In the pharmaceutical industry, process validation tasks are based on the raw data and its derived analytical results generated from the process. Process validation failure affects both patient safety and the economic success of the manufacturing company. Hence, data integrity is highly critical in this area. Regulatory agencies, such as the Food and Drug Administration (FDA), reacted to past data integrity breaches by publishing new guidelines on data integrity for the correct handling of data in the pharmaceutical context. In this contribution, we want to show how data integrity can be improved on a technological level, removing the need for trusted third parties and centralized systems for this task. Therefore, we implemented an approach that uses existing tools, currently mostly used by software developers, and combined them with a new smart contract built on top of the Ethereum blockchain. In a case study, we test how data manipulation or backdating of results can be easily detected and how regulatory agencies can audit the complete data flow from the regulatory report back to the original raw data. The results of this contribution outline a possible road map for the development of production-ready tools, such as versioned database systems that natively interoperate with distributed ledgers. This will improve the trustworthiness of pharmaceutical manufacturing data by both protecting the intellectual property of the industrial company and improving the safety of the patients. <i>LAY ABSTRACT:</i> In the pharmaceutical industry, economically driven manufacturing companies are regulated and controlled by regulatory agencies. The pharmaceutical manufacturing companies need to produce large amounts of process and analytical data to show that their products are safe for patients. As the decisions of the regulatory agencies rely on this data, manufacturing companies need to prove how their generated data can be protected from technical breaches or data manipulation. As of today, the available technical solutions to provide data integrity are not working well enough. Regulatory agencies have published multiple documents highlighting the current data integrity issues. In this contribution, we show how blockchain, a technology that multiple cryptocurrencies like Bitcoin rely on, can help to improve the integrity of manufacturing data and data science analysis procedures. Therefore, we combined a smart contract on the Ethereum blockchain with tools currently mostly used by software developers. The presented workflow shows how data integrity can be guaranteed on a technological level without the need for trusted third parties.
In recent years, the rapid development of cryptocurrencies and their underlying blockchain technology has revived Szabo’s original idea of smart contracts, i.e., computer protocols that are designed to automatically facilitate, verify, and enforce the negotiation and implementation of digital contracts without central authorities. Smart contracts can find a wide spectrum of potential application scenarios in the digital economy and intelligent industries, including financial services, management, healthcare, and Internet of Things, among others, and also have been integrated into the mainstream blockchain-based development platforms, such as Ethereum and Hyperledger. However, smart contracts are still far from mature, and major technical challenges such as security and privacy issues are still awaiting further research efforts. For instance, the most notorious case might be “The DAO Attack” in June 2016, which led to more than $50 million Ether transferred into an adversary’s account. In this paper, we strive to present a systematic and comprehensive overview of blockchain-enabled smart contracts, aiming at stimulating further research toward this emerging research area. We first introduced the operating mechanism and mainstream platforms of blockchain-enabled smart contracts, and proposed a research framework for smart contracts based on a novel six-layer architecture. Second, both the technical and legal challenges, as well as the recent research progresses, are listed. Third, we presented several typical application scenarios. Toward the end, we discussed the future development trends of smart contracts. This paper is aimed at providing helpful guidance and reference for future research efforts.
Shayan Eskandari, Seyedehmahsa Moosavi, Jeremy Clark
We consider front-running to be a course of action where an entity benefits from prior access to privileged market information about upcoming transactions and trades. Front-running has been an issue in financial instrument markets since the 1970s. With the advent of the blockchain technology, front-running has resurfaced in new forms we explore here, instigated by blockchains decentralized and transparent nature. In this paper, we draw from a scattered body of knowledge and instances of front-running across the top 25 most active decentral applications (DApps) deployed on Ethereum blockchain. Additionally, we carry out a detailed analysis of Status.im initial coin offering (ICO) and show evidence of abnormal miners behavior indicative of front-running token purchases. Finally, we map the proposed solutions to front-running into useful categories.
A decentralized application (dapp for short) refers to an application that is executed by multiple users over a decentralized network. In recent years, the number of dapp keeps fast growing, mainly due to the popularity of blockchain technology. Despite the increasing importance of dapps as a typical application type that is assumed to promote the adoption of blockchain, little is known on what, how, and how well dapps are used in practice. In addition, the insightful knowledge of whether and how a traditional application can be transformed to a dapp is yet missing. To bridge the knowledge gap, this paper presents a comprehensive empirical study on an extensive dataset of 734 dapps that are collected from three popular open dapp marketplaces, i.e., ethereum, state of the dapp, and DAppRadar. We analyze the popularity of dapps, and summarize the patterns of how smart contracts are organized in a dapp. Based on the findings, we draw some implications to help dapp developers and users better understand and deploy dapps.
Abstract Nowadays, people trade electricity through centralized companies or organizations which is vulnerable to cyber attacks and incapable of coping with increasing demands from stakeholders. In this paper, we propose a new Peer-to-Peer Electricity Blockchain Trading (P2PEBT) system based on the current charging and discharging schemes for electric vehicles (EV) in the smart grid to enable users to participate in the trading process. In order to cope with the current situation of the high volume of EV integration, the proof-of-Benefit (PoB) consensus primitives are proposed for P2PEBT to achieve demand response by providing incentives to balance local electricity demand in the novel blockchain system. PoB is implemented by executing the smart contracts on the Ethereum platform, and the process of achieving the maximal benefits is completed by submitting the transaction in the decentralized network. Security analysis shows that the P2PEBT system is able to manage a potential protection against up to a number of attacks. We demonstrate that the proposed system using the PoB consensus mechanism can achieve lower power fluctuation without requiring a third-party intermediary.
Dongxiao Liu, Amal Alahmadi, Jianbing Ni, Xiaodong Lin · 5 authors
Industrial Internet of Things (IIoT) is revolutionizing the retail industry for manufacturers, suppliers, and retailers to improve operational efficiency and consumer experience. In IIoT-enabled retail marketing, reputation systems play a critical role to boost mutual trust among industrial entities and build consumer confidence. In this paper, we focus on reputation management in the consumer–retailer channel, where retailers can accumulate reputations from consumer feedbacks. To encourage consumers to post feedbacks without worrying about being tracked or retaliated, we propose an anonymous reputation system that preserves consumer identities and individual review confidentialities. To increase system transparency and reliability, we further exploit the tamper-proof nature and the distributed consensus mechanism of the blockchain technology. With system designs based on various cryptographic primitives and a Proof-of-Stake consensus protocol, our blockchain-based reputation system is more efficient to offer high levels of privacy guarantees compared with existing ones. Finally, we explore the implementation challenges of the blockchain-based architecture and present a proof-of-concept prototype system by Parity Ethereum. We measure the on/off -chain performance with the scalability discussion to demonstrate the feasibility of the proposed system.
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Supply chain traceability is one of the most promising use cases to benefit from characteristics of blockchain, such as decentralization, immutability and transparency, not required to build prior trust relationships among entities. A plethora of supply chain traceability solutions based on blockchain has been proposed recently. However, current systems are limited to tracing simple goods that have not been part of the manufacturing process. We recommend a method that allows for the traceability of manufactured goods, including their components. Products are represented using non-fungible digital tokens that are created on a blockchain for each batch of manufactured products. To create a link between a product and the components that are needed to produce it, we propose “token recipes” that define the amount of tokenized goods required for minting a new token. As input tokens are automatically and transparently consumed when creating a product token, the physical process of producing a new item out of existing components is projected onto the ledger. This ultimately leads to the complete traceability of goods, including the origin of inputs. Evaluating the performance of the system, we show that a prototypical implementation for the Ethereum Virtual Machine (EVM) scales linearly with the amount of the input and goods tracked.
With the advent of blockchain technologies, the idea of decentralized applications has gained traction. Smart contracts permit the implementation of application logic to foster distributed systems that are capable of removing intermediaries. Hereby, lock in effects originating from isolated data storage and central authorities are mitigated. Yet, smart contracts deployed to a ledger generate dependencies on the underlying blockchain. Over time, requirements regarding contract execution may detach from the utilized blockchain due to contradicting incentives and security or performance issues. To avoid a novel form of lock in effect towards a host blockchain, we introduce a concept for smart contract portability that permits any user to migrate contract logic and state between blockchains in a flexible and verifiable manner. As the Ethereum Virtual Machine (EVM) is supported by a multitude of blockchain implementations, it poses a common execution environment for smart contracts. We provide a toolbox that facilitates smart contract portability between EVM-compatible blockchains without trust requirements in the entity executing the migration process. To prove the concept's soundness, we transfer token contracts based on the ERC20 standard as well as applications containing dependencies to other smart contracts. Our evaluation shows the validity of ported applications including their current states.
The blockchain is one of the most interesting technologies developed in recent years. Blockchain is a ledger, a register, a decentralized and public shared database, reachable by accessing a peer-to-peer network. Each unit of the register represents a block. The blocks are linked together in the same order in which they were created and are connected using cryptographic algorithms that make them and the information stored therein not modifiable. \nSoftware development needs to be supported by architectural models or blockchain oriented meta-models. The introduction of smart contracts, small computer programs stored inside the Ethereum blockchain, modifies the typical software engineering methodologies. The distributed applications developed on blockchain technologies, can in fact follow rules different from used for the development of the normal centralized applications. The blockchain is instead based on a totally different assumption: the information stored on the blockchain and therefore the smart contracts can not be modified or deleted without compromising the integrity of the blockchain itself. Moreover the smart contracts run in an isolated environment and their results must be the same whatever node they run in. They cannot access the external world that changes with time, but can access and send messages to the blockchain itself that is immutable. \nSuch an innovative context entails new challenges in software engineering. Greater emphasis on specific security and testing practices, new development tools, specific modeling languages and new metrics to evaluate software quality are needed. These new metrics are required to measure complexity, communication, decentralized systems, but also resource consumption (e.g. the so-called gas in the ethereum system). \nIn this scenario Agile methodologies, that are suited to system whose requirements are not completely understood, or tend to change, could be a good strategy of software development for blockchain applications. Some of the characteristics of the Agile methodologies are in fact present in decentralized applications (DApps). \nOne of the most interesting applications based on blockchain are the Initial Coin Offerings (ICOs). An ICO is an innovative way to raise funds and launch a startup. It is also an opportunity to take part in a project, or in a DAO (Decentralized Autonomous Organization). \nThis fund-raising tool contains however some critical issues, such as the use of tokens that have no intrinsic value and do not generate direct liquidity, and the role of investors in the startup’s management. The Lean software development, an approach that maximizes the value given to the customer, and aims to eliminate waste and optimize across organizations, could be helpful to face these critical aspects. \nThe ICOs and, more generally the decentralized applications are based on smart contracts. Considering the technological break through introduced by blockchain it is important to know characteristics and measures and quality parameters of the development process and its phases, as well as metrics to help ensure that the development process is under control to meet the product’s quality goals. This thesis analyzes the software development process of blockchain-based applications. In particular this work analyzes the following aspects. \n• Investigating software engineering activities related to ICOs, recognize the ICOs developed using Agile methods and make a comparison between the characteristics of ICOs and those of Agile ICOs. \n• Evaluating the lean startup approach as a methodology for the implementation of an ICO. \n• Analizyng smart contracts deployed on the Ethereum blockchain relatively to smart contracts features, their interaction with the blockchain, the role of the development community, and the source code characteristics.
innovations in peer-to-peer software protocols 3 commonly known as blockchain technology.These protocols make it possible for individuals to safely and securely complete transactions in digital information of some value, also known as "cryptocurrency," 4 without the need for either a central authority 5 to act as a third party or government-enforced rule of law. 6 But what happens when code fails to protect the basic rights that our existing laws have always sought to protect?Bitcoin-a cryptocurrency that is one form of blockchain information-continues to dominate the daily headlines, primarily due to its wild fluctuations in market price. 7 The all-time-high market price reached in 2017 correlates, unsurprisingly, with the record number of transactions 8 and wallet users 9 achieved.But the meteoric rise in price occurred without much public discussion of blockchain's technological innovation outside of a relatively small group of COINREPORT (July 27, 2016), https://coinreport.net/into-the-ether-ethereum/[https://perma.cc/GB9X-K53K].3. Protocols, in this sense, are the rules written into the code that govern how the software may be used.See PEDRO FRANCO, UNDERSTANDING BITCOIN:
The Ethereum block chain as a decentralized platform is so successful that many applications deployed on it. However, for the inherent transparency properties and the lack of privacy, deploying a financial application on top of it is always a challenge. In this paper, we tackle this challenge and propose an anonymous sealed-bid auction protocol based on time-released encryption atop Consortium Block chain. We adopt a strict digital certificate-based identity mechanism of the consortium block chain to permit legitimate participants, and utilize the blind signature based on elliptic curve technology to allowing anonymous participation. Moreover, a timed release public key encryption algorithm is adopted to encrypt bids and prevent auctioneer from colluding with bidders. This is completely different from the method (zero-knowledge proof) used in other papers to prevent collusion between auctioneer and bidder. We provide a specific analysis of our protocol, which shows that our protocol meets anonymity and applicability.
Cryptocurrency such as bitcoin, Ethereum, and, more recently, Monero has become the currency of choice for many drug dealers and extortionists. The criminal activities extend to tax evasion, money laundering, Ponzi schemes, and the theft of cryptocurrencies to kidnapping for ransom. As the demand for cryptocurrencies increases, it provides opportunities for criminals to hide behind the presumed privacy and anonymity. Identifying these cryptocurrency-related crimes have posed challenges for law enforcement due to the cross-border nature of transactions, the use of evasion technology to mask the identity of users, and inconsistent regulations. To address the role of cryptocurrencies in criminal activities, the study focused on four research questions: (1) What role do cryptocurrencies such as bitcoin (BTC) play in criminal activities? (2) What factors facilitate cryptocurrency-related criminal activities? (3) What role do politics play in regulating cryptocurrencies? and (4) What are the challenges they pose for regulators and law enforcement? To answer the questions, the study utilized a systematic content review of the news reports, court cases, scholarly articles, online search engines, and commentaries relevant to regulations and reforms. The findings help to understand the current climate of virtual currencies, their use in criminal activities, and the complexities involved in regulating cryptocurrencies.
Smart contract platforms, the most notable of which is probably Ethereum, facilitate the development of important and diverse distributed applications (e.g., naming services and fungible tokens) in a simple manner. This simplicity stems from the inherent utility of employing the state of smart contracts to store, query and verify the validity of application data. In Ethereum, data storage incurs an underpriced, non-recurring, predefined fee. Furthermore, as there is no incentive for freeing or minimizing the state of smart contracts, Ethereum is faced with a tragedy of the commons problem with regards to its monotonically increasing state. This issue, if left unchecked, may lead to centralization and directly impact Ethereum's security and longevity. In this work, we introduce an alternative paradigm for developing smart contracts in which their state is of constant size and facilitates the verification of application data that are stored to and queried from an external, potentially unreliable, storage network. This approach is relevant for a wide range of applications, such as any key-value store. We evaluate our approach by adapting the most widely deployed standard for fungible tokens, i.e., the ERC20 token standard. We show that Ethereum's current cost model penalizes our approach, even though it minimizes the overhead to Ethereum's state and aligns well with Ethereum's future. We address Ethereum's monotonically increasing state in a two-fold manner. First, we introduce recurring fees that are proportional to the state of smart contracts and adjustable by the miners that maintain the network. Second, we propose a scheme where the cost of storage-related operations reflects the effort that miners have to expend to execute them. Lastly, we show that under such a pricing scheme that encourages economy in the state consumed by smart contracts, our ERC20 token adaptation reduces the incurred transaction fees by up to an order of magnitude.
Public key infrastructures (PKIs) are one of the main building blocks for securing communications over the Internet. Currently, PKIs are under the control of centralized authorities, which is problematic as evidenced by numerous incidents where they have been compromised. The distributed, fault tolerant log of transactions provided by blockchains and more recently, smart contract platforms, constitutes a powerful tool for the decentralization of PKIs. To verify the validity of identity records, blockchain-based identity systems store on chain either all identity records, or, a small (or even constant) sized amount of data for verifying identity records stored off chain. However, as most of these systems have never been implemented, there is little information regarding the practical implications of each design's tradeoffs. In this work, we first implement and evaluate the only provably secure, smart contract based PKI of Patsonakis et al. on top of Ethereum. This construction incurs constant-sized storage at the expense of computational complexity. To explore this tradeoff, we propose and implement a second construction which, eliminates the need for trusted setup, preserves the security properties of Patsonakis et al. and, as illustrated through our evaluation, is the only version with constant-sized state that can be deployed on the live chain of Ethereum. Furthermore, we compare these two systems with the simple approach of most prior works, e.g., the Ethereum Name Service, where all identity records are stored on the smart contract's state, to illustrate several shortcomings of Ethereum and its cost model. We propose several modifications for fine tuning the model, which would be useful to be considered for any smart contract platform like Ethereum so that it reaches its full potential to support arbitrary distributed applications.
S.V. Juno Bella Gracia, Dipendra Raghav, R Santhoshkumar, B Velprakash
Blockchain Based Aadhaar uses Blockchain platform for securing Aadhaar information. The system stores the Aadhaar data in a group of computers interconnected to each other. The Blockchain uses a hashing function to transform the data and produces a hash code. The hash code ensures the identity of user is kept secure. The data is stored in blocks in the nodes. The system also uses Ethereum Smart Contracts to ensure to only the authenticated data is accessed by the third parties. The Blockchain based Aadhaar uses distributed databases (decentralized databases) math and cryptography to record transactions, transactional data is secured and the data is stored in distributed small chunks and spreads across the entire network of computers, and so it is difficult to hack these systems than hacking the centralized or traditional servers.
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques
Yustus Eko Oktian, Elizabeth Nathania Witanto, Sandra Kumi, Sang-Gon Lee
The payment of a subscription-based model for the cloud service is regularly operated with the association of the bank as a centralized trustful third party. This system taxes the parties involved by requiring them to pay high transaction costs to the bank. In this paper, we propose a protocol to enable Fixed Subscription and Pay As You Go Subscription payments in the cloud service without the use of the third party. We achieve this goal by decentralizing the payment with blockchain. In return, this decentralized system generates low transaction costs. We implement our idea in the form of two smart contracts in Ethereum network. We also evaluate the security properties of our protocol. Based on the performance analysis, we can argue that all of the operations in the smart contract produces reasonable gas costs and the contracts are usable in the real network.
Manisa Pipattanasomporn, Saifur Rahman, Murat Kuzlu
Over the past decade, high penetration of rooftop solar photovoltaics (PV) has been observed in many countries. The availability of rooftop solar PV at customer premises has transformed a house into an energy prosumer that can both consume and export electricity. With proper regulations in place, homeowners can become a market participant who can buy and sell excess solar electricity in a peer-to-peer (P2P) trading environment. With the emerging blockchain technology, it will be possible to securely keep track of such solar electricity exchange without a third party oversight. The objective of this paper is to discuss the conceptual architecture of the blockchain-based platform for exchange of solar electricity in a neighborhood. Several open-source blockchain platforms are reviewed, including Hyperledger, Ethereum and Corda. Experiments developed on one of the well-known open-source blockchain platforms are discussed that describe how a P2P exchange of solar electricity can be set up in a laboratory environment.
In this paper, we present Tendermint: a Byzantine Fault Tolerant (BFT) application-based blockchain. We show that Tendermint promotes another perception of blockchain programming. Unlike Ethereum which is a blockchain holding many applications, Tendermint proposes to have one application per blockchain. We discuss the idiosyncrasies of Tendermint and how it could, potentially, ease blockchain programming and improve performance. We finish by showing weaknesses of Tendermint, good practices to adopt to hinder security attacks when handling Tendermint nodes, and some potential adjustments in the IBC protocol - an interoperability protocol designed for Tendermint. Our goal is to introduce Tendermint by showing its main characteristics over traditional blockchain platforms such as Bitcoin or Ethereum.
With the increasing popularity of online shopping, privacy concerns in E-commerce are attracting more and more attention. Existing E-commerce models are trapped in a dilemma between the proof of ownership and privacy protection. To address this issue, in this paper we design a privacy-preserving business protocol by employing private smart contracts in the negotiation phase. The protocol allows counterparties make deals without the disclosure of private information such as identities, addresses, and phone numbers. Moreover, we employ the zero-knowledge proof to guarantee the ownership. To understand the feasibility for implementing the proposed model, we also conduct extensive experiments to evaluate the performance of existing blockchain development platforms, Ethereum Quorum and SERO.
A blockchain can be referred to as a collection of house, phone phone and rarity or it should be non-physical, for instance, offers of Associate in Nursing affiliation. It have to records or open record that gets shared amongst participating parties. Every transaction that gets incorporated is first verified by all the participants of that transaction. Once the data gets recorded by the blockchain, can never be rewritten or changed. Thus the blockchain can be termed as a record book of all the transactions held. Cryptocurrencies, the decentralized bitcoin or say ethereum which can be termed as peertopeer computerized cash also uses the blockchain technology. This paper includes history of bitcoin, a few literary reviews, working of the blockchain and its application.
Maximiliano Geier, Claudio J. Tessone, Marco Vanotti, Silvio Vilerino · 6 authors
Large-scale distributed systems are becoming more widespread and, at the same time, their sizes grow day by day. In this type of systems, the adoption of blockchains is gaining particular traction for data storage in a secure and distributed manner. Nevertheless, design and testing of new protocols and features face the challenge of determining whether the proposed modifications would actually improve the system as expected. In the case of existing cryptocurrency systems, building an evaluation platform poses additional difficulties due to the resource-consuming nature of the associated processes. In this paper, we propose a novel methodology that relies on container-based network emulation to create scalable local testbeds in which Proof-of-Work-based blockchain systems can be evaluated. Using one of the mainstream Ethereum clients, we replaced the mining algorithm with a simulation model built upon the statistical characteristics of the mining process and instrumented the client to capture relevant network events. These events are used to create an offline reconstruction of the global view of the blockchain and all forking events, and to completely characterize the working conditions under arbitrary setups. Based on the versatility and scalability of our platform, we are able to test several network scenarios of increasing size in which we analyze the incidence of the target time in the generation of contradictory views of the blockchain (i.e. forks). We show that even using a limited testbed constituted by just commodity hardware, it is possible to use our platform to study the dynamics of blockchain-based systems up to hundreds of nodes.