K. S. Sagar Bharadwaj, Tejas Kalburgi, Chandra Mouli, Dr.Vikram Palodia
We are investigating the troubles within-side the election balloting structures and seeking to suggest the e-voting version with the usage of blockchain which could solve the issues. Also, our attempts aim to assess the software of blockchain as provider to enforce dispensed digital voting structures. The phase of paper will spotlight a number of famous blockchain structures that provide blockchain as a provider and related digital e-balloting machine, that’s primarily based totally on decentralised system that addresses all obstacles respectively, it additionally preserves participant’s anonymity whilst nonetheless being open to public inspection.
Smart contract (SC) is a user-defined program code over blockchain, which holds the characteristics of immutability and auditability without requiring trust third party and is crucial to provide in-network computation for green applications. Herein we investigate the interactions among the SCs, where the functions defined in one SC are called by another one. The existing work, Ethereum name service (ENS), provides a method to map human-readable names to machine-readable addresses. However, it still suffers the problems induced from the ossification of SC, such as no mechanism to call functions in a non-existing SC, to update SC, to acquire the SC information (e.g. contract application binary interface and address), and to achieve access control. To solve these problems, we propose a flexible smart contract interaction framework with access control (FSCC), where SC name and information are separately stored at blockchain and the distributed off-chain storage to reduce on-chain storage overhead. With the FSCC, interactions with non-existing SC, update of SC, and access control of SC can be achieved. Furthermore, performance evaluations show that on-chain storage overhead can be greatly reduced with keeping the communication delay at a low level.
Voting is the fundamental characteristics of every democratic country. E-Voting or electronic voting is a means for the election process to be conducted without the use of traditional paper ballots. An election, which takes place in the form of voting, is a process that involves members in mutual competition. Voting is the activity of choosing someone or something in an election. Blockchain technology is providing various opportunities for developing the new and existing digital services by providing the blockchain characteristics such as immutability, integrity, transparency, anonymity, etc. Blockchain is distributed ledger technology which provides decentralization. Electronic voting system using blockchain services provides the security, transparency. The working of blockchain will ensure the votes are maintained and the systems are not rigged by any third party. Every vote that is casted will be considered as an individual transaction. These votes will be counted and the voting results and winner of the election will be announced.
In recent years, the number of Internet-of-Things (IoT) devices has grown at an explosive rate. With the dramatic surge of the IoT, security issues have also come to the fore. Consequently, ensuring the security of the IoT communication community environment and trust between entities have become important research topics. In this paper, we design a passwordless IoT authentication mechanism, namely, T-Auth, to address these issues. The identity of a device in T-Auth is based on physical unclonable functions (PUFs), a hardware-based device fingerprint technology, which can greatly improve the security level compared to hardcoded passwords. A smart contract is a program that runs on the blockchain, which provides design flexibility and operational reliability. Our mechanism establishes a new trust architecture that enables devices to exchange information securely and reliably. The main contribution of this paper is to propose a new authentication mechanism that utilizes PUFs and combines them with blockchain to greatly improve the security and reliability of a system. Additionally, by leveraging Ethereum smart contracts, our mechanism supports cross-service group authentication.
Physical Unclonable Functions (PUFs) and Hardware Security
User Authentication and Security Systems
Advanced Steganography and Watermarking Techniques
Electronic voting can greatly reduce the cost of voting activities and solve many problems of voting information leakage caused by traditional paper voting. As the development and extension of blockchain technology, Ethereum technology can well solve the centralization problem of traditional electronic voting. This solution proposes an electronic voting system based on Ethereum technology to meet the security requirements of electronic voting, and uses Ethereum smart contract technology to replace the traditional trusted third party, which solves the possible drawbacks of the centralized voting system and improves Security and voters' trust in the voting system reduce voting costs. Finally, the electronic voting function is realized, and the normal operation of the system is guaranteed through the test.
Goldfinger-Attacken zielen darauf ab, den Wert einer Ziel-Kryptowährung zum Absturz zu bringen, indem die Mehrheit der Stimmrechte im System genutzt wird das zu Grunde liegende Konsensprotokoll untergraben. In einem Proof-of-Stake-Kontext, in dem die Stimmkraft auf der Menge der gehaltenen Kryptowährung basiert, kann dies in Form eines Buy-out-Angriffs erreicht werden, bei dem eine Mehrheit der Zielwährung gekauft wird. In diesem Zusammenhang wurde der Race to the Door (RTTD)-Effekt beschrieben, der dazu führt, dass immer mehr Inhaber aus der Zielwährung aussteigen, bevor diese wertlos wird. Dieser Effekt senkt den Preis für weitere Stimmenanteile, wodurch der Angriff billiger wird, je weiter er fortschreitet. Diese Arbeit soll zeigen, dass ein Angriff im Stil von Race to the Door auch in einem Proof-of-Work (PoW)-Kontext technisch möglich ist, ohne eine Mehrheit der Stimmrechte (d. h. der Hash-Rate) zu erlangen. Zu diesem Zweck werden die technische Machbarkeit und die Kosten eines solchen Angriffs am Beispiel von Ethereum untersucht. Zunächst wird ein Systemmodell für RTTD-Angriffe auf PoW-basierte Kryptowährungen vorgestellt, um einen Überblick zu geben. Der Angriff wird dabei in die Phasen Vorbereitung, Rennen und Angriff unterteilt. Um die technische Machbarkeit zu demonstrieren, werden diese Phasen in Form von Smart Contracts auf Ethereum umgesetzt. Für die Angriffsphase werden drei Varianten vorgestellt, die jeweils einen unterschiedlichen Denial-of-Service-Angriff realisieren. Dazu werden In-Band-Zahlungen genutzt, um entweder das Auslösen zusätzlicher Transaktionen oder die Erzeugung leerer Blöcke durch Miner zu incentivieren. Um die Kosten der vorgeschlagenen Angriffsvarianten abzuschätzen, wird eine empirische Analyse durchgeführt, bei der Transaktionsdaten von historischen Überlastungsphasen der Ethereum-Blockchain untersucht werden. Anhand der Ergebnisse werden die Kosten der Angriffsvarianten geschätzt und verglichen. Die stündlichen Kosten für das Blockieren von Transaktionen durch das auslösen weiterer Transaktionen betragen etwa 870 Ether. Die Incentivierung von Minern, die ein Drittel der Blöcke leer lassen, kostet etwa 790 Ether pro Stunde. Die Arbeit zeigt, dass Race to the Door-Attacken auch im Kontext von PoW-basierten Kryptowährungen technisch durchführbar sind. Die Kosten des Angriffs hängen dabei von seiner Intensität und Dauer ab. Die Intensität kann in der Angriffsphase konfiguriert werden und die Dauer hängt von der für den Angriff verfügbaren Geldmenge ab.
Smart contracts present a uniform approach for deploying distributed computation and have become a popular means to develop security critical applications. A major barrier to adoption for many applications is the public nature of existing systems, such as Ethereum. Several systems satisfying various definitions of privacy and requiring various trust assumptions have been proposed; however, none achieved the universality and uniformity that Ethereum achieved for non-private contracts: One unified method to construct most contracts. We provide a unified security model for private smart contracts which is based on the Universal Composition (UC) model and propose a novel core protocol, KACHINA, for deploying privacy-preserving smart contracts, which encompasses previous systems. We demonstrate the KACHINA method of smart contract development, using it to construct a contract that implements privacy-preserving payments, along the lines of Zerocash, which is provably secure in the UC setting and facilitates concurrency.
Matthieu Nadini, Laura Alessandretti, Flavio Di Giacinto, Mauro Martino · 6 authors
Non Fungible Tokens (NFTs) are digital assets that represent objects like art, collectible, and in-game items. They are traded online, often with cryptocurrency, and are generally encoded within smart contracts on a blockchain. Public attention towards NFTs has exploded in 2021, when their market has experienced record sales, but little is known about the overall structure and evolution of its market. Here, we analyse data concerning 6.1 million trades of 4.7 million NFTs between June 23, 2017 and April 27, 2021, obtained primarily from Ethereum and WAX blockchains. First, we characterize statistical properties of the market. Second, we build the network of interactions, show that traders typically specialize on NFTs associated with similar objects and form tight clusters with other traders that exchange the same kind of objects. Third, we cluster objects associated to NFTs according to their visual features and show that collections contain visually homogeneous objects. Finally, we investigate the predictability of NFT sales using simple machine learning algorithms and find that sale history and, secondarily, visual features are good predictors for price. We anticipate that these findings will stimulate further research on NFT production, adoption, and trading in different contexts.
With the advent of the Internet, the gaming industry has grown tremendously in business, which also raises concerns for cheating and unfair gameplay. In this paper, we propose a novel approach (GiNA) using Blockchain technology to address a few problems with online Peer-to-Peer (P2P) games. GiNA uses two different data packet transfer schemes to ensure the security and authenticity of the data packet sent and received by game clients. More sensitive data uses a Smart contract-based ON-CHAIN data packet transfer solution and less sensitive data uses an OFF-CHAIN data packet transfer solution with end-to-end encryption for data security. A marketplace where peers can buy and sell purchasable assets with the help of Gicoins. Gicoins is a stable token with compliance with the ERC 20 token of Etheruem Blockchain. Later, a low cost and low bandwidth utilization data storage solution is proposed for storing data in a decentralized and distributed manner. Results show that the performance of the proposed approach GiNA is better in comparison to the traditional approaches with parameters such as latency, scalability, packet loss percentage, Blockchain (BC) performance, and data storage comparison.
Rodrigo Dutra Garcia, Gabriel Augusto Zutiao, Gowri Ramachandran, Jó Ueyama
Electronic prescription (e-Prescription) is a digital way to manage medical prescriptions and reduce inconsistencies in the communication between doctors, patients, and pharmacies. Smart contracts allow the automation of tasks and business rules in a decentralized architecture (i.e., without the need for an intermediary or central authority). Platforms such as Ethereum and Hyperledger Fabric support smart contracts development through a consensus mechanism such as Proof-of-Work or another criterion among the network's participating nodes. This paper explores Tendermint, a Byzantine Fault Tolerant (BFT) based consensus mechanism that has not yet been widely adopted for smart contracts platforms. We apply our devised model to the healthcare application domain, more precisely in the field of e-prescription, and our results demonstrate that smart contracts can be implemented on a BFT-based platform. To the best of our knowledge, this is the first study investigating the implementation of smart contracts in a BFT-based platform such as Tendermint. We exploit this domain as there can exist some conflicting interests of profit-taking. For example, pharmacists can increase the medication dosage above the one prescribed by doctors for profit-taking. Such a scenario can occur particularly in countries where healthcare is free of charge and offered as a public service (e.g., Brazil). We show that smart contracts in BFT-based blockchain can help in solving problems in these application scenarios. Finally, our two key contributions in this paper are two-fold: (i) exploit smart-contracts in BFT-based platforms where they (smart contracts) are not very established yet in the blockchain domain; (ii) provide a smart-contract-based e-prescription solution to reduce the costs (no need for a central authority) and scams particularly in countries where the medical service is free and public.
Possible scenarios for using blockchain technology in the field of education are considered. Methods and technologies of tokenization of assets, related to the educational process, are investigated. It is concluded, that the blockchain technology is decentralized and transparent with a high degree of reliability, which ensures the equality of all users of the chain's services. The transparency of the technology guarantees the participants in the process against abuse and forgery of documents. The study of the features of smart contracts made it possible to form the advantages of smart contracts in the field of education. This is, first of all, the conclusion of agreements without the participation of third parties, as well as the security and confidentiality of agreements. This ensures that the terms and subject of the agreement are kept secret, and that no one else can amend the agreement. At the same time, storing the contract in encrypted form ensures its confidentiality. A decrease in the cost of operations was noted. Tokenization of educational assets is considered on the example of preparing and defending a thesis with the subsequent registration of a diploma. The processes of passing the thesis in the context of using blockchain technology and issuing smart contracts are considered in detail. The advantages of using blockchain technology and smart contracts are illustrated with specific examples. A study of the means and mechanisms for ensuring the confirmation of the authenticity of educational documents, the confidentiality of students' personal cards, and student identification has been carried out. To create a decentralized distributed ledger for tokenization of educational assets, it is proposed to use blockchain technology and smart contracts based on the Ethereum platform
With the development of blockchain technologies, the number of smart contracts deployed on blockchain platforms is growing exponentially, which makes it difficult for users to find desired services by manual screening. The automatic classification of smart contracts can provide blockchain users with keyword-based contract searching and helps to manage smart contracts effectively. Current research on smart contract classification focuses on Natural Language Processing (NLP) solutions which are based on contract source code. However, more than 94% of smart contracts are not open-source, so the application scenarios of NLP methods are very limited. Meanwhile, NLP models are vulnerable to adversarial attacks. This paper proposes a classification model based on features from contract bytecode instead of source code to solve these problems. We also use feature selection and ensemble learning to optimize the model. Our experimental studies on over 11K real-world Ethereum smart contracts show that our model can classify smart contracts without source code and has better performance than baseline models. Our model also has good resistance to adversarial attacks compared with NLP-based models. In addition, our analysis reveals that account features used in many smart contract classification models have little effect on classification and can be excluded.
Ponzi schemes are financial scams that lure users under the promise of high profits. With the prosperity of Bitcoin and blockchain technologies, there has been growing anecdotal evidence that this classic fraud has emerged in the blockchain ecosystem. Existing studies have proposed machine-learning based approaches for detecting Ponzi schemes, i.e., either based on the operation codes (opcodes) of the smart contract binaries or the transaction patterns of addresses. However, state-of-the-art approaches face several major limitations, including lacking interpretability and high false positive rates. Moreover, machine-learning based methods are susceptible to evasion techniques, and transaction-based techniques do not work on smart contracts that have a small number of transactions. These limitations render existing methods for detecting Ponzi schemes ineffective. In this paper, we propose SADPonzi, a semantic-aware detection approach for identifying Ponzi schemes in Ethereum smart contracts. Specifically, by strictly following the definition of Ponzi schemes, we propose a heuristic-guided symbolic execution technique to first generate the semantic information for each feasible path in smart contracts and then identify investor-related transfer behaviors and the distribution strategies adopted. Experimental result on a well-labelled benchmark suggests that SADPonzi can achieve 100% precision and recall, outperforming all existing machine-learning based techniques. We further apply SADPonzi to all 3.4 million smart contracts deployed by EOAs in Ethereum and identify 835 Ponzi scheme contracts, with over 17 million US Dollars invested by victims. Our observations confirm the urgency of identifying and mitigating Ponzi schemes in the blockchain ecosystem.
3 source records
Blockchain Technology Applications and Security
Spam and Phishing Detection
Advanced Steganography and Watermarking Techniques
Decentralized systems and protocols are becoming more popular every year. The main limitations of public permissionless blockchains are low bandwidth and high fees. There are various ways to reduce the load on the network to address these drawbacks, the majority of them were developed for Ethereum but stay valid for many other chains. The paper considers the following options for scaling decentralized systems: consensus modification and sharding that are embedded in the core of a blockchain, second layer solutions and sidechains that can be built on top of a network.
Bütün sektörler dahilinde finans sektöründe de müşterilere ait fikir ve düşüncelerinin belirlenmesi, firma ve kurumların ileriki dönemler için sunacağı hizmetleri etkilemektedir. Kripto para birimlerinin (Bitcoin, Ethereum, Ripple vb.) ekonomik ve sosyal etkileri hızla artmaya devam ettikçe, ilgili haber makalelerinin ve sosyal medya yayınlarının, özellikle de tweetlerin yaygınlığı da artmaktadır. Bu çalışmada, Twitter kullanıcılarının finans sektörü konularından biri olan Bitcoin ile ilgili yorumları derlenerek bir duygu analizi çalışması yapılmıştır. Kullanıcı yorumları, Twitter’ın sunmuş olduğu API hizmeti vasıtasıyla Python Programlama Dili kullanılarak alınmış; yorumlar olumlu, nötr ve olumsuz etiketler ile ayrıştırılmış, etiket bulutunda toplanmıştır. Naïve Bayes ve Lojistik Regresyon algoritmaları kullanılarak oluşturulan modellerde başarı oranları karşılaştırılmıştır. Naïve Bayes uygulamasının tweetlerin duygularını tahmin etmedeki başarı oranı %72,19 olurken, Lojistik Regresyon uygulamasında bu oran %75,53 olmuştur. Çalışmanın ikinci aşamasında ise, duygu analizinden sonra “Bitcoin” anahtar kelimesi içeren günlük pozitif tweet oranı ile Bitcoin günlük açılış değeri beraber kullanılarak Bitcoin kapanış değeri tahminlemesi yapılmıştır. Finans verileri Yahoo Finance web sitesi üzerinden alınmış; Doğrusal Regresyon ve Rastgele Orman Regresyon yöntemleri ile modeller oluşturulmuştur. Doğrusal Regresyon için r² değeri %88,97 çıkarken, Rastgele Orman Regresyonu için ise %94,16 olmuştur.Anahtar Kelimeler: Duygu analizi, Twitter, Bitcoin, Makine öğrenmesi, Veri madenciliği, Finans
One of the most important discoveries and creative developments that is playing a vital role in the professional world today is blockchain technology. A blockchain is a distributed, digitized and consensus-based secure information storage mechanism. Blockchain technology moves in the direction of persistent revolution and change. In the last couple of years, the upsurge in blockchain technology has obliged scholars and specialists to scrutinize new ways to apply blockchain technology with a wide range of domains. The dramatic increase in blockchain technology has provided many new application opportunities, including e-voting application. The present article provides a systematic review of emerging blockchain-based e-voting systems. In this paper, we call attention to the open research matters in this fast-growing field, explaining them in some details. It was concluded that frameworks needed enhancements in order to be used in voting systems due to these reservations. KEYWORDS: blockchain, e-voting, cloud computing, ethereum; ballot
Svetislav D. Simić, Marko Marković, Stevan Gostojić
This paper presents theoretical and practical research on the possibilities of applying smart contracts in the field of law and a contract management system which allows users to conclude contracts based on blockchain technology. The transition from traditional contracting to smart contracting would significantly improve the contracting process as contracts concluded in this way would be without intermediaries. Therefore, they could be concluded more efficiently and the costs related to the contracts could be reduced. Allotment contract was selected as an example, i.e., a contract by which the hotel representative assigns certain accommodation capacities to a travel agency and by which the agency provides those capacities in their arrangements. A smart allotment contract has been written using the Solidity programming language, to run on the Ethereum platform.
Car sharing facilitates car owners and renters to share and use their cars conveniently. The popular car-sharing systems like Car2Go or Zipcar provide such facilities; however, they work line an intermediary or broker and thus pose various security and privacy threats. This paper proposes an alternate car-sharing model by constructing a decentralized cab consortium where the car owners and the renters can directly interact and share the car based on certain predefined agreements. We utilize the concept of smart contracts on top of a blockchain platform to realize such a system that provides a secured, tampered-proof, fair, and transparent interface for car sharing. We have implemented the proposed platform over an Ethereum-based environment and show that its runtime cost and performance are within a considerable margin.
Machine learning has become ubiquitous across many fields in the last decade and modern real world applications often require a decentralized solution for training such models. This demand sprouted the research in federated learning, which solves some of the challenges with centralized machine learning, but at the same times raises further questions in regard to security, privacy and scalability. We have designed and implemented DecFL, an ubiquitous protocol for decentralized model training. The protocol is machine-learning-model-, vendor-, and technology-agnostic and provides a basis for practitioner's own implementations. The implemented DecFL framework presented in this article is an exemplary realization of the carefully designed protocol stack based on Ethereum and IPFS and offers a scalable baseline solution for decentralized machine learning. In this article, we present a study based on the proposed protocol, its theoretical bounds and experiments based on the implemented framework. Using open-source datasets (MNIST and CIFAR10), we demonstrate key features, the actual cost of training a model (in euro) and the communication overhead. We further show that through a proper choice of technologies DecFL achieves a linear scaling, which is a non-trivial task in a decentralized setting. Along with discussing some of the security challenges in the field, we highlight aggregation poisoning as a relevant attack vector, its associated risks and a possible prevention strategy for decentralized model training through DecFL.
Hemant Kumar Srivastava, Ravi Yadav, Gaurav Baranwal
The paper presents an Ethereum based service selection framework that is decentralized in nature and aids people in finding the best services using a smart contract. We have used Solidity, a language to develop the smart contract for Ethereum, to tackle the problem that occurs in broker-based systems or centralized systems. As for the result, we show that the functionalities performed by a broker can be implemented on Ethereum smart contract. We present a methodology that one can refer to develop Ethereum smart contract for service selection.
William Hughes, Alejandro Russo, Gerardo Schneider
Smart contracts are self-executing programs running in the blockchain allowing for decentralised storage and execution without a middleman. On-chain execution is expensive, with miners charging fees for distributed execution according to a cost model defined in the protocol. In particular, transactions have a high fixed cost. In this paper we present MultiCall, an interpreter that reduces the cost of smart contract execution by emulating sequences of transactions from multiple users in one transaction. We have implemented and integrated MultiCall into Ethereum. Our evaluation shows that using MultiCall provides a saving between 56.8% and 98.9% of the fixed per-transaction cost compared to the standard approach of sending transactions individually.