Nowadays security is major concern for any user connected to the internet. Various types of attacks are to be performed by intruders to obtaining user information as manin-middle attack, denial of service, malware attacks etc. Malware attacks specifically ransomware attack become very famous recently. Ransomware attack threaten the users by encrypting their most valuable data, lock the user screen, play some random videos and by various more means. Finally attacker take benefits by users through paid ransom. In this paper, we propose a framework which prevent the ransomware attack more appropriately using various techniques as blockchain, honeypot, cloud & edge computing. This framework is analysed mainly through the IoT devices and generalized to the any malware attack.
Zhipeng Gao, Lingxiao Jiang, Xin Xia, David Lo · 5 authors
Smart contracts have been increasingly used together with blockchains to automate financial and business transactions. However, many bugs and vulnerabilities have been identified in many contracts which raises serious concerns about smart contract security, not to mention that the blockchain systems on which the smart contracts are built can be buggy. Thus, there is a significant need to better maintain smart contract code and ensure its high reliability. In this paper, we propose an automated approach to learn characteristics of smart contracts in Solidity, which is useful for clone detection, bug detection and contract validation on smart contracts. Our new approach is based on word embeddings and vector space comparison. We parse smart contract code into word streams with code structural information, convert code elements (e.g., statements, functions) into numerical vectors that are supposed to encode the code syntax and semantics, and compare the similarities among the vectors encoding code and known bugs, to identify potential issues. We have implemented the approach in a prototype, named SmartEmbed,11.The anonymous replication packages can be accessed at:https://drive.google.com/file/d/1kauLT3y2IiHPkUlVx4FSTda-dVAyL4za/view?usp=sharing.and evaluated it with more than 22,000 smart contracts collected from the Ethereum blockchain. Results show that our tool can effectively identify many repetitive instances of Solidity code, where the clone ratio is around 90 percent. Code clones such as type-III or even type-IV semantic clones can also be detected accurately. Our tool can identify more than 1000 clone related bugs based on our bug databases efficiently and accurately. Our tool can also help to efficiently validate any given smart contract against a known set of bugs, which can help to improve the users’ confidence in the reliability of the contract.
In recent years, blockchain technology has received unparalleled attention from academia, industry, and governments all around the world. It is considered a technological breakthrough anticipated to disrupt several application domains. This has resulted in a plethora of blockchain systems for various purposes. However, many of these blockchain systems suffer from serious shortcomings related to their performance and security, which need to be addressed before any wide-scale adoption can be achieved. A crucial component of any blockchain system is its underlying consensus algorithm, which in many ways, determines its performance and security. Therefore, to address the limitations of different blockchain systems, several existing as well novel consensus algorithms have been introduced. A systematic analysis of these algorithms will help to understand how and why any particular blockchain performs the way it functions. However, the existing studies of consensus algorithms are not comprehensive. Those studies have incomplete discussions on the properties of the algorithms and fail to analyse several major blockchain consensus algorithms in terms of their scopes. This article fills this gap by analysing a wide range of consensus algorithms using a comprehensive taxonomy of properties and by examining the implications of different issues still prevalent in consensus algorithms in detail. The result of the analysis is presented in tabular formats, which provides a visual illustration of these algorithms in a meaningful way. We have also analysed more than hundred top crypto-currencies belonging to different categories of consensus algorithms to understand their properties and to implicate different trends in these crypto-currencies. Finally, we have presented a decision tree of algorithms to be used as a tool to test the suitability of consensus algorithms under different criteria.
The state-of-the-art approach to manage blockchains is to process blocks of transactions in a shared-nothing environment. Although blockchains have the potential to provide various services for high-performance computing (HPC) systems, HPC will not be able to embrace blockchains before the following two missing pieces become available: (i) new consensus protocols being aware of the shared-storage architecture in HPC, and (ii) new fault-tolerant mechanisms compensating for HPC's programming model---the message passing interface (MPI)---that is vulnerable for blockchain-like workloads. To this end, we design a new set of consensus protocols crafted for the HPC platforms and a new fault-tolerance subsystem compensating for the failures caused by faulty MPI processes. Built on top of the new protocols and fault-tolerance mechanism, a prototype system is implemented and evaluated with two million transactions on a 500-core HPC cluster, showing $6\times$, $12\times$, and $75\times$ higher throughput than Hyperldeger, Ethereum, and Parity, respectively.
We propose in this paper BlockHouse, a decentralized/P2P storage system fully based on private blockchains. Each participant can rent his unused storage in order to host data of other members. This system uses a dual Smart Contract and Proof of Retrievability system to automatically check at a fixed frequency if the file is still hosted. In addition to transparency, the blockchain allows a better integration with all payments associated to this type of system ( regular payments, sequestration to ensure good behaviors of users, ...). Except the data transferred between the client and the server, all the actions go through a smart contract in the blockchain in order to log, pay and secure the entire storage process.
Yasar Khan, Toqeer Ali Syed, Megat Fariz, Fernando Moreira · 7 authors
Abstract An electronic business transaction among untrusted bodies without consulting a mutually trusted party has remained widely accepted problem. Blockchain resolves this problem by introducing peer‐to‐peer network with a consensus algorithm and trusted ledger. Blockchain originally introduced for cryptocurrency that came with proof‐of‐work consensus algorithm. Due to some performance issues, scientists brought concept of permissioned Blockchain. Hyperledger Fabric is a permissioned Blockchain targeting business‐oriented problems for industry. It is designed for efficient transaction execution over Blockchain with pluggable consensus model; however, there is limitation of rapid application development. Hyperledger introduced a new layer called Hyperledger Composer on top of the Fabric layer, which provides an abstract layer to model the business application readily and quickly. Composer provides a smart contract to extend the functionality and flexibility of Fabric layer and provides a way of communication with other systems to meet business requirements. Hyperledger Composer uses role‐based access control (RBAC) model to secure access to its valuable assets. However, RBAC is not enough because many business deals require continuous assets monitoring. Our proposed model, BlockU, covers all possible access control models required by a business. BlockU can monitor assets continuously during transactions and updates attributes accordingly. Moreover, we incorporate hooks in Hyperledger Composer to implement extended permission model that provides extensive permission management capability on an asset. Subsequently, our proposed enhanced access control model is implemented with a minimal change to existing Composer code base and is backward compatible with the current security mechanism.
Julio Moreno, Manuel Serrano, Eduardo B. Fernández, Eduardo Fernández‐Medina
Big data ecosystems are increasingly important for the daily activities of any type of company. They are decisive elements in the organization, so any malfunction of this environment can have a great impact on the normal functioning of the company; security is therefore a crucial aspect of this type of ecosystem. When approaching security in big data as an issue, it must be considered not only during the creation and implementation of the big data ecosystem, but also throughout its entire lifecycle, including operation, and especially when managing and responding to incidents that occur. To this end, this paper proposes an incident response process supported by a private blockchain network that allows the recording of the different events and incidents that occur in the big data ecosystem. The use of blockchain enables the security of the stored data to be improved, increasing its immutability and traceability. In addition, the stored records can help manage incidents and anticipate them, thereby minimizing the costs of investigating their causes; that facilitates forensic readiness. This proposal integrates with previous research work, seeking to improve the security of big data by creating a process of secure analysis, design, and implementation, supported by a security reference architecture that serves as a guide in defining the different elements of this type of ecosystem. Moreover, this paper presents a case study in which the proposal is being implemented by using big data and blockchain technologies, such as Apache Spark or Hyperledger Fabric.
Md Sadek Ferdous, Mohammad Jabed Morshed Chowdhury, Mohammad A. Hoque, Alan Colman
In recent years, blockchain technology has received unparalleled attention from academia, industry, and governments all around the world. It is considered a technological breakthrough anticipated to disrupt several application domains. This has resulted in a plethora of blockchain systems for various purposes. However, many of these blockchain systems suffer from serious shortcomings related to their performance and security, which need to be addressed before any wide-scale adoption can be achieved. A crucial component of any blockchain system is its underlying consensus algorithm, which in many ways, determines its performance and security. Therefore, to address the limitations of different blockchain systems, several existing as well novel consensus algorithms have been introduced. A systematic analysis of these algorithms will help to understand how and why any particular blockchain performs the way it functions. However, the existing studies of consensus algorithms are not comprehensive. Those studies have incomplete discussions on the properties of the algorithms and fail to analyse several major blockchain consensus algorithms in terms of their scopes. This article fills this gap by analysing a wide range of consensus algorithms using a comprehensive taxonomy of properties and by examining the implications of different issues still prevalent in consensus algorithms in detail. The result of the analysis is presented in tabular formats, which provides a visual illustration of these algorithms in a meaningful way. We have also analysed more than hundred top crypto-currencies belonging to different categories of consensus algorithms to understand their properties and to implicate different trends in these crypto-currencies. Finally, we have presented a decision tree of algorithms to be used as a tool to test the suitability of consensus algorithms under different criteria.
Background : The healthcare domain is undergoing a major shift towards electronic health records (EHR) and data management as illustrated by the global trend in with a shift over recent times from passive technology adopters towards more investigators and explorers. There is a vital need for a universal patient record in a distributed ledger and new approaches to ensure collaborative health when we can manage our own wellness outside of the system to improve outcomes and contain healthcare costs. There are a few immediate needs to address which are patient-centric management regarding high incidence chronic diseases and identification and optimization of at-risk parameters. Methods: This is an ideation for exploring “Blockchain” implementation to match the correct individual to their health data which is critical to their medical care. It is recognized that a significant proportion of EHR are not accurately matched within the same healthcare system and this hinders critical success factors such as effective patient management, patient satisfaction, and continuity of quality care (Figure 2). Results: The following outcomes and advantages are expected to be delivered for patient care records management offering transparent and verifiable records which are encrypted to provide streamlined clinical data flow benefitting patients. Core benefits also include enhancing transparency to patients, reducing threats of hacking, increasing patient records safety, eliminating workarounds, and minimizing IT expenditures and downtimes. Conclusion: As a promising breakthrough, this idea should result in patients no longer needing to perform the tedious task of gathering records from various providers. Instead patients would only need to provide access to their health blockchain, hence retaining control of their data and not spending time and energy keeping their data up to date .
Leidy Catherinne Sánchez Ascanio, John A. Arredondo
Globalization and new technologies have incentivized the growth of the cryptocurrency market, which has meant that they are included in the usual trading assets. Since so far its market value has been wrapped in a cloak of speculation and volatility, we must ask ourselves, can we anticipate in a short and long time, the market value of a cryptocurrency? Under this premise, in this article we will perform the analysis of the prices of Bitcoin, the most capitalized digital currency in the market, applying the basic principles of the Elliott waves technique. We will observe that this technique yields a margin of effectiveness in prediction quite acceptable, and given the simplicity of its structure, it will be a tool that can be used by any person interested in the cryptocurrency market.
Purpose Blockchain, which was originally created to enable peer-to-peer digital payment systems (bitcoin), is considered to have several benefits for different sectors, such as the real estate one. In a standard European-wide real estate transaction, several intermediaries are involved. As a consequence, these agreements are usually time-consuming and involve extra difficulties to cross-border operations. As blockchain, combined with smart contracts, may have an important role in these transactions, this paper aims to explore its prospective challenges, limitations and opportunities in the real estate sector and discover how the traditional intermediaries have to face a possible implementation of this technology. Design/methodology/approach This paper analyses the current intermediaries in the real estate sector in European Union (EU), their functions and how can blockchain strengthen the security of these transactions while reducing their time. The author uses a legal methodology to approach it. Findings Blockchain, combined with smart contracts, has both challenges and opportunities for the real estate sector. On the one hand, it may improve procedures, allow EU transactions and the interconnection between public administration. However, to not reduce parties rights, this blockchain should have some special features, such as the possibility of being amended. Originality/value This paper provides a valuable overview of all the intermediaries that could be affected by blockchain protocols. It is of interest of blockchain developers, public administrations and researchers who are working on blockchain and property conveyancing.
The Shariʿa Law has a comprehensive vision of all human activities, including commerce. The peculiarities of the commercial legal system that derives from the legal principles of Shariʿa emanates from the concepts of forbidden or Haram and permissible or Halal. These principles are applied today to breakthrough commercial developments such as the Blockchain/Digital Ledger Technologies. On the other hand, there is a growing debate about the possibility of the application of Shariʿa Law in the Member States of the European Union, either for social reasons or for commercial reasons. The controversy and opportunities created in the smallest State of the Union, Malta, serves as a sample.
A decade long thrive of cryptocurrency has shown its potential as a source of alternative-finance and the security and the robustness of the underpinning blockchain technology. However, most cryptocurrencies fail to show inimitability and their meanings in the real world. As a result, they usually start off as favourites but quickly become the outcasts of the digital asset market. The blockchain society attempts to anchor the value of cryp-tocurrency with real values by employing smart contracts and link it with computation resources and the digital-productivity that have value and demands in the real world. But their attempts have some undesirable effects due to a limited number of practical applications. This limitation is caused by the dilemma between high performance and decentralisation (universal join-ability). The emerging of blockchain sharding models, however, has offered a possible solution to address this dilemma. In this paper, we explore a financial model for blockchain sharding that will build an active link between the value of cryptocurrency and computation resources as well as the market and labour behaviours. Our model can adjust the price of resources and the compensation for maintaining a system based on those behaviours. We anchor the value of cryptocurrency by the amount of computation resources participated in and give the cryptocurrency a meaning as the exchange between computation resources globally. Finally, we present a working example which, through financial regularities, regulates the behaviour of anonymous participants, also incents/discourages participation dynamically.
Katarina Preikschat, Moritz Böhmecke‐Schwafert, Jan‐Paul Buchwald, Carolin Stickel
Summary Blockchain technology has the potential to bring transparency and trust to a multitude of use cases. Our research demonstrates that the technology can reduce asymmetric information in markets by bridging trust gaps. The combination of blockchain and Internet of Things technology that automatically collects sensor data, provides a feasible, decentralized technological solution for such an inefficient “Market of Lemons” coined by nobel laureate Georg Akerlof. In this paper, we develop a system prototype to reduce mileage fraud on the used car markets. Our work demonstrates the feasibility of a trusted system of records for (vehicle) data such as mileage data using a distributed database based on the public Ethereum network and smart contracts. We have identified eight requirements that are fulfilled by the prototype and the functional logic and design of thesolution can be reproduced to any other application area characterized by a lack of trust between actors or by the absence of a trusted central authority. However, the developed prototype suffers from similar limitations and challenges as the technology itself. Low throughput causes limitations in scalability and transaction costs are unpredictable. Further development of the blockchain technology and considering more cost‐efficient consensus mechanisms will address these issues.
In the area of blockchains, a wallet is anything that manages the access to cryptocurrencies and tokens. Off-chain wallets appear in different forms, from paper wallets to hardware wallets to dedicated wallet apps, while on-chain wallets are realized as smart contracts. Wallet contracts are supposed to increase trust and security by being transparent and by offering features like daily limits, approvals, multiple signatures, and recovery mechanisms. The most prominent platform for smart contracts in general and the token ecosystem im particular, and thus also for wallet contracts is Ethereum. Our work aims at a better understanding of wallet contracts on Ethereum, since they are one of the most frequently deployed smart contracts. By analyzing source code, bytecode, and execution traces, we derive usage scenarios and patterns. We discuss methods for identifying wallet contracts in a semi-automatic manner by looking at the deployed bytecodes and the on-chain interaction patterns. We extract blueprints for wallets and compile a ground truth. Furthermore, we differentiate characteristics of wallets in use, and group them into six types. We provide numbers and temporal perspectives regarding the creation and use of wallets. For the 40 identified blueprints, we compile detailed profiles. We analyze the data of the Ethereum main chain up to block 11,500,000, mined on December 22, 2020.
Traditional public distributed ledgers have not been able to scale-out well and work efficiently. Sharding is deemed as a promising way to solve this problem. By partitioning all nodes into small committees and letting them work in parallel, we can significantly lower the amount of communication and computation, reduce the overhead on each node's storage, as well as enhance the throughput of the distributed ledger. Existing sharding-based protocols still suffer from several serious drawbacks. The first thing is that all non-faulty nodes must connect well with each other, which demands a huge number of communication channels in the network. Moreover, previous protocols have faced great loss in efficiency in the case where the honesty of each committee's leader is in question. At the same time, no explicit incentive is provided for nodes to actively participate in the protocol. We present CycLedger, a scalable and secure parallel protocol for distributed ledger via sharding. Our protocol selects a leader and a partial set for each committee, who are in charge of maintaining intra-shard consensus and communicating with other committees, to reduce the amortized complexity of communication, computation, and storage on all nodes. We introduce a novel semi-commitment scheme between committees and a recovery procedure to prevent the system from crashing even when leaders of committees are malicious. To add incentive for the network, we use the concept of reputation, which measures each node's trusty computing power. As nodes with a higher reputation receive more rewards, there is an encouragement for nodes with strong computing ability to work honestly to gain reputation. In this way, we strike out a new path to establish scalability, security, and incentive for the sharding-based distributed ledger.
Fiscal asymmetric decentralization is seen as the panacea in solving persistent income inequalities facing developing economies. Despite efforts to finance County governments, about 42% of Kenyan’s 47.6 million people still live below the poverty level. This study evaluates the influence of County fiscal autonomy on household effects in Kenya. Both primary and secondary data, collected from households in 47 county governments and the Commission on Revenue Allocation, respectively. A Sample of 4,813 households was drawn from 96,251 lists of households developed by Kenya National Bureau of Statistics. Cochran's correction formula was used. The result finds an insignificant negative correlation between county fiscal autonomy and household effects in Kenya. Further studies are recommended with diverse indicators. Findings in this paper are generalizable and a point of reference for policymakers in Kenya.
Applications from finance to epidemiology and cyber-security require accurate forecasts of dynamic phenomena, which are often only partially observed. We demonstrate that a system's predictability degrades as a function of temporal sampling, regardless of the adopted forecasting model. We quantify the loss of predictability due to sampling, and show that it cannot be recovered by using external signals. We validate the generality of our theoretical findings in real-world partially observed systems representing infectious disease outbreaks, online discussions, and software development projects. On a variety of prediction tasks---forecasting new infections, the popularity of topics in online discussions, or interest in cryptocurrency projects---predictability irrecoverably decays as a function of sampling, unveiling fundamental predictability limits in partially observed systems.
Online trackers personalize ads campaigns, exponentially increasing their efficacy compared to traditional channels. The downside of this is that thousands of mostly unknown systems own our profiles and violate our privacy without our awareness. IPPO turns the table and re-empower users of their data, through anonymised data publishing via a Blockchain-based Decentralized Data Marketplace. We also propose a service based on machine learning and big data analytics to automatically identify web trackers and build Privacy Labels (PLs), based on the nutrition labels concept. This paper describes the motivation, the vision, the architecture and the research challenges related to IPPO.
We model the competition over mining resources and over several cryptocurrencies as a non-cooperative game. Leveraging results about congestion games, we establish conditions for the existence of pure Nash equilibria and provide efficient algorithms for finding such equilibria. We account for multiple system models, varying according to the way that mining resources are allocated and shared and according to the granularity at which mining puzzle complexity is adjusted. When constraints on resources are included, the resulting game is a constrained resource allocation game for which we characterize a normalized Nash equilibrium. Under the proposed models, we provide structural properties of the corresponding types of equilibrium, e.g., establishing conditions under which at most two mining infrastructures will be active or under which no miners will have incentives to mine a given cryptocurrency.
This paper suggests a model for optimization of societal carbon footprints one person at a time through the decentralization of electricity use and accounting. Our model describes steps involved with developing a decentralized accounting system considering electricity as a "credit product". While describing the basic characteristics of both schemes, we also emphasize capabilities of the proposed model for reducing carbon footprints from other societal choices, for example, purchasing water (energy-water nexus), managing waste, or designing sustainable transportation systems. A simple yet complex model involved with familiar societal financial systems' rules and routines is proposed for achieving a resilient, sustainable, and prosperous future. The proposed model calls for creating a dynamic society (as a system) that can be efficiently adopted to take on challenges threatening the function, survival, and future developments of the societies.
Giovanni Ciatto, Stefano Mariani, Alfredo Maffi, Andrea Omicini
A common use case for blockchain smart contracts (SC) is that of governing interaction amongst mutually untrusted parties, by automatically enforcing rules for interaction. However, while many contributions in the literature assess SC computational expressiveness, an evaluation of their power in terms of coordination (i.e., governing interaction) is still missing. This is why in this paper we test mainstream SC implementations by evaluating their expressive power in coordinating both inter-users and inter-SC activities. To do so, we exploit the archetypal Linda coordination model as a benchmark—a common practice in the field of coordination models and languages—by discussing to what extent mainstream blockchain technologies support its implementation. As they reveal some notable limitations (affecting, in particular, coordination between SC) we then show how Tenderfone, a custom blockchain implementation providing for a more expressive notion of SC, addresses the aforementioned limitations.
Diogo Pacheco, Pik-Mai Hui, Christopher Torres-Lugo, Bao Tran Truong · 6 authors
Coordinated campaigns are used to influence and manipulate social media platforms and their users, a critical challenge to the free exchange of information online. Here we introduce a general, unsupervised network-based methodology to uncover groups of accounts that are likely coordinated. The proposed method constructs coordination networks based on arbitrary behavioral traces shared among accounts. We present five case studies of influence campaigns, four of which in the diverse contexts of U.S. elections, Hong Kong protests, the Syrian civil war, and cryptocurrency manipulation. In each of these cases, we detect networks of coordinated Twitter accounts by examining their identities, images, hashtag sequences, retweets, or temporal patterns. The proposed approach proves to be broadly applicable to uncover different kinds of coordination across information warfare scenarios.
The blockchain concept forms the backbone of a new wave technology that promises to be deployed extensively in a wide variety of industrial and societal applications. Governments, financial institutions, banks, industrial supply chains, service companies, and even educational institutions and hospitals are investing in a substantial manner in the hope of improving business efficiency and operational robustness through deployment of blockchain technology. This thesis work is concerned with designing trustworthy business-to-business (B2B) market platforms drawing upon blockchain technology and game theory. The proposed platform is built upon three key ideas. First, we use permissioned blockchains with smart contracts as a technically sound approach for building the B2B platform. The blockchain deploys smart contracts that govern the interactions of enterprise buyers and sellers. Second, the smart contracts are designed using a rigorous analysis of a repeated game model of the strategic interactions between buyers and sellers. We show that such smart contracts induce honest behavior from buyers and sellers. Third, we embed cryptographic regulation protocols into the permissioned blockchain to ensure that business sensitive information is not revealed to the competitors. We believe our work is an important step in the direction of building a powerful B2B platform that maximizes social welfare and enables trusted collaboration between strategic enterprise agents.