Muhammad Zunnurain Hussain, Muhammad Zulkifl Hasan, Adnan N. Qureshi, Ghulam Mustafa
Abstract The distributed ledger known as blockchain is designed to record transactions in a manner that makes hacking, tampering, and fraud very difficult, if not impossible. Blockchains are digital distributed ledgers that keep track of transactions across several computers. The blockchain is a revolutionary financial innovation that will change the face of commercial transactions forever. This decentralized system employs and supports a wide variety of encryption methods. Due to the cloud computing paradigm, financial transactions are safe, reliable, and adaptable. This chapter provides a secure method for implementing cloud assurance using blockchain technology. The blockchain transactions are first recorded using the SHA-256 cryptographic method. After that point, the characteristics of blocks are stored, and the transactions are serialized. Finally, the blockchain would produce new blocks if certain transaction and condition criteria were satisfied. Each step of the transaction is monitored using a Merkle tree to guarantee its security and authenticity. The research did, however, highlight several major gaps in the available literature and the implications of those gaps.
Tácito Augusto Farias Júnior, Rafael Oliveira Vasconcelos, Admilson de Ribamar Lima Ribeiro
Privacy protection ensures that individuals have control over personal data, preventing abuse and preserving trust in the use of online services. In the “Digital Era”, where the collection, storage and processing of personal information have become ubiquitous, data privacy emerges as a relevant topic. In this sense, laws were created, such as the General Data Protection Law (LGPD) in Brazil and the General Data Protection Regulation (GDPR) in Europe, to control privacy and the processing of personal data. The article presents a comparative analysis of 2 (two) data privacy mechanisms, the Zero-Knowledge Proof (ZKP) and Ring Signatures, used in Blockchain, aiming at the legal and regulatory implications with the LGPD and GDPR. The comparative study between ZKP and Ring Signatures highlights the flexibility of ZKP in various contexts, including voting and secure authentication systems, while Ring Signatures offer significant advantages in terms of scalability and efficiency in systems where subscriber anonymity is considered fundamental. Furthermore, the legal and regulatory implications of the ZKP are discussed, mainly in relation to LGPD and GDPR. Finally, the article concludes that the comparative analysis offers insights into applications, challenges and legal and regulatory implications, particularly in relation to data privacy and compliance with regulations such as LGPD and GDPR.
This paper explores the relationship between the development of the internet and health care, highlighting their parallel growth and mutual influence. It delves into the transition from the early, static days of Web 1.0, akin to siloed physician expertise in health care, to the more interactive and patient-centric era of Web 2.0, which was accompanied by advancements in medical technologies and patient engagement. This paper then focuses on the emerging era of Web3-the decentralized web-which promises a transformative shift in health care, particularly in how patient data are managed, accessed, and used. This shift toward Web3 involves using blockchain technology for decentralized data storage to enhance patient data access, control, privacy, and value. This paper also examines current applications and pilot projects demonstrating Web3's practical use in health care and discusses key questions and considerations for its successful implementation.
The rapid expansion of the Internet of Things (IoT) has introduced significant challenges in data authentication, necessitating a balance between scalability and security. Traditional approaches often rely on third parties, while blockchain-based solutions face computational and storage bottlenecks. Our novel framework employs edge aggregating servers and Ethereum Layer 2 rollups, offering a scalable and secure IoT data authentication solution that reduces the need for continuous, direct interaction between IoT devices and the blockchain. We utilize and compare the Nova and Risc0 proving systems for authenticating batches of IoT data by verifying signatures, ensuring data integrity and privacy. Notably, the Nova prover significantly outperforms Risc0 in proving and verification times; for instance, with 10 signatures, Nova takes 3.62 s compared to Risc0's 369 s, with this performance gap widening as the number of signatures in a batch increases. Our framework further enhances data verifiability and trust by recording essential information on L2 rollups, creating an immutable and transparent record of authentication. The use of Layer 2 rollups atop a permissionless blockchain like Ethereum effectively reduces on-chain storage costs by approximately 48 to 57 times compared to direct Ethereum use, addressing cost bottlenecks efficiently.
To address the challenges of low credibility, difficult data sharing, and regulatory supervision issues involving electronic evidence storage in the judicial preservation process, this paper proposes a blockchain-based judicial evidence preservation scheme. The scheme utilizes the characteristics of blockchain's immutability to achieve credible forensics of electronic evidence on the chain and employs the decentralized storage of the interplanetary file system for secure and efficient off-chain storage. Simultaneously, it resolves the problem of declining throughput due to limited block capacity. Additionally, it leverages smart contract technology to encompass major aspects of the judicial process, including user case registration, authority management, judicial evidence uploading and downloading, case data sharing, partial disclosure of case information, and regulatory review. Simulation experiments demonstrate that the scheme significantly improves throughput and stability. Performance tests indicate that the transfer speed of the interplanetary file system can meet the data-sharing needs among judicial organizations.
The metaverse has dramatically transformed the traditional online realm and garnered significant interest from researchers and industry experts. By integrating with consumer electronics such as wearables and smart devices, it presents an immersive virtual world where individuals can engage in diverse activities. As this integration accelerates, there is an increasing need for robust and efficient methods to secure digital communications and transactions. The distributed Identity-Based Digital Signature (IBS) scheme has emerged as a promising solution to address the challenges of authenticity and integrity. However, most distributed IBS schemes are designed to rely on a trusted Key Generation Center (KGC), which introduces security risks of key escrow and a single point of failure. Meanwhile, the extensive use of cryptographic primitives such as homomorphic encryption and zero-knowledge proofs leads to the inefficiency of most schemes. Therefore, this paper proposes a blockchain-assisted fully distributed IBS scheme for integrating consumer electronics in the metaverse that complies with the IEEE P1363 Standard. In detail, our proposal completely eliminates the need for the trusted KGC and the signing key generation process is distributed among multiple users. In addition, we utilize oblivious transfer instead of homomorphic encryption to construct the signature’s additive share, making our scheme more efficient. Under the discrete logarithm assumption, it has been demonstrated that our scheme possesses existential unforgeability. Finally, based on the theoretical and experimental simulation analyses, our work shows outstanding effectiveness and practicality.
Rafael Belchior, Limaris Torres, Jonas Pfannschmidt, André Vasconcelos · 5 authors
With the evolution of distributed ledger technology (DLT), several blockchains that provide enhanced privacy guarantees and features, including Corda, Hyperledger Fabric, and Canton, are being increasingly adopted. These distributed ledgers only provide partial consistency, meaning that participants can observe the same ledger differently, i.e., observe some transactions but not others, providing higher levels of privacy to the end-user. Choosing privacy instead of transparency leads to delicate trade-offs that are difficult to manage during runtime, hampering the development of applications that depend on reasoning about shared state, e.g., asset transfers across blockchains. We propose using the concept of blockchain view (view) – an abstraction of the state a participant can access at a certain point to address this problem. Views allow us to systematically reason about either state partitions within the same DLT or an integrated view spanning across several DLTs. We introduce BUNGEE (Blockchain UNifier view GEnErator), the first DLT view generator, to allow capturing snapshots, constructing views from these snapshots, and merging views according to a set of rules specified by the view stakeholders. Creating views and operating views allows new applications built on top of dependable blockchain interoperability, such as stakeholder-centric snapshots for audits, cross-chain analysis, blockchain migration, and combined on-chain-off-chain analytics.
Due to the large-scale data streams produced by distributed terminals, hybrid-storage blockchain (HSB) that combines on-chain and off-chain storages has emerged as a promising solution for secure data storage in decentralized applications. Because all the raw data is outsourced to an untrusted service provider (SP), existing solutions suggest to utilize an on-chain authenticated data structure (ADS) to verify query results retrieved off-chain. However, existing solutions support onlycoarse-grained authenticationmaking a user abandon all the query results once the validation fails. In this paper, we focus on realizingfine-grained authenticationfor range queries, enabling a user to distinguish authentic data from falsified results. Considering the heavy gas consumption of on-chain storage, we propose two multi-dimensional parity-based verification (MPV) schemes with a trade-off between off-chain and on-chain efficiencies. Our main idea is to design an accumulator-based ADS to summarize well-designed verifiable hypercubes, so that fake results can be quickly located by combining multi-dimensional faces failed validation. Compared with previous solutions, our MPV schemes allow a user to make efficient use of query results by filtering out errors, and thus have higher data utility. The detailed security analysis and extensive experiments demonstrate the security and effectiveness of our MPV schemes, respectively.
The rapid digitization of various industries has underscored the critical need for secure and reliable document verification methods. Traditional verification techniques, including signature and stamp verification, image processing, and machine learning, often grapple with issues of scalability, accuracy, and security. Blockchain technology, renowned for its decentralization, immutability, and transparency, presents a transformative solution to these challenges. This research proposes a unified framework that integrates blockchain with traditional document verification methods, aiming to create a scalable, secure, and robust system for both electronic and printed documents. The framework is designed with several core components: a blockchain layer for immutable and transparent record-keeping, a traditional verification layer augmented by machine learning for accurate document analysis, and an integration layer that facilitates seamless interaction between these components. Smart contracts are employed to automate the verification process, enhancing efficiency and reducing human error. Key aspects of the framework include strategies to overcome technical challenges such as scalability using off-chain solutions and sharding and ensuring data privacy with advanced cryptographic techniques. The framework also incorporates regulatory and compliance considerations, ensuring that the system meets legal standards across different jurisdictions. Case studies from sectors such as finance, healthcare, and legal services illustrate the practical implementation and benefits of the proposed framework. These examples demonstrate the framework’s ability to enhance document security, streamline verification processes, and provide a reliable audit trail. This research offers a comprehensive approach to modernizing document verification, leveraging the strengths of both blockchain and traditional methods to meet the evolving needs of a digital world.
Renewable Energy Certificates (RECs) serve as vital instruments in incentivizing and verifying the production and consumption of clean and sustainable energy sources. The traditional REC management processes are often burdened with challenges related to transparency, security, and efficiency. This research paper presents an innovative approach to addressing these challenges by leveraging blockchain technology. The paper explores the design and implementation of a blockchain-based system for the issuance, transfer, and real-time ownership verification of RECs. By employing smart contracts and decentralized ledger technology, this system enhances REC management in several key aspects. Blockchain's transparent and immutable nature ensures that the entire lifecycle of a REC, from its creation to transfer, is securely recorded, reducing the potential for fraud and errors. The proposed system introduces a decentralized approach, granting users partial control over REC transfers while maintaining a centralized issuance process. This decentralization enhances user benefits and ensures a comprehensive record for each REC. In leveraging blockchain technology, the system transforms REC management, providing a secure, transparent, and efficient solution for issuance, transfer, and ownership verification. To gain more control over REC issuance, The proposed system encourages using decentralized identifiers (DIDs) and IOT devices to ensure a more decentralized REC issuance process.
Abstract Cloud storage has been widely used in remote data management, although correct storage of the outsourced file is still challenging in practice. Proofs of Retrievability (PoRs), a storage-oriented cryptographic tool, support integrity checking and efficient retrieval of the file. However, due to the lack of a fully credible oversight mechanism or a serious dependence on a trusted third party, most PoRs are incapable of achieving essential and straightforward trust between participants (i.e. the client and server). While blockchain shows promise in solving this trust issue, existing blockchain-based storage systems are scenario-constrained as they require private/permissioned or special-construct blockchains. Consequently, none of these systems provide robust and decentralized trustworthiness. We propose a general Blockchain-based Automatic Audit (BAA) scheme for PoR without limitations based on specific blockchain types. Specifically, we present BAA via stitching together a carefully designed or chosen array of sub-components such as storage proofs and Turing-complete smart contracts. We also integrate BAA with specific PoR models to prove its strong generality and availability. To our best knowledge, our proposal is the first blockchain-based approach that enhances traditional PoR models with both automatic audit and fair payment. The final analysis and implemented prototype on Ethereum demonstrate the utility of BAA.
Iván Abellán Álvarez, Vincent Gramlich, Johannes Sedlmeir
With the increasing adoption of decentralized information systems based on a variety of permissionless blockchain networks, the choice of consensus mechanism is at the core of many controversial discussions. Ethereum's recent transition from proof-of-work (PoW) to proof-of-stake (PoS)-based consensus has further fueled the debate on which mechanism is more favorable. While the aspects of energy consumption and degree of (de-)centralization are often emphasized in the public discourse, seminal research has also shed light on the formal security aspects of both approaches individually. However, related work has not yet comprehensively structured the knowledge about the security properties of PoW and PoS. Rather, it has focused on in-depth analyses of specific protocols or high-level comparative reviews covering a broad range of consensus mechanisms. To fill this gap and unravel the commonalities and discrepancies between the formal security properties of PoW- and PoS-based consensus, we conduct a systematic literature review over 26 research articles. Our findings indicate that PoW-based consensus with the longest chain rule provides the strongest formal security guarantees. Nonetheless, PoS can achieve similar guarantees when addressing its more pronounced tradeoff between safety and liveness through hybrid approaches.
Ahmed Akhtar, Masoud Barati, Basit Shafiq, Omer Rana · 7 authors
The use of blockchain technology has been proposed to provide auditable access control for individual resources. Unlike the case where all resources are owned by a single organization, this work focuses on distributed applications such as business processes and distributed workflows. These applications are often composed of multiple resources/services that are subject to the security and access control policies of different organizational domains. Here, blockchains provide an attractive decentralized solution to provide auditability. However, the underlying access control policies may have event-driven constraints and can be overlapping in terms of the component conditions/rules as well as events. Existing work cannot handle event-driven constraints and does not sufficiently account for overlaps leading to significant overhead in terms of cost and computation time for evaluating authorizations over the blockchain. In this work, we propose an automata-theoretic approach for generating a cost-efficient composite access control policy. We reduce this composite policy generation problem to the standard weighted set cover problem. We show that the composite policy correctly captures all the local access control policies and reduces the policy evaluation cost over the blockchain. We have implemented the initial prototype of our approach using Ethereum as the underlying blockchain and empirically validated the effectiveness and efficiency of our approach. Ablation studies were conducted to determine the impact of changes in individual service policies on the overall cost.
The increasing complexity of identity verification in U.S. banking and fintech ecosystems has highlighted thelimitations of traditional centralized Know Your Customer (KYC) processes, which often involve redundantdata collection, slow onboarding, and increased risk of data breaches. This study explores the design andimplementation of a Decentralized Identity (DID) architecture to enable secure, privacy-preserving, and usercentric KYC. By leveraging self-sovereign identity (SSI) principles, verifiable credentials (VCs), andcryptographic proofs, the proposed framework allows individuals to control their identity data while banks,fintechs, and regulatory authorities can authenticate users efficiently and compliantly. The architectureintegrates permissioned networks, identity wallets, credential issuers, and verifier nodes, supportinginteroperability with existing financial systems. Security, privacy, and regulatory compliance—including AML,FinCEN, and OFAC requirements—are embedded through robust cryptography, zero-knowledge proofs, andselective disclosure mechanisms. The study concludes that DID-enabled KYC can streamline onboarding,reduce operational costs, enhance user privacy, and strengthen overall financial ecosystem trust, providing aviable path for next-generation identity verification in U.S. banking and fintech.
The technological advancements in the field of E-healthcare have resulted in unprecedented generation of medical data which increases the risk of data security and privacy. Ensuring the privacy of Electronic Health Records (EHR) has become challenging due to outsourcing of healthcare information in the cloud. This increases the chance of data leakage to unauthorized users and affects the privacy and integrity of the user data. It requires a trustworthy central authority to protect the sensitive patient information from both internal and external attacks. This paper presents a blockchain based privacy preservation framework for securing EHR data. The proposed framework integrates the immutability and decentralized nature of blockchain with advanced cryptographic techniques to ensure the confidentiality, integrity and availability of EHR. The EHR data are stored in an InterPlanetary File System (IPFS) which is encrypted using a hybrid cryptographic algorithm. In addition, a novel smart contact based patient-centric access control is designed in this paper using a blockchain-based SHA-256 hashing algorithm to protect the privacy of patient data. The experimental results show that the proposed framework enables secure sharing of health information between network users with improved data privacy and security. Furthermore, the optimized search process reduces the time and space complexity compared to the traditional search process. Through the utilization of smart contracts, this framework enforces patient-centric access controls and allows patients to manage and authorize access to their medical data.
Cloud computing has emerged as a transformative paradigm, providing scalable and on-demand access to a variety of computing resources. However, concerns about the security and integrity of data in the cloud persist. This study proposes a novel approach to enhance the security and efficiency of data delivery in cloud computing through the integration of blockchain technology. The proposed system leverages the decentralized and tamper-resistant nature of blockchain to establish a secure and transparent data delivery platform. Blockchain's distributed ledger ensures the integrity of data by recording transactions in a way that is resistant to modification. Smart contracts, executable code within the blockchain, are utilized to automate and enforce secure data delivery protocols. To achieve smooth data delivery, a decentralized consensus mechanism is implemented, eliminating the need for a central authority and mitigating the risk of a single point of failure. This not only enhances security but also improves the overall reliability and availability of the data delivery platform. The integration of blockchain also introduces cryptographic techniques for secure data encryption and access control. Each data transaction is cryptographically signed, providing a robust mechanism for authentication and authorization. Additionally, the use of private and public keys ensures that only authorized parties can access and modify the data. Furthermore, the system incorporates a dynamic and adaptive resource allocation model, optimizing the utilization of cloud resources based on real-time demand. This ensures that the data delivery platform remains scalable and cost-effective while adapting to changing workloads. The proposed solution is evaluated through a series of experiments, demonstrating its effectiveness in enhancing security, transparency, and efficiency in cloud-based data delivery. The results indicate a significant reduction in vulnerabilities, improved data integrity, and increased overall system performance.
Identity Management Systems (IMS) manage individual profiles, user authorization, authentication, and access privileges. Paper-based profiles and defacement are vulnerable to spoofing, loss, and theft. Digital platforms with efficient IMS boost administrative processes and bring transparency and interoperability among establishments. The traditional paper-based identity systems are slow and rigid. Conventional centralized IMS lack transparency and are vulnerable to single-point failure. This paper presents a blockchain-aware decentralized identity management and access control (BADIMAC) model that mitigates these barriers. BADIMAC allows users to keep their digital identity within their control (i.e., self-sovereign identity). On the other hand, with the help of BADIMAC, service providers across enterprise boundaries can verify their identity without depending on any central authority. BADIMAC offers transparency and better security. The decentralized consensus-based design of BADIMAC enables the verifier to validate claims and establish proof of digital identity with process effectiveness.
Andrea Flamini, Giada Sciarretta, Mario Scuro, Amir Sharif · 6 authors
Verifiable credentials are a digital analogue of physical credentials. Their authenticity and integrity are protected by means of cryptographic techniques, and they can be presented to verifiers to reveal attributes or even predicates about the attributes included in the credential. One way to preserve privacy during presentation consists in selectively disclosing the attributes in a credential. In this paper we present the most widespread cryptographic mechanisms used to enable selective disclosure of attributes identifying two categories: the ones based on hiding commitments - e.g., mdl ISO/IEC 18013-5 - and the ones based on non-interactive zero-knowledge proofs - e.g., BBS signatures. We also include a description of the cryptographic primitives used to design such cryptographic mechanisms. We describe the design of the cryptographic mechanisms and compare them by performing an analysis on their standard maturity in terms of standardization, cryptographic agility and quantum safety, then we compare the features that they support with main focus on the unlinkability of presentations, the ability to create predicate proofs and support for threshold credential issuance. Finally we perform an experimental evaluation based on the Rust open source implementations that we have considered most relevant. In particular we evaluate the size of credentials and presentations built using different cryptographic mechanisms and the time needed to generate and verify them. We also highlight some trade-offs that must be considered in the instantiation of the cryptographic mechanisms.
The evolving landscape of Decentralized Finance (DeFi) has raised critical security concerns, especially pertaining to Protocols for Loanable Funds (PLFs) and their dependency on price oracles, which are susceptible to manipulation. The emergence of flash loans has further amplified these risks, enabling increasingly complex oracle manipulation attacks that can lead to significant financial losses. Responding to this threat, we first dissect the attack mechanism by formalizing the standard operational and adversary models for PLFs. Based on our analysis, we propose SecPLF, a robust and practical solution designed to counteract oracle manipulation attacks efficiently. SecPLF operates by tracking a price state for each crypto-asset, including the recent price and the timestamp of its last update. By imposing price constraints on the price oracle usage, SecPLF ensures a PLF only engages a price oracle if the last recorded price falls within a defined threshold, thereby negating the profitability of potential attacks. Our evaluation based on historical market data confirms SecPLF's efficacy in providing high-confidence prevention against arbitrage attacks that arise due to minor price differences. SecPLF delivers proactive protection against oracle manipulation attacks, offering ease of implementation, oracle-agnostic property, and resource and cost efficiency.
Christian Delgado‐von‐Eitzen, Luis Anido, Manuel J. Fernández Iglesias
The issuance and verification of academic certificates face significant challenges in the digital era. The proliferation of counterfeit credentials and the lack of a reliable, universally accepted system for issuing and validating them pose critical issues in the educational domain. Certificates, traditionally issued by centralized educational institutions using their proprietary systems, pose challenges for straightforward verification, generating uncertainty about the credibility of academic achievements. In addition to diplomas issued by academic entities, it is now necessary in virtually all professional fields to stay updated and obtain accreditation for certain skills or experiences, which is a determining factor in securing or enhancing employment. Yet, there is no platform available to consistently demonstrate these capabilities and experiences. This article introduces a novel model for issuing and verifying academic information using non-fungible tokens (NFTs) supported by blockchain technologies, focused on compliance with the General Data Protection Regulation (GDPR). It describes a model that grants control to the data subject, enabling the management of information access while adhering to key GDPR principles. Simultaneously, it remains compatible with existing systems within organizations, and is flexible in certifying various types of academic information. The implications of this model are discussed, emphasizing the importance of addressing privacy in blockchain-based applications.