Jan 14, 2021·International Workshop on Blockchain and Mobile Applications (BlockApp 2020) during the International Conference on Distributed Computing Systems (ICDCS 2020)
Peter Hillmann, Marcus Knüpfer, Erik Heiland, Andreas Karcher
The constantly growing size of blockchains becomes a challenge with the increasing usage. Especially the storage of unwanted data in a blockchain is an issue, because it cannot be removed naturally. In order to counteract this problem, we present the first concept for the selective deletion of single entries in a blockchain. For this purpose, the general consensus algorithm is extended by the functionality of regularly creating summary blocks. Previous data of the chain are summarized and stored again in a new block, leaving out unwanted information. With a shifting marker of the Genesis Block, data can be deleted from the beginning of a blockchain. In this way, the technology of the blockchain becomes fully transactional. The concept is independent of a specific block structure, network structure, or consensus algorithm. Moreover, this functionality can be adapted to current blockchains to solve multiple problems related to scalability. This approach enables the transfer of blockchain technology to further fields of application, among others in the area of Industry 4.0 and Product Life-cycle Management.
José Luis Hernández-Ramos, Georgios Karopoulos, Dimitris Geneiatakis, Tania Martin · 6 authors
This work proposes a scalable, blockchain-based platform for the secure sharing of COVID-19 or other disease vaccination certificates. As an indicative use case, we simulate a large-scale deployment by considering the countries of the European Union. The proposed platform is evaluated through extensive simulations in terms of computing resource usage, network response time and bandwidth. Based on the results, the proposed scheme shows satisfactory performance across all major evaluation criteria, suggesting that it can set the pace for real implementations. Vis-à-vis the related work, the proposed platform is novel, especially through the prism of a large-scale, full-fledged implementation and its assessment.
In most websites, the online rating system provides the ratings of products and services to users. Lack of trust in data integrity and its manipulation has hindered fulfilling user satisfaction. Since existing online rating systems deal with a central server, all rating data is stored on the central server. Therefore, all rating data can be removed, modified, and manipulated by the system manager to change the ratings in favor of the service or product provider. In this paper, an online rating system using distributed ledger technologies has been presented as the proposed system to solve all the weaknesses of current systems. Distributed ledger technologies are completely decentralized and there is no centralization on them by any institution. Distributed ledger technologies have different variants. Among distributed ledger technologies, blockchain technology has been used in the proposed rating system because of its support for smart contracts. In the proposed online rating system, the Ethereum platform has been chosen from different blockchain platforms that have a public permission network. In this system, the raters cannot rate unless they submit a request to the system and be authorized to take part in the online product rating process. The important feature of the Ethereum platform is its support for smart contracts, which can be used to write the rating contract in the Solidity language. Also, using Proof of Authority consensus mechanisms, all rating transactions are approved by the surveyors. Since in the real Ethereum system, each rating transaction is sent to the network by the raters, some gas must be paid for each rating transaction. However, since this method is expensive, TestNet blockchain can be used in the rating system. Finally, the proposed rating system was used for rating the restaurants of a website and its features were tested.
Because a fast vaccination rollout against coronavirus disease 2019 (COVID-19) is critical to restore daily life and avoid virus mutations, it is tempting to have a relaxed vaccination-administration management system. However, a rigorous management system can support the enforcement of preventive measures, and in turn, reduce incidence and deaths. Here, we model a trustable and reliable management system based on blockchain for vaccine distribution by extending the Susceptible-Exposed-Infected-Recovery (SEIR) model. The model includes prevention measures such as mask-wearing, social distancing, vaccination rate, and vaccination efficiency. It also considers negative social behavior, such as violations of social distance and attempts of using illegitimate vaccination proofs. By evaluating the model, we show that the proposed system can reduce up to 2.5 million cases and half a million deaths in the most demanding scenarios.
The developers of Ethereum smart contracts often implement administrating patterns, such as censoring certain users, creating or destroying balances on demand, destroying smart contracts, or injecting arbitrary code. These routines turn an ERC20 token into an administrated token - the type of Ethereum smart contract that we scrutinize in this research. We discover that many smart contracts are administrated, and the owners of these tokens carry lesser social and legal responsibilities compared to the traditional centralized actors that those tokens intend to disrupt. This entails two major problems: a) the owners of the tokens have the ability to quickly steal all the funds and disappear from the market; and b) if the private key of the owner's account is stolen, all the assets might immediately turn into the property of the attacker. We develop a pattern recognition framework based on 9 syntactic features characterizing administrated ERC20 tokens, which we use to analyze existing smart contracts deployed on Ethereum Mainnet. Our analysis of 84,062 unique Ethereum smart contracts reveals that nearly 58% of them are administrated ERC20 tokens, which accounts for almost 90% of all ERC20 tokens deployed on Ethereum. To protect users from the frivolousness of unregulated token owners without depriving the ability of these owners to properly manage their tokens, we introduce SafelyAdministrated - a library that enforces a responsible ownership and management of ERC20 tokens. The library introduces three mechanisms: deferred maintenance, board of trustees and safe pause. We implement and test SafelyAdministrated in the form of Solidity abstract contract, which is ready to be used by the next generation of safely administrated ERC20 tokens.
Victor von Wachter, Johannes Rude Jensen, Omri Ross
Decentralized financial (DeFi) applications on the Ethereum blockchain are highly interoperable because they share a single state in a deterministic computational environment. Stakeholders can deposit claims on assets, referred to as 'liquidity shares', across applications producing effects equivalent to rehypothecation in traditional financial systems. We seek to understand the degree to which this practice may contribute to financial integration on Ethereum by examining transactions in 'composed' derivatives for the assets DAI, USDC, USDT, ETH and tokenized BTC for the full set of 344.8 million Ethereum transactions computed in 2020. We identify a salient trend for 'composing' assets in multiple sequential generations of derivatives and comment on potential systemic implications for the Ethereum network.
Our contributions with this paper are twofold. First, we elucidate the methodological requirements for a risk framework of custodial operations and argue for the value of this type of risk model as complementary with cryptographic and blockchain security models. Second, we present a risk model in the form of a library of attack-trees for Revault -- an open-source custody protocol. The model can be used by organisations as a risk quantification framework for a thorough security analysis in their specific deployment context. Our work exemplifies an approach that can be used independent of which custody protocol is being considered, including complex protocols with multiple stakeholders and active defence infrastructure.
Geoffrey Goodell, Hazem Danny Al-Nakib, Paolo Tasca
Objective : to present the new approach to perform monetary transactions with digital currency. Methods : abstract-logical, analytical methods. Results : in recent years, electronic retail payment mechanisms, especially e-commerce and card payments at the point of sale, have increasingly replaced cash in many developed countries. As a result, societies are losing a critical public retail payment option, and retail consumers are losing important rights associated with using cash. To address this concern, we propose an approach to digital currency that would allow people without banking relationships to transact electronically and privately, including both e-commerce purchases and point-of-sale purchases that are required to be cashless. The article shows the advantages of cash payments compared to non-cash ones and defines the possibility to transform these advantages into the central bank digital currencies. The disputable issues of commercial banks development under the spread of digital currencies are discussed. The architecture of digital currencies is described, including distributed ledgers technology. It was shown that, for the digital currency to function effectively, it is necessary to include the privacy of end-users into its architecture; measures to achieve that are determined. Scientific novelty : the approached proposed in the article should be used to develop the digital currencies infrastructure. It should be government-backed, privately-operated and ensure that every transaction is registered by a bank or money services business, relying upon non-custodial wallets backed by privacy-enhancing technology, such as blind signatures or zero-knowledge proofs, to ensure that transaction counterparties are not revealed. This approach can also facilitate more efficient and transparent clearing, settlement, and management of systemic risk. We argue that our system can restore and preserve the salient features of cash, including privacy, owner-custodianship, fungibility, and accessibility, while also preserving fractional reserve banking and the existing two-tiered banking system. Practical significance : the proposed approach can be applied in the practical organization of perform monetary transactions using digital currencies. The article was first published in English language by Future Internet. For more information please contact the editorial office. For original publication: Goodell G., Al-Nakib H. D., Tasca P. A Digital Currency Architecture for Privacy and Owner-Custodianship, Future Internet, 2021, 13, 130. https://doi.org/10.3390/fi13050130 Publication URL: https://www.mdpi.com/1999-5903/13/5/130
Jan 1, 2021·Proceedings of the 36th IFIP TC 11 International Conference on ICT Systems Security and Privacy Protection (IFIP SEC 2021)/IFIP Advances in Information and Communication Technology, vol. 625, 2021, 19-35
Stefan More, Peter Grassberger, Felix Hörandner, Andreas Abraham · 5 authors
Recruiters and institutions around the world struggle with the verification of diplomas issued in a diverse and global education setting. Firstly, it is a nontrivial problem to identify bogus institutions selling education credentials. While institutions are often accredited by qualified authorities on a regional level, there is no global authority fulfilling this task. Secondly, many different data schemas are used to encode education credentials, which represents a considerable challenge to automated processing. Consequently, significant manual effort is required to verify credentials. In this paper, we tackle these challenges by introducing a decentralized and open system to automatically verify the legitimacy of issuers and interpret credentials in unknown schemas. We do so by enabling participants to publish transformation information, which enables verifiers to transform credentials into their preferred schema. Due to the lack of a global root of trust, we utilize a distributed ledger to build a decentralized web of trust, which verifiers can query to gather information on the trustworthiness of issuing institutions and to establish trust in transformation information. Going beyond diploma fraud, our system can be generalized to tackle the generalized problem for other domains lacking a root of trust and agreements on data schemas.
Yogesh N. Patil, Arvind W. Kiwelekar, Laxman D. Netak, S. B. Deosarkar
Administering standardized examinations is a challenging task, especially for those universities for which colleges affiliated to it are geographically distributed over a wide area. Some of the challenges include maintaining integrity and confidentiality of examination records, preventing mal-practices, issuing unique identification numbers to a large student population and managing assets required for the smooth conduct of examinations. These challenges aggravate when colleges affiliated to universities demand academic and administrative autonomy by demonstrating best practices consistently over a long period. In this chapter, we describe a model for decentralized and autonomous examination system to provide the necessary administrative support. The model is based on two emerging technologies of Blockchain Technology and Internet of Things (IoT). We adopt a software architecture approach to describe the model. The prescriptive architecture consists of {\em architectural mappings} which map functional and non-functional requirements to architectural elements of blockchain technology and IoT. In architectural mappings, first, we identify common use-cases in administering standardized examinations. Then we map these use-cases to the core elements of blockchain, i.e. distributed ledgers, cryptography, consensus protocols and smart-contracts and IoT. Such kind of prescriptive architecture guide downstream software engineering processes of implementation and testing
Peer-review is a necessary and essential quality control step for scientific publications but lacks proper incentives. Indeed, the process, which is very costly in terms of time and intellectual investment, not only is not remunerated by the journals but is also not openly recognized by the academic community as a relevant scientific output for a researcher. Therefore, scientific dissemination is affected in timeliness, quality, and fairness. Here, to solve this issue, we propose a blockchain-based incentive system that rewards scientists for peer-reviewing other scientists' work and that builds up trust and reputation. We designed a privacy-oriented protocol of smart contracts called Ants-Review that allows authors to issue a bounty for open anonymous peer-reviews on Ethereum. If requirements are met, peer-reviews will be accepted and paid by the approver proportionally to their assessed quality. To promote ethical behavior and inclusiveness the system implements a gamified mechanism that allows the whole community to evaluate the peer-reviews and vote for the best ones.
Epidemic situations typically demand intensive data collection and management from different locations/entities within a strict time constraint. Such demand can be fulfilled by leveraging the intensive and easy deployment of the Internet of Things (IoT) devices. The management and containment of such situations also rely on cross-organizational and national collaboration. Thus, this paper proposes an Intelligent-Health (I-Health) system that aims to aggregate diverse e-health entities in a unique national healthcare system by enabling swift, secure exchange and storage of medical data. In particular, we design an automated patients monitoring scheme, at the edge, which enables the prompt discovery, remote monitoring, and fast emergency response for critical medical events, such as emerging epidemics. Furthermore, we develop a blockchain optimization model that aims to optimize medical data sharing between different health entities to provide effective and secure health services. Finally, we show the effectiveness of our system, in adapting to different critical events, while highlighting the benefits of the proposed I-Health system.
Due to the widespread COVID-19 pandemic, there has been a push for `immunity passports' and even technical proposals. Although the debate about the medical and ethical problems of immunity passports has been widespread, there has been less inspection of the technical foundations of immunity passport schemes. These schemes are envisaged to be used for sharing COVID-19 test and vaccination results in general. The most prominent immunity passport schemes have involved a stack of little-known standards, such as Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs) from the World Wide Web Consortium (W3C). Our analysis shows that this group of technical identity standards are based on under-specified and often non-standardized documents that have substantial security and privacy issues, due in part to the questionable use of blockchain technology. One concrete proposal for immunity passports is even susceptible to dictionary attacks. The use of `cryptography theater' in efforts like immunity passports, where cryptography is used to allay the privacy concerns of users, should be discouraged in standardization. Deployment of these W3C standards for `self-sovereign identity' in use-cases like immunity passports could just as well lead to a dangerous form identity totalitarianism.
Arvind W. Kiwelekar, Sanil S. Gandhi, Laxaman D. Netak, Shankar B. Deosarkar
Humanitarian Engineers need innovative methods to make technological interventions for solving societal problems. The emerging blockchain technology has the enormous potential to provide effective interventions in various developmental sectors, including Agriculture, Education, Health, and Transportation. In these sectors, mediators have been considered as one of the impediments for developmental work. Blockchain technology facilitates peer-to-peer business transactions, thus eliminating the role of mediators. Hence, the blockchain technology is emerging as an alternative to conventional mediator-centred solutions adopting client-server based Internet technologies. A combination of blockchain technology with other technologies can be used to address domain-specific challenges. For example, the combination of blockchain technology and Internet-of-Thing (IoT) has the potential to monitor the usage of scarce resources such as the level of ground-water and amount of energy consumption. The aims of this chapter are twofold. Firstly, it describes the primary building blocks of blockchain technology. Secondly, it illustrates various use-case scenarios of blockchain technology in the fields of Agriculture, Energy Health and others.
In tracing the (robotically automated) logistics of large quantities of goods, inexpensive passive RFID tags are preferred for cost reasons. Accordingly, security between such tags and readers have primarily been studied among many issues of RFID. However, the authenticity of data cannot be guaranteed if logistics services can give false information. Although the use of blockchain is often discussed, it is simply a recording system, so there is a risk that false records may be written to it. As a solution, we propose a design in which a digitally signing, location-constrained and tamper-evident reader atomically writes an evidence to blockchain along with its reading and writing a tag. By semi-formal modeling, we confirmed that the confidentiality and integrity of the information can be maintained throughout the system, and digitally signed data can be verified later despite possible compromise of private keys or signature algorithms, or expiration of public key certificates. We also introduce a prototype design to show that our proposal is viable. This makes it possible to trace authentic logistics information using inexpensive passive RFID tags. Furthermore, by abstracting the reader/writer as a sensor/actuator, this model can be extended to IoT in general.
Shize Qin, Lena Klaaßen, Ulrich Gallersdörfer, Christian Stoll · 5 authors
The carbon footprint of Bitcoin has drawn wide attention, but Bitcoin's long-term impact on the climate remains uncertain. Here we present a framework to overcome uncertainties in previous estimates and project Bitcoin's electricity consumption and carbon footprint in the long term. If we assume Bitcoin's market capitalization grows in line with the one of gold, we find that the annual electricity consumption of Bitcoin may increase from 60 to 400 TWh between 2020 and 2100. The future carbon footprint of Bitcoin strongly depends on the decarbonization pathway of the electricity sector. If the electricity sector achieves carbon neutrality by 2050, Bitcoin's carbon footprint has peaked already. However, in the business-as-usual scenario, emissions sum up to 2 gigatons until 2100, an amount comparable to 7% of global emissions in 2019. The Bitcoin price spike at the end of 2020 shows, however, that progressive development of market capitalization could yield an electricity consumption of more than 100 TWh already in 2021, and lead to cumulative emissions of over 5 gigatons by 2100. Therefore, we also discuss policy instruments to reduce Bitcoin's future carbon footprint.
Digital identity seems like a prerequisite for digital democracy: how can we ensure "one person, one vote" online without identifying voters? But digital identity solutions - ID checking, biometrics, self-sovereign identity, and trust networks - all present flaws, leaving users vulnerable to exclusion, identity loss or theft, and coercion. These flaws may be insurmountable because digital identity is a cart pulling the horse. We cannot achieve digital identity secure enough for the weight of digital democracy, until we build it on a solid foundation of "digital personhood." While identity is about distinguishing one person from another through attributes or affiliations, personhood is about giving all real people inalienable digital participation rights independent of identity, including protection against erosion of their democratic rights through identity loss, theft, coercion, or fakery. We explore and analyze alternative approaches to "proof of personhood" that may provide this missing foundation. Pseudonym parties marry the transparency of periodic physical-world events with the power of digital tokens between events. These tokens represent limited-term but renewable claims usable for purposes such as online voting or liquid democracy, sampled juries or deliberative polls, abuse-resistant social communication, or minting universal basic income in a permissionless cryptocurrency. Enhancing pseudonym parties to provide participants a moment of enforced physical security and privacy can address coercion and vote-buying risks that plague today's E-voting systems. We also examine other proposed approaches to proof of personhood, some of which offer conveniences such as all-online participation. These alternatives currently fall short of satisfying all the key digital personhood goals, unfortunately, but offer valuable insights into the challenges we face.
While democracy is founded on the principle of equal opportunity to manage our lives and pursue our fortunes, the forms of money we have inherited from millenia of evolution has brought us to an unsustainable dead-end of exploding inequality. PoPCoin proposes to leverage the unique historical opportunities that digital cryptocurrencies present for a "clean-slate" redesign of money, in particular around long-term equitability and sustainability, rather than solely stability, as our primary goals. We develop and analyze a monetary policy for PoPCoin that embodies these equitability goals in two basic rules that maybe summarized as supporting equal opportunity in "space" and "time": the first by regularly distributing new money equally to all participants much like a basic income, the second by holding the aggregate value of these distributions to a constant and non-diminishing portion of total money supply through demurrage. Through preliminary economic analysis, we find that these rules in combination yield a unique form of money with numerous intriguing and promising properties, such as a quantifiable and provable upper bound on monetary inequality, a natural "early adopter's reward" that could incentivize rapid growth while tapering off as participation saturates, resistance to the risk of deflationary spirals, and migration incentives opposite those created by conventional basic incomes.
The current situation of COVID-19 demands novel solutions to boost healthcare services and economic growth. A full-fledged solution that can help the government and people retain their normal lifestyle and improve the economy is crucial. By bringing into the picture a unique incentive-based approach, the strain of government and the people can be greatly reduced. By providing incentives for actions such as voluntary testing, isolation, etc., the government can better plan strategies for fighting the situation while people in need can benefit from the incentive offered. This idea of combining strength to battle against the virus can bring out newer possibilities that can give an upper hand in this war. As the unpredictable future develops, sharing and maintaining COVID related data of every user could be the needed trigger to kick start the economy and blockchain paves the way for this solution with decentralization and immutability of data.
Received wisdom portrays digital records as guaranteeing perpetuity; as the New York Times wrote a decade ago: "the web means the end of forgetting". The reality however is that digital records suffer similar risks of access loss as the analogue versions they replace. Often this risk is outsourced to specialised third parties. Common use cases include Personal Information Management (PIM): e.g. calendars, diaries, tasks, etc. Frequently these are outsourced at two removes - firstly by the individual to their employer (e.g. using a company system) and then by their employer to an external provider. So enters a new risk: organisational change; by the time the information is required the organisational chain that links user to data may be broken: the employer transitions to a different provider, the employee leaves the company, the IS provider pivots to new offerings. The advent of Distributed Ledger Technology (DLT) could help mitigate these risks; and has led to a re-evaluation of the relationship between data creation and ownership. Although DLT is an imprecise term, it typically involves data storage across organisationally separate entities in a cryptographically secure form; and therefore could present a partial solution to the risk. This project presents the first research that applies DLT to the field of PIM, furthering design science state of the art by a novel implementation of a calendar application on the Ethereum blockchain. It also extends current research in utilising DLT in digital preservation, namely by enacting a continuum approach within a DL that allows for transfer of ownership of digital objects as they transition from individual to collective relevance. Finally it provides guidelines for future use of DLT within digital preservation.
Companies today are racing to leverage the latest digital technologies, such as artificial intelligence, blockchain, and cloud computing. However, many companies report that their strategies did not achieve the anticipated business results. This study is the first to apply state of the art NLP models on unstructured data to understand the different clusters of digital strategy patterns that companies are Adopting. We achieve this by analyzing earnings calls from Fortune Global 500 companies between 2015 and 2019. We use Transformer based architecture for text classification which show a better understanding of the conversation context. We then investigate digital strategy patterns by applying clustering analysis. Our findings suggest that Fortune 500 companies use four distinct strategies which are product led, customer experience led, service led, and efficiency led. This work provides an empirical baseline for companies and researchers to enhance our understanding of the field.
Paulo Henrique Alves, Isabella Z. Frajhof, Fernando A. Correia, Clarisse de Souza · 5 authors
Data privacy is a trending topic in the internet era. Given such importance, many challenges emerged in order to collect, manage, process, and publish data. In this sense, personal data have got attention, and many regulations emerged, such as GDPR in the European Union and LGPD in Brazil. This regulation model aims to protect users' data from misusage and leakage and allow users to request an explanation from companies when needed. In pandemic situations, such as the COVID-19 and Ebola outbreak, the action related to sharing health data between different organizations is/ was crucial to develop a significant movement to avoid the massive infection and decrease the number of deaths. However, the data subject, i.e., the users, should have the right to request the purpose of data use, anonymization, and data deletion. In this sense, permissioned blockchain technology emerges to empower users to get their rights providing data ownership, transparency, and security through an immutable, unified, and distributed database ruled by smart contracts. The governance model discussed in blockchain applications is usually regarding the first layer governance, i.e., public and permissioned models. However, this discussion is too superficial, and they do not cover compliance with the data regulations. Therefore, in order to organize the relationship between data owners and the stakeholders, i.e., companies and governmental entities, we developed a second layer data governance model for permissioned blockchains based on the Governance Analytical Framework principles applied in pandemic situations preserving the users' privacy and their duties. From the law perspective, we based our model on the UE GDPR in regard to data privacy concerns.
Sarad Venugopalan, Ivan Homoliak, Zengpeng Li, Pawel Szalachowski
Voting is a means to agree on a collective decision based on available choices (e.g., candidates), where participants agree to abide by their outcome. To improve some features of e-voting, decentralized blockchain-based solutions can be employed, where the blockchain represents a public bulletin board that in contrast to a centralized bulletin board provides extremely high availability, censorship resistance, and correct code execution. A blockchain ensures that all entities in the voting system have the same view of the actions made by others due to its immutability and append-only features. The existing remote blockchain-based boardroom voting solution called Open Voting Network (OVN) provides the privacy of votes, universal & End-to-End verifiability, and perfect ballot secrecy; however, it supports only two choices and lacks robustness enabling recovery from stalling participants. We present BBB-Voting, an equivalent blockchain-based approach for decentralized voting such as OVN, but in contrast to it, BBB-Voting supports 1-out-of-$k$ choices and provides robustness that enables recovery from stalling participants. We make a cost-optimized implementation using an Ethereum-based environment respecting Ethereum Enterprise Alliance standards, which we compare with OVN and show that our work decreases the costs for voters by 13.5% in normalized gas consumption. Finally, we show how BBB-Voting can be extended to support the number of participants limited only by the expenses paid by the authority and the computing power to obtain the tally.
Carlos Molina-Jiménez, Hazem Danny Al-Nakib, Linmao Song, Ioannis Sfyrakis · 5 authors
We suggest the re-introduction of bartering to create a cryptocurrencyless, currencyless, and moneyless economy segment. We contend that a barter economy would benefit enterprises, individuals, governments and societies. For instance, the availability of an online peer-to-peer barter marketplace would convert ordinary individuals into potential traders of both tangible and digital items and services. For example, they will be able to barter files and data that they collect. Equally motivating, they will be able to barter and re-introduce to the economy items that they no longer need such as, books, garden tools, and bikes which are normally kept and wasted in garages and sheds. We argue that most of the pieces of technology needed for building a barter system are now available, including blockchains, smart contracts, cryptography, secure multiparty computations and fair exchange protocols. However, additional research is needed to refine and integrate the pieces together. We discuss potential research directions.