Morit Zwang, Shahar Somin, Alex Pentland, Yaniv Altshuler
The Ethereum blockchain network is a decentralized platform enabling smart contract execution and transactions of Ether (ETH) [1], its designated cryptocurrency. Ethereum is the second most popular cryptocurrency with a market cap of more than 100 billion USD, with hundreds of thousands of transactions executed daily by hundreds of thousands of unique wallets. Tens of thousands of those wallets are newly generated each day. The Ethereum platform enables anyone to freely open multiple new wallets [2] free of charge (resulting in a large number of wallets that are controlled by the same entities). This attribute makes the Ethereum network a breeding space for activity by software robots (bots). The existence of bots is widespread in different digital technologies and there are various approaches to detect their activity such as rule-base, clustering, machine learning and more [3,4]. In this work we demonstrate how bot detection can be implemented using a network theory approach.
Fadhlan Hafizhelmi Kamaruzaman, Ahmad Ihsan Mohd Yassin, Azlee Zabidi, Fadhlan Hafizhelmi Kamaru Zaman · 7 authors
In recent years, an individual under the pseudonym of Satoshi Nakamoto devised a revolutionary technology called blockchain as the engine behind the first decentralized virtual currency called Bitcoin. A radical concept departing from government-centric controlled currencies, Bitcoin has emerged as a disruptive technology with the power to revolutionize business and its processes. Advantages of the blockchain include decentralized control, immutability, elimination of central authority and solution of concurrency problems in traditional databases. Leveraging on the advantages of blockchain technology defined above, this paper discusses the potential application of blockchain technology for storage of Islamic marriage certificates. Marriage certificates are documents issued to couples to legally recognize their marriage. Due to its paper-based nature, there is significant risk for them to be forged or frauded. These issues can be addressed effective using blockchain. The proposed application was implemented using smart contracts on a simulated Ethereum platform. A smart contract is designed to execute automatically under certain predefined conditions. The use of smart contracts eliminate manipulation by a single party. In addition, the immutable concept of blockchain ensures that data integrity is always preserved, greatly reducing the risk of fraud. Â
Space situation awareness (SSA) includes tracking of active and inactive resident space objects and assessing the space environment through sensor data collection and processing. To enhance SSA, the dynamic data-driven application systems framework couples online data with offline models to enhance performance by using feedback control, sensor management, and communications reliability. For information management, there is a need for identity authentication and access control (AC) to ensure the integrity of exchanged data as well as to grant authorized entities access right to data and services. Due to decentralization and heterogeneity of SSA systems, it is challenging to build an efficient centralized AC system, which can either be a performance bottleneck or the single point of failure. Inspired by the blockchain and smart contract technology, we introduce blockchain-enabled, decentralized, capability-based access control (BlendCAC), a decentralized authentication, and capability-based AC mechanism to enable effective protection for devices, services, and information in SSA networks. To achieve secure identity authentication, the BlendCAC leverages the blockchain to create virtual trust zones, in which distributed components can identify and update each other in a trustless network environment. A robust identity-based capability token management strategy is proposed, which takes advantage of the smart contract for registration, propagation, and revocation of the access authorization. A proof-of-concept prototype has been implemented on both resources-constrained devices (i.e., Raspberry Pi nodes emulating satellites with sensor observations) and more powerful computing devices (i.e., laptops emulating a ground network) and is tested on a private Ethereum blockchain network. The experimental results demonstrate the feasibility of the BlendCAC scheme to offer a decentralized, scalable, lightweight, and fine-grained AC solution for space system toward SSA.
Michael Hinterstocker, Florian Haberkorn, Andreas Zeiselmair, Serafin von Roon
Only a small share of German households make use of the opportunity to regularly switch their electricity supplier in order to fulfill their needs. Besides the relatively low possible monetary savings, another reason is the fact of long running contracts. The process of supplier switching for stakeholders in the energy market is quite time-consuming. This is caused by inefficient design of the process steps due to a lack of automation, of common data management and of direct communication between these stakeholders. Two options for optimizing this by means of a blockchain-based system are described and discussed here. These allow simplified communication between participating parties and therefore potentially quicker completion of the process. They enable automation of the whole process, prevent delays due to inconsistent data and therefore, allow intraday switching. An exemplary proof-of-concept implementation on the Ethereum blockchain shows the feasibility of the approach. Nevertheless, the advantages and disadvantages when compared to an alternative automated implementation, which is not blockchain-based, are still to be thoroughly examined.
The growing adoption of photovoltaic panels on roof-tops increases the pressure on grid operators for offsetting surplus or deficiency in generation. A multi-carrier energy system allows energy to be converted and stored using different energy carriers, thus relieving the stress from grid operators. However, these systems require efficient operation to unfold their full potential. This paper proposes a novel blockchain-enabled process to coordinate, allocate, and settle intra-day energy transactions in a district multi-carrier energy system with electricity and heating sub-networks. An incentive mechanism is designed for an optimal allocation of local green energy generation. The mechanism is implemented for the Ethereum blockchain and operates fully on-chain. The design leaves energy producers the freedom to choose their preferred pricing strategy for profit maximization while restricting them to behavior favoring the common good. We test three pricing strategies, with different levels of knowledge on users’ pricing behaviors, that energy producers may adopt. The price-availability-based allocation system guarantees consumers the lowest possible cost.
Pietro Danzi, Sarah Hambridge, Čedomir Stefanović, Petar Popovski
In the power grid, the Balance Responsible Parties (BRPs) purchase energy based on a forecast of the user consumption. The forecasts are imperfect, and the corrections of their real-time deviations are managed by a System Operator (SO), which charges the BRPs for the procured imbalances. Flexible consumers, associated with a BRP, can be involved in a demand response (DR) program to reduce the imbalance costs. However, running the DR program requires the BRP to invest resources in the infrastructure and increases its operating costs. To limit the intervention of BRP, we implement the DR via a blockchain smart contract. Moreover, to reduce the delay of publication of the imbalance price, caused by the inefficient accounting process of the current balancing markets, a second blockchain is adopted at the SO layer, procuring a fast and auditable credit settlements. The feasibility of the proposed architecture is evaluated over an Ethereum blockchain platform. The results show that block chains can enable a high automation of the balancing market, by providing (i) the implementation of aggregators with low operating cost and (ii) the timely and transparent access to the balancing information, thus fostering new business models for the BRPs.
Ahmed S. Almasoud, Maged M. Eljazzar, Farookh Hussain
In recent years, Blockchain technology has been highly valued and disruptive. Several researches have presented a merge between blockchain and current application i.e. medical, supply chain, and e-commerce. Although Blockchain architecture does not have a standard yet, IBM, MS, AWS offer BaaS (Blockchain as a Service). In addition to the current public chains i.e. Ethereum, NEO, and Cardeno; there are some differences between several public ledgers in terms of development and architecture. This paper introduces the main factors that affect integration of Artificial Intelligence with Blockchain. As well as, how it could be integrated for forecasting and automating; building self-regulated chain.
In the age of Big Data, releasing protected sensitive data at a future point in time is critical for various applications. Such self-emerging data release requires the data to be protected until a prescribed data release time and be automatically released to the recipient at the release time, even if the data sender goes offline. While straight-forward centralized approaches provide a basic solution to the problem, unfortunately they are limited to a single point of trust and involve a single point of control. This paper presents decentralized techniques for supporting self-emerging data using smart contracts in Ethereum blockchain networks. We design a credible and enforceable smart contract for supporting self-emerging data release. The smart contract employs a set of Ethereum peers to jointly follow the proposed timed-release service protocol allowing the participating peers to earn the remuneration paid by the service users. We model the problem as an extensive-form game with imperfect information to protect against possible adversarial attacks including some peers destroying the private data (drop attack) or secretly releasing the private data before the release time (release-ahead attack). We demonstrate the efficacy and attack-resilience of the proposed techniques through rigorous analysis and experimental evaluation. Our implementation and experimental evaluation on the Ethereum official test network demonstrate the low monetary cost and the low time overhead associated with the proposed approach and validate its guaranteed security properties.
Blockchain is a peer-to-peer (P2P) technology that records and verifies transactions in a decentralised, cryptography-secure manner. Blockchain applications can globally manage records of any sort, such as import-export declarations, invoices, bills of lading (BLs) and certificates of origin (COs). It is a promising technology for several areas, including international trade. This paper presents blockchain, comments on blockchain platforms such as Ethereum, gives examples of private sector initiatives, shares an idea for a CO blockchain application, and discusses regulatory issues. In doing so, the paper aims to attract attention for blockchain in international trade.
U ovom završnom radu obrađen je pojam hardvera za rudarenje kriptovaluta. Nakon uvoda u prvom poglavlju opisana je prva kriptovaluta "Bitcoin". U drugom poglavlju objašnjen je protokol "Blockchain" na koji Bitcoin funkcionira. U trećem poglavlju opisane su transakcije, te posao rudara u bitcoin mreži. U četvrtom poglavlju je opisana povijest hardvera, te detaljan opis hardvera ovisno o generaciji. U zadnjem poglavlju je opisan suvremeni hardver te najbolje rješenje za Bitcoin i Ethereum, drugu najvrjedniju kriptovalutu.
In December 2017, CryptoKitties, a game on the Ethereum blockchain became an instant success shortly after its launch. It attracted 180,000 users with over $20 million of spend in Ether, and was at one point taking up 12% of all Ethereum transactions.
Technically speaking, CryptoKitties is a smart contract - a piece of code with storage capability that resides on a blockchain. Smart contracts are gaining increasing popularity in recent years. We present a comprehensive review of smart contracts with a focus on existing applications and challenges they face. We have covered the smart contract mechanisms, promising use cases, as well as relevant research work and the open issues.
Today, the number of Internet of Things (IoT) devices in all aspects of life is increasing exponentially. Our cities are getting smarter and informing us about our surroundings in a contextual manner. However, we face significant challenges in deploying, managing, and collecting data from these devices. In addition, we must address the problem of storing and mining that data for higher-quality IoT services. Blockchain technology, even in today's nascent form, has the potential to be the foundation for a common, distributed, trustless, and autonomous infrastructure system. This article describes a standardized IoT infrastructure where data are stored on a distributed storage service that is fault-tolerant and resistant to distributed denial of service (DDOS) attacks and data access is managed by a decentralized, trustless blockchain. The illustrated system used LoRa as the emerging network technology, Swarm as the distributed data storage platform, and Ethereum as the blockchain platform. Such a data back end will ensure high availability with minimal security risks while replacing traditional back-end systems with a single "smart contract".
Today, the number of IoT devices in all aspects of life is exponentially increasing. The cities we are living in are getting smarter and informing us about our surroundings in a contextual manner. However, there lay significant challenges of deploying, managing and collecting data from these devices, in addition to the problem of storing and mining that data for higher-quality IoT services. Blockchain technology, even in today's nascent form, contains the pillars to create a common, distributed, trustless and autonomous infrastructure system. This paper describes a standardized IoT infrastructure; where data is stored on a DDOS-resistant, fault-tolerant, distributed storage service and data access is managed by a decentralized, trustless blockchain. The illustrated system used LoRa as the emerging network technology, Swarm as the distributed data storage and Ethereum as the blockchain platform. Such a data backend will ensure high availability with minimal security risks while replacing traditional backend systems with a single "smart contract".
Without the design for inherent security, the Border Gateway Protocol (BGP) is vulnerable to prefix/subprefix hijacks and other attacks. Though many BGP security approaches have been proposed to prevent or detect such attacks, the unsatisfactory cost-effectiveness frustrates their deployment. In fact, the currently deployed BGP security infrastructure leaves the chance for potential centralized authority misconfiguration and abuse. It actually becomes the critical yield point that demands the logging and auditing of misbehaviors and attacks in BGP security deployments. We propose a blockchain-based Internet number resource authority and trustworthy management solution, named BGPcoin, to facilitate the transparency of BGP security. BGPcoin provides a reliable origin advertisement source for origin authentication by dispensing resource allocations and revocations compliantly against IP prefix hijacking. We perform and audit resource assignments on the tamper-resistant Ethereum blockchain by means of a set of smart contracts, which also interact as one to provide the trustworthy origin route examination for BGP. Compared with RPKI, BGPcoin yields significant benefits in securing origin advertisement and building a dependable infrastructure for the object repository. We demonstrate it through an Ethereum prototype implementation, and we deploy it and do experiment on a locally-simulated network and an official Ethereum test network respectively. The extensive experiment and evaluation demonstrate the incentives to deploy BGPcoin, and the enhanced security provided by BGPcoin is technically and economically feasible.
With the rapid development of distributed renewable energy (DRE), demand response (DR) programs, and the proposal of the energy internet, the current centralized trading of the electricity market model is unable to meet the trading needs of distributed energy. As a decentralized and distributed accounting mode, blockchain technology fits the requirements of distributed energy to participate in the energy market. Corresponding to the transaction principle, a blockchain-based integrated energy transaction mechanism is proposed, which divides the trading process into two stages: the call auction stage and the continues auction stage. The transactions among the electricity and heat market participants were used as examples to explain the details of the trading process. Finally, the smart contracts of the transactions were designed and deployed on the Ethereum private blockchain site to demonstrate the validity of the proposed transaction scheme.
Lexi Brent, Anton Jurisevic, Michael Kong, Eric Liu · 8 authors
The rise of modern blockchains has facilitated the emergence of smart contracts: autonomous programs that live and run on the blockchain. Smart contracts have seen a rapid climb to prominence, with applications predicted in law, business, commerce, and governance. Smart contracts are commonly written in a high-level language such as Ethereum's Solidity, and translated to compact low-level bytecode for deployment on the blockchain. Once deployed, the bytecode is autonomously executed, usually by a %Turing-complete virtual machine. As with all programs, smart contracts can be highly vulnerable to malicious attacks due to deficient programming methodologies, languages, and toolchains, including buggy compilers. At the same time, smart contracts are also high-value targets, often commanding large amounts of cryptocurrency. Hence, developers and auditors need security frameworks capable of analysing low-level bytecode to detect potential security vulnerabilities. In this paper, we present Vandal: a security analysis framework for Ethereum smart contracts. Vandal consists of an analysis pipeline that converts low-level Ethereum Virtual Machine (EVM) bytecode to semantic logic relations. Users of the framework can express security analyses in a declarative fashion: a security analysis is expressed in a logic specification written in the \souffle language. We conduct a large-scale empirical study for a set of common smart contract security vulnerabilities, and show the effectiveness and efficiency of Vandal. Vandal is both fast and robust, successfully analysing over 95\% of all 141k unique contracts with an average runtime of 4.15 seconds; outperforming the current state of the art tools---Oyente, EthIR, Mythril, and Rattle---under equivalent conditions.
Reza M. Parizi, Ali Dehghantanha, Kim‐Kwang Raymond Choo, Amritraj Singh
The emerging blockchain technology supports decentralized computing paradigm shift and is a rapidly approaching phenomenon. While blockchain is thought primarily as the basis of Bitcoin, its application has grown far beyond cryptocurrencies due to the introduction of smart contracts. Smart contracts are self-enforcing pieces of software, which reside and run over a hosting blockchain. Using blockchain-based smart contracts for secure and transparent management to govern interactions (authentication, connection, and transaction) in Internet-enabled environments, mostly IoT, is a niche area of research and practice. However, writing trustworthy and safe smart contracts can be tremendously challenging because of the complicated semantics of underlying domain-specific languages and its testability. There have been high-profile incidents that indicate blockchain smart contracts could contain various code-security vulnerabilities, instigating financial harms. When it involves security of smart contracts, developers embracing the ability to write the contracts should be capable of testing their code, for diagnosing security vulnerabilities, before deploying them to the immutable environments on blockchains. However, there are only a handful of security testing tools for smart contracts. This implies that the existing research on automatic smart contracts security testing is not adequate and remains in a very stage of infancy. With a specific goal to more readily realize the application of blockchain smart contracts in security and privacy, we should first understand their vulnerabilities before widespread implementation. Accordingly, the goal of this paper is to carry out a far-reaching experimental assessment of current static smart contracts security testing tools, for the most widely used blockchain, the Ethereum and its domain-specific programming language, Solidity to provide the first...
Blockchain platforms such as Ethereum and several others execute complex transactions in blocks through user-defined scripts known as smart contracts. Normally, a block of the chain consists of multiple transactions of smart contracts which are added by a miner. To append a correct block into the blockchain, miners execute these transactions of smart contracts sequentially. Later the validators serially re-execute the smart contract transactions of the block. If the validators agree with the final state of the block as recorded by the miner, then the block is said to be validated. It is then added to the blockchain using a consensus protocol. In Ethereum and other blockchains that support cryptocurrencies, a miner gets an incentive every time such a valid block successfully added to the blockchain. In most of the current day blockchains the miners and validators execute the smart contract transactions serially. In the current era of multi-core processors, by employing the serial execution of the transactions, the miners and validators fail to utilize the cores properly and as a result, have poor throughput. By adding concurrency to smart contracts execution, we can achieve better efficiency and higher throughput. In this paper, we develop an efficient framework to execute the smart contract transactions concurrently using optimistic Software Transactional Memory systems (STMs). Miners execute smart contract transactions concurrently using multi-threading to generate the final state of blockchain. STM is used to take care of synchronization issues among the transactions and ensure atomicity. Now when the validators also execute the transactions (as a part of validation) concurrently using multi-threading, then the validators may get a different final state depending on the order of execution of conflicting transactions. To avoid this, the miners also generate a block graph of the transactions during the concurrent execution and store it in the block. This graph captures the conflict relations among the transactions and is generated concurrently as the transactions are executed by different threads. The miner proposes a block which consists of set of transactions, block graph, hash of the previous block, and final state of each shared data-objects. Later, the validators re-execute the same smart contract transactions concurrently and deterministically with the help of block graph given by the miner to verify the final state. If the validation is successful then proposed block appended into the blockchain and miner gets incentive otherwise discard the proposed block. We execute the smart contract transactions concurrently using Basic Time stamp Ordering (BTO) and Multi-Version Time stamp Ordering (MVTO) protocols as optimistic STMs. BTO and MVTO miner achieves 3.6x and 3.7x average speedups over serial miner respectively. Along with, BTO and MVTO validator outperform average 40.8x and 47.1x than serial validator respectively.
It is commonly believed that blockchain is a revolutionary technology for doing business on the Internet. Blockchain is a decentralized, distributed database or ledger of records. It ensures that the records are tamper-proof but publicly readable. Blockchain platforms such as Ethereum [3] and several others execute complex transactions in blocks through user-defined scripts known as smart contracts. Normally, a block of the chain consists of multiple transactions of smart contracts which are added by a miner. To append a correct block into the blockchain, miners execute these transactions of smart contracts sequentially. Later the validators serially re-execute the smart contract transactions of the block. If the validators agree with final state of the blocks as recorded by the miner, then the block is said to be valid and added to the blockchain using a consensus protocol.
Blockchain has received great attention in recent years and motivated innovations in different scenarios. However, many vital issues which affect its performance are still open. For example, it is widely convinced that high level of security and scalability and full decentralization are still impossible to achieve simultaneously. In this paper, we propose Bicomp, a bilayer scalable Nakamoto consensus protocol, which is an approach based on high security and pure decentralized Nakamoto consensus, and with a significant improvement on scalability. In Bicomp, two kinds of blocks are generated, i.e., microblocks for concurrent transaction packaging in network, and macroblocks for leadership competition and chain formation. A leader is elected at beginning of each round by using a macroblock header from proof-of-work. An elected leader then receives and packages multiple microblocks mined by different nodes into one macroblock during its tenure, which results in a bilayer block structure. Such design limits a leader's power and encourages as many nodes as possible to participate in the process of packaging transactions, which promotes the sharding nature of the system. Furthermore, several mechanisms are carefully designed to reduce transaction overlapping and further limit a leader's power, among which a novel transaction diversity based metric is proposed as the second level criteria besides the longest-chain-first principle on selecting a legitimate chain when fork happens. Security issues and potential attacks to Bicomp are extensively discussed and experiments for evaluation are performed. From the experimental results based on 50 nodes all over the world, Bicomp achieves significant improvement on scalability than that of Bitcoin and Ethereum, while the security and decentralization merits are still preserved.
Marian Gidea, Daniel Goldsmith, Yuri A. Katz, Pablo Roldan · 5 authors
We analyze the time series of four major cryptocurrencies (Bitcoin, Ethereum,\nLitecoin, and Ripple) before the digital market crash at the end of 2017 -\nbeginning 2018. We introduce a methodology that combines topological data\nanalysis with a machine learning technique -- $k$-means clustering -- in order\nto automatically recognize the emerging chaotic regime in a complex system\napproaching a critical transition. We first test our methodology on the complex\nsystem dynamics of a Lorenz-type attractor, and then we apply it to the four\nmajor cryptocurrencies. We find early warning signals for critical transitions\nin the cryptocurrency markets, even though the relevant time series exhibit a\nhighly erratic behavior.\n
BlAsT is an efficient scheme for achieving certification of data continuity through a history attached to a public blockchain. The scheme guarantees the properties of linearity, non-equivocation, time-stamping and transparency. We discuss the implementation of BlAsT over the Bitcoin and the Ethereum blokchains, provide a techno-economic analysis to evaluate the costs related to blockchain adoption, and numerically assess the performance of the proposed architecture in terms of storage and bandwidth requirements. Results show that the above properties can be guaranteed with a small cryptocurrency payment. The proposed scheme can be used for IoT devices under the assumption that the device is able to either perform blockchain validation or delegate it to a trusted node.
Fear of stigmatization and discrimination from colleagues, friends and family drives patients with various type of mental health problems away from a traditional face-to-face therapy and enforces them to look for an alternative treatment methods. Internet-based mental health therapy helps patients to get their needed therapies and support from healthcare professional and peers, or as a part of automated online form of therapy. Conducting Internet based therapy anonymously is vital for the patient privacy. However, lack of trust, access permission, ownership control and traceability undermines patient safety and security. Blockchain technology is an innovative technology initially designed for a cryptocurrency. However, with the introduction of programming blockchain and smart contracts, the technology has extended its importance to other areas for developing decentralized application (DApp), such as mental health related information management, which is the primary focus of this thesis. Privacy and security are very crucial for patient safety and to preserve patient’s medical history from adversaries. Sharing of private medical information online between the patient and their respective provider contains sensitive information that can easily be compromised if a proper security measure is not put in place. Blockchain is consensus-based peer-to-peer distributed ledger technology that stores and maintains an updated copy of all transactions within the network. It makes trust more transparent and traceable by keeping auditable-logs of all transactions in the form of blocks. In this thesis, Blockchain and its underlying technology are studied, and a prototype has been developed to explore the potential of the blockchain technology. Furthermore, we explore alternative distributed ledger technologies and their respective security models such as consensus protocols, cryptographic techniques, privacy and scalability. The prototype was proposed based on Ethereum blockchain.
Open access
Artificial Intelligence in Healthcare and Education