Blockchain Papers

Gerrit Köchling, Philipp Schmidtke, Peter N. Posch

No abstract is available for this record.

Nishani Edirisinghe Vincent, Anne M. Wilkins

SUMMARY The novelty, ambiguity, and the lack of official guidance surrounding cryptocurrency transactions impose additional audit risks that should be considered during client acceptance and retention and planning audit procedures. We develop a four-quadrant model to assist auditors in client acceptance and continuance decisions and identify cryptocurrency risks that should be considered during audit planning and audit evidence gathering.

Wouter Lueks, Bogdan Kulynych, Jules Fasquelle, Simon Le Bail-Collet · 5 authors

Zero-knowledge proofs are an essential building block in many privacy-preserving systems. However, implementing these proofs is tedious and error-prone. In this paper, we present zksk, a well-documented Python library for defining and computing sigma protocols: the most popular class of zero-knowledge proofs. In zksk, proofs compose: programmers can convert smaller proofs into building blocks that then can be combined into bigger proofs. zksk features a modern Python-based domain-specific language. This makes possible to define proofs without learning a new custom language, and to benefit from the rich Python syntax and ecosystem. The library is available at https://github.com/spring-epfl/zksk

Zhifeng Jia, Rui Chen, Jie Li

In this paper, we design DeLottery, a decentralized lottery system based on block chain technology and smart contracts. Lottery is a classical form of entertainment and charity for centuries. Facing the bottleneck of the combination between lottery and information technology, we use smart contracts and blockchain in decentralized, intelligent, and secure systems for lottery industries. Moreover, we are inspired by the algorithm of RANDAO, an outstanding way of random number generation in blockchain scenario. The components and the functions of the novel system are described in details. We implement DeLottery in a blockchain network and show functioning procedure and security of the proposed lottery system.

Emmanouil Karampinakis, Michalis Pachilakis, Panagiotis Papadopoulos, Antonis Krithinakis · 5 authors

Bitcoin is the first and undoubtedly most successful cryptocurrecny to date with a market capitalization of more than 100 billion dollars. Today, Bitcoin has more than 100,000 supporting merchants and more than 3 million active users. Besides the trust it enjoys among people, Bitcoin lacks of a basic feature a substitute currency must have: stability of value. Hence, although the use of Bitcoin as a mean of payment is relative low, yet the wild ups and downs of its value lure investors to use it as useful asset to yield a trading profit. In this study, we explore this exact nature of Bitcoin aiming to shed light in the newly emerged and rapid growing marketplace of cryptocurencies and compare the investmet landscape and patterns with the most popular traditional stock market of Dow Jones. Our results show that most of Bitcoin addresses are used in the correct fashion to preserve security and privacy of the transactions and that the 24/7 open market of Bitcoin is not affected by any political incidents of the offline world, in contrary with the traditional stock markets. Also, it seems that there are specific longitudes that lead the cryptocurrency in terms of bulk of transactions, but there is not the same correlation with the volume of the coins being transferred.

Timothy Peter Hulick

For an oscillator that is periodically swept in frequency between some upper and lower bound, the output amplitude may easily be made constant and therefore known with a high degree of certainty. The instantaneous frequency exists only at a point in time and therefore possesses a zero probability of existing at any point. This thesis deals with the development of a method for interchanging the probability density functions of amplitude and frequency so that the latter becomes known with certainty while the former is known only to the extent that it is within a certain range. The method developed makes practical the use of the fast tuned voltage controlled oscillator as the local oscillator in a frequency scanning superheterodyne receiver. Exact frequency is expressed by a digital word of finite bit length that, in actuality, expresses the value of a quantized amplitude variable whose quantized value represents a precise frequency. Because of the interrelationship of amplitude, frequency, and time through the Fourier Transform, functions of these variables are also interrelated suggesting the possibility that the original certainty of amplitude information may be traded with the original uncertainty of frequency information. The success of the method presented makes use of the precise knowledge of the frequencies of the sidebands generated by the angle modulation process rather than make direct use of the instantaneous frequency. After mathematical development, a design example addresses the actual frequency range in the microwave region where the scanning superheterodyne receiver finds military application. To demonstrate the concept of precise frequency control with words of finite length, a practical frequency model is designed and constructed by scaling megahertz to hertz. Extensive use is made of monolithic waveform generators, balanced mixers, and operational amplifiers used as active filters and time domain summers. All assemblies within the model have practical microwave counterparts. Time and frequency domain waveforms are observed at virtually every major point of the model corresponding to the functional block interfaces and are compared with the mathematical predictions. The ultimate goal of precise frequency selection as a function of an imprecise independent variable is also obtained with the aid of a spectrum analyzer and dual trace oscilloscope. The causes of less than optimum signal level separation of adjacent discrete frequencies are analyzed in a qualitative manner. Reasons for the ineffectiveness of a quantitative critique are also presented. Experimental results, however, are demonstrated proof of the feasibility of the concept of exchanging probability density functions of related variables and that refinement is the only ingredient missing to render the fast scan VCO a useful local oscillator.

Валерія Аркадіївна Динту, А. А. Мітрофанов

Статтю присвячено дослідженню криптовалюти Bitcoin, її значення у реалізації кримі­нальних правопорушень. Визначено механізм використання Bitcoin як елемента системи легалізації доходів, одержаних злочинним шляхом.

Gasim Alandjani

Internet of Things have brought exciting changes in the social norms, work environments and the prospects for future generations. These devices (Things) have already changed the way our networks are used for communication. With the introduction of machine to machine communication (M2M), where devices communicate without human involvement to perform routine day to day tasks.

Ethan Cecchetti, Ben Fisch, Ian Miers, Ari Juels

We present a new primitive supporting file replication in distributed storage networks (DSNs) called a Public Incompressible Encoding (PIE). PIEs operate in the challenging public DSN setting where files must be encoded and decoded with public randomness-i.e., without encryption-and retention of redundant data must be publicly verifiable. They prevent undetectable data compression, allowing DSNs to use monetary rewards or penalties in incentivizing economically rational servers to properly replicate data. Their definition also precludes critical, demonstrated attacks involving parallelism via ASICs and other custom hardware. Our PIE construction is the first to achieve experimentally validated near-optimal performance-within a factor of 4 of optimal by one metric. It also allows decoding orders of magnitude faster than encoding, unlike other comparable constructions. We achieve this high security and performance using a graph construction called a Dagwood Sandwich Graph (DSaG), built from a novel interleaving of depth-robust graphs and superconcentrators. PIEs' performance makes them appealing for DSNs, such as the proposed Filecoin system and Ethereum data sharding. Conversely, their near-optimality establishes concerning bounds on the practical financial and energy costs of DSNs allowing arbitrary data.

Universidad Juárez del Estado de Durango, Facultad de Economía Contaduría y Administración., Julieta Evangelina Sánchez Cano

El bitcoin es una criptomoneda que ha tomado cada vez mayor importancia en terreno económico y financiero; fue creada para usos potenciales como moneda de compra y venta de bienes y servicios y como una base para aplicaciones, pero últimamente se ha estado convirtiendo en reserva de valor en tiempos de crisis. Las plantas de minado están proliferando siendo consideradas un modelo de negocio; éstas funcionan a través de nodos que forman una red descentralizada. No obstante, la gran cantidad de energía eléctrica utilizada en la producción y protección de las criptomonedas, les genera altos costos y esto podría ser su talón de Aquiles. Además, está causando polémica porque podría invalidar los esfuerzos hechos para la producción sostenible de la energía, a causa del crecimiento exponencial de la demanda de energía que se está gestando en los centros de datos dedicados al minado. Esta investigación tiene el objetivo de elaborar un análisis y una revisión de la creación y desenvolvimiento de la primera criptomoneda, su oferta y la demanda exponencial de energía que pone en entredicho la factibilidad de su crecimiento y desarrollo en el tiempo por factores económicos y de sostenibilidad.

Gaurav Panwar, Roopa Vishwanathan, Satyajayant Misra, Austin Bos

Organized surveillance, especially by governments poses a major challenge to individual privacy, due to the resources governments have at their disposal, and the possibility of overreach. Given the impact of invasive monitoring, in most democratic countries, government surveillance is, in theory, monitored and subject to public oversight to guard against violations. In practice, there is a difficult fine balance between safeguarding individual's privacy rights and not diluting the efficacy of national security investigations, as exemplified by reports on government surveillance programs that have caused public controversy, and have been challenged by civil and privacy rights organizations. Surveillance is generally conducted through a mechanism where federal agencies obtain a warrant from a federal or state judge (e.g., the US FISA court, Supreme Court in Canada) to subpoena a company or service-provider (e.g., Google, Microsoft) for their customers' data. The courts provide annual statistics on the requests (accepted, rejected), while the companies provide annual transparency reports for public auditing. However, in practice, the statistical information provided by the courts and companies is at a very high level, generic, is released after-the-fact, and is inadequate for auditing the operations. Often this is attributed to the lack of scalable mechanisms for reporting and transparent auditing. In this paper, we present SAMPL, a novel auditing framework which leverages cryptographic mechanisms, such as zero knowledge proofs, Pedersen commitments, Merkle trees, and public ledgers to create a scalable mechanism for auditing electronic surveillance processes involving multiple actors. SAMPL is the first framework that can identify the actors (e.g., agencies and companies) that violate the purview of the court orders. We experimentally demonstrate the scalability for SAMPL for handling concurrent monitoring processes without undermining their secrecy and auditability.

Ting Chen, Yufei Zhang, Zihao Li, Xiapu Luo · 8 authors

Motivated by the success of Bitcoin, lots of cryptocurrencies have been created, the majority of which were implemented as smart contracts running on Ethereum and called tokens. To regulate the interaction between these tokens and users as well as third-party tools (e.g., wallets, exchange markets, etc.), several standards have been proposed for the implementation of token contracts. Although existing tokens involve lots of money, little is known whether or not their behaviors are consistent with the standards. Inconsistent behaviors can lead to user confusion and financial loss, because users/third-party tools interact with token contracts by invoking standard interfaces and listening to standard events. In this work, we take the first step to investigate such inconsistent token behaviors with regard to ERC-20, the most popular token standard. We propose a novel approach to automatically detect such inconsistency by contrasting the behaviors derived from three different sources, including the manipulations of core data structures recording the token holders and their shares, the actions indicated by standard interfaces, and the behaviors suggested by standard events. We implement our approach in a new tool named TokenScope and use it to inspect all transactions sent to the deployed tokens. We detected 3,259,001 transactions that trigger inconsistent behaviors, and these behaviors resulted from 7,472 tokens. By manually examining all (2,353) open-source tokens having inconsistent behaviors, we found that the precision of TokenScope is above 99.9%. Moreover, we revealed 11 major reasons behind the inconsistency, e.g., flawed tokens, standard methods missing, lack of standard events, etc. In particular, we discovered 50 unreported flawed tokens.

Iddo Bentov, Yan Ji, Fan Zhang, Lorenz Breidenbach · 6 authors

We propose Tesseract, a secure real-time cryptocurrency exchange service. Existing centralized exchange designs are vulnerable to theft of funds, while decentralized exchanges cannot offer real-time cross-chain trades. All currently deployed exchanges are also vulnerable to frontrunning attacks. Tesseract overcomes these flaws and achieves a best-of-both-worlds design by using a trusted execution environment. The task of committing the recent trade data to independent cryptocurrency systems presents an all-or-nothing fairness problem, to which we present ideal theoretical solutions, as well as practical solutions. Tesseract supports not only real-time cross-chain cryptocurrency trades, but also secure tokenization of assets pegged to cryptocurrencies. For instance, Tesseract-tokenized bitcoins can circulate on the Ethereum blockchain for use in smart contracts. We provide a demo implementation of Tesseract that supports Bitcoin, Ethereum, and similar cryptocurrencies.

Max Hoffmann, Michael Klooß, Andy Rupp

Zero-knowledge arguments have become practical, and widely used, especially in the world of Blockchain, for example in Zcash. This work revisits zero-knowledge proofs in the discrete logarithm setting. First, we identify and carve out basic techniques (partly being used implicitly before) to optimise proofs in this setting. In particular, the linear combination of protocols is a useful tool to obtain zero-knowledge and/or reduce communication. With these techniques, we are able to devise zero-knowledge variants of the logarithmic communication arguments by Bootle et al. (EUROCRYPT '16) and Bünz et al. (S&P '18) thereby introducing almost no overhead. We then construct a conceptually simple commit-and-prove argument for satisfiability of a set of quadratic equations. Unlike previous work, we are not restricted to rank 1 constraint systems (R1CS). This is, to the best of our knowledge, the first work demonstrating that general quadratic constraints, not just R1CS, are a natural relation in the dlog (or ideal linear commitment) setting. This enables new possibilities for optimisation, as, eg., any degree n2 polynomial f(X) can now be "evaluated" with at most 2n quadratic constraints. Our protocols are modular. We easily construct an efficient, logarithmic size shuffle proof, which can be used in electronic voting. Additionally, we take a closer look at quantitative security measures, eg. the efficiency of an extractor. We formalise short-circuit extraction, which allows us to give tighter bounds on the efficiency of an extractor.

Xiaoying Zheng, Yongxin Zhu, Xueming Si

Blockchain naturally fits multiple industry sectors due its characteristics of decentralization, enhanced security, tamper-proof, improved traceability and transparency. However, there is a significant concern of blockchain’s performance, since blockchain trades off its performance for a completely distributed feature, which enhances its security. In this paper, we investigate the state-of-the-art progress of blockchain, mainly from a performance and security perspective. We extracted 42 primary papers from major scientific databases and 34 online technical articles. The objective is to understand the current research trends, challenges and future directions. We briefly introduce the key technologies of blockchain including distributed ledger, cryptography, consensus, smart contracts and benchmarks. We next summarize the performance and security concerns raised in the investigation. We discuss the architectural choices, performance metrics, database management enhancements, and hybrid blockchains, and try to identify the effort that the state-of-the-art has made to balance between the performance and security. We also make experiments on Ethereum and survey other popular blockchain platforms on the scalability feature of blockchain. We later discuss the potential applications and present the lessons learned. Finally, we attempt to identify the open issues and possible research directions.

Zhuotao Liu, Yangxi Xiang, Jian Shi, Peng Gao · 8 authors

Blockchain interoperability, which allows state transitions across different blockchain networks, is critical functionality to facilitate major blockchain adoption. Existing interoperability protocols mostly focus on atomic token exchanges between blockchains. However, as blockchains have been upgraded from passive distributed ledgers into programmable state machines (thanks to smart contracts), the scope of blockchain interoperability goes beyond just token exchanges. In this paper, we present HyperService, the first platform that delivers interoperability and programmability across heterogeneous blockchains. HyperService is powered by two innovative designs: (i) a developer-facing programming framework that allows developers to build cross-chain applications in a unified programming model; and (ii) a secure blockchain-facing cryptography protocol that provably realizes those applications on blockchains. We implement a prototype of HyperService in approximately 35,000 lines of code to demonstrate its practicality. Our experiments show that (i) HyperService imposes reasonable latency, in order of seconds, on the end-to-end execution of cross-chain applications; (ii) the HyperService platform is scalable to continuously incorporate new large-scale production blockchains.

Vivek Bagaria, Sreeram Kannan, David Tse, Giulia Fanti · 5 authors

The concept of a blockchain was invented by Satoshi Nakamoto to maintain a distributed ledger. In addition to its security, important performance measures of a blockchain protocol are its transaction throughput and confirmation latency. In a decentralized setting, these measures are limited by two underlying physical network attributes: communication capacity and speed-of-light propagation delay. In this work we introduce Prism, a new proof-of-work blockchain protocol, which can achieve 1) security against up to 50% adversarial hashing power; 2) optimal throughput up to the capacity C of the network; 3) confirmation latency for honest transactions proportional to the propagation delay D, with confirmation error probability exponentially small in the bandwidth-delay product CD; 4) eventual total ordering of all transactions. Our approach to the design of this protocol is based on deconstructing Nakamoto's blockchain into its basic functionalities and systematically scaling up these functionalities to approach their physical limits.

Qin Huang, Li Quan, Shengli Zhang

Blockchain is considered to be able to solve the problem of trust between distributed nodes. However, it's a challenge to store the large amount of data produced by blockchain. Therefore, it is necessary to reduce node storage overhead while ensuring node independence and data recoverability. This paper proposes to downsample these data to reduce the storage overhead of nodes. These nodes keep good independence, if downsampling follows the entropy of blockchain and the block bodies are continuously stored. Moreover, it demonstrates that the entire blockchain history can be efficiently recovered through the cooperative decoding of a group of nodes like fountain codes, if reserved data over these nodes obey the soliton distribution. However, these data on nodes are transparent (stored data are uncoded and can be used directly by the node without decoding). Thus, the proposed algorithm not only keeps decentralization and security, but also has good scalability in independence and recoverability.

Kishore Gade

Data mesh architecture is revolutionizing the field of data analytics, offering a fresh approach to how organizations manage and utilize data. Traditionally, centralized data warehouses and data lakes have dominated the landscape, but as the volume and complexity of data grow, these systems struggle to keep pace. Data mesh breaks away from the centralized model by promoting a decentralized and domain-oriented approach, where individual teams take ownership of their data. This shift enables organizations to treat data as a product, with each domain team responsible for managing and serving their data assets. The goal is to make data more accessible and usable across the organization while reducing bottlenecks that occur in centralized systems. Implementing data mesh architecture has profound implications for data management. It encourages better data governance, scalability, and flexibility, while fostering innovation and collaboration. However, it also introduces challenges, such as ensuring consistency, standardization, and proper integration across domains. The success of a data mesh strategy depends on a strong cultural shift, requiring both technical infrastructure and organizational alignment to support autonomous teams. Ultimately, data mesh offers the promise of unlocking the full potential of data in large organizations by making it more agile, democratized, and efficient. By embracing this architecture, businesses can better respond to the increasing demands of modern data management and gain a competitive edge in the digital landscape.

Ying‐Chang Liang

Blockchain is believed to bring new opportunities to dynamic spectrum management (DSM). With features of blockchain, the traditional spectrum management method, such as the spectrum auction, can be improved. It can also help to overcome the challenges about the security or the lack of incentive mechanisms for collaboration in DSM. Moreover, with blockchain, spectrum usage of the DSM system can be recorded in a decentralized manner. In this chapter, we will discuss the potentials of blockchain for spectrum management in a systematic way and using multiple case studies.

Mousa Ajouz, Adam Abdullah, Salina Kassim

In the crypto world, there is a proverbial (and literal) gold rush now occurring. Currently, more than 37 gold‐backed cryptocurrency companies have now emerged. Interestingly, some of them also claim to be Sharīʿah ‐compliant. Introducing precious metal‐backed cryptocurrencies is perceived to be an innovation among global payment systems, hampered in part by lack of supporting empirical evidence. Therefore, this research investigates potential users' tendency to adopt a Sharīʿah ‐compliant precious metal‐backed cryptocurrency. As such, this study adopts an extended adoption model, which consists of eight factors. Partial least squares structural equation modeling (PLS‐SEM) analysis was conducted on data elicited from economic active residents in Klang Valley from questionnaires. Overall, it was found six out of the eight constructs specified to influence the adoption of precious metal‐backed cryptocurrency were statistically significant where 54.5% of the variation in adoption of PMBC can be explained by the structure model provided by this research. It was also found 63.55% of the respondents are willing to adopt precious metal‐backed cryptocurrency in their future transactions.

Joon-Seok Kim, Nina Shin

Blockchain technology is now considered a next generation information technology tool for sustainable growth in supply chain (SC) management. However, its study is relatively rare in the literature on SC collaboration and sustainability management research, despite its advantages in sustaining connectivity and reliability among SC partners. This study investigates how the use of blockchain in SC activities can influence (increase or decrease) SC partnership efficiency and growth, thereby affecting SC performance outcomes. Specifically, this study empirically validates a measurement and structural equation model with 306 SC experts from various industries. The findings show that the blockchain technology characteristics (information transparency, information immutability, and smart contracts) have significant positive effects on partnership growth and marginal effects on partnership efficiency. Though partnership growth has a positive effect on firm performance, partnership efficiency shows a negative effect.

Ermyas Abebe, Dushyant Behl, Chander Govindarajan, Yining Hu · 9 authors

The adoption of permissioned blockchain networks in enterprise settings has seen an increase in growth over the past few years. While encouraging, this is leading to the emergence of new data, asset and process silos limiting the potential value these networks bring to the broader ecosystem. Mechanisms for enabling network interoperability help preserve the benefits of independent sovereign networks, while allowing for the transfer or sharing of data, assets and processes across network boundaries. However, a naive approach to interoperability based on traditional point-to-point integration is insufficient for preserving the underlying trust decentralized networks provide. In this paper, we lay the foundation for an approach to interoperability based on a communication protocol that derives trust from the underlying network consensus protocol. We present an architecture and a set of building blocks that can be adapted for use in a range of network implementations and demonstrate a proof-of-concept for trusted data-sharing between two independent trade finance and supply-chain networks, each running on Hyperledger Fabric. We show how existing blockchain deployments can be adapted for interoperation and discuss the security and extensibility of our architecture and mechanisms.

Nick James, Max Menzies, Lamiae Azizi, Jennifer Chan

This paper proposes a new method for determining similarity and anomalies between time series, most practically effective in large collections of (likely related) time series, by measuring distances between structural breaks within such a collection. We introduce a class of \emph{semi-metric} distance measures, which we term \emph{MJ distances}. These semi-metrics provide an advantage over existing options such as the Hausdorff and Wasserstein metrics. We prove they have desirable properties, including better sensitivity to outliers, while experiments on simulated data demonstrate that they uncover similarity within collections of time series more effectively. Semi-metrics carry a potential disadvantage: without the triangle inequality, they may not satisfy a "transitivity property of closeness." We analyse this failure with proof and introduce an computational method to investigate, in which we demonstrate that our semi-metrics violate transitivity infrequently and mildly. Finally, we apply our methods to cryptocurrency and measles data, introducing a judicious application of eigenvalue analysis.