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13,493 results · page 380 of 563
Ata Assaf, Mehmet Hüseyin Bilgin, Ender Demir
No abstract is available for this record.
K. S. Arikumar, Deepak Kumar A, GowthamC, Sahaya Beni Prathiba
The most shocking events were was the recent discovery of the fraudulent activities in the Punjab National Bank. This is due to frequent systemic failures that detect human errors. Blockchain technology is the greatest solution for this issue. It is surprisingly common for the information settlement mechanism like SWIFT to be on a isolated ledger from the payment settlement mechanism. If the banks uses a ledger that stores information settlement distributed across all the participants, then the fraudulent user may reflect on all the available participants in the transactions, auditors and regulators. Our Paper is a Decentralised Loan Management Web Application (DApp) built on Ethereum blockchain which targets on preventing such fraudulent attacks on Loans sanctions by decentralising the processes. The security features authentication of the user identity, authentication of bank officials and multiple levels of verification of details are implemented using Public Key Infrastructure (PKI).
Mega Apriani, Riri Fitri Sari
ISO/IEC 29192-5 defines three lightweight cryptography hash function algorithms. Some of the lightweight cryptography based on sponge construction are PHOTON and SPONGENT. Given the importance of the hash functions in blockchain technology and the vulnerability and computational power gaps that affect the performance of the blockchain platform, this research will evaluate the SPONGENT-256 and PHOTON-256 hash algorithms to be implemented on Ethereum-based blockchain systems. The implementation of the SPONGENT-256 and PHOTON-256 hash algorithms on an Ethereum-based blockchain system produces output in the form of addresses, public keys and wallets. The experiment results of the SPONGENT-256 algorithm produces is average 0.0328 seconds, with the user time is 0.0208 seconds and the system time is 0.0118 seconds. This will give significant results if implemented on an Ethereum-based blockchain system with many nodes and data to be generated. However, the SPONGENT-256 algorithm requires a lot of memory for processing with 75%. While the KECCAK-256 algorithm uses less memory from the PHOTON-256 and the SPONGENT-256 algorithms with an average memory usage of 55%. Based on the implementation of the SPONGENT-256 hash algorithm on the Ethereum-based blockchain and analysis of the results, it can be concluded that the SPONGENT-256 algorithm can be used as an alternative hash function algorithm for Ethereum-based blockchain system.
Niclas Kannengieser, Sebastian Lins, Christian Sander, Klaus Winter · 6 authors
Smart contracts are a promising means of formalizing and reliably enforcing agreements between entities using distributed ledger technology (DLT). Research has revealed that a significant number of smart contracts are subject to programming flaws, making them vulnerable to attacks and leading to detrimental effects, such as asset loss. Researchers and developers call for a thorough analysis of challenges to identify their causes and propose solutions. To respond to these calls, we conducted two literature reviews and diverse expert interviews and synthesized scattered knowledge on challenges and solutions. We identified 29 challenges (e.g., code visibility, code updateability, and encapsulation) and 60 solutions (e.g., gas limit specification, off-ledger computations, and shadowing). Moreover, we developed 20 software design patterns (SDPs) in collaboration with smart contract developers. The SDPs help developers adjust their programming habits and thus support them in their daily development practices. Our results provide actionable knowledge for smart contract developers to overcome the identified challenges and offer support for comparing smart contract integration concepts across three fundamentally different DLT protocols (i.e., Ethereum, EOSIO, and Hyperledger Fabric). Moreover, we support developers in becoming aware of peculiarities in smart contract development and the resulting benefits and drawbacks.
Shasha Li, Xiaodong Bai, Songjie Wei
Crowdsourcing relies on Internet-wide capability to solve the complicated or large-scale tasks that are difficult to accomplish separately by individuals. However, traditional centralized crowdsourcing systems highly depend on the centralized coordination server to operate, making it extremely vulnerable to the single-point bottleneck and failure. And the whole system lacks verifiable trustworthiness among the participants. This paper proposes a blockchain-based framework for the distributed crowdsourcing without relying solely on any single trusted entity. The solutions for the outsourced tasks are verified with consensus among the participants with a reputation mechanism. We prove by theoretical security analysis that the proposed scheme resists malicious attacks better comparing to other typical crowdsourcing schemes. A prototype system is implemented based on Ethereum to demonstrate the overhead performance in various aspects. Theoretical and experimental evaluations show that the proposed scheme possesses reliability, security, quality, and feasibility.
RICARDO CARREÑO AGUILERA, Miguel Patiño-Ortiz, Julián Patiño-Ortiz, Erick Velázquez Lozada
Due to the exponential growth in the use of systems with applications of blockchain technology, this paper develops a funding system, with donations and offers of shares, through the Ethereum platform with blockchain technology. Given the benefits that blockchain provides data protection and has high security, this paper offers a decentralized donation expert system using smart contracts that makes fully reliable donation systems to attract more funds to this urgent global health issue. Smart contracts provide faithful donations and meet the characteristics of being versatile, accessible, and sustainable to combat the COVID-19 pandemic. This expert system found the Merkle grid as an optimum method to work efficiently on the blockchain. The expert system proved to be steady and efficient by using an essential test dataset. A reliable donation system expects more donors and investors since a sustainable and reliable approach is always a milestone. The primary purpose of developing this system is to attract donors to bring down the COVID-19 pandemic by providing a faithful donation system.
Dewi Setiowati
The process of educational informatization in the digital era of big data is one of the significant changes in the transformation of the educational model from traditional classrooms (face to face) to online teaching and learning based, which brings innovations from various e-learning. E-Learning is distance learning that uses computer technology, computer networks and the internet. The E-Learning system in higher education in Indonesia which is still centralized is a problem in developing E-Learning in this research in implementing the Independent Campus Policy, one of the manifestations of student-centered and decentralized learning launched by the Ministry of Education and Culture (Kemdikbud). This research takes advantage of blockchain technology to achieve breakthrough E-Learning in Higher Education that is not centralized or decentralized. Blockchain technology provides the advantages of decentralized digital certificate issuance as well as secure storage using the Ethereum blockchain. The results show blockchain technology to solve weaknesses in the field of online education based on Merdeka Campus, namely the issuance of certificates as evidence of student learning outcomes in the form of a formal digital certificate in decentralized E-Learning and insecurity in storage for verification using the Ethereum blockchain. The digital certificate from the transaction will identify block hash, gas usage, block number and block time as different private keys.\n\nKeywords: E-Learning, Independent Campus, Blockchain, Digital Certificate Verification Abstrak \n\nProses informatisasi pendidikan di era digital data besar (big data) merupakan salah satu perubahan signifikan transformasi model pendidikan dari kelas trandisional (tatap muka) menjadi berbasis belajar-mengajar secara online, yang membawa inovasi dari berbagai e-learning. E-Learning adalah pembelajaran jarak jauh yang menggunakan teknologi komputer, jaringan komputer, dan internet. Sistem E-Learning pada Pendidikan tinggi di Indonesia yang masih terpusat menjadi permasalahan pengembangan E-Learning penelitian ini dalam menerapkan Kebijakan Kampus Merdeka salah satu perwujudan pembelajaran berpusat pada mahasiswa (student centered learning) dan terdesentralisasi yang diluncurkan oleh Kementerian Pendidikan dan Kebudayaan (Kemdikbud). Penelitian ini mengambil keunggulan teknologi blockchain agar dicapai terobosan E-Learning pada Pendidikan Tinggi yang tidak terpusat atau terdesentralisasi. Teknologi blockchain memberikan keunggulan penerbitan sertifikat digital terdesentralisasi serta penyimpanan aman menggunakan Ethereum blockchain. Hasil penelitian menunjukkan teknologi blockchain menyelesaikan kelemahan di bidang pendidikan online berbasis Kampus Merdeka yaitu penerbitan sertifikat digital sebagai bukti hasil belajar mahasiswa berupa sertifikat digital secara legal formal pada E-Learning secara terdesentralisasi dan ketidakamanan dalam penyimpanan untuk verifikasi sertifikat digital menggunakan Ethereum blockchain. Sertifikat digital hasil transaksi tersebut akan teridentifikasi block hash, gas usage, block number dan block time sebagai private key yang berbeda satu dengan lainnya.\n\nKata kunci: E-Learning, Kampus Merdeka, Blockchain, Verifikasi Sertifikat Digital
Luca Franceschi, Andrea Lisi, Andrea De Salve, Paolo Mori · 5 authors
In the past years, trust management systems have been proven suitable for solving the authorization problem in distributed systems, such as peer to peer systems, social networks, cloud, mobile ad-hoc networks, and Internet of things. Trust management systems could be either managed by a central authority or decentralized. In both cases the entity or, respectively, the set of entities managing the system need to be trusted for all users. To overcome this limitation, this paper brings blockchain technology into trust management systems, proposing a novel implementation of the Role-based Trust management framework (RT) on blockchain. The approach relies on smart contracts to represent user trust networks and to infer new trust relations through the chain discovery algorithm. We evaluated a prototype implemented on Ethereum on a representative set of policies related to different scenarios.
Zhiyuan Huang, Jun Zheng, Mingjun Xiao
Crowdsourcing Data Trading is a novel paradigm, where a platform can aggregate data collected by a group of mobile users. Traditional crowdsourcing data trading systems rely on trusted data trading brokers, which increase costs and cannot prevent collusion. What’s more, they don’t take of data quality and truthfulness into consideration con-currently. The emergence of blockchain and smart contracts brings in a decentralized scheme. However, the selection of the most effective providers remains challenging. To tackle these problems, we propose a dynamic-game-with-complete-information-and-Blockchain-based Crowdsourcing data Trading system (CBCT), which mainly includes a smart contracts called CBCToken. Firstly, we replace the data trading broker and adopt the Stackelberg Game, a Dynamic Game with complete information (DGC), to manage the selection of providers. Moreover, homomorphic watermarking technology is applied to protect the data copyright. Lastly, we deploy BCDToken on an Ethereum test network to demonstrate its practicability and significant performances.
WAN ATIQAH WAN JAMARUL IMRAN, Mohamed Hisham Yahya, Muhammad Hafiz Ali, MOHD AKBAL QAMAS ABDUL BASIR .
This research studies the factors that affect volatility in cryptocurrency markets. The relationship between information asymmetry and cybercriminal risks are studied against the volatility and return of cryptocurrencies, namely, Bitcoin (BTC), Ethereum (ETH), Bitcoin Cash (BCH) dan Ripple (XRP). These cryptocurrencies are selected as they are cryptocurrencies that are being traded by Luno, Sinergy and Tokenzie (the exchange companies regulated by the Securities Commissions of Malaysia). 730 observations were collected for each cryptocurrency via the CoinMarketCap website, from 1 January 2019 to 30 December 2020. The ADF test and the Kolmogorov-Smirnov test have been conducted before the analysis of the data. The results show the stationarity and non-normality of the data collected. The EGARCH-GED model is used to analyse the relationship between information asymmetry and volatility. The findings indicate a significant relationship between information asymmetry and volatility in BTC, ETH ad XRP. The Event Study Method (ESM) is used to analyse the effect of cybercriminal risks on returns. The result shows that all four cryptocurrencies show a significant relationship between cybercriminal risks and returns.
Qianyun Gong, Chengjin Zhou, Le Qi, Jianbin Li · 6 authors
The payment channel networks (PCNs), as the main method of blockchain off-chain expansion, have received extensive attention in recent years. Using the PCNs, two unconnected parties in a transaction can forward payments through existing payment channels of other nodes, which dramatically reduces interactions with the blockchain. But in large-scale dynamic PCNs, the routing mechanism is a challenge. Existing PCNs routing algorithms have some limitations. The landmark routing destroys the decentralization of blockchain. The static routing requires nodes having a global view and ultra-high computing power, which can not be applied to light nodes. We propose VEIN, a dynamic multi-path source routing algorithm, which is suitable for not only full nodes but also light nodes. We present an ingenious routing protocol, a modified max-flow algorithm to find edge-disjoint paths, and a path selection algorithm to deal with the NP-hard multi-path selection problem. Extensive experiments show that VEIN increases the transaction success ratio by 34% with the state-of-art algorithm, and realizes multiple orders of magnitude reduction in storage. In addition, we implement a prototype of VEIN on the Ethereum testnet to verify its feasibility.
Fátima Leal, Bruno Veloso, Benedita Malheiro, Juan C. Burguillo · 6 authors
Explainable recommendations enable users to understand why certain items are suggested and, ultimately, nurture system transparency, trustworthiness, and confidence. Large crowdsourcing recommendation systems ought to crucially promote authenticity and transparency of recommendations. To address such challenge, this paper proposes the use of stream-based explainable recommendations via blockchain profiling. Our contribution relies on chained historical data to improve the quality and transparency of online collaborative recommendation filters – Memory-based and Model-based – using, as use cases, data streamed from two large tourism crowdsourcing platforms, namely Expedia and TripAdvisor. Building historical trust-based models of raters, our method is implemented as an external module and integrated with the collaborative filter through a post-recommendation component. The inter-user trust profiling history, traceability and authenticity are ensured by blockchain, since these profiles are stored as a smart contract in a private Ethereum network. Our empirical evaluation with HotelExpedia and Tripadvisor has consistently shown the positive impact of blockchain-based profiling on the quality (measured as recall) and transparency (determined via explanations) of recommendations.
Muhammad Danil Muis, Muhammad Rifki Fauzan, Parman Sukarno, Aulia Arif Wardana
This reserach build access control and file distribution management system for electronic diploma and transcript using ethereum smart contract and InterPlanetary File System (IPFS). The falsification of diplomas/transcripts is one of the problems in education. In Indonesia, falsification of diplomas/transcripts is a form of criminal act of falsifying letters. In addition, diplomas/transcripts that have not been digitalized make them easily damaged, lost, and difficult to manage. Therefore, this research developed digital diploma/transcript as digital twin from the hardcopy of diploma/tramscript. This research used IPFS to store data in a distributed system and Smart Contracts Blockchain to store and protect the digital diploma/transcript. The system also comes with access control to create and give approval for diplomas or transcripts to be published and saved into the system. Access control settings will be saved using the blockchain. This research using Quality of Service test method for measurethroughput, packet loss, and delay. Beside that, tis research also analysis the usage of Central Processing Unit and Random Access Memory from the system. Based on the test that has been done, the fake diploma/transcript detection system can be run properly by using 1 node to 5 nodes. The best throughput value during the process of making and validating the diploma/transcript is to use 1 node. The value of packet loss in the process of making and validating the certificate/transcript has a very good category. The value of delay in the process of making and validating the diploma/transcript has a very good category.
Noama Fatima Samreen
Ethereum Blockchain based Smart Contracts are computer programs that enable decentralized transactions among its participants. The development of smart contracts is a complex process because of the characteristics of Blockchain Technology like the immutability of blocks added to the blockchain. Also, the current evolving nature of this novice technology makes the development process insubstantial. Therefore, this doctoral dissertation highlights the vulnerabilities and complexities in smart contracts and proposes a model-driven engineering framework for designing secure smart contracts at the model level and generating vulnerability-free smart contract code.
Zehao Chen, Bingzhe Li, Xiaojun Cai, Zhiping Jia · 7 authors
Ethereum as one of the largest blockchain systems plays an important role in the distributed ledger, database systems, etc. As more and more blocks are mined, the storage burden of Ethereum is significantly increased. The current Ethereum system uniformly transforms all its data into key-value (KV) items and stores them to the underlying Log-Structure Merged tree (LSM-tree) storage engine ignoring the software semantics. Consequently, it not only exacerbates the write amplification effect of the storage engine but also hurts the performance of Ethereum. In this paper, we proposed a new Ethereum-aware storage model called Block-LSM, which significantly improves the data synchronization of the Ethereum system. Specifically, we first design a shared prefix scheme to transform Ethereum data into ordered KV pairs to alleviate the key range overlaps of different levels in the underlying LSM-tree based storage engine. Moreover, we propose to maintain several semantic-orientated memory buffers to isolate different kinds of Ethereum data. To save space overhead, Block-LSM further aggregates multiple blocks into a group and assigns the same prefix to all KV items from the same block group. Finally, we implement Block-LSM in the real Ethereum environment and conduct a series of experiments. The evaluation results show that Block-LSM significantly reduces up to 3.7× storage write amplification and increases throughput by 3× compared with the original Ethereum design.
Samvid Dharanikota, Suvam Mukherjee, Chandrika Bhardwaj, Aseem Rastogi · 5 authors
We present CELESTIAL, a framework for formally verifying smart contracts written in the Solidity language for the Ethereum blockchain. CELESTIAL allows programmers to write expressive functional specifications for their contracts. It translates the contracts and the specifications to F⋆ to formally verify, against an F⋆ model of the blockchain semantics, that the contracts meet their specifications. Once the verification succeeds, CELESTIAL performs an erasure of the specifications to generate Solidity code for execution on the Ethereum blockchain. We use CELESTIAL to verify several real-world smart contracts from different application domains. Our experience shows that CELESTIAL is a valuable tool for writing high-assurance smart contracts.
Shaimaa Bajoudah, Paolo Missier
Trading data as valuable assets has become a trend. Data such as IoT data constitute a new source of profit for their owners and they have become tradeable assets in data marketplaces. In this work, we present the technical implementation and evaluation of our marketplace model, which was introduced in a previous work. The marketplace supports the trading of streaming data, from offering data for sale and negotiating trade agreements, to automating trade obligations and fulfilment. It ends with payment settlement and the scoring of trade parties. We show that by using Ethereum blockchain technology and Ethereum smart contracts in particular, we can offer a trade-off between the gas price paid for transaction confirmation and the transaction latency, the time taken for an Ethereum network to process and confirm our marketplace transactions. We experimentally assess such trade-offs on a testbed using our marketplace implementation as a DApp.
Akshay M. Fajge, Subhasish Goswami, Arpit Srivastava, Raju Halder
The gas mechanism on the Ethereum blockchain attempts to set charges for every smart contract operation in order to prevent infinite control of computational resources by the executing transactions. To satisfy this requirement, users need to specify in their transactions how much gas fees (in terms of gas limit and gas price) they would like to pay for. In essence, these gas fees are paid to the miners in return for their computational services. Naturally, miners tend to maximize their profits by considering the transactions with higher gas fees, and as a result, the transactions with lower gas fees remain in the waiting pool for a long time. This paper proposes a machine learning-based approach to predict whether a transaction with offered gas fees is likely to be included in the blockchain within the expected time or not. Such prior prediction of transactions' waiting time definitely assists users to reset their gas fees accordingly. The proposed model is evaluated on nearly one million real transactions from Ethereum mainnet, and the experimental results demonstrate a better performance than the existing one in the literature, with an achievement of 90.18% accuracy and 0.897 F1-score when the model is trained with Random Forest on the dataset balanced with SMOTETomek.
Insaf Achour, Hanen Idoudi, Samiha Ayed
Access control in Blockchain context is a crucial step. During this process it is important to verify that users have the right roles to get access to the protected resources. To model its access control, the Ethereum Blockchain is based on RBAC model. The whole process is written in a smart Contract imported from The OpenZepplin Library [1]. However, the automatic generation of the access control policy still missing. This automation can widely enhance and simplify the implementation of access control for developers of blockchain based applications. In this paper, we propose a new model for automatically generating the access control smart contract. Our approach is based on the Model Driven Engineering (MDE).
Xun Sun, Xingwei Lin, Zhou Liao
Due to the rapid increasing of smart contracts in Ethereum, retrieving the related smart contracts has become an important issue. A key step of recognizing the related smart contracts is to classify them. Nowadays most of the classification methods of smart contracts are based on source code or bytecode analysis. However, as the interface of a smart contract, ABI has key information about the smart contract's function and behavior. Aiming to find out the effect of ABI on the classification of smart contracts, we propose an automatic classification method that utilize popular text classification method on ABI granularity. Our experiments are based on basic machine learning algorithms - SVM, XGBoost, Stacking and Bagging, which take TF-IDF vectors of ABIs as input, and the results indicate that ABI-based smart contracts classification is an effective approach. Compared with source code-based classification method, the MCC score of our method increased by more than 0.1 on average.
Keyao Huang, Jingyu Ma, Xinyuan Wang
With the development of blockchain, various blockchain-based applications emerged. Of which Bitcoin and Ethereum are the most representative and popular blockchain applications. Therefore, it is important to compare Bitcoin with Ethereum and infer their developing trends. In the paper, we compare Bitcoin and Ethereum from different perspectives, including consensus algorithm, transaction cost, extension, and security. Comparative results demonstrate that Ethereum is better than Bitcoin on extension and transaction mechanism. Also, based on the results, we discuss about the essential development trend about blockchain applications. In the future, blockchain applications will be a platform which can provide more functions than digital currencies.
Mihai Duguleană, Florin Gîrbacia
Non-fungible tokens are one of the newest use-cases of blockchain technology. Ethereum Virtual Machine (EVM)-based blockchains such as Ethereum, Binance Smart Chain (BSC), or Polygon/Matic have standardized this type of tokens using interfaces such as ERC721 and ERC1155. This development fostered a connection between blockchain and Mixed Reality technologies, which can now coexist in cohesive applications. In this paper, we present the opportunities and challenges resulting from using Augmented Reality NFTs, with a particular focus on the preservation of property, whether it is physical or purely digital. We present a methodology that can ensure the protection of privacy and the preservation of intellectual property when transitioning assets from the virtual to the physical world.
Akash Arora, Kanisk, Shailender Kumar
No abstract is available for this record.
Yuxing Tang, Zihao Li, YanXu Bai
Smart contract is one of the key technologies of the blockchain and is becoming more and more popular. But at the same time, the economic losses caused by the vulnerabilities of smart contracts have also emerged in recent years. One of the most famous smart contract security issues is reentrancy. There have been many related reports and researches on reentrancy. However, the existing methods only pay attention to offensive reentrancy one-sidedly, but do not conduct a systematic and comprehensive analysis of reentrancy and some existing reentrant detection methods for smart contracts often have high false positives(FPs). We proposed a more accuracy and comprehensive detection and analysis method of reentrancy from real Ethereum transactions. In general, we used Datalog-based formulation to detect reentrant transactions in real world of Ethereum, and compared the detection results with other tools. We finally detected 2,712 reentrant transactions and 10 vulnerable smart contracts with zero false positive, furthermore, we found that many vulnerable contracts detected by other tools did not trigger real reentrant transactions. We summarized the problems in the existing detection tools and gave effective preventive measures. In addition, we also analyzed the detected benign reentrancy to further confirm the above findings, and the discovery that benign reentrancy also has its certain application scenario.