Blockchain Papers

Jean-Luc Verhelst

Brussels Area, Belgium<br>

Chinmay Patel

BlockX Labs, Toronto, ON, Canada

Bogdan Derevyanko, Olha Turkot

In Ukraine, the cryptocurrency is viewed as a monetary surrogate. In many countries of the world, operations with cryptocurrency are more or less permitted. You can name countries such as Australia, Austria, Bulgaria, Brazil, Israel, Canada, China, Norway, Singapore, USA, Thailand, Germany, Croatia, Switzerland, Japan and others. On the basis of objective analysis and the study of examples from foreign experience, the legal regime of operations with the cryptocurrency is proposed to equalize with the legal regime of operations with foreign currency; legalize the mining of the cryptocurrency as a type of economic activity, introduce its licensing and taxation of income from it. Citizens of Ukraine are not forbidden to keep savings in foreign currency and exchange foreign currency for hryvnia and other foreign currency. Ukrainians can not receive wages or any remuneration in foreign currency on the territory of Ukraine, but they can earn or win foreign currency on the Internet. The same regime should receive cryptocurrency. And operations on mining of cryptocurrency should be licensed as highly profitable and requiring a special knowledge and skills type of economic activity. Applying income tax to miners is offered on general terms. Three ways of determining the amount of taxes are proposed: 1) granting access to representatives of the fiscal body to the computer program and purses of the cryptocurrency; 2) through the calculation by the representatives of the fiscal body of the average monthly volume of production of units of crypto currency for a certain equipment and, accordingly, in proportion to it, the amount of tax; 3) in proportion to the amount of electricity spent. The last two look the most real. In the case of taxation of operations on «mining» of cryptocurrencies, the state through the amount of electricity consumed can identify and control miners. It is concluded that the legalization of the state of the budget. REFERENCES Derevianko B.V. Ryzyky zdiisnennia operatsii z kryptovaliutoiu (bitkoinamy) hromadian i subiektiv hospodariuvannia Ukrainy. Forum prava. 2017. No. 3: 33—39. URL: http://nbuv.gov.ua/j-pdf/FP_index.htm_2017_3_8.pdf [in Ukrainian]. Protsenko A.T. Pravove rehuliuvannia obihu elektronnykh hroshei v Ukraini: dys. ... kand. yuryd. nauk : 12.00.07. K., 2016 [in Ukrainian]. Vyshnevska A.O. Rol kryptovaliuty dlia informatsiinoi ekonomiky Ukrainy ta svitu. Zbirnyk naukovykh prats Cherkaskoho derzhavnoho tekhnolohichnoho universytetu. Ser. Ekonomichni nauky. 2017. No. 47: 13—17 [in Ukrainian]. Halushka Ye.O. Sutnist kryptovaliut ta perspektyvy yikh rozvytku. Molodyi vchenyi. 2017. № 4 (44): 634—638 [in Ukrainian]. Petruk O.M., Novak O.S. Sutnist kryptovaliuty yak metodolohichna peredumova yii oblikovoho vidobrazhennia. Visnyk ZhDTU. Ser. "Ekonomichni nauky". 2017. No. 4 (82): 48—55 [in Ukrainian]. Sokhatska O., Kurant T. Kryptovaliuty: zasib platezhu chy investytsiinyi instrument? Pershi naukovi chytannia pamiati S.I. Yuriia: zbirnyk nauk. prats. Za red. d.e.n., prof. O.P. Kyrylenko (26.11.2015. m. Ternopil). Ternopil: TNEU, 2015. S. 42—47 [in Ukrainian]. Yatskiv N.H., Yatskiv S.V. Perspektyvy vykorystannia tekhnolohii blokchein u merezhi internet rechei. Naukovyi visnyk NLTU Ukrainy. 2016. Vypusk 26.8: 381—387 [in Ukrainian]. Pro Natsionalnyi bank Ukrainy: Zakon Ukrainy vid 20.05.1996 No. 679-XIV. Vidomosti Verkhovnoi Rady Ukrainy. 1999. No. 29. St. 238 [in Ukrainian]. Pro platizhni systemy ta perekaz koshtiv v Ukraini: Zakon Ukrainy vid 05.04..2001 № 2346-III. Vidomosti Verkhovnoi Rady Ukrainy. 2001. No. 29. St. 137 [in Ukrainian]. Roziasnennia shchodo pravomirnosti vykorystannia v Ukraini “virtualnoi valiuty/kryptovaliuty” Bitcoin: Roziasnennia Natsionalnoho banku Ukrainy vid 10.11.2014. Ofitsiinyi sait Natsionalnoho banku Ukrainy. URL: https://www.bank.gov.ua/control/uk/publish/article?art_id=11879608 [in Ukrainian]. Konstytutsiia Ukrainy vid 28.06.1996 No. 254k/96-VR. Vidomosti Verkhovnoi Rady Ukrainy. 1996. No. 30. St. 141 [in Ukrainian]. Tsyvilnyi kodeks Ukrainy: Zakon Ukrainy vid 16.01.2003 No. 435—IV. Vidomosti Verkhovnoi Rady Ukrainy. 2003. No. 40—44. St. 356 [in Ukrainian]. Pro systemu valiutnoho rehuliuvannia i valiutnoho kontroliu: Dekret Kabinetu Ministriv Ukrainy vid 19.02.1993 No. 15— 93. Vidomosti Verkhovnoi Rady Ukrainy. 1993. No. 17. St. 184 [in Ukrainian]. Pro litsenzuvannia vydiv hospodarskoi diialnosti: Zakon Ukrainy vid 02.03.2015 No. 222-VIII. Vidomosti Verkhovnoi Rady Ukrainy. 2015. No. 23. St. 158 [in Ukrainian]. Pro zatverdzhennia pereliku orhaniv litsenzuvannia ta vyznannia takymy, shcho vtratyly chynnist, deiakykh postanov Kabinetu Ministriv Ukrainy: Postanova Kabinetu Ministriv Ukrainy vid 05.08.2015 No. 609. URL: http://zakon5.rada.gov.ua/laws/show/609-2015-%D0%BF [in Ukrainian]. Podatkovyi kodeks Ukrainy vid 02.12.2010 No. 2755-VI. Vidomosti Verkhovnoi Rady Ukrainy. 2011. No. 13—14, 15—16, 17. St. 112 [in Ukrainian]. Kryminalnyi kodeks Ukrainy vid 05.04.2001 No. 2341-III. Vidomosti Verkhovnoi Rady Ukrainy. 2001. No. 25—26. St. 131 [in Ukrainian]. Kodeks Ukrainy pro administratyvni pravoporushennia vid 07.12.1984 No. 8073-X. Vidomosti Verkhovnoi Rady Ukrainskoi RSR. 1984. Dodatok do No. 51. St. 1122 [in Ukrainian].

V.A. Ustymenko, N.Yu. Polishchuk

The development of information technologies is accelerated in the modern world. The digitization of socio-economic relations is carried out on the basis of peer-to-peer blockchain technology. Bitcoin is a cryptographic protocol. The article shows that, to date, there is no common understanding of Cryptocurrency, in some sources they are treated as currency and other goods or raw materials in other. At this moment, cryptocurrency in Ukraine is not regulated at all. This article discusses the potential legal classification of Bitcoin and the consequences thereto. Bitcoin has been, and continues to be, used by some for the purchase of illegal substances and in furtherance of crimes. Nonetheless, Bitcoin possesses significant economic upside over traditional currencies and methods of transaction online. The National Bank of Ukraine (NBU) has not yet recognized bitcoin or other encrypted currencies. Several bills to regulate encrypted money have been submitted, but none has yet been passed. The Ukrainian parliament has been actively trying to find a solution for creating a legislative and regulatory framework specific to the cryptocurrency industry. Ukrainian draft laws give their own definition of crypto-currency, mining and other specific terms; stipulate those who have the right to engage in mining, how the activities of exchanges are regulated, and the attendant moments, such as legal responsibility and specific taxation. Yet, the proposed legislation has not yet been passed into the law. Ukraine should monitor world trends and not miss a chance to use new technologies and innovations in the financial sector. On the basis of the analysis of domestic and foreign practices, a number of non-regulated by Ukrainian law of the creation and circulation of cryptocurrencies have been identified by the law of Ukraine, proposed ways of resolving issues of determining their legal nature and legal regulation. The situation regarding the definition of legal status of cryptographic goods in foreign countries and Ukraine is analyzed. The main points to be solved in the course of approval of the right regulation of cryptocurrencies in Ukraine are determined. REFERENCES Liashenko V.I., Vyshnevskyi O.S. Tsyfrova modernizatsiia ekonomiky Ukrainy yak mozhlyvist proryvnoho rozvytku: monohrafiia. Kyiv, 2018 [in Ukrainian]. Cryptocurrency Market Capitalizations. Top 100 Cryptocurrencies by Market Capitalization. URL: https://coinmarketcap.com Ponsford M.A Comparative Analysis of Bitcoin and Other Decentralised Virtual Currencies: Legal Regulation in the People’s Republic of China, Canada, and the United States. Hong Kong Journal of Legal Studies. 2015. Vol. 9. URL: http://ssrn.com/abstract=2554186 Kryptovaliuta: Zibraty po kryptakh. Kryptofakhivtsi roziasniuiut yurystam znachennia naiposhyrenishykh sliv “latyny maibutnoho” kryptomovy. Za materialamy vydannia “Ukrainskyi Yuryst”. URL: http://axon.partners/uk/blog/cryproalphabet/ [in Ukrainian]. Nermin Hajdarbegovic. Japan Makes First Bitcoin-Related Drug Arrest. Coindesk. May 9, 2014. URL: . https://www.coindesk.com/japan-makes-first-bitcoin-related-drug-arrest Pravove rehuliuvannia kryptovaliutnoho biznesu. Axon Partners, ForkLog Research. URL: http://axon.partners/wpcontent/uploads/2017/02/Global-Issues-of-Bitcoin-Businesses-Regulation.pdf [in Ukrainian]. The Federal Reserve System’s semiannual monetary policy report to the Congress. The U.S. Government Printing Office. September 17, 2015. URL: http://www.cftc.gov/PressRoom/PressReleases/pr7231-15 Directive 2009/110/EC of the European Parliament and of the Council of 16 September 2009 on the taking up, pursuit and prudential supervision of the business of electronic money institutions amending Directives 2005/60/EC and 2006/48/EC and repealing Directive 2000/46/EC (Text with EEA relevance). Official Journal of the European Union. L 267. 10.10.2009. P. 7—17. Court of Justice of the European Union PRESS RELEASE No 128/15. URL: https://curia.europa.eu/jcms/upload/docs/application/pdf/2015-10/cp150128en.pdf O razvitii tsifrovoy ekonomiki: Dekret Prezidenta Respubliki Belorus ot 21.12.2017 No. 8. URL: http://president.gov.by/ru/official_documents_ru/view/dekret-8-ot-21-dekabrja-2017-g-17716/ [in Russian]. V instytuti Patona pratsiuvala nezakonna fabryka Bitcoin. Informatsiinyi Aktsent. URL: https://www.infa.ua/v-insty-tutipatona-pratsyuvala-nezakonna-fabry-ka-bitcoin/ [in Ukrainian]. Prokuratura y SBU vyluchyly v Kyievi 400 bitkoin-ferm. Informatsiinyi Aktsent. URL: https://www.infa.ua/v-insty-tutipatona-pratsyuvala-nezakonna-fabry-ka-bitcoin/ [in Ukrainian]. Pro obih kryptovaliuty v Ukraini: proekt Zakonu Ukrainy vid 06.10.2017 No. 7183. URL: http://w1.c1.rada.gov.ua/pls/zweb2/webproc4_1?pf3511=62684 [in Ukrainian]. Pro stymuliuvannia rynku kryptovaliut ta yikh pokhidnykh v Ukraini: proekt Zakonu Ukrainy vid 10.10.2017 No. 7183-1. URL: http://w1.c1.rada.gov.ua/pls/zweb2/webproc4_1?pf3511=62710 [in Ukrainian].

David Meijer, Jolien Ubacht

Blockchain Technology is considered as a general-purpose technology with far reaching effects. As can be seen from the discussions on blockchain applications, both practitioners and researchers struggle to get to the core of blockchain technology consequences. Especially practitioners in the governmental sector explore adequate responses to this new technology. Therefore, our aim is to provide a conceptualization of the consequences of blockchain systems from an institutional perspective, and to use this conceptualization to provide insights into the governance of blockchain systems.

Jannice Käll

Blockchain technology is often discussed and theorized in relation to cryptocurrencies such as Bitcoin. Its quality as a technology that produces advanced encryption keys between objects, however, also makes it interesting to those who seek to connect physical objects to digital elements. The reason for this is that the link between objects needs to be ‘secure’ from undesired external interference. In relation to such interests, blockchain has been identified as a highly attractive technology to support the general digitalization of society towards the Internet of Things, smart cities etc. In extension, the implementation of blockchain technology implies that it may work as a tool that has the capacity to direct which objects may/may not interact with each other. The ‘ledger of everything’ that blockchain may possibly produce as regards the ‘Internet of Everything’ is even suggested to make humans and other intermediary technologies redundant. In this essay, I argue that in order to sustain legal critique when the world moves into the next era of digitalization, we need to understand - and question - how technological control operates through e.g. blockchain technology by locking physical and digital elements to each other.

Konny Light

No abstract is available for this record.

Lingjun Fan, J. Ramón Gil-García, Derek Werthmuller, Geraldine Burke · 5 authors

This poster describes an ongoing research project that builds an IoT data management experimental environment based on Ethereum Blockchain and smart contracts. The goal of the project is to simulate the application of IoT devices in smart city initiatives, and explore how IoT data management could benefit from Blockchain technology. In this project, there are three basic questions we are attempting to answer. 1) How do you link various kinds of IoT devices to the Blockchain, as they have different computing capabilities? 2) How do you store data on Blockchain from different IoT devices, and retrieve data for further utilization? 3) To what extent, smart contracts can be designed to implement automated data access management?

Svein Ølnes, Arild Jansen

The blockchain technology has evolved beyond traditional payment solutions in the finance sector and offers a potential for transforming many sectors including the public sector. The novel integration of technology and economy that open public block-chains have brought represents both challenges to and opportunities for enhancing digital public services. So far, the public sector has lagged behind other sectors in both research and exploration of this technology, but pilot cases show that there is a great potential for reforming and even transforming public service delivery.

Mohd Hwaidi

Nottingham Trent University, Nottingham Law School, Chaucer 5010, Goldsmith Street, Nottingham, NG1 5LP, United Kingdom.

Lemuria Carter, Jolien Ubacht

In the past few years, researchers and practitioners have highlighted the potential of Blockchain (BC) and distributed ledger technology to revolutionize government processes. Blockchain technology enables distributed power and embedded security. As such, Blockchain is regarded as an innovative, general purpose technology, offering new ways of organization in many domains, including e-government for transactions and information exchange. However, due to its very characteristics of peer to peer information exchange, its distributed nature, the still developing technology, the involvement of new actors, roles, etc., the implementation of blockchain applications raise issues that need governance attention. BC initiatives have implications for citizen trust, privacy, inclusion and participation. Governmental organizations need a thorough understanding of the BC design principles, the possible applications in the domain of e-government and the exploration of governance mechanisms to deal with the limitations and challenges of the BC technology when used in a myriad of sectors, ranging from the financial and business sector to the social domains of healthcare and education. In this panel we explore the impact of block chain technology on all levels of government and create an awareness of effects or applications in society that raise governance issues.

Peter Seele

No abstract is available for this record.

Rodrigo Couto de Souza, Edimara Mezzomo Luciano, Guilherme Costa Wiedenhöft

The increasing demands for more transparency in public administration worldwide ask for open data, and the establishing of other mechanisms as well as keep using the contributions of new technologies to increment the management capacity, focusing on better controls and governance mechanisms. One of the new technologies that presents potential to be used to protect organizations from corruption is Blockchain. An important point when dealing with corruption perpetrated by frauds is the use of technology to avoid wrongdoing or to reduce its impact. Contracts are a very complex subject provided they are the main way governments transfer money to other organizations, including private ones. This document presents a study proposal about the use of Smart Contracts technology in Blockchain environments as a way to face corruption in governmental instances. Smart Contracts can be used to all government payments as a way to increase transactions transparency, as well as to avoid overbilling, provided that contracts and bids are typical ways to exert frauds and money misappropriation. As future researches it is important to verify barriers to Blockchain adoption as well as its main vulnerabilities.

Shahar Somin, Goren Gordon, Yaniv Altshuler

Blockchain technology, which has been known by mostly small technological circles up until recently, is bursting throughout the globe, with a potential economic and social impact that could fundamentally alter traditional financial and social structures. Issuing cryptocurrencies on top of the Blockchain system by startups and private sector companies is becoming a ubiquitous phenomenon, inducing the trading of these crypto-coins among their holders using dedicated exchanges. Apart from being a trading ledger for tokens, Blockchain can also be observed as a social network. Analyzing and modeling the dynamics of the "social signals" of this network can contribute to our understanding of this ecosystem and the forces acting within in. This work is the first analysis of the network properties of the ERC20 protocol compliant crypto-coins' trading data. Considering all trading wallets as a network's nodes, and constructing its edges using buy--sell trades, we can analyze the network properties of the ERC20 network. Examining several periods of time, and several data aggregation variants, we demonstrate that the network displays strong power-law properties. These results coincide with current network theory expectations, however nonetheless, are the first scientific validation of it, for the ERC20 trading data. The data we examined is composed of over 30 million ERC20 tokens trades, performed by over 6.8 million unique wallets, lapsing over a two years period between February 2016 and February 2018.

Fakhruddin Rizal Batubara, Jolien Ubacht, Marijn Janssen

The ability of blockchain technology to record transactions on distributed ledgers offers new opportunities for governments to improve transparency, prevent fraud, and establish trust in the public sector. However, blockchain adoption and use in the context of e-Government is rather unexplored in academic literature. In this paper, we systematically review relevant research to understand the current research topics, challenges and future directions regarding blockchain adoption for e-Government. The results show that the adoption of blockchain-based applications in e-Government is still very limited and there is a lack of empirical evidence. The main challenges faced in blockchain adoption are predominantly presented as technological aspects such as security, scalability and flexibility. From an organizational point of view, the issues of acceptability and the need of new governance models are presented as the main barriers to adoption. Moreover, the lack of legal and regulatory support is identified as the main environmental barrier of adoption. Based on the challenges presented in the literature, we propose future research questions that need to be addressed to inform how the public sector should approach the blockchain technology adoption.

Parth Thakkar, Senthil Nathan, Balaji Vishwanathan

The rise in popularity of permissioned blockchain platforms in recent time is significant. Hyperledger Fabric is one such permissioned blockchain platform and one of the Hyperledger projects hosted by the Linux Foundation. The Fabric comprises various components such as smart-contracts, endorsers, committers, validators, and orderers. As the performance of blockchain platform is a major concern for enterprise applications, in this work, we perform a comprehensive empirical study to characterize the performance of Hyperledger Fabric and identify potential performance bottlenecks to gain a better understanding of the system. We follow a two-phased approach. In the first phase, our goal is to understand the impact of various configuration parameters such as block size, endorsement policy, channels, resource allocation, state database choice on the transaction throughput & latency to provide various guidelines on configuring these parameters. In addition, we also aim to identify performance bottlenecks and hotspots. We observed that (1) endorsement policy verification, (2) sequential policy validation of transactions in a block, and (3) state validation and commit (with CouchDB) were the three major bottlenecks. In the second phase, we focus on optimizing Hyperledger Fabric v1.0 based on our observations. We introduced and studied various simple optimizations such as aggressive caching for endorsement policy verification in the cryptography component (3x improvement in the performance) and parallelizing endorsement policy verification (7x improvement). Further, we enhanced and measured the effect of an existing bulk read/write optimization for CouchDB during state validation & commit phase (2.5x improvement). By combining all three optimizations1, we improved the overall throughput by 16x (i.e., from 140 tps to 2250 tps).

Xin Sun, Quanlong Wang, Piotr Kulicki, Mirek Sopek

This paper proposes a simple voting protocol based on Quantum Blockchain. Despite its simplicity, our protocol satisfies the most important properties of secure voting protocols: is anonymous, binding, non-reusable, verifiable, eligible, fair and self-tallying. The protocol could also be implemented using presently available technology.

Melanie Swan

This paper articulates the notion of the cryptocitizen who thinks freely of the traditional dictates of authority. The analysis looks beyond the immediate economic benefits and risks of blockchain technology to consider the broader implications for the individual and society. The possibility of creating and participating in different and multiple self-determined political and economic systems could mobilize how we instantiate ourselves as individuals and societies. Blockchain technology invites the possibility of making a social world with greater prominence of the values we apparently care about: freedom, trust, and dignity. There is a need for social structures that ensure and promote coexistence among diverse individuals and groups, particularly looking ahead to the possibilities of machine intelligence and space settlement. The hidden novelty and benefit of blockchain technology is serving as a tool for the design of smart city cryptopolises and cryptocitizen social structures. The bigger stakes of blockchain technology are the possibility of having new modes of social organization.

Rim K. Nurmukhametov, P.D. Stepanov, National Settlement Depository, T.R. Novikova

Ключевые слова:

Angelique Faye Loe, Elizabeth A. Quaglia

Proof of Work systems are used in cryptocurrencies to obtain consensus in distributed peer-to-peer systems that share no trust. Miners of cryptocurrency compete by engaging in the Proof of Work to solve a cryptographic challenge. The first to successfully provide a solution to the challenge wins by minting new currency. The process of mining also simultaneously prevents double-spending through the creation of an append-only distributed database known as the blockchain. The most widely adopted Proof of Work is the Hashcash scheme and the most widely deployed miners are ASIC-based. Despite the popularity of Hashcash, two issues are commonly identified its use. Firstly, the high energy consumption of the scheme is perceived as wasteful because the solutions found provide no useful output, and secondly, the computational complexity class of the scheme is not formally known. Based on these deficiencies, we propose a novel Proof of Work system which achieves the following goals:

Arnaud Durand, Pascal Gremaud, Jacques Pasquier

Low power communication is a major milestone for the Internet of Things (IoT). Low-Power Wide-Area Network (LPWAN) technologies seek to provide a large coverage area and long battery life at the cost of a reduced bandwidth compared to traditional networks. Commercially-available LPWAN solutions typically involve the usage of a wireless infrastructure from a network provider; with the notable exception of crowd-sourced networks, which use gateways from other users for wireless communication to end-devices. In this paper, we analyse the feasability of a fully decentralized LPWAN infrastructure and build a working prototype based on the LoRaWAN protocol.

Mandava Geetha Bhargava, Duvvada Rajeswara Rao

Sentimental Analysis is an ongoing research field in Text Mining Arena to determine the situation of market on particular entity such as Product, Services...Etc. and it can be called as computational treatment of reviews, subjectivity and sentiment of text. Cryptocurrency can be explained as a type of digital estate and devised to mechanize as a form of trade and exchanges that uses cryptography as an encryption technique to secure the transactions and acts as decentralized controlled transaction which is opposed to centralized transactions. Cryptocurrency are a type of virtual currency, digital currency and alternative currency, On basis of categorical, there are different architecture and security protocols which are used in the cryptocurrencies to secure transactions, the different types of cryptocurrency are available in the market such as Bitcoin, Litecoin, and Namecoin…etc. This paper focuses on survey on different types of sentimental analysis methods and main contribution of this paper include sentimental analysis of social media data on different types of cryptocurrencies on basis of categorical and different terms of cryptocurrency such as Cryptocurrency, virtual currency, digital currency and discussed on trends of crypto currency in present market.

Antonio Tenorio-Fornés, Samer Hassan, Juán Pavón

In recent years, the increasing concerns around the centralized cloud web services (e.g. privacy, governance, surveillance, security) have triggered the emergence of new distributed technologies, such as IPFS or the Blockchain. These innovations have tackled technical challenges that were unresolved until their appearance. Existing models of peer-to-peer systems need a revision to cover the spectrum of potential systems that can be now implemented as peer-to-peer systems. This work presents a framework to build these systems. It uses an agent-oriented approach in an open environment where agents have only partial information of the system data. The proposal covers data access, data discovery and data trust in peer-to-peer systems where different actors may interact. Moreover, the framework proposes a distributed architecture for these open systems, and provides guidelines to decide in which cases Blockchain technology may be required, or when other technologies may be sufficient.

Paul Ezhilchelvan, Amjad Aldweesh, Aad van Moorsel

Summary The two‐phase commit (2PC) protocol has long been known to have a provably inevitable vulnerability to blocking or non‐progress amidst server crashes, even when the distributed database system guarantees the most demanding timing‐related or “synchrony” requirements. Our aim here is to eliminate this vulnerability by using a blockchain for coordinating 2PC execution. We present the impossibilities, the possibilities, the cost, and the trade‐offs in this blockchain‐based approach to blocking‐free management of distributed transactions. We prove that a non‐blocking and blockchain‐coordinated 2PC protocol can exist only if both the blockchain and distributed database systems meet synchrony requirements; otherwise, although blocking remains eliminated, transactions can unnecessarily abort. We present a blockchain‐coordinated 2PC protocol and provide rigorous arguments for its correctness under the synchrony requirements. We then implement this protocol on the Ethereum Testnet and demonstrate, through our experiments, that the monetary cost of executing smart contracts is quite small, that the protocol performance slows down when using a public blockchain like Ethereum, and that even major violations of synchrony requirements lead only to relatively small increases in unnecessary aborts. We thus identify a trade‐off between improving protocol performance and admitting a risk that transactions could occasionally abort unnecessarily.