Many important cryptographic primitives offer probabilistic guarantees of security that can be specified as quantitative hyperproperties; these are specifications that stipulate the existence of a certain number of traces in the system satisfying certain constraints. Verification of such hyperproperties is extremely challenging because they involve simultaneous reasoning about an unbounded number of different traces. In this paper, we introduce a technique for verification of quantitative hyperproperties based on the notion of trace enumeration relations. These relations allow us to reduce the problem of trace-counting into one of model-counting of formulas in first-order logic. We also introduce a set of inference rules for machine-checked reasoning about the number of satisfying solutions to first-order formulas (aka model counting). Putting these two components together enables semi-automated verification of quantitative hyperproperties on infinite state systems. We use our methodology to prove confidentiality of access patterns in Path ORAMs of unbounded size, soundness of a simple interactive zero-knowledge proof protocol as well as other applications of quantitative hyperproperties studied in past work.
Abstract Solidity is the dominant programming language for Ethereum smart contracts. This paper presents a high-level formalization of the Solidity language with a focus on the memory model. The presented formalization covers all features of the language related to managing state and memory. In addition, the formalization we provide is effective: all but few features can be encoded in the quantifier-free fragment of standard SMT theories. This enables precise and efficient reasoning about the state of smart contracts written in Solidity. The formalization is implemented in the SOLC-VERIFY verifier and we provide an extensive set of tests that covers the breadth of the required semantics. We also provide an evaluation on the test set that validates the semantics and shows the novelty of the approach compared to other Solidity-level contract analysis tools.
Utz Nisslmueller, Klaus-Tycho Foerster, Stefan Schmid, Christian Decker
Cryptocurrency off-chain networks such as Lightning (e.g., Bitcoin) or Raiden (e.g., Ethereum) aim to increase the scalability of traditional on-chain transactions. To support nodes in learning about possible paths to route their transactions, these networks need to provide gossip and probing mechanisms. This paper explores whether these mechanisms may be exploited to infer sensitive information about the flow of transactions, and eventually harm privacy. In particular, we identify two threats, related to an active and a passive adversary. The first is a probing attack: here the adversary aims to detect the maximum amount which is transferable in a given direction over a target channel by actively probing it and differentiating the response messages it receives. The second is a timing attack: the adversary discovers how close the destination of a routed payment actually is, by acting as a passive man-in-the middle and analyzing the time deltas between sent messages and their corresponding responses. We then analyze the limitations of these attacks and propose remediations for scenarios in which they are able to produce accurate results.
Federated learning (FL) is an emerging collaborative machine learning method to train models on distributed datasets with privacy concerns. To properly incentivize data owners to contribute their efforts, Shapley Value (SV) is often adopted to fairly assess their contribution. However, the calculation of SV is time-consuming and computationally costly. In this paper, we propose FedCoin, a blockchain-based peer-to-peer payment system for FL to enable a feasible SV based profit distribution. In FedCoin, blockchain consensus entities calculate SVs and a new block is created based on the proof of Shapley (PoSap) protocol. It is in contrast to the popular BitCoin network where consensus entities "mine" new blocks by solving meaningless puzzles. Based on the computed SVs, a scheme for dividing the incentive payoffs among FL clients with nonrepudiation and tamper-resistance properties is proposed. Experimental results based on real-world data show that FedCoin can promote high-quality data from FL clients through accurately computing SVs with an upper bound on the computational resources required for reaching consensus. It opens opportunities for non-data owners to play a role in FL.
The COVID-19 is an exponentially growing disease that has intentioned nations to use technologies to detect the coronavirus infection. Several nations are working greatly to fight against COVID-19. Many nations have been using a range of devices to combat the pandemic, seeking information about growth, monitoring as well as the leaking the confidential information of the residents. This research aims to assist infected people online using the Internet of Things (IoT) and Blockchain technologies through smart devices. IoT-based healthcare devices gather useful information, provide additional insight through symptoms and behaviors, allow remote monitoring, and simply give people better self - determination and healthcare. Blockchain allows the secure transfer of patient health information, regulates the medical distribution network. A four-layer architecture is proposed using IoT and Blockchain to detect and prevent individuals to be COVID 19. This research provides a framework for patients with COVID-19 infectious disease and recognizes health issues and diagnoses online. Smart devices such as smartphones can install any mobile apps such as Aarogya Setu, Tawakkalna, and so on. These applications can track COVID-19 patients properly. The installation of mobile apps on smart devices focuses to reduce the time and cost and increase the performance of the infectious patient’s condition. A four-layer architecture is proposed using IoT and Blockchain technologies. Many research works focus on investigating, analyzing, and highlighting the affected individuals through guiding the COVID-19 infection. Eventually, various mobile apps are recognized and addressed in this paper.
Contract production and transaction are very common and important since it can greatly reduce future uncertainty and is well-organized by buyers, sellers, and trusted third parties (TTPs). However, current commodity trading systems (such as spot, futures, and forward contract) are still traditional centralized structures, which means that there may always be concerned about the single point of failure and data corruption. Besides, even though there already exists fragmentary decentralized applications (DApps) for the marketplace, order management, resale, delivery, financing, and insurance, they are not integrated for operating contract production and transaction comprehensively. In this work, a blockchain-enabled integrated marketing platform (BeIMP) is proposed for contract production and transactions. BeIMP is a consortium blockchain (CsBc) framework that enables better safety, efficiency, and interoperability among stakeholders. BeIMP can directly match producers and consumers and reduce the problem of intermediaries' improper market operation. BeIMP has a three-tier risk diversification mechanism. First, both parties can know the quantity and price according to the contract specification (CSpec) in advance to avoid future uncertainty. Second, the buyers can resell the established order if they need, thereby diversifying the risk. Third, the concept of insurance is introduced to reduce force majeure and other systemic risks. BeIMP can also help producers get the loan from the financial institution (FI) if they need fund for production. We implement and demonstrate the prototype in contract farming (CF) first and discuss its generalizability to other scenarios. Experiment results show that the smart contract (SC) function is stable enough and the proof of authority (PoA) has the advantage in throughput and can give users a better experience.
Delay in progress payment is a widespread problem in the construction industry which adversely affects the entire processes of the projects. Difficulties in the cashflow of the contracts, and consequently the subcontractors are the main consequences of delayed payments. Despite its significance, few research focused on development of methods guaranteeing timely payments of the participants throughout the project. Recent developments in blockchain and smart contract technologies presents a potential for development of a secure platform for the construction projects. Smart contract based payment systems not only provides an opportunity for minimizing the payment problems, but also enables building trust among the project parties for successful completion of construction projects. By taking advantage of the blockchain and smart contract technologies, this thesis aims to design and develop smart contract-based payment systems for guaranteed and timely payment of construction projects. A Smart Contract System for Security of Payment of Construction Contracts (SMTSEC)is presented to ensure security of payment of construction progress payments. , BIM-smart-contract-based progress payment system (BIMSMRTPAY) is developed to expedite the conventional progress payment process and to minimize potential payment disputes. The smart contract based retention payment system (RETPAY) is designed to expedite and automate the retention payments. The contributions and limitations of the SMTSEC, BIMSMRTPAY, and RETPAY are illustrated and discussed through case projects.
Smart contracts are computer programs that are deployed on the blockchain and can then be executed. Fees in form of gas have to be paid for deploying a smart contract on the blockchain, depending on the size of the byte code. Additional fees have to be paid, whenever a function of a smart contract is executed, depending on the needed computational steps and required storage space. On the Ethereum blockchain, millions of USD are paid in form of gas fees every single day. Since gas cost can increase if a contract is not well-implemented, there is a lot of incentive to reduce these gas cost in order to save money. We identified 19 optimization strategies from the field of software engineering, which can be applied to Solidity smart contracts in order to reduce the required gas cost. To show how these rules can be used to optimize smart contracts, we developed a prototype. The prototype detects rule violations from 9 of these rules and in addition automatically optimizes 6 of them. The prototype analyzed 3,018 verified open source smart contracts from etherscan.io. We found 471 rule violations in our test data set spread across 204 different contract files. That means, roundabout 6.8% of the data set violated at least one of the rules. We deployed the automatically optimized contracts in a test environment before and after the optimization, to compare the gas usage. We were on average able to save 1,213 gas for deploying an optimized contract version compared to the initial one. For calling an optimized function once, we were able to save on average 123 gas, compared to the initial function call.
Virtual currencies have undoubtably been a topic of conversation and uncertainty for some time. Many countries have jumped ahead of the industry and regulated cryptocurrencies, while others have taken a back seat to see exactly how the market responds. This Note explores the history behind cryptocurrency and Blockchain and how governments worldwide have dealt with the growing concern regarding regulation of the often volatile and decentralized industry. By way of comparative analysis, this Note examines how China, Switzerland, and the United States have taken measures to either embrace or repudiate the industry, as well as how they have succeeded and failed at a regulatory scheme. This Note ends with a recommendation that the industry be regulated by its own constituents through a self-regulatory organization, similar to that of FINRA, and discusses whether this form of regulation can coexist with a centralized governmental authority.
Subscriber authentication is a primitive operation in mobile networks required by each operator prior to offering any service to end users. In this paper, we propose a novel blockchain-based Authentication and Key Agreement (AKA) protocol for roaming services in 5G networks. Each Home Network (HN) creates its own smart contract and publishes its address to inform other operators who want to offer roaming services to HN subscribers. All subsequent communication between the HN and Serving Network (SN) is done by calling the function of this smart contract. The proposed protocol eliminates the need for a secure channel between the HN and SN, which is a primary requirement of current 5G AKA protocols. In practice, a secure channel requires the HN and SN to establish a secure session before running the AKA protocol. Further, the proposed protocol leverages the benefits of blockchain, such as auditable log, decentralized architecture, and the prevention of Denial of Service (DoS) attacks. Furthermore, we provide a security proof of the protocol through formal verification using ProVerif. The results show that our scheme tends to preserve user privacy and at the same time provides mutual authentication of the participants. Finally, our evaluation of the Ethereum blockchain shows that the protocol is efficient in terms of both transaction and execution costs.
In the era of digital revolution many contemporary events that changed the world were shaped through the internet. Nowadays, the emergence of internet of things (IoT), combining physical objects with virtual networks is expected to have even more influence. This new 'decentralised' structure in the world raises questions such as power, governance and the notion of democracy online. The aim of this paper is to investigate these notions. We have taken the examples of Bitcoin and Wikipedia and examined their decision-making process. Our analysis has found some inconsistencies in their policies, that are in contradiction with democracy and consensus principles of governance. Starting from our findings, we present further improvements that can be used to achieve more democracy and equity in the digital context.
Sarah Iqbal, Asad Waqar Malik, Anis Ur Rahman, Rafidah Md Noor
With the widespread adoption of the internet of things (IoT) technologies towards building a smart city, connected devices often offload computation tasks to nearby edge locations (base stations) to reduce overall computation and network delay. However, serving an ever-increasing number of end devices at these traditional edge locations is becoming impossible, subsequently making them fail to deliver the agreed quality of service to all requesting devices. However, the backend cloud data center is available to serve these requests but incurred additional communication delay, thus, unsuitable for delay-sensitive applications. Furthermore, the fact that the underlying network is inherently ad hoc which makes it prone to malicious nodes affecting its overall performance. In this work, we propose a secure fog computing paradigm where roadside units (RSUs) are used to offload tasks to nearby fog vehicles based on repute scores maintained at a distributed blockchain ledger. The experimental results demonstrate a significant performance gain in terms of queuing time, end-to-end delay, and task completion rate when compared to the baseline queuing-based task offloading scheme.
Masoud Barati, Omer Rana, Ioan Petri, George Theodorakopoulos
Data privacy in Internet of Things (IoT) applications remains a major concern of regulation bodies. The introduction of the European General Data Protection Regulation (GDPR) enables users to control how their data is accessed and processed, requiring consent from users before any data manipulation is carried out on their (personal) data by smart devices or cloud-hosted services. Blockchains provide the benefits of a distributed and immutable ledger recording digital transactions across a global network of peer nodes. Blockchain support for tracking of operations carried out by an IoT-based system provides greater confidence to a user that the IoT device is not infringing user privacy (as the Blockchain can be audited to verify which operation was carried out, by which actor). A formal model (following the privacy-bydesign approach) is proposed for supporting GDPR compliance checking for smart devices. The privacy requirements of such applications are related to GDPR obligations of device (and software systems) operators (such as user consent, data protection, right to forget etc). Three smart contracts are proposed as a practical solution to support automated verification of operations carried out by devices on user data, in accordance with GDPR rules. We evaluate the performance and scalability costs of our approach using a Blockchain test network.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Maria Luisa Di Silvestre, Pierluigi Gallo, Eleonora Riva Sanseverino, Giuseppe Sciumè · 5 authors
This article describes the possibility of using the blockchain technology for load and generation aggregation in a new distributed demand response (DR) service and customer remuneration system. The blockchain technology and the use of smart contracts for DR allow the creation of a distributed system, in which customers can communicate directly, in a transparent, secure, and traceable way, with the grid operator to provide their flexibility. In this article, the DR problem formulation takes into account several aspects, which are periodically executed. First, the blockchain records customers' energy consumption or production; then, the smart contract starts calculating the baseline and the potential support provided by each customer to fulfill the requested load adaptation. Customers' availability for generation and load profile modulation is also taken into account, as well as their privacy and an updated definition of the roles of grid and market operators in a new DR scenario supported by the blockchain technology. The blockchain used is Hyperledger Fabric, since it turned to be flexible for smart contract implementation while supporting multitenancy. Results show the possibility of successfully applying the blockchain technology to this particular topic, even considering privacy-preserving issues.
The utility of Artificial Intelligence (AI) in healthcare strongly depends upon the quality of the data used to build models, and the confidence in the predictions they generate. Access to sufficient amounts of high-quality data to build accurate and reliable models remains problematic owing to substantive legal and ethical constraints in making clinically relevant research data available offsite. New technologies such as distributed learning offer a pathway forward, but unfortunately tend to suffer from a lack of transparency, which undermines trust in what data are used for the analysis. To address such issues, we hypothesized that, a novel distributed learning that combines sequential distributed learning with a blockchain-based platform, namely Chained Distributed Machine learning C-DistriM, would be feasible and would give a similar result as a standard centralized approach. C-DistriM enables health centers to dynamically participate in training distributed learning models. We demonstrate C-DistriM using the NSCLC-Radiomics open data to predict two-year lung-cancer survival. A comparison of the performance of this distributed solution, evaluated in six different scenarios, and the centralized approach, showed no statistically significant difference (AUCs between central and distributed models), all DeLong tests yielded p -val >0.05. This methodology removes the need to blindly trust the computation in one specific server on a distributed learning network. This fusion of blockchain and distributed learning serves as a proof-of-concept to increase transparency, trust, and ultimately accelerate the adoption of AI in multicentric studies. We conclude that our blockchain-based model for sequential training on distributed datasets is a feasible approach, provides equivalent performance to the centralized approach.
Open access
Radiomics and Machine Learning in Medical Imaging
Advanced X-ray and CT Imaging
Artificial Intelligence in Healthcare and Education
The global implementation architecture of the traditional stock market distributes responsibilities and data across different intermediaries, including financial and governmental organizations. Each organization manages its system and collaborates with the others to facilitate trading on the stock exchange platform, and typically buy-sell orders go through different parties before settlement. This design architecture that involves a complex chain of intermediaries has several limitations and shortcomings, such as a single point of failure, a longer time for financial settlements, and weak transparency. Blockchain technology consists of a network of computer nodes that securely share a common ledger without the need of having any kind of intermediaries. In this paper, we present a novel blockchain-based architecture for a fully decentralized stock market. Our architecture is based on a private Ethereum blockchain to create a consortium network leveraging organizations that are already involved in the traditional stock exchange to act as validating nodes. In our architecture, the stock exchange trading logic is completely implemented on a smart contract, while considering the existing governmental market regulations. Since the new platform does not introduce significant changes to the stock exchange trading logic and does not eliminate any of the traditional parties from the system, our proposal promotes efficient adoption and deployment of decentralized stock exchange platforms. In addition, we present a proof of concept implementation of the new architecture, including the smart contract for trade exchange, as well as a virtualization-based test network to assess the platform performance. The test network consists of virtual nodes that run the developed stock exchange smart contract where we measure the buy-sell orders throughput and latency under different network sizes and trading workload scenarios. The obtained results have shown that the proposed trading platform can reach a throughput of 311.8 tx/sec, which is equivalent to 89% of the optimal throughput when the sending rate is 350 tx/sec. This throughput is largely sufficient to meet the requirement of major stock exchanges, such as Singapore stock market.
Abstract A blockchain is a decentralized distributed public database. It does not have a central authority to maintain this public database by running a cryptographic protocol with distributed nodes. Bitcoin is currently the hottest item in the blockchain, and the Bitcoin node can verify the transaction content and package it into the block. The blockchain guarantees the consistency of the books through the underlying consensus agreement. These consensus algorithms are different because the algorithm security assumptions are different from the actual requirements. This paper sorts and compares various blockchain consensus algorithms, sorts out the development based on blockchain consensus, and points out the advantages and disadvantages of various algorithms, and proposes the development direction of blockchain consensus algorithm. CCS Concepts •Anonymity and privacy issues and measures to enhance them➝Consensus protocols for blockchains
Die Blockchain Technologie hat das Potential die Wirtschaft im Zeitalter der Digitalisierung zu revolutionieren. In zentralisierten Organisationen werden die Entscheidungen von einem Verantwortlichen oder einer Gruppe getroffen. In der Blockchain gibt es keinen bestimmten Entscheidungsträger. Um eine Entscheidung zu treffen, muss ein Konsens erreicht werden. Um diesen Konsens zu erreichen, wird von jeder Blockchain Plattform ein so genannter Konsens-Mechanismus eingesetzt. Damit Blockchains ihr volles ökonomisches Potential ausschöpfen können, muss eine gute Skalierbarkeit gegeben sein. Doch dazu müssen Kompromisse in anderen Bereichen eingegangen werden. Das Blockchain-Trilemma besagt, dass man die drei Haupteigenschaften Skalierbarkeit, Sicherheit und Dezentralität immer zulasten der anderen erreicht, bzw. dass alle drei Eigenschaften nicht gleichzeitig maximiert werden können. Die implementierten Konsens-Mechanismen versuchen dieses Dilemma mit unterschiedlichen Ansätzen zu lösen. Daher sind sie einer der wichtigsten Aspekte sowie Unterscheidungsmerkmale der Blockchain Plattformen. Diese Arbeit bietet einen Überblick sowie eine technische Analyse über die zur Zeit existierenden Konsens-Mechanismen. Darüber hinaus werden Smart Contract Plattformen analysiert und die dort eingesetzten Konsens-Mechanismen detailliert beleuchtet. Außerdem wird die Umstellung des Konsens-Mechanismus von Proof of Work zu Proof of Stake in der Ethereum-Plattform anhand Ihres Einflusses auf zukünftige Smart Contracts analysiert. Die Analyse liefert einen Überblick über 62 Konsens-Mechanismen und 21 Smart Contract-Plattformen die im Moment eingesetzt werden. Weiter werden Kriterienkataloge vorgestellt, welche für den Vergleich von Smart Contract-Plattformen sowie deren Konsens-Mechanismen eingesetzt werden können.
Habeeb Ilufoye, Oluwatolani Vivian Akinrinoye, Chinelo Harriet Okolo
This paper proposes a strategic product innovation model specifically designed for launching digital lending solutions within the financial technology sector. Recognizing the unique challenges posed by rapid technological advancements, stringent regulatory requirements, and evolving customer expectations, the model integrates market opportunity identification, technology enablement, agile development, and cross-functional governance to guide successful product launches. Emphasizing a customer-centric and risk-aware approach, the framework facilitates alignment among diverse stakeholders and fosters continuous improvement through iterative feedback mechanisms. The study underscores the importance of balancing innovation speed with compliance and ethical considerations to build trust and ensure sustainability. Implications for both industry practitioners and policymakers are discussed, highlighting how the model can inform best practices and regulatory strategies that promote responsible fintech growth. Finally, the paper explores future directions for evolving the model alongside emerging technologies such as AI, blockchain, and decentralized finance, advocating for ongoing adaptation to maintain relevance in dynamic markets. This comprehensive approach aims to enhance the accessibility, inclusivity, and resilience of digital lending products, contributing to more equitable financial ecosystems.