Follow blockchain research across journals, conferences, and preprint repositories.
13,620 results · page 464 of 568
Sangyeon Woo, Je-Ho Song, Sanghyeok Kim, Youngjae Kim · 5 authors
No abstract is available for this record.
Rafael Ordóñez Alba
No abstract is available for this record.
Vivi Vivi Indah Setiawati
No abstract is available for this record.
Younghun Lee, Shailendra Rathore, Jin Ho Park, Jong Hyuk Park · 6 authors
Abstract With the advancement of Information and Communication Technology (ICT) and the proliferation of sensor technologies, the Internet of Things (IoT) is now being widely used in smart home for the purposes of efficient resource management and pervasive sensing. In smart homes, various IoT devices are connected to each other, and these connections are centered on gateways. The role of gateways in the smart homes is significant, however, its centralized structure presents multiple security vulnerabilities such as integrity, certification, and availability. To address these security vulnerabilities, in this paper, we propose a blockchain-based smart home gateway network that counters possible attacks on the gateway of smart homes. The network consists of three layers including device, gateway, and cloud layers. The blockchain technology is employed at the gateway layer wherein data is stored and exchanged in the form blocks of blockchain to support decentralization and overcome the problem from traditional centralized architecture. The blockchain ensures the integrity of the data inside and outside of the smart home and provides availability through authentication and efficient communication between network members. We implemented the proposed network on the Ethereum blockchain technology and evaluated in terms of standard security measures including security response time and accuracy. The evaluation results demonstrate that the proposed security solutions outperforms over the existing solutions.
Mudabbir Kaleem, Anastasia Mavridou, Áron Lászka
Vyper has been proposed as a new high-level language for Ethereum smart contract development due to numerous security vulnerabilities and attacks witnessed on contracts written in Solidity since the system's inception. Vyper aims to address these vulnerabilities by providing a language that focuses on simplicity, auditability and security. We present a survey where we study how well-known and commonly-encountered vulnerabilities in Solidity feature in Vyper's development environment. We analyze all such vulnerabilities individually and classify them into five groups based on their status in Vyper. To the best of our knowledge, our survey is the first attempt to study security vulnerabilities in Vyper.
Mudabbir Kaleem, Anastasia Mavridou, Áron Lászka
Vyper has been proposed as a new high-level language for Ethereum smart\ncontract development due to numerous security vulnerabilities and attacks\nwitnessed on contracts written in Solidity since the system's inception. Vyper\naims to address these vulnerabilities by providing a language that focuses on\nsimplicity, auditability and security. We present a survey where we study how\nwell-known and commonly-encountered vulnerabilities in Solidity feature in\nVyper's development environment. We analyze all such vulnerabilities\nindividually and classify them into five groups based on their status in Vyper.\nTo the best of our knowledge, our survey is the first attempt to study security\nvulnerabilities in Vyper.\n
Muhammad Salek Ali, Massimo Vecchio, Guntur Dharma Putra, Salil S. Kanhere · 5 authors
Within the Internet of Things (IoT) and blockchain research, there is a growing interest in decentralizing health monitoring systems, to provide improved privacy to patients, without relying on trusted third parties for handling patients' sensitive health data. With public blockchain deployments being severely limited in their scalability, and inherently having latency in transaction processing, there is room for researching and developing new techniques to leverage the security features of blockchains within healthcare applications. This paper presents a solution for patients to share their biomedical data with their doctors without their data being handled by trusted third party entities. The solution is built on the Ethereum blockchain as a medium for negotiating and record-keeping, along with Tor for delivering data from patients to doctors. To highlight the applicability of the solution in various health monitoring scenarios, we have considered three use-cases, namely cardiac monitoring, sleep apnoea testing, and EEG following epileptic seizures. Following the discussion about the use cases, the paper outlines a security analysis performed on the proposed solution, based on multiple attack scenarios. Finally, the paper presents and discusses a performance evaluation in terms of data delivery time in comparison to existing centralized and decentralized solutions.
Oey Laurensia Dewi Warsito, Robiyanto Robiyanto
This research was conducted to analyze cryptocurrency volatility. Gold, Dollar Index, and Composite Stock Prices Index in the Indonesia Stock Exchange (IDX) variable are used as independent variables. The cryptocurrency objects in this study are Bitcoin and Ethereum which have the largest market capitalization. The data used in this study is from 1st January 2017 to 31st December 2019. This study uses GARCH analysis. The result of this study indicates that the volatility of Bitcoin and Ethereum is not influenced by other variables, but it is influenced by the prices of each Bitcoin and Ethereum at past prices. This shows that the cryptocurrency market is an inefficient market.
K SRI, J. S. Supriya, Ms. P. Geetha Nanditha Sai, P. Siva Prasad
Crowdfunding is an innovative way of financing projects that allows anyone to contribute money online and support various initiatives, such as businesses, causes, or solutions. However, traditional crowdfunding platforms face some challenges, such as lack of transparency and security, high fees, and limited control over the funds by the contributors and the project owners. Blockchain technology, which is a P2P, decentralized ledger, which is distributed can offer a more reliable, secure, and transparent solution for crowdfunding. Blockchain-based crowdfunding can leverage smart contracts, which are self-executing agreements that encode the rules and conditions of the funding process and ensure that the funds are released only when the predefined criteria are met. This paper aims to propose a concept for designing efficient smart contracts for crowdfunding, which can enable both the contributors and the project owners to have more control and influence over the funds and the project outcomes. Unlike the existing literature-based ideas, our proposed method not only allows the contributors to invest their own money, but also guarantees them that their token values will be preserved. This method can be integrated without disrupting the existing logic of the blockchain. The methodology provides higher control and transparency for all the parties involved in the crowdfunding process.
Daniël Reijsbergen, Tien Tuan Anh Dinh
Consensus protocols are currently the bottlenecks that prevent blockchain systems from scaling. However, we argue that transaction execution is also important to the performance and security of blockchains. In other words, there are ample opportunities to speed up and further secure blockchains by reducing the cost of transaction execution. Our goal is to understand how much we can speed up blockchains by exploiting transaction concurrency available in blockchain workloads. To this end, we first analyze historical data of seven major public blockchains, namely Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Ethereum, Ethereum Classic, and Zilliqa. We consider two metrics for concurrency, namely the single-transaction conflict rate per block, and the group conflict rate per block. We find that there is more concurrency in UTXO-based blockchains than in account-based ones, although the amount of concurrency in the former is lower than expected. Another interesting finding is that some blockchains with larger blocks have more concurrency than blockchains with smaller blocks. Next, we propose an analytical model for estimating the transaction execution speed-up given an amount of concurrency. Using results from our empirical analysis, the model estimates that 6x speed-ups in Ethereum can be achieved if all available concurrency is exploited.
Christof Ferreira Torres, Mathis Baden, Robert Norvill, Beltrán Borja Fiz Pontiveros · 6 authors
In recent years, smart contracts have suffered major exploits, cost- ing millions of dollars. Unlike traditional programs, smart contracts are deployed on a blockchain. As such, they cannot be modified once deployed. Though various tools have been proposed to detect vulnerable smart contracts, the majority fails to protect vulnera- ble contracts that have already been deployed on the blockchain. Only very few solutions have been proposed so far to tackle the issue of post-deployment. However, these solutions suffer from low precision and are not generic enough to prevent any type of attack. In this work, we introduce ÆGIS, a dynamic analysis tool that protects smart contracts from being exploited during runtime. Its capability of detecting new vulnerabilities can easily be extended through so-called attack patterns. These patterns are written in a domain-specific language that is tailored to the execution model of Ethereum smart contracts. The language enables the description of malicious control and data flows. In addition, we propose a novel mechanism to streamline and speed up the process of managing attack patterns. Patterns are voted upon and stored via a smart contract, thus leveraging the benefits of tamper-resistance and transparency provided by the blockchain. We compare ÆGIS to current state-of-the-art tools and demonstrate that our solution achieves higher precision in detecting attacks. Finally, we perform a large-scale analysis on the first 4.5 million blocks of the Ethereum blockchain, thereby confirming the occurrences of well reported and yet unreported attacks in the wild.
Gwan‐Hwan Hwang, Pei-Chun Tien, Yi-Hsiang Tang
In this paper we propose a blockchain-based automatic indemnification mechanism. Clients and service providers (SPs) exchange signed messages according to a predefined protocol that enables clients to utilize service-provider services with simultaneous cryptographic proof of service. When a client has discovered an SP to have violated a service level agreement based on cryptographic proof, then they can obtain cryptocurrency as a compensation by raising objections to a smart contract on a public blockchain. When an objection has been judged successful by programs located in the smart contract, a portion of the deposit (cryptocurrency in the smart contract) will be transferred to the account of the objection-raiser. In this way, the need to establish and run a customer service center with employees for processing such claims and refunds is obviated. Moreover, the traditional third-party trust is no longer needed. Focusing on services for cloud-storage service, we propose protocols and implementation of an indemnification system in the Ethereum. The feasibility of the proposed application has been demonstrated through pilot implementation and testing.
Suporn Pongnumkul, Chanop Khonnasee, Swiss Lertpattanasak, Chantri Polprasert
Land title deeds are important documents that can be used to verify ownership and transfer history of lands. In Thailand, the Department of Lands operates and facilitates the transfer of ownership and other operations related to lands. The current technology used in the operations often encounters problems with the reliability of operations and complexities that cause delays. This paper investigates a proof-of-concept (PoC) of the integration of blockchain in the land registration system to improve the reliability of storage and reduces the steps in the process. The process of loan contracts with banks is used in the PoC and an Ethereum-based private blockchain is developed and tested. Performance evaluation of our proposed system can handle at least 26 transactions per second over a range of a number of transactions of interest. The results show promising potential both in the reduction of process and the performance of blockchain for the proposed use case.
Shahar Somin, Yaniv Altshuler, Goren Gordon, Alex Pentland · 5 authors
Global financial crises have led to the understanding that classical econometric models are limited in comprehending financial markets in extreme conditions, partially since they disregarded complex interactions within the system. Consequently, in recent years research efforts have been directed towards modeling the structure and dynamics of the underlying networks of financial ecosystems. However, difficulties in acquiring fine-grained empirical financial data, due to regulatory limitations, intellectual property and privacy control, still hinder the application of network analysis to financial markets. In this paper we study the trading of cryptocurrency tokens on top of the Ethereum Blockchain, which is the largest publicly available financial data source that has a granularity of individual trades and users, and which provides a rare opportunity to analyze and model financial behavior in an evolving market from its inception. This quickly developing economy is comprised of tens of thousands of different financial assets with an aggregated valuation of more than 500 Billion USD and typical daily volume of 30 Billion USD, and manifests highly volatile dynamics when viewed using classic market measures. However, by applying network theory methods we demonstrate clear structural properties and converging dynamics, indicating that this ecosystem functions as a single coherent financial market. These results suggest that a better understanding of traditional markets could become possible through the analysis of fine-grained, abundant and publicly available data of cryptomarkets.
Christof Ferreira Torres, Mathis Baden, Robert Norvill, Beltrán Borja Fiz Pontiveros · 6 authors
In recent years, smart contracts have suffered major exploits, costing\nmillions of dollars. Unlike traditional programs, smart contracts are deployed\non a blockchain. As such, they cannot be modified once deployed. Though various\ntools have been proposed to detect vulnerable smart contracts, the majority\nfails to protect vulnerable contracts that have already been deployed on the\nblockchain. Only very few solutions have been proposed so far to tackle the\nissue of post-deployment. However, these solutions suffer from low precision\nand are not generic enough to prevent any type of attack.\n In this work, we introduce {\\AE}GIS, a dynamic analysis tool that protects\nsmart contracts from being exploited during runtime. Its capability of\ndetecting new vulnerabilities can easily be extended through so-called attack\npatterns. These patterns are written in a domain-specific language that is\ntailored to the execution model of Ethereum smart contracts. The language\nenables the description of malicious control and data flows. In addition, we\npropose a novel mechanism to streamline and speed up the process of managing\nattack patterns. Patterns are voted upon and stored via a smart contract, thus\nleveraging the benefits of tamper-resistance and transparency provided by the\nblockchain. We compare {\\AE}GIS to current state-of-the-art tools and\ndemonstrate that our solution achieves higher precision in detecting attacks.\nFinally, we perform a large-scale analysis on the first 4.5 million blocks of\nthe Ethereum blockchain, thereby confirming the occurrences of well reported\nand yet unreported attacks in the wild.\n
Ye-Byoul Son, Jong-Hyuk Im, Hee-Yong Kwon, Seong-Yun Jeon · 5 authors
Advanced smart grid technologies enable energy prosumers to trade surplus energy from their distributed renewable energy sources with other peer prosumers through peer-to-peer (P2P) energy trading. In many previous works, P2P energy trading was facilitated by blockchain technology through blockchain’s distributive nature and capacity to run smart contracts. However, the feature that all the data and transactions on a blockchain are visible to all blockchain nodes may significantly threaten the privacy of the parties participating in P2P energy trading. There are many previous works that have attempted to mitigate this problem. However, all these works focused on the anonymity of participants but did not protect the data and transactions. To address this issue, we propose a P2P energy trading system on a blockchain where all bids are encrypted and peer matching is performed on the encrypted bids by a functional encryption-based smart contract. The system guarantees that the information encoded in the encrypted bids is protected, but the peer matching transactions are performed by the nodes in a publicly verifiable manner through smart contracts. We verify the feasibility of the proposed system by implementing a prototype composed of smart meters, a distribution system operator (DSO) server, and private Ethereum blockchain.
Weifeng Hao, Jiajie Zeng, Xiaohai Dai, Jiang Xiao · 8 authors
Blockchain technology offers an intelligent amalgamation of distributed ledger, Peer-to-Peer (P2P), cryptography, and smart contracts to enable trustworthy applications without any third parties. Existing blockchain systems have successfully either resolved the scalability issue by advancing the distributed consensus protocols from the control plane, or complemented the security issue by updating the block structure and encryption algorithms from the data plane. Yet, we argue that the underlying P2P network plane remains as an important but unaddressed barrier for accelerating the overall blockchain system performance, which can be discussed from how fast and reliable the network is. In order to improve the blockchain network performance about enabling fast and reliable broadcast, we establish a trust-enhanced blockchain P2P topology which takes transmission rate and transmission reliability into consideration. Transmission rate reflects blockchain network speed to disseminate transactions and blocks, and transmission reliability reveals whether transmission rate changes drastically on unreliable network connection. This paper presents BlockP2P-EP, a novel trust-enhanced blockchain topology to accelerate transmission rate and meanwhile retain transmission reliability. BlockP2P-EP first operates the geographical proximity sensing clustering, which leverages K-Means algorithm for gathering proximity peer nodes into clusters. It follows by the hierarchical topological structure that ensures strong connectivity and small diameter based on node attribute classification. Then we propose establishing trust-enhanced network topology. On top of the trust-enhanced blockchain topology, BlockP2P-EP conducts the parallel spanning tree broadcast algorithm to enable fast data broadcast among nodes both intra- and inter- clusters. Finally, we adopt an effective node inactivation detection method to reduce network load. To verify the validity of BlockP2P-EP protocol, we carefully design and implement a blockchain network simulator. Evaluation results show that BlockP2P-EP can exhibit promising network performance in terms of transmission rate and transmission reliability compared to Bitcoin and Ethereum.
Stefano Bistarelli, Gianmarco Mazzante, Matteo Micheletti, Leonardo Mostarda · 6 authors
No abstract is available for this record.
Gustavo A. Oliva, Ahmed E. Hassan, Zhen Ming Jiang
No abstract is available for this record.
Muhammad Abubakr Naeem, Saqib Farid, Faruk Balli, Syed Jawad Hussain Shahzad
Today, commodities are exposed to ever-increasing price volatilities due to extreme market uncertainties linked with financialization. The paper addresses a timely question of whether cryptocurrencies are hedge and safe-haven for commodities. We focus on this literature gap by using individual commodities from four groups, including metal, agriculture, precious metal, and energy. Further, we also consider four major cryptocurrencies, namely, Bitcoin, Ethereum, Litecoin, and Ripple for our analysis. Our findings show the functional role of cryptocurrencies as hedge and safe-haven for individual commodities. Moreover, the underlying properties are persistent during the crisis period.
Christos Karapapas, Iakovos Pittaras, Nikos Fotiou, George C. Polyzos
Decentralized systems, such as distributed ledgers and the InterPlanetary File System (IPFS), are designed to offer more open and robust services. However, they also create opportunities for illegal activities. We demonstrate how these technologies can be used to launch a ransomware as a service campaign. We show that criminals can transact with affiliates and victims without having to reveal their identity. Furthermore, by exploiting the robustness and resilience to churn of IPFS, as well as the decentralized computing capabilities of Ethereum, criminals can remain offline during most procedures, with many privacy guarantees.
Vincenzo Matarrese
Mastering cryptocurrencies. Initial coin offerings (ICOs). Factor loadings and exposures on cryptocurrencies. Factor loadings and exposures. Specific factors of cryptocurrencies. Industry exposure.
Khamis Hamed Al‐Yahyaee, Walid Mensi, Hee-Un Ko, Seong‐Min Yoon · 5 authors
No abstract is available for this record.
Kaihua Qin, Liyi Zhou, Benjamin Livshits, Arthur Gervais
Credit allows a lender to loan out surplus capital to a borrower. In the traditional economy, credit bears the risk that the borrower may default on its debt, the lender hence requires upfront collateral from the borrower, plus interest fee payments. Due to the atomicity of blockchain transactions, lenders can offer flash loans, i.e., loans that are only valid within one transaction and must be repaid by the end of that transaction. This concept has lead to a number of interesting attack possibilities, some of which were exploited in February 2020. This paper is the first to explore the implication of transaction atomicity and flash loans for the nascent decentralized finance (DeFi) ecosystem. We show quantitatively how transaction atomicity increases the arbitrage revenue. We moreover analyze two existing attacks with ROIs beyond 500k%. We formulate finding the attack parameters as an optimization problem over the state of the underlying Ethereum blockchain and the state of the DeFi ecosystem. We show how malicious adversaries can efficiently maximize an attack profit and hence damage the DeFi ecosystem further. Specifically, we present how two previously executed attacks can be "boosted" to result in a profit of 829.5k USD and 1.1M USD, respectively, which is a boost of 2.37x and 1.73x, respectively.