentive payment mechanism, we adopt the concept of the group bargaining solution by considering a peer‐to‐peer relationship, and it is practically applied to a distributed computation network system. Based on the cooperative game model, we explore an efficient solution that can maximise Bitcoin users' rewards. Through system level simulations, the proposed scheme is evaluated and compared with other existing schemes. The simulation results show that our group bargaining game approach outperforms the existing Bitcoin schemes in providing a better fair‐efficient system performance. Copyright © 2016 John Wiley & Sons, Ltd.

Aggelos Kiayias, Ηλίας Κουτσουπιάς, Maria Kyropoulou, Yiannis Tselekounis

We study the strategic considerations of miners participating in the bitcoin's protocol. We formulate and study the stochastic game that underlies these strategic considerations. The miners collectively build a tree of blocks, and they are paid when they create a node (mine a block) which will end up in the path of the tree that is adopted by all. Since the miners can hide newly mined nodes, they play a game with incomplete information. Here we consider two simplified forms of this game in which the miners have complete information. In the simplest game the miners release every mined block immediately, but are strategic on which blocks to mine. In the second more complicated game, when a block is mined it is announced immediately, but it may not be released so that other miners cannot continue mining from it. A miner not only decides which blocks to mine, but also when to release blocks to other miners. In both games, we show that when the computational power of each miner is relatively small, their best response matches the expected behavior of the bitcoin designer. However, when the computational power of a miner is large, he deviates from the expected behavior, and other Nash equilibria arise.

Luke Anderson, Ralph Holz, Alexander Ponomarev, Paul Rimba · 5 authors

Half a decade after Bitcoin became the first widely used cryptocurrency, blockchains are receiving considerable interest from industry and the research community. Modern blockchains feature services such as name registration and smart contracts. Some employ new forms of consensus, such as proof-of-stake instead of proof-of-work. However, these blockchains are so far relatively poorly investigated, despite the fact that they move considerable assets. In this paper, we explore three representative, modern blockchains---Ethereum, Namecoin, and Peercoin. Our focus is on the features that set them apart from the pure currency use case of Bitcoin. We investigate the blockchains' activity in terms of transactions and usage patterns, identifying some curiosities in the process. For Ethereum, we are mostly interested in the smart contract functionality it offers. We also carry out a brief analysis of issues that are introduced by negligent design of smart contracts. In the case of Namecoin, our focus is how the name registration is used and has developed over time. For Peercoin, we are interested in the use of proof-of-stake, as this consensus algorithm is poorly understood yet used to move considerable value. Finally, we relate the above to the fundamental characteristics of the underlying peer-to-peer networks. We present a crawler for Ethereum and give statistics on the network size. For Peercoin and Namecoin, we identify the relatively small size of the networks and the weak bootstrapping process.

Percy Venegas

No abstract is available for this record.

Menelaos Makriyiannis, Tudor Lung, Robert Craven, Francesca Toni · 5 authors

No abstract is available for this record.