Transactions between individuals have always been a part and parcel of human society for the division of labour made people interdependent. The medium of transaction has also been evolving along with the evolution of society and human consciousness from barter system to commodity money to fiat currency and now to digital currency or cryptocurrency. But since evolution is a form of error correction, the problem of double spending in digital currency was solved by a distributed ledger system called Blockchain. Since 2008 onwards the blockchain technology has been separated from bitcoins to be injected to many other problems related especially to banking transactions. Blockchain technology enables the creation of decentralized currencies, smart contracts and intelligent assets that can be controlled over the Internet
Abstract Blockchains are distributed data structures that are used to achieve consensus in systems for cryptocurrencies (like Bitcoin) or smart contracts (like Ethereum). Although blockchains gained a lot of popularity recently, there are only few logic-based models for blockchains available. We introduce $\mathsf{BCL}$, a dynamic logic to reason about blockchain updates, and show that $\mathsf{BCL}$ is sound and complete with respect to a simple blockchain model.
Robert Norvill, Beltrán Borja Fiz Pontiveros, Radu State, Irfan Awan · 5 authors
Smart contracts have recently attracted interest from diverse fields including law and finance. Ethereum in particular has grown rapidly to accommodate an entire ecosystem of contracts which run using its own crypto-currency. Smart contract developers can opt to verify their contracts so that any user can inspect and audit the code before executing the contract. However, the huge numbers of deployed smart contracts and the lack of supporting tools for the analysis of smart contracts makes it very challenging to get insights into this eco-environment, where code gets executed through transactions performing value transfer of a crypto-currency. We address this problem and report on the use of unsupervised clustering techniques and a seed set of verified contracts, in this work we propose a framework to group together similar contracts within the Ethereum network using only the contracts publicly available compiled code. We report qualitative and quantitative results on a dataset and provide the dataset and project code to the research community.
Článek se zabývá možností uzavření smluv formou kódu (algoritmu) zapsaného v rámci blockchainové databáze. Tyto smlouvy jsou označovány jako smart contract, i když samotný pojem smart contract byl poprvé použit již v roce 1997 na začátku internetové éry před blockchainem pro smlouvy samostatně vykonávající smluvní závazek skrze hardware či software. Blockchainová technologie dokázala překlenout některé nedostatky tehdejšího řešení a je předvídáno možné masovější využití možnosti uzavírání smluv touto formou. Cílem článku je nalézt odpověď, zda lze v rámci českého právního prostředí uzavřít smlouvu formou kódu a nastínit možné výzvy, které z této technologické možnosti mohou vyplývat v perspektivě českého práva.
This chapter looks beyond the novelty of self-executing ‘smart contracts’ in blockchain networks and explores developments against the background fact that commercial parties have, for centuries, used documentary credit to simulate autonomous performance. Blockchain-based smart contracts and documentary credit share three core functionalities which are essential to any effective autonomous performance, analogue or digital—they both (i) act through internalized media of exchange; (ii) operate as closed systems; and (iii) provide means of securing sufficient resources to guarantee contractual performance. Using these three functionalities as a framework, this chapter conducts a comparative analysis of mechanisms for effecting autonomous contractual performance in a commercial setting. From this comparison, a few hypotheses are drawn regarding the potential areas where smart contract technology is more likely to find fruitful application. In particular, the chapter considers potential limitations to applying smart contracts to scenarios beyond digital asset transfers, how dispute resolution mechanisms should be designed to complement (rather impair) the autonomous nature of contractual performance under smart contracts, and potential capital cost implications which might arise in some cases when parties seek to replace human intermediaries with smart contracts.
Peng Zhang, Jules White, Douglas C. Schmidt, Gunther Lenz
Since the inception of the Bitcoin technology, its underlying data structure--the blockchain--has garnered much attention due to properties such as decentralization, transparency, and immutability. These properties make blockchains suitable for apps that require disintermediation through trustless exchange, consistent and incorruptible transaction records, and operational models beyond cryptocurrency. In particular, blockchain and its smart contract capabilities have the potential to address healthcare interoperability issues, such as enabling effective interactions between users and medical applications, delivering patient data securely to a variety of organizations and devices, and improving the overall efficiency of medical practice workflow. Despite the interest in using blockchain for healthcare interoperability, however, little information is available on the concrete architectural styles and patterns for applying blockchain to healthcare apps. This paper provides an initial step in filling this gap by showing: (1) the features and implementation challenges in healthcare interoperability, (2) an end-to-end case study of a blockchain-based healthcare app we are developing, and (3) how applying foundational software patterns can help address common interoperability challenges faced by blockchain-based healthcare apps.
Thomas Lundqvist, Andreas de Blanche, H. Robert H. Andersson
Thing-to-thing payments are a key enabler in the Internet of Things (IoT) era, to ubiquitously allow for devices to pay each other for services without any human interaction. Traditional credit card-based systems are not able to handle this new paradigm, however blockchain technology is a promising payment candidate in this context. The prominent example of blockchain technology is Bitcoin, with its decentralized structure and ease of account creation. This paper presents a proof-of-concept implementation of a smart cable that connects to a smart socket and without any human interaction pays for electricity. In this paper, we identify several obstacles for the widespread use of bitcoins in thing-to-thing payments. A critical problem is the high transaction fees in the Bitcoin network when doing micro transactions. To reduce this impact, we present a single-fee micro-payment protocol that aggregates multiple smaller payments incrementally into one larger transaction needing only one transaction fee. The proof-of concept shows that trustless, autonomous, and ubiquitous thing-to-thing micro-payments is no longer a future technology.
Tareq Ahram, Arman Sargolzaei, Saman Sargolzaei, Jeff Daniels · 5 authors
Digital world has produced efficiencies, new innovative products, and close customer relationships globally by the effective use of mobile, IoT (Internet of Things), social media, analytics and cloud technology to generate models for better decisions. Blockchain is recently introduced and revolutionizing the digital world bringing a new perspective to security, resiliency and efficiency of systems. While initially popularized by Bitcoin, Blockchain is much more than a foundation for crypto currency. It offers a secure way to exchange any kind of good, service, or transaction. Industrial growth increasingly depends on trusted partnerships; but increasing regulation, cybercrime and fraud are inhibiting expansion. To address these challenges, Blockchain will enable more agile value chains, faster product innovations, closer customer relationships, and quicker integration with the IoT and cloud technology. Further Blockchain provides a lower cost of trade with a trusted contract monitored without intervention from third parties who may not add direct value. It facilitates smart contracts, engagements, and agreements with inherent, robust cyber security features. This paper is an effort to break the ground for presenting and demonstrating the use of Blockchain technology in multiple industrial applications. A healthcare industry application, Healthchain, is formalized and developed on the foundation of Blockchain using IBM Blockchain initiative. The concepts are transferable to a wide range of industries as finance, government and manufacturing where security, scalability and efficiency must meet.
In the absence to date of any specific pre-emptive federal regulation of blockchain distributed ledger technology in fintech, smart contracts, or other uses, this paper discusses early state legislation including Arizona, California, Delaware, Hawaii, Illinois, Maine, New York, Nevada and Vermont. While the list comprises usual suspects for early adoption of disruptive technology regulation, especially of its real-time aspects that were recognized in In re Dole Food Co (Del. Ch. Feb. 15, 2017), the mechanics of blockchain are still evolving and restrictive regulations appear both premature and at risk of expedited obsolescence. Before expanding to general record-keeping transactions, blockchain was first used in bitcoin, a virtual currency. Then, blockchain evolved towards self-executing smart contracts using ethereum technology and may eventually reach an “Internet of Agreements.” While its promise for applications like virtual currencies and payments is obvious and vigorously explored by major financial institutions, blockchain’s real strength lies in authentication and keeping records up-to-date, especially for valuable, highly liquid assets like securities. Key developments for blockchain’s regulation and implementation in an evidentiary context occurred in Arizona (recognition of smart contracts), Vermont (blockchain as evidence), Chicago (real estate records), and, most importantly, Delaware (pending initiative authorizing registration of shares of Delaware companies in blockchain form). Since 64 percent of Fortune 500 companies and over 1 million entities are incorporated in Delaware, an enactment of Delaware’s initiative will change regulatory landscape for securities by setting precedent in the most important corporate jurisdiction of the U.S. Other states competing for corporate taxes and fees would be sure to follow.
Tyler B. Wray, Philip A. Chan, Erik M. Simpanen, Don Operario
BACKGROUND: Men who have sex with men (MSM) are the group at highest risk for contracting human immunodeficiency virus (HIV) in the United States, but many do not test as frequently as recommended. Home-based self-testing (HBST) for HIV holds promise for promoting regular testing among these individuals, but currently available HBSTs have limited follow-up options, providing only a 1-800 number that participants can call. Failure to actively conduct follow-up counseling and referrals after HBST use could result in delays in seeking confirmatory testing and care among users receiving reactive (preliminary positive) test results. HBST also fails to connect users who test negative with other prevention services that can reduce their future risk for HIV. OBJECTIVE: The aim of our study was to use qualitative research methods with high-risk MSM to inform development of a "smart" HBST kit. The kit utilizes existing Internet-of-Things (IoT) technologies to monitor HBST use in real-time and enable delivery of timely, active follow-up counseling and referrals over the phone. METHODS: In phase 1, individual interviews (n=10) explored how participants might use HBST and their views and preferences for conducting counseling and referral after HBST. Based on these perspectives, we developed a smartphone app (iOS, Android) that uses data from light sensors on Bluetooth low energy (BLE) beacons to monitor when HBST kits are opened, facilitating timely follow-up phone contact with users. In phase 2, a usability study conducted among high-risk MSM (n=10) examined the acceptability and feasibility of this system and provided user perspectives after using the system along with HBST. RESULTS: Phase 1 themes suggested that MSM preferred HBST, that most thought active follow-up after HBST would be valuable, and that doing so over the phone within 24 h after testing was preferable. Phase 2 results showed that the eTEST system successfully detected HBST use in nearly all cases. Participant perspectives also suggested that the timing, method (ie, phone call), and duration of follow-up were appropriate and helpful. CONCLUSIONS: Using BLE beacons and a smartphone app to enable follow-up counseling and referral over the phone after HBST use is feasible and acceptable to high-risk MSM. Future research is needed to compare the effects of follow-up counseling on rates of repeat testing and receipt of referral services (eg, testing for sexually transmitted infections and initiation of preexposure prophylaxis) and to explore the acceptability of the eTEST system over longer periods of time.
Pietro Danzi, Marko Angjelichinoski, Čedomir Stefanović, Petar Popovski
Residential microgrids (MGs) may host a large number of Distributed Energy Resources (DERs). The strategy that maximizes the revenue for each individual DER is the one in which the DER operates at capacity, injecting all available power into the grid. However, when the DER penetration is high and the consumption low, this strategy may lead to power surplus that causes voltage increase over recommended limits. In order to create incentives for the DER to operate below capacity, we propose a proportional-fairness control strategy in which (i) a subset of DERs decrease their own power output, sacrificing the individual revenue, and (ii) the DERs in the subset are dynamically selected based on the record of their control history. The trustworthy implementation of the scheme is carried out through a custom-designed blockchain mechanism that maintains a distributed database trusted by all DERs. In particular, the blockchain is used to stipulate and store a smart contract that enforces proportional fairness. The simulation results verify the potential of the proposed framework.
Pietro Danzi, Marko Angjelichinoski, Čedomir Stefanović, Petar Popovski
Residential microgrids (MGs) may host a large number of Distributed Energy\nResources (DERs). The strategy that maximizes the revenue for each individual\nDER is the one in which the DER operates at capacity, injecting all available\npower into the grid. However, when the DER penetration is high and the\nconsumption low, this strategy may lead to power surplus that causes voltage\nincrease over recommended limits. In order to create incentives for the DER to\noperate below capacity, we propose a proportional-fairness control strategy in\nwhich (i) a subset of DERs decrease their own power output, sacrificing the\nindividual revenue, and (ii) the DERs in the subset are dynamically selected\nbased on the record of their control history. The trustworthy implementation of\nthe scheme is carried out through a custom-designed blockchain mechanism that\nmaintains a distributed database trusted by all DERs. In particular, the\nblockchain is used to stipulate and store a smart contract that enforces\nproportional fairness. The simulation results verify the potential of the\nproposed framework.\n
Igor Zikratov, Alexander Kuzmin, Vladislav Akimenko, Viktor Niculichev · 5 authors
Blockchain is a relatively new technology that has shown a lot of possibilities. It emerged in 2009 as a public ledger of all Bitcoin transactions. Blockchain technology is finding applications in wide range of areas: digital assets and stocks, smart contracts, record keeping, ID systems, cloud storage, ride sharing, etc. We investigate the blockchains' activity in terms of how to store, retrieve and share files in decentralized network.
Ali Dorri, Marco Steger, Salil S. Kanhere, Raja Jurdak
Interconnected smart vehicles offer a range of sophisticated services that benefit the vehicle owners, transport authorities, car manufacturers and other service providers. This potentially exposes smart vehicles to a range of security and privacy threats such as location tracking or remote hijacking of the vehicle. In this article, we argue that BlockChain (BC), a disruptive technology that has found many applications from cryptocurrencies to smart contracts, is a potential solution to these challenges. We propose a BC-based architecture to protect the privacy of the users and to increase the security of the vehicular ecosystem. Wireless remote software updates and other emerging services such as dynamic vehicle insurance fees, are used to illustrate the efficacy of the proposed security architecture. We also qualitatively argue the resilience of the architecture against common security attacks.
Distributed ledger technology, a method of storing and maintaining the integrity of multiple copies of critical data using a massively redundant network of participating machines, has found a “killer application” in blockchain, a type of distributed ledger. A blockchain consists of sequential blocks that may never be modified or reordered, leaving a public, auditable record that is consistent and highly resistant to tampering and deletion. These qualities make blockchain eminently suitable for its most common use, cryptocurrency, and its occasional variants in the form of cryptocurrency tokens, used to represent ownership or some other right to virtual or physical goods and capabilities. Blockchain also enables smart contracts, discrete bodies of software written to serve both as the memorial and the means of execution of an agreement between parties. Smart contracts can have all the elements of a traditional contract, and as jurisdictions legislate or jurists rule on the fine points of enforceability and the acceptability of smart contracts as traditional contracts, applications in nearly every area of commerce have emerged. Digital lawyers may not need to become software developers, but deepening their understanding of the capabilities and limitations of the technology, developing a keen awareness of the issues at the intersection between code and the law, as well as the law’s readiness in this area, will be of great advantage to them and their clients in this rapidly evolving area at the intersection of technology, commerce and law.
Online trust systems are playing an important role in to-days world and face various challenges in building them. Billions of dollars of products and services are traded through electronic commerce, files are shared among large peer-to-peer networks and smart contracts can potentially replace paper contracts with digital contracts. These systems rely on trust mechanisms in peer-to-peer networks like reputation systems or a trustless public ledger. In most cases, reputation systems are build to determine the trustworthiness of users and to provide incentives for users to make a fair contribution to the peer-to-peer network. The main challenges are how to set up a good trust system, how to deal with security issues and how to deal with strategic users trying to cheat on the system. The Sybil attack, the most important attack on reputation systems is discussed. At last match making in two sided markets and the strategy proofness of these markets are discussed.
Bitcoin is an application that runs on blockchain technology. Blockchain is a foundational technology that is bringing in the second era of the Internet – the era where value can be transferred, rather than just information. Blockchain is developing along a four-stage path similar to that which TCP/IP took. Both are foundational technologies. TCP/IP brought the Internet, and eventually brought significant (transformational) technological changes in business like Amazon.com and Skype. These are changes that could not have been forecast at the beginning of the Internet age. Blockchain is an immutable distributed ledger. It replaces the inefficient use of multiple centralized ledgers. It will support smart contracts that automatically make payments, adjust accounts, and coordinate records among multiple organizations. A payroll application on blockchain’s distributed ledger will allow employees to be paid, and all related deductions and deposits to be made in real-time. It will allow multiple government agencies to immediately have audit-level access to all employee records, and all employer matching-payments. With a fiat crypto-currency a payroll application on the blockchain will allow immediate global payroll compliance at a fraction of the cost of current payroll compliance. Based on the trajectory of ITP/IP’s development it is reasonable to assume that a payroll application will be seen on a blockchain (most likely Quorum, a private/permissioned blockchain based on the Ethereum platform) by 2018-2021. The first one will be constructed either by a government (Finland or Estonia) or by a private company (in the USA). Costs will be so low that the industry will consolidate (picture the arrival of Amazon.com among the group of brick and mortar books stores that preceded it in the late 1990’s). A traditional payroll service provider today needs to prepare for this change by developing a pilot program internally that will educate its workforce to the advantages and operational intricacies of a service based in the blockchain.
Bitcoin is an application that runs on blockchain technology. Blockchain is a foundational technology that is bringing in the second era of the Internet – the era where value can be transferred, rather than just information.
Blockchain is developing along a four-stage path similar to that which TCP/IP took. Both are foundational technologies. TCP/IP brought the Internet, and eventually brought significant (transformational) technological changes in business like Amazon.com and Skype. These are changes that could not have been forecast at the beginning of the Internet age.
Blockchain is an immutable distributed ledger. It replaces the inefficient use of multiple centralized ledgers. It will support smart contracts that automatically make payments, adjust accounts, and coordinate records among multiple organizations.
A payroll application on blockchain’s distributed ledger will allow employees to be paid, and all related deductions and deposits to be made in real-time. It will allow multiple government agencies to immediately have audit-level access to all employee records, and all employer matching-payments. With a fiat crypto-currency a payroll application on the blockchain will allow immediate global payroll compliance at a fraction of the cost of current payroll compliance.
Based on the trajectory of ITP/IP’s development it is reasonable to assume that a payroll application will be seen on a blockchain (most likely Quorum, a private/permissioned blockchain based on the Ethereum platform) by 2018-2021. The first one will be constructed either by a government (Finland or Estonia) or by a private company (in the USA). Costs will be so low that the industry will consolidate (picture the arrival of Amazon.com among the group of brick and mortar books stores that preceded it in the late 1990’s).
A traditional payroll service provider today needs to prepare for this change by developing a pilot program internally that will educate its workforce to the advantages and operational intricacies of a service based in the blockchain.
Emanuele Di Pascale, Jasmina McMenamy, Irene Macaluso, Linda Doyle
The disruptive power of blockchain technologies represents a great opportunity to re-imagine standard practices of telecommunication networks and to identify critical areas that can benefit from brand new approaches. As a starting point for this debate, we look at the current limits of infrastructure sharing, and specifically at the Small-Cell-as-a-Service trend, asking ourselves how we could push it to its natural extreme: a scenario in which any individual home or business user can become a service provider for mobile network operators, freed from all the scalability and legal constraints that are inherent to the current modus operandi. We propose the adoption of smart contracts to implement simple but effective Service Level Agreements (SLAs) between small cell providers and mobile operators, and present an example contract template based on the Ethereum blockchain.
Tien Tuan Anh Dinh, Ji Wang, Gang Chen, Rui Liu · 6 authors
Blockchain technologies are taking the world by storm. Public blockchains, such as Bitcoin and Ethereum, enable secure peer-to-peer applications like crypto-currency or smart contracts. Their security and performance are well studied. This paper concerns recent private blockchain systems designed with stronger security (trust) assumption and performance requirement. These systems target and aim to disrupt applications which have so far been implemented on top of database systems, for example banking, finance applications. Multiple platforms for private blockchains are being actively developed and fine tuned. However, there is a clear lack of a systematic framework with which different systems can be analyzed and compared against each other. Such a framework can be used to assess blockchains' viability as another distributed data processing platform, while helping developers to identify bottlenecks and accordingly improve their platforms. In this paper, we first describe BlockBench, the first evaluation framework for analyzing private blockchains. It serves as a fair means of comparison for different platforms and enables deeper understanding of different system design choices. Any private blockchain can be integrated to BlockBench via simple APIs and benchmarked against workloads that are based on real and synthetic smart contracts. BlockBench measures overall and component-wise performance in terms of throughput, latency, scalability and fault-tolerance. Next, we use BlockBench to conduct comprehensive evaluation of three major private blockchains: Ethereum, Parity and Hyperledger Fabric. The results demonstrate that these systems are still far from displacing current database systems in traditional data processing workloads. Furthermore, there are gaps in performance among the three systems which are attributed to the design choices at different layers of the software stack.
Ponzi schemes are financial frauds which lure users under the promise of high profits. Actually, users are repaid only with the investments of new users joining the scheme: consequently, a Ponzi scheme implodes soon after users stop joining it. Originated in the offline world 150 years ago, Ponzi schemes have since then migrated to the digital world, approaching first the Web, and more recently hanging over cryptocurrencies like Bitcoin. Smart contract platforms like Ethereum have provided a new opportunity for scammers, who have now the possibility of creating "trustworthy" frauds that still make users lose money, but at least are guaranteed to execute "correctly". We present a comprehensive survey of Ponzi schemes on Ethereum, analysing their behaviour and their impact from various viewpoints.
Fintech business models based on distributed ledgers -- and their smart-contract variants in particular -- offer the prospect of democratizing access to faster, anywhere-accessible, lower cost, reliable-and-secure high-quality financial services. In addition to holding great, economically transformative promise, these business models pose new, little-studied risks and transaction costs. However, these risks and transaction costs are not evident during the demonstration and testing phases of development, when adopters and users are drawn from the community of developers themselves, as well as from among non-programmer fintech evangelists. Hence, when the new risks and transaction costs become manifest -- as the fintech business models are rolled out across the wider economy -- the consequences may also appear to be new and surprising. The present study represents an effort to get ahead of these developments by delineating risks and transaction costs inherent in distributed-ledger- and smart-contracts-based fintech business models. The analysis focuses on code risk and moral-hazard risk, as well as on mixed-economy risks and the unintended consequences of replicating bricks-and-mortar-generation contract forms within the ultra-low transaction-cost environment of fintech.
Multi-agents systems communication is a technology, which provides a way for multiple interacting intelligent agents to communicate with each other and with environment. Multiple-agent systems are used to solve problems that are difficult for solving by individual agent. Multiple-agent communication technologies can be used for management and organization of computing fog and act as a global, distributed operating system. In present publication we suggest technology, which combines decentralized P2P BOINC general-purpose computing tasks distribution, multiple-agents communication protocol and smart-contract based rewards, powered by Ethereum blockchain. Such system can be used as distributed P2P computing power market, protected from any central authority. Such decentralized market can further be updated to system, which learns the most efficient way for software-hardware combinations usage and optimization. Once system learns to optimize software-hardware efficiency it can be updated to general-purpose distributed intelligence, which acts as combination of single-purpose AI.
Andrew Miller, Iddo Bentov, Surya Bakshi, Ranjit Kumaresan · 5 authors
Bitcoin, Ethereum and other blockchain-based cryptocurrencies, as deployed today, cannot scale for wide-spread use. A leading approach for cryptocurrency scaling is a smart contract mechanism called a payment channel which enables two mutually distrustful parties to transact efficiently (and only requires a single transaction in the blockchain to set-up). Payment channels can be linked together to form a payment network, such that payments between any two parties can (usually) be routed through the network along a path that connects them. Crucially, both parties can transact without trusting hops along the route. In this paper, we propose a novel variant of payment channels, called Sprites, that reduces the worst-case "collateral cost" that each hop along the route may incur. The benefits of Sprites are two-fold. 1) In Lightning Network, a payment across a path of $\ell$ channels requires locking up collateral for $Θ(\ellΔ)$ time, where $Δ$ is the time to commit an on-chain transaction. Sprites reduces this cost to $O(\ell + Δ)$. 2) Unlike prior work, Sprites supports partial withdrawals and deposits, during which the channel can continue to operate without interruption. In evaluating Sprites we make several additional contributions. First, our simulation-based security model is the first formalism to model timing guarantees in payment channels. Our construction is also modular, making use of a generic abstraction from folklore, called the "state channel," which we are the first to formalize. We also provide a simulation framework for payment network protocols, which we use to confirm that the Sprites construction mitigates against throughput-reducing attacks.