Stablecoins are cryptocurrencies with the aim to reduce the price volatility by design. This increases their acceptance as an instrument of payment. Centralized approaches facilitate stable organizational structures, at the cost of introducing dependencies. Decentralized projects, on the other hand, face several challenges, one of them at the core of stablecoins: stability. In this paper, we assess the stability of the MakerDAO protocol, one of the major decentralized stablecoins. We conduct a measurement study regarding MakerDAO's resilience during the first year of its full protocol, from November 2019 to 2020, including the cryptocurrency crisis in March 2020. Our analysis is based on the publicly available transaction data of Ethereum that documents the activities of MakerDAO's contracts executing the protocol. We state requirements for resilience and introduce empirical metrics, based on which we test the resilience hypotheses against the transaction data. While the events of March 2020 were unfortunate for several users, the resilience at protocol level proved to be good even under stress.
Second-layer or off-chain protocols aim to increase the throughput of permissionless blockchains by enabling parties to lock funds into smart-contracts and perform payments through peer-to-peer communication, only resorting to the smart-contracts for protection against fraud. Current protocols have fixed periods during which participants can dispute any fraud attempts. However, current blockchains have limited transaction processing capacity, so a fixed dispute period will not always be sufficient to deter all fraudulent behaviour in an off-chain protocol. In this paper we present a novel mechanism for adaptive dispute cutoffs (ADCs) which ensure that users retain the opportunity to dispute fraudulent behaviours despite blockchain congestion, while increasing second-layer protocol efficiency by reducing dispute period lengths when the number of disputes is low. We present a non-interactive argument system for setting adaptive dispute periods under the current Ethereum Virtual Machine, and describe how to efficiently integrate built-in support for adaptive dispute periods in any blockchain using binary-indexed trees. We empirically demonstrate that an ADC-enabled second -layer protocol can handle a larger number of disputes and prevent more fraud than its non-adaptive counterparts even when users are slow to issue disputes, due to denial of service or blockchain congestion.
Matea Vasilj, Sven Skender, Mia Jurdana, Marko Horvat
Student non-profit organizations are a specific type of small associations that congregate students from diverse backgrounds around a common purpose. These organizations are non-profit driven, autonomous, and typically have largely similar statutes and regulations. In the context of software engineering, information systems that support their business processes have similar software requirements specifications. DESPRO is a web-based platform that fully supports principal use cases of students' non-profit organizations. The platform has three uses: accounting, voting, and fundraising management. DESPRO allows such organizations to begin with their principal operations practically immediately without unnecessary overhead. Unique features that distinguish DESPRO from other similar systems are: 1) lightweight and streamlined deployment process, 2) minimal required remote maintenance, 3) pre-defined functionalities specifically suited for student non-profit organizations, 4) user anonymity customized to specific functional requirements, 5) voting without prior user registration. The platform was developed with open-source technologies Node.js, Vue.js, Vuetify, Bootstrap, Sequalize, Axios, Web3, MariaDB, and smart contracts for Ethereum. It is freely available for noncommercial use by contacting the first author.
Akshay M. Fajge, Siddharth Thakur, Rahul Kumar, Raju Halder
With the advancement of blockchain technology at a breakneck pace, numerous organizations are now experimenting with blockchain solutions for their operations. In this nascent stage, due to the scarcity of blockchain domain experts, there is a growing trend towards an automated conversion of legacy systems to blockchain-based systems. To this aim, this paper presents an automated framework that facilitates the migration of centralized Java-based applications to decentralized Solidity-based Ethereum applications. The experimental results are encouraging, demonstrating its ability to handle large-scale Java codebase. To the best of our knowledge, this is the first proposal of its kind that enables the translation of Java source codes to Solidity source codes.
Eduardo Takeo Ueda, Marcelo Moro Da Silva, Anderson Silva, Norisvaldo Ferraz · 8 authors
Transparency and security in an electoral process are fundamental to the legitimacy of the results and the confidence of voters. Thus, it is necessary to assess opportunities to improve traditional voting systems. Among the main problems is the lack of transparency, due to the impossibility of a voter checking their vote and the lack of access to the source from which the results are obtained. Another problem is mobility, due to the impossibility of performing remote voting, as traditional voting systems continue to require the physical presence of the voter in an electoral zone. Thus, the objective of this work is to propose a voting system that is functional, transparent, safe, and accessible to everyone. Voters can vote through a mobile application with biometric authentication using fingerprint and password access. In our proposal, votes are registered in an Ethereum Blockchain through a Smart Contract, allowing the voter to check their vote. The results are expected to collaborate with the evolution of studies necessary to improve traditional voting systems, especially in fundamental aspects such as security, transparency, and mobility.
Ignacio Amores-Sesar, Christian Cachin, Anna Parker
Despite the tremendous interest in cryptocurrencies like Bitcoin and Ethereum today, many aspects of the underlying consensus protocols are poorly understood. Therefore, the search for protocols that improve either throughput or security (or both) continues. Bitcoin always selects the longest chain (i.e., the one with most work). Forks may occur when two miners extend the same block simultaneously, and the frequency of forks depends on how fast blocks are propagated in the network. In the GHOST protocol, used by Ethereum, all blocks involved in the fork contribute to the security. However, the greedy chain selection rule of GHOST does not consider the full information available in the block tree, which has led to some concerns about its security.
Juan Ma, Yuling Chen, Ziping Wang, Guoxu Liu · 5 authors
Abstract The delegating computation has become an irreversible trend, together comes the pressing need for fairness and efficiency issues. To solve this problem, we leverage game theory to propose a smart contract-based solution. First, according to the behavioral preferences of the participants, we design an incentive contract to describe the motivation of the participants. Next, to satisfy the fairness of the rational delegating computation, we propose a rational delegating computation protocol based on reputation and smart contract. More specifically, rational participants are to gain the maximum utility and reach the Nash equilibrium in the protocol. Besides, we design a reputation mechanism with a reputation certificate, which measures the reputation from multiple dimensions. The reputation is used to assure the client’s trust in the computing party to improve the efficiency of the protocol. Then, we conduct a comprehensive experiment to evaluate the proposed protocol. The simulation and analysis results show that the proposed protocol solves the complex traditional verification problem. We also conduct a feasibility study that involves implementing the contracts in Solidity and running them on the official Ethereum network. Meanwhile, we prove the fairness and correctness of the protocol.
With the emergence of a large number of virtual currencies represented by Bitcoin and Ethereum and the continuous rise of their prices, a large number of investors have been attracted to invest in them. The attention and research based on virtual currencies have aroused the wide concern of the social public. The price prediction of the virtual currencies is one of the research hotspots, obtaining and analyzing the historical data of virtual currency price for the prediction of future price. We find that some commonly used machine learning algorithms have a great deviation in the price prediction of virtual currency. To solve this problem, we propose a novel support vector regression (SVR) based on data segmentation, which can significantly improve the accuracy and effectiveness of price prediction of virtual currency. The experimental results show that our algorithm has obvious advantages over the traditional SVR algorithm and other eight classical machine learning algorithms.
Realizing process data traceability of industrial products is an important way to solve the problem of product quality analysis and achieve optimal design. At present, research on product data traceability mainly relies on centralized service provider storage, and product data rarely covers the whole life cycle, resulting in the opacity and incomplete of the product traceability process data. In this paper, blockchain technology is introduced into the traceability management of product data, and a product life cycle data traceability method based on multi-blockchain is proposed. The data sharing and communication mechanisms among blockchains are analyzed. Moreover, the block structure of product traceability data, the upload process of block data and the tracing process of multi-chain product data are elaborated in detail. Finally, based on the open source ethereum architecture, the system application platform is developed to verify the feasibility and rationality of the proposed method.
H S Govinda, Yogesh Chandrakant, D S Girish, S. Lokesh · 6 authors
Online voting system the most suitable replacement for the older generations paper ballot system and the nowadays trending Electronic Voting Machines (EVM). Every year by year the technology tries to reach its peak with immense exploration by revolutionizing the technology which makes the human life with more coloring. Today's Internet gives us access to a wide range of resources, information easily in a second. Among other such experiments is Blockchain. With its special features such as consistency and architecture, many companies, applications are increasingly moving towards them. One major usage of blockchain can be found in electronic-voting system. We can ensure the transparency of the election by placing all messages or details in the Ethereum blockchain, which keeps the privacy of each voter protected with maximum security and provides an effective sign-up process. Blockchain advantages on online-voting systems includes nonchangeable feature called immutable ledger of votes casted using time stamp method, security of voting system, instant validation of votes and counting of votes and updating in public ledger which does not depending upon the number of nodes in the blockchain network.
In recent years, increasingly many companies have entered the pay-as-you-go business because it has become easier to monitor services constantly due to the development and increase in the number of Internet of Things (IoT) devices. Research is in progress to introduce cryptographic assets into the payment, but if a private key is stolen, the cryptographic assets associated with it can be stolen. To address this issue, this paper proposes a secure automated payment system using contract wallets. This method ensures the security of cryptographic assets even if the private key is stolen. Secure automated payments are enabled by issuing transactions from IoT devices and using internal transactions to link contract wallets and smart contracts that handle the payment of cryptographic assets. Furthermore, the effectiveness of the proposed system is demonstrated on the Ethereum blockchain as a proof of concept, and the cost of gas is measured.
Open access
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Blockchain-based crowdfunding is one of the new, upcoming alternatives to the traditional centralized approach to crowdfunding. Traditional crowdfunding platforms are vulnerable to data leaks, high transaction and platform fees, and rampant frauds which happens due to the anonymity of user’s identity i.e., users cannot be identified when they commit cybercrimes. As blockchain is immutable and decentralized, it can reduce the possibility of data breaches. This brings in transparency as there is no central authority over the blockchain-based crowdfunding system. This paper attempts to solve these existing issues with the aid of a digital identity management system with an underlying Blockchain system. By implementing blockchain in a digital identity management system, malicious users can be identified and action can be taken against them. This paper explores donation-based crowdfunding using Ethereum as a framework and has been tested on the Rinkeby Test Network. This system can conduct several crowdfunding campaigns simultaneously. This paper explains the smart contract written in Solidity language in detail.
U ovom diplomskom radu je izrađena mobilna aplikacije za glasovanje koristeći blockchain tehnologiju. Aplikacija pruža funkcionalnost kreiranja vlastitih izbora i glasovanje na drugim izborima preko skeniranja QR koda ili unosom adrese glasovanja. Za autentikaciju je korišten Firebase servis dok je za pohranu podataka korišten ethereum blockchain uz pomoć alata Truffle, Ganache, web3 i Solidity programskog jezika. Mobilna aplikacija je kreirana unutar Flutter programskog okvira po DDD arhitekturalnom dizajnu programske podrške. Kroz rad je opisano i trenutno stanje elektroničkog glasovanja i njegove tehnologije, doprinos blockchaina konceptu mobilnog glasovanja i sigurnosne mane ovakvog načina glasovanja.
Smart contract is the heart of the Blockchain based decentralized applications. Smart contracts are the programs that get executed automatically on the Blockchain when the pre-set conditions are met. Ethereum is one of the world's largest platforms for creating decentralized applications. In Ethereum, gas (in Ether, Ethereum cryptocurrency) is used to pay miners for using their resources and running the smart contracts. It has been observed that if a smart contract is not optimized, it costs more than the required gas and therefore, the user is overcharged. Hence, optimization techniques are required to apply on smart contracts before deploying it onto the main chain. The work is broken into three modules. (1.) Designing a smart contract for storing an educational certificate on Blockchain, (2.) Writing the smart contract in Solidity using Sublime Text 3 and Remix Ethereum IDE for storing an educational certificate and then finally, (3.) Analyzing the smart contract for calculation of the gas cost which has been optimized based on the following three parameters:(a.) data types - when applied bytes32 data type is used in place of string data type, gas cost is reduced to 0.18%, (b) packaging variables into a single slot through the SOLC-using structure for packing reduces the gas cost up to the 256 bits (32 bytes) length of packed variables. Here, packed variables' length is more than 256 bits (32 bytes), hence it did not reduce the gas cost and, (c) error handling functions - no change in the cost of gas while using revert () in place of throw. So, optimization of gas cost has been considerably achieved and it can be further enhanced by increasing the number of transactions.
In a competitive market, online auction systems enable optimal trading of digital products and services. Bidders can participate in existing blockchain-based auctions while protecting the confidentiality of their bids in a decentralized, transparent, secure, and auditable manner. However, in a competitive market, parties would prefer not to disclose their interests to competitors, and to remain anonymous during auctions. In this paper, we firstly analyze the specific requirements for blockchain-based anonymous fair auctions. We present a formal model tailored to study auction systems that facilitate anonymity, as well as a generic protocol for achieving bid confidentiality and bidder anonymity using existing cryptographic primitives such as designated verifier ring signature. We demonstrate that it is secure using the security model we presented. Towards the end, we demonstrate through extensive simulation results on Ethereum blockchain that the proposed protocol is practical and has minimal associated overhead. Furthermore, we discuss the complexity and vulnerabilities that a blockchain environment might introduce during implementation.
Open access
Blockchain Technology Applications and Security
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
Blockchain tehnologija u svijetu kriptovaluta donosi sustav decentraliziranog načina poslovanja. Bitcoin kao predstavnik u kriptovaluta donosi izvršavanje transakcija bez centralnog autoriteta. Takvo poslovanje postiže se određenim mehanizmima uz točno određena pravila i algoritme koji moraju zadovoljiti sve uvjete ispravnosti. Štoviše, velik broj ljudi mora provjeriti ispravnost transakcija kako bi bile valjane što donosi čvrstu i sigurnu provjeru i povezanost. Blockchain tehnologija i kriptovalute objašnjene su pomoću Bitcoina, izrađenog simulatora i Ethereuma. Dodatno je navedena primjena blockchain tehnologije u zdravstvenoj industriji i pri glasanju na izborima kao moguće rješenje za opisane probleme. Blockchain tehnologija ima priliku za napredak i razvoj primjenom umjetne inteligencije.
The object of research is software for financial accounting and distribution of funds in a non-profit charitable foundation using smart contracts of the Ethereum platform. The work is aimed at designing and implementing a software application for a charitable foundation, which allows to exclude the misuse of funds of a non-profit charitable foundation. The paper proposes an implementation of the Ethereum smart contract for the software of a charitable foundation. In the app, users can apply for financial aid or make a charitable donation. The request for financial support is confirmed by administrators to avoid abuse by those seeking help. Anyone who has a crypto wallet can become a sponsor by transferring funds from its account to a selected request. The sponsor remains incognito when making a charitable contribution. After collecting the entire declared amount, the funds are automatically transferred to the crypto wallet of the request’s owner. A smart contract and a corresponding decentralized web application for interacting with it were experimentally deployed, and their joint work was tested. To implement the smart contract, the Solidity programming language was chosen; developed smart contract converted to bytecode using remix. The resulting bytecode is ready to be deployed on the Ethereum platform. Decentralized web application for interacting with the contract is implemented using Web3.js, Vue.js. A rough estimate of the cost of deploying a project on the Ethereum platform has been made. The deployment and operation of smart contracts and web applications comes with a certain overhead, which is most dependent on the cost of ether. However, this is a justified price to pay for the transparency of transactions and the shadowing of the turnover of funds of the charitable foundation. The results of the research can be used as a basis for further transformation into full-fledged software with the ability to submit all reporting documents to the relevant government agencies and sponsors.
Consensus protocols can help guarantee security and sustainability to maintain the decentralized Blockchain system used in different scenarios and applications due to their different features. There are two main prevalent protocols, Proof of Work (PoW) used in Bitcoin and Proof of Stake (PoS) used in Ethereum. This paper reviews these two consensus protocols, PoW and PoS, and their related improvements and applications. We first introduce the basic concepts, implementations, advantages, and disadvantages of PoW and PoW and make a detailed comparison between these two protocols. We find that though providing security when honest participants are the majority, PoW may lead to excessive power consumption. While PoS is relatively insecure and leads to monopoly (centralization), though energy efficient by discarding complex hash operations. Therefore, some newly proposed consensus protocols have attempted to find a pleasant compromise between these two classic protocols. After a detailed analysis, we investigate the researches related to the defect improvements of PoS and PoW. Finally, we describe various applications of PoS and PoW, including cryptocurrencies and information storage.
The object of research is software for financial accounting and distribution of funds in a non-profit charitable foundation using smart contracts of the Ethereum platform. The work is aimed at designing and implementing a software application for a charitable foundation, which allows to exclude the misuse of funds of a non-profit charitable foundation. The paper proposes an implementation of the Ethereum smart contract for the software of a charitable foundation. In the app, users can apply for financial aid or make a charitable donation. The request for financial support is confirmed by administrators to avoid abuse by those seeking help. Anyone who has a crypto wallet can become a sponsor by transferring funds from its account to a selected request. The sponsor remains incognito when making a charitable contribution. After collecting the entire declared amount, the funds are automatically transferred to the crypto wallet of the request’s owner. A smart contract and a corresponding decentralized web application for interacting with it were experimentally deployed, and their joint work was tested. To implement the smart contract, the Solidity programming language was chosen; developed smart contract converted to bytecode using remix. The resulting bytecode is ready to be deployed on the Ethereum platform. Decentralized web application for interacting with the contract is implemented using Web3.js, Vue.js. A rough estimate of the cost of deploying a project on the Ethereum platform has been made. The deployment and operation of smart contracts and web applications comes with a certain overhead, which is most dependent on the cost of ether. However, this is a justified price to pay for the transparency of transactions and the shadowing of the turnover of funds of the charitable foundation. The results of the research can be used as a basis for further transformation into full-fledged software with the ability to submit all reporting documents to the relevant government agencies and sponsors.
The beacon chain is the backbone of the Ethereum's evolution towards a proof-of-stake-based scalable network. Beacon clients are the applications implementing the services required to operate the beacon chain, namely validators, beacon nodes, and slashers. Security defects in beacon clients could lead to loss of funds, consensus rules violation, network congestion, and other inconveniences. We reported more than 35 issues to the beacon client developers, including various security improvements, specification inconsistencies, missing security checks, exposure to known vulnerabilities. None of our findings appears to be high-severity. We covered the four main beacon clients, namely Lighthouse (Rust), Nimbus (Nim), Prysm (Go), and Teku (Java). We looked for bugs in the logic and implementation of the new security-critical components (BLS signatures, slashing, networking protocols, and API) over a 3-month project that followed a preliminary analysis of BLS signatures code. We focused on Lighthouse and Prysm, the most popular clients, and thus the highest-value targets. Furthermore, we identify protocol-level issues, including replay attacks and incomplete forward secrecy. In addition, we reviewed the network fingerprints of beacon clients, discussing the information obtainable from passive and active searches, and we analyzed the supply chain risk related to third-party dependencies, providing indicators and recommendations to reduce the risk of backdoors and unpatchable vulnerabilities. Our results suggest that despite intense scrutiny by security auditors and independent researchers, the complexity and constant evolution of a platform like Ethereum requires regular expert review and thorough SSDLC practices.
In this paper, I discuss an approach to teaching cryptocurrencies as cryptocultures. Cryptocurrencies are traditionally approached as technical or financial phenomena, but I argue that for students outside those specialist areas, a cultural approach will orient them better. I encourage teachers to first focus on situating students in a place, a shared public commons inhabited by the community of a cryptocurrency. I offer a way to model this place using a hash, bash, cash model of decentralised organisation. I build on this sense of place by then revealing to students the cultural context of a cryptocurrency. The context is comprised of the social imaginaries and the overarching goal animating a cryptocurrency culture. I show how this cryptocultural approach can be used to analyse different cryptocultures through an examination of the competing environmental imaginaries of Bitcoin and Ethereum.
We review different classes of cryptocurrencies with emphasis on their economic properties. Pure-asset coins such as Bitcoin, Ethereum and Ripple are characterized by not being a liability of any economic agent and most resemble commodities such as gold. Central bank digital currencies, at the other end of the economic spectrum, are liabilities of a Central Bank and most resemble cash. In between, there exist a range of so-called stable coins, with varying degrees of economic complexity. We use balance sheet operations to highlight the properties of each class of cryptocurrency and their potential uses. In addition, we propose the basic structure for a macroeconomic model incorporating all the different types of cryptocurrencies under consideration.