Low-altitude aerial networks play an increasingly critical role in urban logistics, emergency response, and intelligent airspace management. These networks must ensure reliable identity authentication while addressing privacy, efficiency, and security challenges. Traditional authentication mechanisms—such as PKI-based certificates and remote identification—either overexpose identity data or lack support for flexible attribute disclosure. Moreover, existing anonymous credential (AC) schemes, though offering privacy, often incur high computational and communication costs and exist vulnerable to replay attacks. To address these limitations, we proposeDVA-ACLF(Designated Verifier Asymmetric Anonymous Credential Scheme for Low-Altitude Flight), a lightweight credential system tailored for UAVs. DVA-ACLF leverages an efficient MAC-based construction combined with non-interactive zero-knowledge proofs to enable selective attribute disclosure without relying on pairings. It supports designated verification to prevent credential misuse and replay. Experimental results show that DVA-ACLF reduces credential size by 49% (2720 bits vs. 5369 bits in Idemix) and mitigates the linear growth of credential size with respect to attribute count observed in CL and BBS+ schemes. It requires only four single-base and$2(k-l)$double-base exponentiations on UAVs, where$k$is the number of selected attributes and$l$is the number of disclosed attributes—both typically small. These features make DVA-ACLF a strong candidate for secure, efficient, and privacy-preserving authentication in low-altitude flight applications.
Isaac Amankona Obiri, Qi Xia, Jianbin Gao, Hu Xia · 5 authors
The growing adoption of electronic personal health records (ePHRs) demands cryptographic solutions that ensure secure and efficient data access. Threshold cryptography provides a framework for controlled multi-party access, yet existing schemes face practical limitations. Many require trusted key dealers, creating single points of failure and key escrow vulnerabilities, while others rely on pairing-based constructions that scale poorly. Furthermore, batch-oriented processing in previous schemes fails to support individual on-demand access patterns typical in healthcare applications. We propose a Distributed Identity-Based Threshold Decryption (DIBTD) scheme that addresses these limitations. First, our protocol removes all trusted setup assumptions through a fully distributed key generation mechanism based on verifiable secret sharing. Second, it achieves constant-time encryption and decryption operations, independent of committee size, by using efficient elliptic curve operations on secp256k1 rather than computationally heavy pairings, yielding up to 56× faster encryption than prior work. Third, DIBTD integrates the detection of malicious actors via zero-knowledge proofs, allowing the dynamic exclusion of compromised participants during system initialization. We provide formal security proofs showing the security of IND-CCA2 in the random oracle model under the discrete logarithm of the elliptic curve (ECDLP) and computational Diffie-Hellman (CDH) assumptions. The scheme remains secure against adaptive adversaries that control up to$t-1$participants. Experimental evaluation demonstrates practical efficiency: ciphertexts of only 86 bytes, constant 33-byte public keys, and sub-millisecond encryption latency. A pure Rust implementation on commodity hardware achieves 0.065ms per patient record while maintaining 128-bit security.
This study presents a comprehensive bibliometric analysis of blockchain identity management research published between 2010 and 2025, aiming to map its intellectual structure, thematic evolution, and global collaboration patterns. Using data retrieved from the Scopus database and analyzed with VOSviewer, the study applies network visualization, overlay visualization, density mapping, citation analysis, and co-authorship analysis to uncover dominant research streams and emerging frontiers. The results reveal that the field is conceptually centered on blockchain-based authentication and decentralized identity management systems, with increasing scholarly attention toward privacy-preserving mechanisms such as zero-knowledge proofs, anonymity, and data protection. Thematic evolution indicates a clear transition from foundational infrastructure-oriented studies to application-driven and regulatory-sensitive research domains, including e-government, IoT, healthcare, and digital governance. Collaboration analysis highlights the leading role of China and India, supported by strong transcontinental linkages with the United States and European countries, reflecting a globally interconnected yet regionally concentrated research landscape. By systematically mapping publication trends, thematic clusters, and collaboration networks, this study provides a structured knowledge base that supports future theoretical development, guides practical implementation, and informs policy formulation in blockchain-based digital identity ecosystems.
This report examines smart contracts as a key element in the development of decentralized systems and as a factor for a profound transformation of traditional contract law.The analysis focuses on the essence of smart contracts, their technological mechanism of action and the role of cryptography in ensuring trust and security without the need for a central intermediary.Particular attention is paid to the way in which program code begins to perform functions traditionally inherent in legal norms and institutions.Smart contracts are not just a technical tool, but a new socioeconomic mechanism for regulating relations between entities in a digital environment.The report also examines the concept of "Code is Law" as a philosophical and practical framework that questions the classical legal principles of interpretation, flexibility and judicial review.Both the potential benefits of this paradigm and the risks arising from full automation are analyzed.Additionally, the main vulnerabilities of smart contracts that arise as a result of human errors when writing the code and the irreversibility of actions in a blockchain environment are examined.These risks show that technological security does not always mean legal justice.Finally, the legal status of smart contracts in Bulgaria and the European Union is examined.
Open access
Cryptography and Data Security
Advanced Research in Systems and Signal Processing
This research explores the relationship between abnormal investor attention and Bitcoin futures return by using several Google search keywords covering Bitcoin futures to measure investor attention in its futures market. The empirical findings show that abnormal investor attention significantly negatively correlates to Bitcoin futures return when the market declines. We further consider the effect of COVID-19 and Bitcoin market crash on such a correlation and present that the relation becomes more pronounced during the latter downward periods, but find only a weak effect on such a relation during the epidemic. Finally, we provide evidence after controlling for Bitcoin spot return and VIX that the negative relation between investor attention and Bitcoin futures return is still significant, especially during a Bitcoin crash.
Wenjiang Shang, Hailing Li, Jun Wang, Chun Gui · 6 authors
The proliferation of mobile payments has brought about increasingly severe security challenges, including data breaches and identity forgery, which pose a significant threat to user assets and privacy. To meet the stringent security requirements of China’s multi-level protection scheme (MLPS) level 3 for financial systems, this study proposes an innovative privacy-enhancing protection scheme for mobile banking payments. This scheme is designed to provide comprehensive security throughout the entire lifecycle, from payment authentication to subsequent auditing. Specifically, our solution introduces two core mechanisms: the privacy-preserving authentication (PPA) protocol, which ensures the privacy of user identities and transaction data during the payment process by combining the private data access characteristics of oblivious RAM (ORAM) with zero-knowledge proof technology; and the distributed ledger audit mechanism (DLAM), which utilizes the decentralized and immutable features of blockchain, supplemented by ORAM, to guarantee the integrity of system logs and the privacy of the auditing process.
Deny Prasetyo, Siska Narulita, Ahmad Jurnaidi Wahidin, Rosalina Yani Widiastuti · 7 authors
This study introduces a trust centric machine learning framework designed to improve decision making reliability and security in decentralized digital service ecosystems. Traditional machine learning models often focus on accuracy and efficiency but fail to address the challenges of trust and security in decentralized environments. In contrast, the proposed framework integrates dynamic trust indicators and employs Federated Learning (FL) to ensure privacy while enhancing decision making performance. The framework also incorporates Zero Knowledge Proofp based Verifiable Machine Learning (ZKP-VML), which ensures transparency and security without compromising sensitive data. Through continuous real time trust assessments, the framework adapts to changing conditions, improving the accuracy and reliability of decisions in environments where participants may not fully trust each other. The application of this framework in autonomous vehicles and IoT networks demonstrated its ability to make robust, secure decisions, even in complex and uncertain scenarios. The framework’s ability to incorporate both trust and security into its decision making processes sets it apart from traditional models, which typically do not address the trustworthiness of data or participants. This research highlights the importance of integrating trust and security into machine learning models, particularly in decentralized systems, and offers a robust solution to trust management challenges. However, challenges such as scalability and computational efficiency remain, and future work should focus on enhancing these aspects, along with exploring the framework's applicability in other decentralized domains like finance or supply chain management. The integration of privacy preserving technologies and improvements in adversarial robustness are also potential areas for future research.
Muhammad Abduh Tuasikal, Jaih Mubarak, Ibdalsyah, Yulizar Djamaluddin Sanrego
The rapid growth of cryptocurrency investors in Indonesia has sparked debates about its legal status within Islamic jurisprudence. A key focus is the extreme price volatility of cryptocurrencies and whether this should be classified as gharar (excessive uncertainty) or simply as market risk. This study utilizes a normative-legal and doctrinal approach to differentiate between volatility, an inherent characteristic of modern financial instruments, and gharar, a prohibited element in Islamic contracts. The primary data for this research is sourced from classical fiqh texts and contemporary fatwas, while secondary data includes regulations and indexed academic studies on financial volatility. The findings indicate that although cryptocurrencies display higher volatility compared to stocks and gold, not all fluctuations can be classified as gharar fāḥish (excessive uncertainty). Instead, volatility should be viewed as market risk (al-ghurm), which is measurable, manageable, and tolerable under Islamic law, provided that transparency and risk-sharing mechanisms are in place. The study concludes that cryptocurrencies can be considered lawful property under Islamic law when they are free from ribā (usury), maysir (gambling), and excessive gharar, thereby providing a solid foundation for issuing fatwas and designing regulations.
Introduction. In the process of decentralization of power in Ukraine, the role of local governments in the formation and implementation of information policy has significantly increased. This has opened up new opportunities for ensuring transparency, accountability and public involvement in governance processes. However, at the same time, full-scale war, information threats, uneven institutional development of communities and limited resources have created significant challenges. In modern conditions, effective and transparent information policy is critically important for preserving democratic values, mobilizing public support and ensuring the sustainability of local development. Problem Statement. Despite the formation of legal and strategic foundations of information policy, its implementation in decentralization remains fragmented. Communities have different levels of access to digital tools, human resources and financial resources. The lack of unified transparency standards and monitoring mechanisms leads to a decrease in the effectiveness of communications and an increase in distrust on the part of citizens. The purpose of the article is to identify the challenges and prospects of forming a transparent information policy at the level of territorial communities in Ukraine under decentralization, as well as to develop practical recommendations for improving institutional, legal and digital mechanisms for its implementation. Methods. The study applied methods of analyzing the regulatory framework, comparing information policy models at different levels of government, generalizing practical experience of communities, and predicting the consequences of introducing certain management decisions. Results. The article analyzed the main barriers to forming a transparent information policy under decentralization, including limited digital infrastructure, weak institutional capacity, uneven access to information, and a low level of trust in government bodies. The potential of decentralization for introducing flexible and adaptive information policy models is revealed, in particular through the development of open data, local e-government platforms, and involving the public in the information process. The need to create unified standards of openness, digitalization of information procedures and training of local officials is substantiated. Practical recommendations are proposed for the formation of effective information policy on the ground, based on the principles of transparency, participation and trust. Conclusions. Transparent information policy should become an integral part of the development strategies of territorial communities in the context of decentralization. Its effectiveness depends on an integrated approach that includes regulatory support, financing, digital transformation and human capital development. Public administration should ensure not only the creation of favorable conditions for the implementation of openness policy, but also constant monitoring, feedback from citizens and adaptation to new challenges, including threats to information security in war conditions.
The article examines the economic nature of local finance and determines its social role under the transformation of Ukraine's public finance system. The study analyzes the historical evolution of local finance in foreign and domestic contexts, revealing a transition from viewing it as a simple community expenditure estimate to recognizing it as a complex instrument for territorial viability and financial independence. The research highlights that while foreign models followed a gradual path toward autonomy, the Ukrainian experience was marked by a long period of centralization within an administrative-command system, which is currently being overcome through fiscal decentralization. The paper systematizes academic approaches to defining "local finance" into five categories: system-resource, functional, economic, socio-economic, and legal. This classification demonstrates the multidimensional nature of local finance as both a component of public finance and the foundation of local self-government. The authors propose an updated definition, describing local finance as an institutionally regulated system of economic relations that ensures the implementation of both own and delegated powers, satisfies public needs, and promotes sustainable socio-economic development. Under the conditions of martial law and the challenges of post-war recovery, local finance is shown to transform from a mere budgetary tool into a strategic mechanism for social stability. The study concludes that the modern social role of local finance is centered on supporting internally displaced persons, ensuring security, and facilitating the recovery of territorial communities, thereby serving as a fundamental element of public finance sustainability.
Andreas KOLYDAS, Stamatis Kontsas, Stavros Kalogiannidis
The research aims to find out how cryptocurrency aids tax evasion in Greece, the socio-economic factors contributing to the practice, and the efficiency of the Greek taxation legislation in deterring such conduct. A total of 359 questionnaires were completed by respondents who engage in cryptocurrencies in Greece. Cross correlational statistical analysis and multiple regression analysis were used to test the relationship of cryptocurrency usage, anonymity, tax policies and socio-economic factors and their impact on tax evasion. Also, sociodemographic factors such as income levels and education levels greatly affected the ability to engage in tax evasion. The study provides a validation that the frequency of cryptocurrency usage, anonymity, ineffectual tax laws, socio-economic factors have a positive correlation with tax evasion rates and influence tax dodging in Greece. Based on the issues highlighted in this study, the following steps are advised for the improvement of the Greek anti-money laundering and combating the financing of terrorism regime: i) improve the regulation and enforcement measures concerning cryptocurrencies, ii) enhance the transparency of the cryptocurrency transactions, and iii) address the socio-economic circumstances that enable tax evasion.
The rapid proliferation of digital assets — encompassing cryptocurrencies, non-fungible tokens (NFTs), and related virtual instruments — has generated a parallel ecosystem of sophisticated financial crime that challenges the structural architecture of India's legal order. This article provides a critical, multidimensional analysis of the intersection between digital assets and criminal liability in India, with a specific focus on cryptocurrency-enabled cyber offences. Drawing on statutory interpretation, judicial precedent, and comparative regulatory analysis, the article examines the definitional evolution of 'virtual digital assets' under the Income Tax Act, 1961; the extension of the Prevention of Money Laundering Act, 2002 (PMLA) to virtual asset service providers in March 2023; the application of the Information Technology Act, 2000; the transitional criminal jurisprudence introduced by the Bharatiya Nyaya Sanhita, 2023 (BNS); and the Enforcement Directorate's growing arsenal of investigative tools. The article further analyses landmark case law including Internet and Mobile Association of India v. Reserve Bank of India (2020), and the recent WazirX security breach (2024) and its regulatory aftermath. Finally, it critically evaluates the persistent lacunae in India's legal framework — including the absence of dedicated cryptocurrency legislation, low conviction rates, jurisdictional challenges in cross-border offences, and the threat posed by decentralised finance (DeFi) protocols — and proposes a comprehensive reformative agenda rooted in the principles of legal certainty, technological neutrality, and international cooperation.
The thriving Non-Fungible Token(NFT) market, despite its innovative redefinition of digital ownership, faces malicious attacks and challenges, notably from widespread wash trading. In this paper, we examine the underexplored relationship between NFT rarity and wash trading.We present a novel approach to NFT market dynamics, by establishing the first comprehensive formal framework for NFT trait systems, including essential definitions, a robust taxonomy, precise rarity calculation, and verifiable properties. Building upon this, we conduct an empirical analysis of NFT rarity and wash trading across 30 collections including 336,133 NFTs, 764,679 transactions, total volume of 14,394,949 in Ethereum. Our findings reveal the strong inverse correlation between a collection’s price-rarity coefficient and its wash trading volume, showing that the top 5 collections with the lowest price-rarity coefficients are overwhelmingly dominated by wash trading, averaging 89.29% of their total volume, in contrast to the vast majority of other collections which exhibited negligible volumes, consistently below 2%. Case studies further highlight the power of this price-rarity analysis as a novel anomaly detection tool: it exposed wash trading-induced distortions in CryptoPunks by detecting an outlier previously undetectable by existing graph-based approaches. We also demonstrate Rektguy’s remarkable resilience—absorbing 20.04% wash volume possibly due to strong rarity-price correlation. Our findings establish rarity as an intrinsic resilience factor against manipulation, fundamentally reshaping approaches to NFT market analysis and robust anomaly detection.
Open access
Blockchain Technology Applications and Security
Physical Unclonable Functions (PUFs) and Hardware Security
Advanced Steganography and Watermarking Techniques
Li Xu, Mohd Nurul Hafiz Ibrahim, Mustafa Muwafak Alobaedy, S. B. Goyal
This is the first PRISMA-guided systematic review of scalable blockchain digital signatures for healthcare, synthesizing evidence from 85 peer-reviewed studies published between 2015 and 2024. The review examines five thematic areas: digital signatures, consensus mechanisms, smart contracts, hybrid blockchain architectures, and regulatory compliance. Particular emphasis is placed on scalability challenges and the role of alternative consensus protocols, such as Proof-of-Stake and Delegated Proof-of-Authority (DPoA), in addressing the energy and latency limitations of Proof-of-Work (PoW). Findings highlight the value of smart contracts in automating consent and authentication processes, while hybrid blockchain models are shown to balance security with scalability. The synthesis also identifies persistent challenges, including interoperability with legacy systems, energy consumption, and compliance with GDPR and HIPAA regulations. Importantly, emerging approaches such as Layer-2 scaling, AI-enhanced validation, and post-quantum cryptography are highlighted as promising directions. By integrating technical and regulatory perspectives, this review contributes a critical roadmap for researchers, healthcare providers, and system architects seeking secure, efficient, and regulation-compliant blockchain frameworks
Purpose The purpose of this study is to identify how Ethereum transforms the concepts of power, resilience and ethics in decentralized digital systems using the theories of Michel Foucault and Nassim Taleb. Design/methodology/approach The research relies on a conceptual approach that includes a literature review and qualitative analysis of key cases, such as the decentralized autonomous organizations (DAO) hack and Ethereum’s transition to the Proof of Stake mechanism. Data synthesis is carried out through the theoretical frameworks proposed by Foucault and Taleb. Findings Ethereum alters the dynamics of power through the use of smart contracts and DAO. The platform demonstrates antifragility by successfully adapting to crises and embodies the “Skin in the Game” principle through the staking mechanism. However, ethical challenges related to privacy arise, highlighting the importance of finding a balance between transparency and privacy. Research limitations/implications The research focuses exclusively on Ethereum, which limits the generalizability of the findings. Future research should consider other blockchain platforms. Social implications The work emphasizes the need to resolve the conflict between blockchain transparency and the right to privacy in the digital environment. Originality/value This work offers a new conceptual framework for studying decentralized systems by combining Foucault’s ideas on power with Taleb’s theories on antifragility and ethical participation. Special attention is given to the ethical aspects of digital governance.
This article examines the limitations of existing hybrid rollup solutions and presents an adaptive L2 architecture model that leverages artificial intelligence mechanisms. It is shown that current approaches to combining optimistic and ZK verification are largely based on static rules or manual mode selection, which prevents them from effectively accounting for load dynamics, risk profiles, and domain-specific properties of applications. Based on an analysis of optimistic, ZK, and hybrid rollups, an adaptive hybrid rollup model with AI-based transaction routing is proposed. This model combines transaction classification, GNN-based decision making, LSTM-based network condition forecasting, a dual-path execution system, and a continuous learning module. The article describes a Predictive Routing Algorithm that performs proactive selection between ZK and optimistic paths, taking into account cost, latency, security, and risk profile, as well as a Dynamic Resources Allocation mechanism that dynamically redistributes resources between the paths. The proposed multi-criteria optimization framework demonstrates the ability to tune objective weights to the specifics of different classes of DeFi and Web3 protocols. It is shown that the implementation of such a model is promising for systems with high transactional intensity, as it enables a shift from manual configurations to automated, data-driven policies for resource and risk management in hybrid rollup architectures.
The advancement of blockchain technology has introduced new digital economic instruments, notably Non-Fungible Tokens (NFTs), which function not only as representations of digital asset ownership but also as investment vehicles with highly volatile values. This development has sparked debates within Islamic law, particularly regarding the presence of gharar (excessive uncertainty) and maisir (speculative gambling) in NFT investment practices. This study examines the legal status of NFT investment from the perspective of ḥadīth-based muʿāmalah and analyzes the extent to which gharar and maisir are inherent in its transactional mechanisms. Employing a qualitative library research approach, this study uses descriptive-analytical methods to examine Prophetic ḥadīths prohibiting gharar and maisir, and contextualizes them within the technical characteristics and transaction structures of NFTs. Data sources include classical ḥadīth collections, ḥadīth commentaries, fiqh al-muʿāmalah literature, and relevant contemporary scholarly works. The findings indicate that NFTs, as digital assets, possess definable objects, ownership clarity, and verifiable delivery through blockchain technology, and therefore do not inherently constitute gharar. However, the use of cryptocurrency, extreme price volatility, and short-term speculative behavior may introduce elements of gharar and maisir if not accompanied by clear valuation, utility, and investment objectives. Consequently, the permissibility of NFT investment cannot be generalized but must be assessed contextually to uphold justice and the protection of wealth (ḥifẓ al-māl).
Distributed Ledger Technology (DLT) has revolutionized how digital transactions are recorded and verified, enabling decentralized trust without intermediaries. Cryptography plays a foundational role in ensuring the integrity of data within these ledgers by providing mechanisms for secure data hashing, digital signatures, and consensus protocols. This paper explores the cryptographic techniques essential to maintaining integrity in DLT, including hash functions, public-key cryptography, and Merkle trees. We analyze how these tools mitigate tampering and fraud while supporting transparency and immutability in distributed environments. A comparative overview of cryptographic primitives in popular blockchain platforms is also provided. The study concludes by highlighting future challenges and potential advancements in cryptographic methods for enhancing DLT integrity.
In decentralized digital economics era, consumer engagement has transitioned from platform-based loyalty to tokenized participation and co-creation. In Web2 brand communities, gamification often produce short-term loyalty due its reliance on external, platform regulated incentives (Deterding et al., 2011). The development of Web3 technologies has integrated verified ownership, tokenized incentives and decentralized governance, providing fresh pathways for sustained consumer engagement (Tapscott & Tapscott, 2016). This study introduces the Tokenized Co-Creation (TCC) Framework, which combines Self-Determination Theory (SDT) (Ryan & Deci, 2000) and Service-Dominant logic Theory (SDL) (Vargo & Lusch, 2004) to explain how Web3 powered gamification mechanics (NFTs, Token utilities and DAOs), satisfy intrinsic motivational needs and drive brand value co-creation (Hollebeek et al., 2019). This study contributes to the emerging literature of technological possibilities and human motivation under a overarching Tokenized Co-Creation(TCC) Framework, thus providing both theoretical advancement and managerial direction for developing a trust-based, participatory brand communities in decentralized setting.
Qian'ang Mao, Jiaxin Wang, Liu Ya, Li Zhu · 6 authors
The decentralized architecture of Web3 technologies creates fundamental challenges for Anti-Money Laundering and Counter-Financing of Terrorism compliance. Traditional regulatory technology solutions designed for centralized financial systems prove inadequate for blockchain's transparent yet pseudonymous networks. This systematization examines how blockchain-native RegTech solutions leverage distributed ledger properties to enable novel compliance capabilities. We develop three taxonomies organizing the Web3 RegTech domain: a regulatory paradigm evolution framework across ten dimensions, a compliance protocol taxonomy encompassing five verification layers, and a RegTech lifecycle framework spanning preventive, real-time, and investigative phases. Through analysis of 41 operational commercial platforms and 28 academic prototypes selected from systematic literature review (2015-2025), we demonstrate that Web3 RegTech enables transaction graph analysis, real-time risk assessment, cross-chain analytics, and privacy-preserving verification approaches that are difficult to achieve or less commonly deployed in traditional centralized systems. Our analysis reveals critical gaps between academic innovation and industry deployment, alongside persistent challenges in cross-chain tracking, DeFi interaction analysis, privacy protocol monitoring, and scalability. We synthesize architectural best practices and identify research directions addressing these gaps while respecting Web3's core principles of decentralization, transparency, and user sovereignty.
The real estate sector remains highly dependent on manual document handling and verification, making processes inefficient and prone to fraud. This work presents a system that integrates optical character recognition (OCR), natural language processing (NLP), and verifiable credentials (VCs) to automate document extraction, verification, and management. The approach standardizes heterogeneous document formats into VCs and applies automated data matching to detect inconsistencies, while the blockchain provides a decentralized trust layer that reinforces transparency and integrity. A prototype was developed that comprises (i) an OCR-NLP extraction pipeline trained on synthetic datasets, (ii) a backend for credential issuance and management, and (iii) a frontend supporting issuer, holder, and verifier interactions. Experimental results show that the models achieve competitive accuracy across multiple document types and that the end-to-end pipeline reduces verification time while preserving reliability. The proposed framework demonstrates the potential to streamline real estate transactions, strengthen stakeholder trust, and enable scalable, secure digital processes.