Blockchain Papers

Luciano García‐Bañuelos, Alexander Ponomarev, Marlon Dumas, Ingo Weber

Blockchain technology enables the execution of collaborative business processes involving untrusted parties without requiring a central authority. Specifically, a process model comprising tasks performed by multiple parties can be coordinated via smart contracts operating on the blockchain. The consensus mechanism governing the blockchain thereby guarantees that the process model is followed by each party. However, the cost required for blockchain use is highly dependent on the volume of data recorded and the frequency of data updates by smart contracts. This paper proposes an optimized method for executing business processes on top of commodity blockchain technology. The paper presents a method for compiling a process model into a smart contract that encodes the preconditions for executing each task in the process using a space-optimized data structure. The method is empirically compared to a previously proposed baseline by replaying execution logs, including one from a real-life business process, and measuring resource consumption.

Benjamin Jean, Primavera De Filippi

International audience

Rebekah Mercer

Ring signatures are cryptographic protocols designed to allow any member of a group to produce a signature on behalf of the group, without revealing the individual signer's identity. This offers group members a level of anonymity not attainable through generic digital signature schemes. We call this property 'plausible deniability', or anonymity with respect to an anonymity set. We concentrate in particular on implementing privacy on the blockchain, introducing a unique ring signature scheme that works with existing blockchain systems. We implement a unique ring signature (URS) scheme using secp256k1, creating the first implementation compatible with blockchain libraries in this way, so as for easy implementation as an Ethereum smart contract. We review the privacy and security properties offered by the scheme we have constructed, and compare its efficiency with other commonly suggested approaches to privacy on the blockchain.

Imke Lammers, Michiel A. Heldeweg

This article entails an innovative approach to smart grid technology implementation, as it connects governance research with legal analysis. We apply the empirico-legal ‘ILTIAD framework’, which combines Elinor Ostrom’s Institutional Analysis and Development (IAD) framework with institutional legal theory (ILT), to an empirical case study of a local smart grid project. Empirical data were collected in an exploratory, descriptive example study of a single case, focusing on the Action Situation and interactions towards establishing a local Smart Grid. The case was chosen because of its complexity, following the ‘logic of intensity sampling’. Data triangulation took place combining participatory observation, semi-structured interviews, and document analysis. Through an exploratory case study, we showed how the ILTIAD framework can help reduce complexity in local decision-making processes on smart grid implementation, as it allows for analytical description and prescriptive design of local smart grid systems. In the analysis we addressed ownership arrangements and contracts and identified barriers and opportunities for realizing a local smart grid system. The design part includes a scenario which revealed the prescribed patterns of behaviour (liberties and abilities) and the consequential aspects that apply to each situation. Analysing and designing normative alignment ex ante to the planning and implementation of a smart grid system provides clarity to stakeholders about their current opportunities. For this reason, the ILTIAD framework can be used as a design guideline for establishing new and integrated smart grid projects.

Arvind Narayanan, Andrew Miller, Song Han

First, Arvind Narayanan and Andrew Miller, co-authors of the increasingly popular open-access Princeton Bitcoin textbook, provide an overview of ongoing research in cryptocurrencies. Second, Song Han provides an overview of hardware trends related to another long-studied academic problem that has recently seen an explosion in popularity: deep learning.

Martin Zeilinger

In a global economic landscape of hyper-commodification and financialisation, efforts to assimilate digital art into the high-stakes commercial art market have so far been rather unsuccessful, presumably because digital artworks cannot easily assume the status of precious object worthy of collection. This essay explores the use of blockchain technologies in attempts to create proprietary digital art markets in which uncommodifiable digital artworks are financialised as artificially scarce commodities. Using the decentralisation techniques and distributed database protocols underlying current cryptocurrency technologies, such efforts, exemplified here by the platform Monegraph, tend to be presented as concerns with the interest of digital artists and with shifting ontologies of the contemporary work of art. I challenge this characterisation, and argue, in a discussion that combines aesthetic theory, legal and philosophical theories of intellectual property, rhetorical analysis and research in the political economy of new media, that the formation of proprietary digital art markets by emerging commercial platforms such as Monegraph constitutes a worrisome amplification of long-established, on-going efforts to fence in creative expression as private property. As I argue, the combination of blockchain-based protocols with established ambitions of intellectual property policy yields hybrid conceptual-computational financial technologies (such as self-enforcing smart contracts attached to digital artefacts) that are unlikely to empower artists but which serve to financialise digital creative practices as a whole, curtailing the critical potential of the digital as an inherently dynamic and potentially uncommodifiable mode of production and artistic expression.

Primavera De Filippi, Samer Hassan

“Code is law” refers to the idea that, with the advent of digital technology, code has progressively established itself as the predominant way to regulate the behavior of Internet users. Yet, while computer code can enforce rules more efficiently than legal code, it also comes with a series of limitations, mostly because it is difficult to transpose the ambiguity and flexibility of legal rules into a formalized language which can be interpreted by a machine. With the advent of blockchain technology and associated smart contracts, code is assuming an even stronger role in regulating people’s interactions over the Internet, as many contractual transactions get transposed into smart contract code. In this paper, we describe the shift from the traditional notion of “code is law” (i.e., code having the effect of law) to the new conception of “law is code” (i.e., law being defined as code).

Tomáš Krabec, Percy Venegas

According to the World Economic Forum, by 2025 10% of global GDP will be stored on blockchains, a type of decentralised database and distributed shared ledger. Smart contracts are automated computable contracts that are executed in blockchains, with the benefit of removing intermediaries and reducing costs. The use cases in finance include: in cross-border payments, to capture obligations, minimize operational errors and expedite transfers; for property and casualty claims in insurance, to automate claims processing through third-party data sources and codification of business rules; for deposits and lending in syndicated loans, to facilitate real-time loan funding and automated servicing activities without intermediaries; for deposits and lending in trade finance, to automate the creation and management of credit facilities ultimately eliminating correspondent banks; for contingent convertible bonds in capital raising, to alert regulators when loan absorption needs to be activated, minimizing need for point-in-time stress tests; for compliance in investment management, to execute reporting and facilitate the automated creation of periodic filings; for proxy voting in investment management, to automate end-to-end confirmation by the validation of votes, increasing transparency; for asset rehypothecation in market provisioning, to enable the real-time reporting of asset history and the enforcement of regulatory constraints, including facilitating clearing and settlement to eliminate need for intermediaries and reduce settlement time; for equity post-trade in market provisioning, to simultaneously transfer equity and cash in real time, reducing the likelihood of errors impacting settlement.The policy implications introduced by decentralization require that economists and lawyers understand this technological shift, and more importantly, the risks related to tangible (e.g consensus selection as a security choice) and intangible (e.g contract incompleteness/code errors) factors. We demonstrate a decision making method where utility is measured by “levels of trust” using artifacts from fields finance applied to a portfolio of institutional smart contract companies. Expected utility is measured by mapping a demand vector field (the attention level), and funding by plotting a scalar field (the investment level); the associated risk exposure is implicit in the consensus mechanism tradeoffs, according to the progression of firms represented in the system of coordinates. The goal is to provide a device for portfolio analysis and construction. The data comes from a panel of 200 million internet users, and investment databases. The result is a comprehensive and scalable view of decentralised portfolios, inspired in the methods of behavioural finance.

Andreas Bogner, Mathieu Chanson, Arne Meeuw

The sharing economy, the business of collectively using privately owned objects and services, has fuelled some of the fastest growing businesses of the past years. However, popular sharing platforms like Airbnb or Uber exhibit several drawbacks: a cumbersome sign up procedure, lack of participant privacy, overbearing terms and conditions, and significant fees for users. We demonstrate a Decentralised App (DAPP) for the sharing of everyday objects based on a smart contract on the Ethereum blockchain. This contract enables users to register and rent devices without involvement of a Trusted Third Party (TTP), disclosure of any personal information or prior sign up to the service. With increasing distribution of cryptocurrencies the use of smart contracts such as proposed in this paper has the potential to revolutionise the sharing economy.

Raffaella Aversa, Francesco Tamburrino, Relly Victoria Petrescu, Florian Ion Tiberiu Petrescu · 7 authors

The research shows a bioinspired approach to be adopted to design of systems based on Shape Memory Alloys (SMAs), a class of Smart Materials that has in common with muscles the capability to react to an impulse (thermal for SMAs) with a contraction. The biomechanically inspired machine that is discussed in the paper refers to the antagonistic muscles pairs, which belongs to the Skeletal Muscles and are normally arranged in opposition so that as one group of muscles contract another group relaxes or lengthens. The study proposes a model, a solution not only to design a specific application, but also to provide an approach to be used for a wide range of adaptive applications (switchable windows, smart shadow systems, parking and urban shelters, etc.), where the shape changes in response to different external stimuli. The use of antagonist pairs mechanism provides a solution for better optimized systems based on SMAs where the main and proven advantages are: Easier and faster change of shape, lower need of energy for system operation, lower cost for SMA training and no problem of overheating.

Fan Zhang, Ethan Cecchetti, Kyle Croman, Ari Juels · 5 authors

Smart contracts are programs that execute autonomously on blockchains. Their key envisioned uses (e.g. financial instruments) require them to consume data from outside the blockchain (e.g. stock quotes). Trustworthy data feeds that support a broad range of data requests will thus be critical to smart contract ecosystems.

Roman Matzutt, Oliver Hohlfeld, Martin Henze, Robin Rawiel · 6 authors

As transaction fees skyrocket today, blockchains become increasingly expensive, hurting their adoption in broader applications. This work tackles the saving of transaction fees for economic blockchain applications. The key insight is that other than the existing "default'' mode to execute application logic fully on-chain, i.e., in smart contracts, and in fine granularity, i.e., user request per transaction, there are alternative execution modes with advantages in cost-effectiveness. On Ethereum, we propose a holistic middleware platform supporting flexible and secure transaction executions, including off-chain states and batching of user requests. Furthermore, we propose control-plane schemes to adapt the execution mode to the current workload for optimal runtime cost. We present a case study on the institutional accounts (e.g., coinbase.com) intensively sending Ether on Ethereum blockchains. By collecting real-life transactions, we construct workload benchmarks and show that our work saves 18%\sim 47%18%-47% per invocation than the default baseline while introducing 1.81%\sim 16.59%1.81%-16.59% blocks delay.

Karthikeyan Bhargavan, Antoine Delignat-Lavaud, Cédric Fournet, Anitha Gollamudi · 11 authors

Ethereum is a framework for cryptocurrencies which uses blockchain technology to provide an open global computing platform, called the Ethereum Virtual Machine (EVM). EVM executes bytecode on a simple stack machine. Programmers do not usually write EVM code; instead, they can program in a JavaScript-like language, called Solidity, that compiles to bytecode. Since the main purpose of EVM is to execute smart contracts that manage and transfer digital assets (called Ether), security is of paramount importance. However, writing secure smart contracts can be extremely difficult: due to the openness of Ethereum, both programs and pseudonymous users can call into the public methods of other programs, leading to potentially dangerous compositions of trusted and untrusted code. This risk was recently illustrated by an attack on TheDAO contract that exploited subtle details of the EVM semantics to transfer roughly $50M worth of Ether into the control of an attacker.

Timothy Nugent, David M. Upton, Mihai Cimpoeşu

The scientific credibility of findings from clinical trials can be undermined by a range of problems including missing data, endpoint switching, data dredging, and selective publication. Together, these issues have contributed to systematically distorted perceptions regarding the benefits and risks of treatments. While these issues have been well documented and widely discussed within the profession, legislative intervention has seen limited success. Recently, a method was described for using a blockchain to prove the existence of documents describing pre-specified endpoints in clinical trials. Here, we extend the idea by using smart contracts - code, and data, that resides at a specific address in a blockchain, and whose execution is cryptographically validated by the network - to demonstrate how trust in clinical trials can be enforced and data manipulation eliminated. We show that blockchain smart contracts provide a novel technological solution to the data manipulation problem, by acting as trusted administrators and providing an immutable record of trial history.

Juri Mattila, Timo Seppälä, Catarina Naucler, Riitta Stahl · 7 authors

To encourage public discourse on blockchain use case development, this paper provides a pragmatic view on how to develop and to describe blockchain use cases. We approach the issue by developing a tentative use case for autonomous machine-to-machine transactions of electricity in a housing society environment through an iterative process with stakeholders in the energy industry. We proceed by evaluating the outlined concept and its technical specifications against six criteria for a sensible blockchain use case, as identified by blockchain industry specialists. Finally, we conclude with observations and discussion on the use case development process, and its future steps.

Jesse Yli-Huumo, Deokyoon Ko, Sujin Choi, Sooyong Park · 5 authors

Blockchain is a decentralized transaction and data management technology developed first for Bitcoin cryptocurrency. The interest in Blockchain technology has been increasing since the idea was coined in 2008. The reason for the interest in Blockchain is its central attributes that provide security, anonymity and data integrity without any third party organization in control of the transactions, and therefore it creates interesting research areas, especially from the perspective of technical challenges and limitations. In this research, we have conducted a systematic mapping study with the goal of collecting all relevant research on Blockchain technology. Our objective is to understand the current research topics, challenges and future directions regarding Blockchain technology from the technical perspective. We have extracted 41 primary papers from scientific databases. The results show that focus in over 80% of the papers is on Bitcoin system and less than 20% deals with other Blockchain applications including e.g. smart contracts and licensing. The majority of research is focusing on revealing and improving limitations of Blockchain from privacy and security perspectives, but many of the proposed solutions lack concrete evaluation on their effectiveness. Many other Blockchain scalability related challenges including throughput and latency have been left unstudied. On the basis of this study, recommendations on future research directions are provided for researchers.

Elfriede Sixt

Banks, as they exist now, are obsolete and will not exist as we know them in 10 years. Period. Without a doubt. We’ve seen this movie before. Is anyone using Delphi? CompuServe? AOL? What did they have in common? They tried to retrofit the Internet’s HTTP technology into their systems. They tried to force everyone into their closed loopholes. It worked, temporarily. You had a jump in revenues and profit, and then everybody found out you can deal directly with the source. You don’t need them They’re gone. The banking system is trying to do the same thing (Reggie Middleton, CEO of Veritaseum, designing P2P Smart Contracts through blockchain tech & inventor of UltraCoin). Wie schon oft in diesem Buch aufgezeigt, nutzt die Finanzwirtschaft schon jahrzehntelang Softwaresysteme wie das SWIFT-System, hat es aber bis dato geschafft, sich von der Digitalisierung des Internets abzugrenzen.

Michael Zouari, Ilan Alon, Ze’ev Shtudiner

Die Möglichkeit der Programmierbarkeit des Bitcoins ist fast ein nachträglicher Einfall, auch wenn Sidechain‐Vorschläge diese Programmierbarkeit ein wenig leichter machen wollen und es bereits Altcoins mit verschiedenen spezifischen Anwendungen gibt. Im Gegensatz dazu wurde das Kryptowährungstechnologieprojekt Ethereum von Vitalik Buterin, seinem Erfinder, von Tag 1 als Software‐Entwicklungsplattform für dezentrale Applikationen konzipiert, und ihre Blockchain wurde speziell entwickelt, um die Ausführung dieser dezentralen Apps (auch Dapps genannt) zu unterstützen. Vitalik Buterin, 1994 in Russland geboren, war vor der Gründung von Ethereum auch involviert in die Entwicklungsprojekte Colored Coins und Mastercoins. Er gewann 2014 den "World Technology Award" und ein Stipendium des Risikokapitalgebers Peter Thiel. In dem Diskussionspapier zu Ethereum skizzierte Buterin vor allem die Grenzen einer Programmierbarkeit der Bitcoin‐Blockchain und schlug die Erstellung einer neuen komplett programmierbaren Blockchain mit einer turing‐vollständigen Programmiersprache vor. Anders als andere Blockchain‐Projekte soll die Ethereum Software nicht nur für einen Zweck nutzbar sein – sondern soll die Basis für die Erarbeitung aller möglichen Arten von Lösungen sein und dabei die Umsetzung intelligenter Verträge (Smart Contracts) ebenso erfassen als auch die Ethereum‐spezifische Idee von dezentralen autonomen Organisationen (DAOs).

Lee Gibson Grant

DT X is building a next generation model from the grassroots of infrastructure Telecommunications 4.0 to IOT, Industry 4.0, Education 4.0 and financial services (Banking 4.0) leveraging Distributed Ledger technology. (Going beyond code and blockchain.) The aim is to empower and beyond traditional and rational projects by targeting the sore points globally, opposed to the tradition proposals and whitepapers of a target market of 2 billion people who currently don’t have access to banking across the world. DT X is based over four years of trials and errors of sub projects to evaluate the conditions and possible prospects, which in each and every time fall back to National Infrastructure and resources which varies from country to country: Telecommunications, Energy, Financial Services (Fintech & Regulation), Available Funding, Economic Stimulation, Education and Blockchain adoption & use cases. Instead of promoting specific problems and identifying alternative underlying issues DT X is targeting the core root of the issue then apply by layers solutions to solve specific requirements. Western world application will be focused on a similar model of Africa but more evolved around Telecommunication infrastructure merged with Distributed Ledger Technology over its own Network on a national scale thus securing all information and providing Industry 4.0 the infrastructure to grow and create economic growth whilst supporting Fintech, Education and Public or Private services.

A. B. Ackerman, Anne B. Chang, Nadia Diakun-Thibault, Luca Forni · 7 authors

The President’s Precision Medicine Initiative (PMI) is “enabling a new era of clinical care through research, technology, and policies that empower patients, researchers, and providers to work together toward the development of individualized care”. Its commitment to privacy and security in the setting of responsible data sharing and transparency is articulated in the “Privacy and Trust Principles” and the “Data Security Policy Principles and Framework”, developed by an interagency working groups including the Office of the National Coordinator for Health Information Technology in conjunction with multiple stakeholders. In this paper, we review the threats to the security, confidentiality, integrity, and availability of PMI data. PMI organizations can mitigate these challenges through a new system architecture in development at MIT -- the OPAL/Enigma project -- which creates a peer-to-peer network that enables parties to jointly store and analyze data with complete privacy, based on highly optimized version of multi-party computation with a secret-sharing. An auditable, tamper-proof distributed ledger (a permissioned blockchain) records and controls access through smart contracts and digital identities. We conclude with an initial use case of OPAL/Enigma that could empower precision medicine clinical trials and research. MIT’s OPAL/Enigma challenges traditional data security paradigms. Centralized databases cannot assure security and data integrity, regardless de-identification and controlled access requirements. Safe, vetted queries that are distributed to private, encrypted databases assure that organizations and participants can share health care data with cryptographic guarantees of privacy with various stakeholders, assuring momentum for a new era of medical research and practice.

Christopher D. Clack, Vikram A. Bakshi, Lee Braine

In this position paper, we consider some foundational topics regarding smart contracts (such as terminology, automation, enforceability, and semantics) and define a smart contract as an automatable and enforceable agreement. We explore a simple semantic framework for smart contracts, covering both operational and non-operational aspects, and describe templates and agreements for legally-enforceable smart contracts, based on legal documents. Building upon the Ricardian Contract, we identify operational parameters in the legal documents and use these to connect legal agreements to standardised code. We also explore the design landscape, including increasing sophistication of parameters, increasing use of common standardised code, and long-term research.

Christopher D. Clack, Vikram A. Bakshi, Lee Braine

In this position paper, we consider some foundational topics regarding smart\ncontracts (such as terminology, automation, enforceability, and semantics) and\ndefine a smart contract as an automatable and enforceable agreement. We explore\na simple semantic framework for smart contracts, covering both operational and\nnon-operational aspects, and describe templates and agreements for\nlegally-enforceable smart contracts, based on legal documents. Building upon\nthe Ricardian Contract, we identify operational parameters in the legal\ndocuments and use these to connect legal agreements to standardised code. We\nalso explore the design landscape, including increasing sophistication of\nparameters, increasing use of common standardised code, and long-term research.\n

Dr Harisha K S

The proliferation of Internet of Things (IoT) devices has transformed various sectors, improving efficiency and connectivity. However, this rise also significantly amplifies security vulnerabilities, exposing IoT ecosystems to various cyber threats. Traditional security mechanisms often fall short in addressing these vulnerabilities due to their centralized nature and scalability issues. Blockchain technology, recognized for its robust security features such as decentralization, transparency, and immutability, offers a promising alternative. This paper explores the application of advanced blockchain technologies, such as smart contracts, zero-knowledge proofs, and off-chain transactions, to enhance IoT security. Through theoretical analysis and empirical data, we demonstrate how blockchain can resolve critical security issues in IoT networks, including data integrity, device authentication, and secure communication. The findings suggest that integrating blockchain technology into IoT frameworks can significantly mitigate risks and bolster security. This research contributes to the academic discourse by highlighting practical implementations, challenges, and future perspectives on the convergence of blockchain and IoT technologies.

Yossi Gilad, Rotem Hemo, Silvio Micali, Georgios Vlachos · 5 authors

A public ledger is a tamperproof sequence of data that can be read and augmented by everyone. Public ledgers have innumerable and compelling uses. They can secure, in plain sight, all kinds of transactions ---such as titles, sales, and payments--- in the exact order in which they occur. Public ledgers not only curb corruption, but also enable very sophisticated applications ---such as cryptocurrencies and smart contracts. They stand to revolutionize the way a democratic society operates. As currently implemented, however, they scale poorly and cannot achieve their potential. Algorand is a truly democratic and efficient way to implement a public ledger. Unlike prior implementations based on proof of work, it requires a negligible amount of computation, and generates a transaction history that will not "fork" with overwhelmingly high probability. Algorand is based on (a novel and super fast) message-passing Byzantine agreement. For concreteness, we shall describe Algorand only as a money platform.