Blockchain Papers

Kedar Iyer, Chris Dannen

This chapter walks you through the setup and installation of tools required to run the Ethereum blockchain. We cover hardware requirements, operating system requirements, and software requirements. After covering the installation of the software, we provide the basic commands required to interact with the Ethereum network.

Shahar Somin, Goren Gordon, Yaniv Altshuler

No abstract is available for this record.

Elvira Albert, Pablo Gordillo, Benjamin Livshits, Albert Rubio · 5 authors

Analyzing Ethereum bytecode, rather than the source code from which it was generated, is a necessity when: (1) the source code is not available (e.g., the blockchain only stores the bytecode), (2) the information to be gathered in the analysis is only visible at the level of bytecode (e.g., gas consumption is specified at the level of EVM instructions), (3) the analysis results may be affected by optimizations performed by the compiler (thus the analysis should be done ideally after compilation). This paper presents EthIR, a framework for analyzing Ethereum bytecode, which relies on (an extension of) OYENTE, a tool that generates CFGs; EthIR produces from the CFGs, a rule-based representation (RBR) of the bytecode that enables the application of (existing) high-level analyses to infer properties of EVM code.

Ilya Grishchenko, Matteo Maffei, Clara Schneidewind

The recent growth of the blockchain technology market puts its main cryptocurrencies in the spotlight. Among them, Ethereum stands out due to its virtual machine (EVM) supporting smart contracts, i.e., distributed programs that control the flow of the digital currency Ether. Being written in a Turing complete language, Ethereum smart contracts allow for expressing a broad spectrum of financial applications. The price for this expressiveness, however, is a significant semantic complexity, which increases the risk of programming errors. Recent attacks exploiting bugs in smart contract implementations call for the design of formal verification techniques for smart contracts. This, however, requires rigorous semantic foundations, a formal characterization of the expected security properties, and dedicated abstraction techniques tailored to the specific EVM semantics. This work will overview the state-of-the-art in smart contract verification, covering formal semantics, security definitions, and verification tools. We will then focus on EtherTrust [ 1 ], a framework for the static analysis of Ethereum smart contracts which includes the first complete small-step semantics of EVM bytecode, the first formal characterization of a large class of security properties for smart contracts, and the first static analysis for EVM bytecode that comes with a proof of soundness.

Matevž Pustišek, Andrej Kos

There are several distributed ledger protocols potentially suitable for the Internet of things (IoT), including the Ethereum, Hyperledger Fabric and IOTA. This paper briefly presents and compares them from the IoT application development perspective. The IoT applications based on blockchain (BC) can incorporate the on-chain logic –the smart contracts– and Web, mobile or embedded client front-end application parts. We present three possible architectures for the IoT front-end BC applications. They differ in positioning of Ethereum blockchain clients (local device, remote server) and in positioning of key store needed for the management of outgoing transactions. The practical constraints of these architectures, which utilize the Ethereum network for trusted transaction exchange, are the data volumes, the location and synchronization of the full blockchain node and the location and the access to the Ethereum key store. Results of these experiments indicate that a full Ethereum node is not likely to reliably run on a constrained IoT devices. Therefore the architecture with remote Ethereum clients seems to be a viable approach, where two sub-options exist and differ in key store location/management. In addition, we proposed the use of architectures with a proprietary communication between the IoT device and remote blockchain client to further reduce the network traffic and enhance security. We expect it to be able to operate over low-power, low-bitrate mobile technologies, too. Our research clarifies differences in architectural approaches, but final decision for a particular ledger protocol and front-end application architecture is at strongly based on the particular intended use case.

Hisham S. Galal, Amr Youssef

The success of the Ethereum blockchain as a decentralized application platform with a distributed consensus protocol has made many organizations start to invest into running their business on top of it. Technically, the most impressive feature behind the success of Ethereum is its support for a Turing complete language. On the other hand, the inherent transparency and, consequently, the lack of privacy poses a great challenge for many financial applications. In this paper, we tackle this challenge and present a smart contract for a verifiable sealed-bid auction on the Ethereum blockchain. In a nutshell, initially, the bidders submit homomorphic commitments to their sealed-bids on the contract. Subsequently, they reveal their commitments secretly to the auctioneer via a public key encryption scheme. Then, according to the auction rules, the auctioneer determines and claims the winner of the auction. Finally, we utilize interactive zero-knowledge proof protocols between the smart contract and the auctioneer to verify the correctness of such a claim. The underlying protocol of the proposed smart contract is partially privacy-preserving. To be precise, no information about the losing bids is leaked to the bidders. We provide an analysis of the proposed protocol and the smart contract design, in addition to the estimated gas costs associated with the different transactions.

Sergei Tikhomirov

No abstract is available for this record.

Ilya Grishchenko, Matteo Maffei, Clara Schneidewind

Smart contracts are programs running on cryptocurrency (e.g., Ethereum) blockchains, whose popularity stem from the possibility to perform financial transactions, such as payments and auctions, in a distributed environment without need for any trusted third party. Given their financial nature, bugs or vulnerabilities in these programs may lead to catastrophic consequences, as witnessed by recent attacks. Unfortunately, programming smart contracts is a delicate task that requires strong expertise: Ethereum smart contracts are written in Solidity, a dedicated language resembling JavaScript, and shipped over the blockchain in the EVM bytecode format. In order to rigorously verify the security of smart contracts, it is of paramount importance to formalize their semantics as well as the security properties of interest, in particular at the level of the bytecode being executed. In this paper, we present the first complete small-step semantics of EVM bytecode, which we formalize in the F* proof assistant, obtaining executable code that we successfully validate against the official Ethereum test suite. Furthermore, we formally define for the first time a number of central security properties for smart contracts, such as call integrity, atomicity, and independence from miner controlled parameters. This formalization relies on a combination of hyper- and safety properties. Along this work, we identified various mistakes and imprecisions in existing semantics and verification tools for Ethereum smart contracts, thereby demonstrating once more the importance of rigorous semantic foundations for the design of security verification techniques.

Weili Chen, Zibin Zheng, Jiahui Cui, Edith C.‐H. Ngai · 6 authors

Blockchain technology becomes increasingly popular. It also attracts scams, for example, Ponzi scheme, a classic fraud, has been found making a notable amount of money on Blockchain, which has a very negative impact. To help dealing with this issue, this paper proposes an approach to detect Ponzi schemes on blockchain by using data mining and machine learning methods. By verifying smart contracts on Ethereum, we first extract features from user accounts and operation codes of the smart contracts and then build a classification model to detect latent Ponzi schemes implemented as smart contracts. The experimental results show that the proposed approach can achieve high accuracy for practical use. More importantly, the approach can be used to detect Ponzi schemes even at the moment of its creation. By using the proposed approach, we estimate that there are more than 400 Ponzi schemes running on Ethereum. Based on these results, we propose to build a uniform platform to evaluate and monitor every created smart contract for early warning of scams.

Adem Efe Gencer, Soumya Basu, Ittay Eyal, Robbert van Renesse · 5 authors

Blockchain-based cryptocurrencies have demonstrated how to securely implement traditionally centralized systems, such as currencies, in a decentralized fashion. However, there have been few measurement studies on the level of decentralization they achieve in practice. We present a measurement study on various decentralization metrics of two of the leading cryptocurrencies with the largest market capitalization and user base, Bitcoin and Ethereum. We investigate the extent of decentralization by measuring the network resources of nodes and the interconnection among them, the protocol requirements affecting the operation of nodes, and the robustness of the two systems against attacks. In particular, we adapted existing internet measurement techniques and used the Falcon Relay Network as a novel measurement tool to obtain our data. We discovered that neither Bitcoin nor Ethereum has strictly better properties than the other. We also provide concrete suggestions for improving both systems.

Michel Rauchs, Andrew Glidden, Brian Gordon, Gina Pieters · 8 authors

The DLT ecosystem is plagued with the use of incomplete and inconsistent definitions and a lack of standardised terminology, creating a needlessly complicated landscape for everyone from experienced policymakers and developers to individuals venturing into the field for the first time. This study sets out to contribute to international discussions to create a shared, common language around DLT systems to clarify terminology and concepts.

Shangping Wang, Yinglong Zhang, Yaling Zhang

In traditional cloud storage systems, attribute-based encryption (ABE) is regarded as an important technology for solving the problem of data privacy and fine-grained access control. However, in all ABE schemes, the private key generator has the ability to decrypt all data stored in the cloud server, which may bring serious problems such as key abuse and privacy data leakage. Meanwhile, the traditional cloud storage model runs in a centralized storage manner, so single point of failure may leads to the collapse of system. With the development of blockchain technology, decentralized storage mode has entered the public view. The decentralized storage approach can solve the problem of single point of failure in traditional cloud storage systems and enjoy a number of advantages over centralized storage, such as low price and high throughput. In this paper, we study the data storage and sharing scheme for decentralized storage systems and propose a framework that combines the decentralized storage system interplanetary file system, the Ethereum blockchain, and ABE technology. In this framework, the data owner has the ability to distribute secret key for data users and encrypt shared data by specifying access policy, and the scheme achieves fine-grained access control over data. At the same time, based on smart contract on the Ethereum blockchain, the keyword search function on the cipher text of the decentralized storage systems is implemented, which solves the problem that the cloud server may not return all of the results searched or return wrong results in the traditional cloud storage systems. Finally, we simulated the scheme in the Linux system and the Ethereum official test network Rinkeby, and the experimental results show that our scheme is feasible.

Henry Kim, Marek Laskowski

Summary An interesting research problem in our age of Big Data is that of determining provenance. Granular evaluation of provenance of physical goods (e.g., tracking ingredients of a pharmaceutical or demonstrating authenticity of luxury goods) has often not been possible with today's items that are produced and transported in complex, interorganizational, often internationally spanning supply chains. Recent adoptions of the Internet of Things and blockchain technologies give promise at better supply‐chain provenance. We are particularly interested in the blockchain, as many favored use cases of blockchain are for provenance tracking. We are also interested in applying ontologies, as there has been some work done on knowledge provenance, traceability, and food provenance using ontologies. In this paper, we make a case for why ontologies can contribute to blockchain design. To support this case, we analyze a traceability ontology and translate some of its representations to smart contracts that execute a provenance trace and enforce traceability constraints on the Ethereum blockchain platform.

Jae-Yong Park, Daegeon Lee, Hoh Peter In

Smart contracts are blockchain-based programs that have developed with the emergence of Ethereum, one of the most well-known blockchains. Gas, paid in Ethers (i.e., the cryptocurrency in Ethereum), is required for the costs to upload and run smart contracts on Ethereum. As cost-inefficiently designed smart contracts result in unnecessary costs, it is vital to eliminate any gas-wasteful code fragments to optimize the deployment costs. In this study, we define five gas-wasteful patterns: 'Over-public variables', 'Redundant initial values', 'Loose packing', 'Non-base unit types', and 'Nonconstant variables', based on the state variables in Solidity, the most commonly used implementation language for smart contracts in Ethereum. We also propose improvement methods related to these patterns and a solution to identify and eliminate the patterns. Furthermore, we analyze 143 real-world contracts deployed on Ethereum and find that 56% of them include the above-mentioned patterns. We also upgrade 43 of the patternmatched contracts and demonstrate that their deployment costs are decreased on an average by 13.47%, and the most-reduced rate is 64%.

김윤정, 이태주

Recently, Interest in virtual currency such as Bitcoin, ethereum etc. is increasing. Trading with virtual currency is also increasing. Virtual...

Arif Sarı, Seyfullah Kilic

Collection of intelligence is one of the key elements to organize more sophisticated methods of attacks. Open Source Intelligence (OSINT) is a technique used by attackers for reconnaissance purposes to gather information about specific targets. The accessibility to critical information about emerging systems through OSINT leads exposure of vulnerabilities and exploitation of these vulnerabilities to form widespread attack. Blockchain is one of the emerging technologies that exposed the use of crypto currencies such as Bitcoin and Ethereum. This research paper explains the use of OSINT to gather critical information about cryptocurrency miners such as Bitcoin Antminer and Ethereum Claymore and expose the vulnerabilities to exploit the configuration file of the miner manager. The research outcomes expose the vulnerability of the existing crypto currencies and use of OSINT for detection and analysis of cyberthreat in crypto currency market.

Jae-Hwan Jin

No abstract is available for this record.

Shelly Grossman, Ittai Abraham, Guy Golan-Gueta, Yan Michalevsky · 7 authors

Callbacks are essential in many programming environments, but drastically complicate program understanding and reasoning because they allow to mutate object's local states by external objects in unexpected fashions, thus breaking modularity. The famous DAO bug in the cryptocurrency framework Ethereum, employed callbacks to steal $150M. We define the notion of Effectively Callback Free (ECF) objects in order to allow callbacks without preventing modular reasoning. An object is ECF in a given execution trace if there exists an equivalent execution trace without callbacks to this object. An object is ECF if it is ECF in every possible execution trace. We study the decidability of dynamically checking ECF in a given execution trace and statically checking if an object is ECF. We also show that dynamically checking ECF in Ethereum is feasible and can be done online. By running the history of all execution traces in Ethereum, we were able to verify that virtually all existing contract executions, excluding these of the DAO or of contracts with similar known vulnerabilities, are ECF. Finally, we show that ECF, whether it is verified dynamically or statically, enables modular reasoning about objects with encapsulated state.

Олексій Джусов, Наталия Рубцова

Цель работы – проанализировать современные тенденции и состояние международного рынка ведущих криптовалют и оценить возможные перспективы их дальнейшего развития и интеграции в мировую финансовую систему.
 Результаты исследования. Ретроспективно прослежена история происхождения и становления Биткоина (Bitcoin), рассмотрены некоторые особенности «Блокчейн» («Blockchain»). Проанализированы положительные и отрицательные стороны работы с криптовалютами. Рассмотрена ближайшая по капитализации к Биткоину криптовалюта Эфир (Ethereum) и проанализированы основные различия между ними. На основе проведенного исследования сформирован прогноз о наиболее вероятном направлении развития рынка криптовалют на ближайшее будущее и о возможности их интеграции в мировую финансовую систему.
 Теоретическое значение исследования. Настоящее исследование и его результаты будут способствовать решению глобальной научной задачи – формированию научно-обоснованного мнения академической науки к новому феномену в экономике – криптовалютам и их роли в мировой финансовой системе.
 Оригинальность/ценность/научная новизна исследования. Работа является одной из немногих, посвященных новому явлению в экономике – криптовалютам; представлены авторские прогнозы о возможных направлениях дальнейшего развития рынка криптовалют.
 Перспективы дальнейших исследований. Настоящая работа открывает возможность дальнейших исследований в области рынка криптовалют, его дальнейшего развития и интеграции в мировую финансовую систему.
 Тип статьи – эмпирическая.

Mark Ivanov, Roman Oliynykov

A mathematical model for smart contracts for deployment of the initial coin offering (ICO), widely used on the Ethereum platform, is proposed. The analysis of dependence of the network capacity on such parameters as the transaction buffer size, the average transaction processing time, is performed. Evaluations are obtained of which parameters have the greatest impact on the capacity of Ethereum within the developed model.

Sidney Amani, Myriam Bégel, Maksym Bortin, Mark Staples

Blockchain technology has increasing attention in research and across many industries. The Ethereum blockchain offers smart contracts, which are small programs defined, executed, and recorded as transactions in the blockchain transaction history. These smart contracts run on the Ethereum Virtual Machine (EVM) and can be used to encode agreements, transfer assets, and enforce integrity conditions in relationships between parties. Smart contracts can carry financial value, and are increasingly used for safety-, security-, or mission-critical purposes. Errors in smart contracts have led and will lead to loss or harm. Formal verification can provide the highest level of confidence about the correct behaviour of smart contracts. In this paper we extend an existing EVM formalisation in Isabelle/HOL by a sound program logic at the level of bytecode. We structure bytecode sequences into blocks of straight-line code and create a program logic to reason about these. This abstraction is a step towards control of the cost and complexity of formal verification of EVM smart contracts.

Yasmin Le

Bitcoin has emerged as a popular digital currency and arouses the interest not only of programmers, but also of investors and academics. What interests them most is its underlying technology, the blockchain. This thesis aims at giving an overview of the current state of cryptocurrencies and compares their different designs and approaches to Bitcoin. The blockchain technology will be explained, as well as how it could impact many aspects in life by showcasing different applications of Ethereum blockchain-based smart contracts. Based on the evaluation of the different cryptocurrencies and preceding conclusions, specific cryptocurrencies will be applied to the Tasklet system before proposing the implementation of the blockchain technology in such a system, in order to establish a reward system. The paper reviews a heterogeneous, scattered body of knowledge including academic literature, but also non-scientific sources due to the constantly evolving technology. On this basis, the advantages of Bitcoin, but also its weaknesses, as well as the vast potential of blockchain are discussed. Results indicate that although Bitcoin’s framework may be limited, it will still play an important role in the future due to its dominance in the cryptocurrency market. The short display of blockchain-fueled applications and its effects has shown its potential to transform the internet, leading to the rise of the Web 3.0. Keywords: Bitcoin, Blockchain, Cryptocurrency, Distributed Ledger Technology, Smart Contract

Maxwell Crabson

No abstract is available for this record.

Shaen Corbet, Brian M. Lucey, Larisa Yarovaya

No abstract is available for this record.