Harlequin is a blockchain protocol in which the right to take part in consensus, governance and adjudication comes solely from reputation earned by verifiable acts — never from capital (proof of stake) or expended computation (proof of work). Reputation is a four-dimensional quantity ("the four suits"), computed deterministically from a public evidence record by a damped trust-propagation function, aggregated conservatively (a strong dimension cannot buy authority in a weak one), and subject to time decay so that standing must be continually re-earned. Block authorship and committee/jury membership are assigned by reputation-weighted cryptographic sortition; finality is provided by a Byzantine-safe gadget over signed votes; disputes are judged by sortitioned juries with interest-exclusion, and the only enforced consequence is reputational — the protocol applies no coercive force. We give the system model, the consensus and justice mechanisms, and a security analysis against a state-level adversary whose goal is capture, censorship or de-anonymization rather than direct theft. Two results are emphasized for their honesty. First, steady-state Sybil resistance is strong: a Sybil farm without earned evidence obtains about 0% of consensus power (17/17 adversarial tests). Second, the cold-start window is not unconditionally safe: a competent adversary present at genesis can capture the bootstrap; we show the security of that window is a race between honest onboarding and adversary mass — bounded, not eliminated, by non-operator personhood verification, an automatic ceiling-halt and the onboarding rate, with the residual risk declared. We report an implementation in Rust (dependency-free cores cross-validated against FRAME pallets) and a reproducible validation record spanning unit tests and multi-node hardware runs. v3 — post-launch revision. The network described here is no longer a design: the chain launched on 18 July 2026, with its genesis seed anchored to Bitcoin block 958536, and has been sealing blocks under the mechanisms this paper describes since. This revision corrects the emission schedule (per-era public ratios: 15/16 for HLQ, 3/4 for SOV, decoupled from the reputational decay constant), documents the launch facts and the first on-chain runtime upgrade executed through the paper's governance mechanism, and updates the evaluation with the live chain's validation record. Both English and Spanish editions are included; the English edition is the primary text.
Electronic voting has become an important digital governance mechanism for remote elections, institutional decision-making, shareholder voting, public consultations, and large-scale Internet-based democratic participation. Despite its growing relevance, secure electronic voting remains difficult to implement because a practical system must simultaneously preserve voter anonymity, verify voter eligibility, prevent double voting, ensure ballot integrity, support public auditability, and maintain acceptable transaction throughput. To address these challenges, this study proposes a post-quantum secure and privacy-preserving blockchain-based electronic voting framework that integrates Dilithium digital signatures, zero-knowledge proofs, nullifier-based double voting prevention, encrypted ballot submission, smart contract-based election rule enforcement, and a Byzantine fault-tolerant consensus mechanism. In the proposed architecture, Dilithium signatures are used for post-quantum authentication of voter transactions and validator messages, whereas the zero-knowledge proof layer is used separately to verify voter eligibility, candidate validity, credential ownership, and correct nullifier generation without revealing the voter identity or ballot choice. Dilithium verification is performed externally at the transaction authentication layer, while the zero-knowledge circuit handles privacy-preserving voting logic. Each voter locally generates a private credential and submits only a public commitment during registration, thereby reducing the risk of authority-based impersonation or identity-to-vote linkage. Smart contracts verify the proof, reject reused nullifiers, enforce voting rules, and record auditable election events on the permissioned blockchain ledger. Experimental evaluation demonstrates that the proposed prototype achieves an average throughput of 408 transactions per second and an average block finalization time of 2.18 s under stress testing. The results indicate that the framework can provide a practical balance between post-quantum security, privacy preservation, verifiability, and transaction efficiency in permissioned electronic voting environments.
Abstract: The aviation industry encounters difficulties with quality and safety because of fragmented and manual data management systems. This survey examines issues related to aviation data sharing within the aviation ecosystem. Data silos, transparency gaps, and security risks are discussed, along with issues concerning traceability. Blockchain and Distributed Ledger Technology (DLT) are reviewed as possible solutions. The review considers how these technologies enable secure, transparent, and permanent data exchange within the aviation ecosystem. Benefits include simpler regulatory compliance, improved supply chain traceability, and better trust among stakeholders. The paper also points out challenges like regulatory acceptance, interoperability, and scalability. Future research directions for a robust aviation quality data-sharing platform are outlined.
Abstract: Product traceability within supply chains is a critical concern that has gained increasing attention in recent years. One promising solution to this problem is the use of Public Blockchain (PBC) technology, which offers an immutable, transparent, and decentralized ledger for storing key information such as ownership transfers and distribution records. These blockchain-based systems significantly enhance traceability by ensuring that data, once recorded, cannot be altered. However, a key challenge arises from the fact that information stored on public blockchains is freely accessible to anyone, potentially exposing sensitive distribution data. In this paper, I introduce a novel method that preserves the privacy of distribution data while maintaining high traceability in supply chain systems leveraging PBC. The proposed method utilizes encryption to safeguard sensitive data and Zero-Knowledge Proofs (ZKPs) to allow supply chain participants to authenticate themselves without revealing private information, such as their blockchain addresses. The solution was implemented using Ethereum smart contracts and evaluated for its cost-effectiveness. The results show that the transaction fee per supply chain participant is capped at USD 2.6, demonstrating that the approach is practical for real-world deployment.
Hayder A. Nahi, Rusul A. Salman, Awring Falah Hassan, Ebtehal Akeel Hamed · 7 authors
Abstract The Internet of Things look out on growing security and privacy defies, principally in light of the up growth of quantum threats. To handle these defies, we suggest a unified security framework that merges post-quantum blockchain technologies and zero-knowledge proofs (ZKPs) to attain secure authentication, decentralized identity management, and advanced data protection. The provided system based on a power-weighted consensus mechanism, compressed and overlapping recursive ZKPs, and transaction batching to decrease on-chain load. The outcomes display that the suggested system outperforms conventional systems and state-of-the-art solutions, with response time reduced to 92 ms, transaction throughput increased to 735 tx/s, energy consumption reduced to 0.37 J/op, and authentication accuracy increased to 97.6%, achieving a privacy score of 0.91.These outcomes emphasize that the offered framework not only attains superior performance but as well supplies strong resistance to quantum attacks and high privacy warranties, making it a promising solution for securing future IoT environments.
Reshma D’Souza, S Sheela, H S Sameena, S Jyothi · 6 authors
Abstract: In this era where technology is used to create unidentical counterfeit products, Finding the original objects is a very tedious task for the users. These Counterfeit Products affect the health of the user in the case of medical and skin care products also. This project implements Blockchain, a new Technology which is used to overcome this problem. Blockchain technology is the distributed, and immutable technology that provides data consistency and security. Here a QR code is generated for each product that is linked to the database which in turn is mapped to the chain nodes. By scanning this QR code the user can detect the original products amongst the fake ones. It highlights the need of cryptocurrency in the broader vision of supply chain security, elaborating on how Blockchain network, particularly using Ethereum Framework, provides a decentralized and transparent ledger for tracking and validating products.
Muhammad Wahid, Shahzaib Khan, Mashhood Ali, Muhammad Hassan · 6 authors
The immutable nature of smart contracts makes it challenging to fix and patch bugs once they are deployed to a blockchain. This implies that security vulnerabilities may be exposed to possible exploitation for a longer period, necessitating comprehensive pre-deployment testing. Property-based testing combined with fuzzing has proven itself as a promising technique for uncovering vulnerabilities. Traditionally, system properties are written by human experts, which is time-consuming and consequently expensive.With the recent advancement in Large Language Models (LLMs) and their ability to 'understand' natural language and code semantics, it may be possible to generate effective properties. This study, leverages state-of-the-art LLMs to generate high-quality properties for Soliditybased smart contracts. We measure the quality of the generated properties using mutation testing. Our results show that LLMs have the potential to generate high-quality properties that are close to those written by human experts. We extensively evaluate LLMs using various prompting techniques (e.g., zero shot, few shot, and prompt chaining). Overall, we find that Gemini Pro 1.5, when combined with prompt chaining, achieves the highest average mutation score of 25.99% among all studied configurations, closely approaching the human written benchmark of 31.75%. However, our per contract analysis reveals notable variance, particularly for the LibBit contract, where Gemini Pro 1.5 under prompt chaining achieves a mutation score of 74.34%, which is on par with human written properties (74.83%). This highlights that while average performance is informative, individual contract level results demonstrate that LLMs can, in some cases, match expert level property generation.
Sourena Khanzadeh, Daniel Platnick, Marjan Alirezaie, Hossein Rahnama
Modern AI systems bring societal risks such as mass surveillance, extreme concentrations of power, and loss of user autonomy---calling into question a model where third-parties collect and control massive amounts of user data. Users require a sovereign system to securely own, govern, and disclose their context while remaining compliant across regulated domains with strict provenance, interpretability, and policy adherence. Perspective-aware AI approaches this by transforming a user's aggregated personal data into a structured identity model called a \emph{Chronicle}: a temporal knowledge graph that represents and grows with the user. Chronicles support the secure disclosure of context across federated networks. A Chronicle holder may expose a queryable, authorized view that a third-party agent may consult without centralizing anyone's data. This paper explores the problem of minimum-necessary disclosure across domain boundaries: when a requester's agent queries a Chronicle, how can the system constrain its response to release only what the requester's relationship, stated purpose, and specific task require? We propose \textbf{Provenance Preserving Chronicles} (PPC), a federated protocol that compiles each holder's Chronicle into a compact \emph{authorized evidence subgraph} governed by one rule: \emph{share no more than the request requires}. Holders keep local sovereignty; an access controller projects relationship-aware views over domain-expert ontologies; and a two-phase flow returns provenance-linked text first, releasing raw artifacts only after explicit holder approval. We frame the problem, map gaps in blockchain, P2P, and holder-sovereign designs, define the core constructs, and sketch the protocol with an explicit threat model.
Yifeng Ye, Rongji Huang, Gerui Wang, Mingchao Wan · 7 authors
In blockchain systems, peer-to-peer (P2P) overlay networks play a crucial role in providing reliable, scalable and efficient message-delivery services to upper layers. However, the consensus layer and the underlying P2P network remain mutually opaque in existing blockchains, waiving the opportunity for further improvement. In contrast to other P2P applications, blockchain can naturally be abstracted as a state machine. We therefore leverage this abstraction to record network topologies and latencies in a trusted and coordinated manner. With this support, we propose three improvements to rotating-leader consensus protocols and their underlying P2P networks: (1) accelerating leader rotation; (2) introducing a reliable-broadcast paradigm that employs tree-based dissemination in the normal case and falls back to gossip only when necessary; and (3) constructing latency-aware dissemination trees. We integrate the above ideas into Tendermint and libp2p, and conduct empirical evaluation on Amazon EC2 platform using up to 300 nodes distributed across 10 regions. The results demonstrate that, compared with gossip-based dissemination over the same topology, our prototype improves peak throughput by up to $7.26\times$.
Intent-based decentralized exchanges delegate execution to a competitive class of agents -- solvers -- whose behavior is shaped by protocol-designed reward rules. We measure how a change to those rules reshapes who captures value, using a governance-dated natural experiment: CoW Protocol CIP-74 (effective 8 December 2025), which replaced a fixed solver-reward cap with one tied to protocol revenue and introduced an ad-valorem volume fee. Using daily solver shares over 395 days, we find the reform reallocated trading value by order size. The robust signature is a monotone size gradient: concentration fell in small orders and rose in large ones across four order-value buckets (Spearman rho=1.00, exact permutation p=0.042) -- a pattern that survives dropping the single largest solver. Aggregate concentration also rose (volume-weighted HHI 0.176->0.241), substantially carried by the incumbent top solver. By trade count the market de-concentrated (count-HHI -0.060). A simple solver-economics model rationalizes the pattern: an ad-valorem fee is competitively neutral, while a revenue-linked reward cap raises the marginal payoff to inventory-rich solvers on large orders -- consistent with restricted-entry predictions (Chitra et al. 2024). A control venue (UniswapX) shows no matching break. We detect no change in average execution quality (~7 bps bound). A triple-difference exploiting a February 2026 fee cut is directionally consistent but underpowered. Reward design measurably reallocates who captures value in intent markets, without moving the average price users receive.
Direct user-specified research topic: Autonomous agent wallets spend under English mandates like 'only stablecoin swaps under $200 daily, never bridge, never touch unaudited pools', yet deployed policy engines (Safe Transaction Guards, ERC-7579 modules, session-key allowlists) enforce only stateless numeric and selector limits and cannot express 'unaudited' or 'per day', while a naive base-model prompt over raw hex calldata cannot recover function, recipient or token flow and confabulates verdicts. Evaluate a tool-augmented structured-decoding LLM judge that fetches ABIs from Sourcify and Etherscan, decodes calldata including multicall and Permit2 payloads, simulates via eth_call state overrides for token-flow and approval deltas, attaches counterparty features (contract age, verification), and emits constrained JSON: in_policy, violated_clause quoted verbatim, offending_calldata_field. Read Ethereum and Base: ERC-20 Transfer/Approval logs, Uniswap/1inch routers, Across/Stargate bridges, Permit2 at 0x000000000022D473030F116dDEE9F6B43aC78BA3. Measure macro-F1 and clause-attribution precision on 600 hand-labeled mandate/transaction pairs plus replay accuracy on transactions whose approvals owners later revoked, beating a naive raw-hex prompt and a Safe Guard numeric-allowlist baseline. Deliver as the prototype a minimal runnable Python MCP server (stdio) exposing the priced AI tool screen_transaction_against_mandate that invokes a language or ML model over onchain data to produce its output, with a typed input/output schema, an x402-style pay-per-call metering stub that records a per-call price in USDT and emits a settlement receipt, and one smoke test that exercises the tool end to end.. Investigate this topic end-to-end: survey the state of the art, identify a concrete tractable research question within it, design and run an experiment, and report results.
The growing presence of institutional capital in crypto asset markets has reopened the debate on whether Bitcoin and similar digital assets can act as safe havens, the way gold or sovereign bonds have been built historically. This thesis tackles that question with a quantitative framework rather than the qualitative arguments that dominated the early literature. The dataset covers November 2019 to May 2026 (2,380 daily observations for Bitcoin, 2,381 for the full asset universe). I fit GARCH-t and EGARCH-t models to capture conditional variance, apply Extreme Value Theory to isolate the tail directly, and run Monte Carlo simulation to estimate capital requirements over 30-day horizon.
Cryptocurrency's convenience is a convenient truth — granted here in full, with receipts. A permissionless ledger settles across borders without account approval, banking hours, or correspondent chains; Nakamoto designed exactly that, on purpose. The correction is that the convenience and the danger are the same property: what makes the transfer fast and unstoppable is that it is final — no chargeback, no administrator, no undo. Institutions can price that trade. A person cannot, and the proposal is that the rational personal policy is a wall, not a judgment call. Offered as a proposal, not a result.
This study investigates critical success factors crucial for the effective implementation of blockchain-based smart contracts in supply chain management. Through qualitative content analysis of expert interviews, diverse perspectives from industry professionals and blockchain technologists were synthesized. The findings emphasize critical dimensions such as technological infrastructure, stakeholder collaboration, regulatory compliance, data privacy, security, organizational culture, and change management. These factors collectively form a comprehensive framework essential for successful adoption. This research offers valuable guidance for organizations aiming to integrate blockchain-based smart contracts into supply chain operations. The insights derived from eight expert interviews provide strategic direction for practitioners, policymakers, and academics navigating the complexities of blockchain and smart contract technology in supply chain ecosystems.
Online disruption of financial systems is one of the most meaningful paradigmatic shifts between centralized institutional frameworks and decentralized blockchain-based infrastructure. In the present research paper, the author thoroughly reviews how blockchain technology and FinTech innovation can transform financial services, payment systems, and capital markets. Our inquiry focuses on the role of distributed ledger technologies (DLTs) in mitigating such areas as transaction speed, cost reduction, improved security, and transparent audit trails. The article dwells upon the ciphertext-policy attribute-based encryption (CP-ABE) systems that are embedded into blockchain networks and used to offer advanced access control and privacy in a multi-cloud financial system. The main technological advancements that are identified by our research are smart contracts, decentralized finance (DeFi) protocols, and blockchain-based custodial solutions. We examine experimental applications that show the increase in performance in terms of transaction processing, efficiency in encryption, and validation of authorization in blockchain-enabled financial networks. The paper deals with issue of regulation, and scalability as well as integration of old financial systems. Results indicate that financial systems based on blockchain are able to cut transaction costs by 87 percent and still have the same level of cryptographic security as current banking systems. The study will add value to comprehending the best blockchain set-ups of financial services providers and give recommendations based on evidence about digital transformation strategies. Future trends are creation of interoperable blockchain networks, high-privacy preserving technologies, and regulatory frameworks that facilitate financial innovation.
This article presents a novel, first-of-its-kind predictive RegTech solution to address this challenge using machine learning methods. The rapid global adoption of Real‑Time Payment Systems (RTPS) has created a significant “velocity gap” in regulatory compliance. While expanding financial accessibility, these systems introduce new vulnerabilities into existing AML frameworks. Static, rule-based systems and batch processing architectures cannot effectively counter money laundering in sub-second transaction environments. This limitation enables sophisticated activities such as digital layering and smurfing that move illicit financial flows across networks faster than regulatory systems can react. The core of our solution involves the use of graph neural networks (GNNs). This approach enables real-time, pre-settlement risk assessment, preventing illicit transactions before execution. Unlike traditional AML systems that evaluate transactions in isolation, this framework analyzes the entire transaction network to detect coordinated illicit behavior in real time. GNNs capture complex structures such as loops, funnels, and bridges that indicate illicit activity. To support efficient implementation, the framework integrates Event-Driven Architecture (EDA). The proposed architecture introduces the concept of the Zero-Knowledge Proof (ZKP) protocol layer in order to make risk-sharing possible in a secure manner across multiple institutions. This allows the banks to cooperate with each other in order to combat financial crimes while maintaining their data sovereignty. With predictive graph analytics, event-driven integration, and private cooperation, the proposed architecture enables proactive compliance in real-time payment environments, including real-time payment systems such as FedNow, against high-speed financial crime.
Cüneyt Gürcan Akçora, Murat Kantarcioglu, Yulia R. Gel
This chapter traces the intellectual and technological lineage of Bitcoin and digital money. While Nakamoto’s white paper launched Bitcoin, its roots extend through decades of economic theory, cryptographic innovation, and activist movements. We examine how the Austrian and Chicago Schools of Economics provided a framework for stateless and non-inflationary money, and how Cypherpunk ideals shaped the push for privacy and decentralization. The chapter reviews early experiments with digital currencies such as DigiCash, b-money, and e-gold, highlighting the technical shortcomings, regulatory battles, and user adoption barriers that prevented their success but furnished essential building blocks for Bitcoin. We then contrast the classical financial attributes of money—medium of exchange, unit of account, and store of value—with additional digital requirements such as offline spendability, identity-less spendability, and fungibility. Finally, we show how Bitcoin resolved the long-standing double-spending problem without a central authority through Proof of Work, situating it as both a culmination of earlier efforts and the starting point for a new era of cryptocurrencies.
Cüneyt Gürcan Akçora, Murat Kantarcioglu, Yulia R. Gel
In this chapter, you will explore the vulnerabilities and attack surfaces of blockchain systems that arise from their open, permissionless nature. You will learn how privacy and security issues manifest at different layers of blockchain architecture, including peer-to-peer networking, transaction propagation, block mining, and smart contract execution. The chapter introduces you to key privacy challenges such as identity leakage, transaction linkability, and deanonymization in UTXO and account-based systems. You will also study how adversaries can mount attacks that exploit consensus protocols, timestamp synchronization, and transaction ordering. The chapter concludes with detailed examples of smart contract vulnerabilities, including reentrancy, front-running, and oracle manipulation, and highlights the economic and technical incentives that make these attacks feasible in Decentralized Finance ecosystems.
Cüneyt Gürcan Akçora, Murat Kantarcioglu, Yulia R. Gel
In this chapter, you will learn about the privacy limitations of public blockchains such as Bitcoin and Ethereum, and how these limitations have led to the development of privacy-focused cryptocurrencies. You will study the motivations for privacy coins and the risks posed by government-issued digital currencies. The chapter introduces and compares three major privacy coins: Zcash, Dash, and Monero. For each, you will explore their underlying technologies, including zero-knowledge proofs (zk-SNARKs), CoinJoin-style mixing, and ring signatures with RingCT and stealth addresses. You will also learn about consensus protocols, supply models, and the trade-offs each project makes between privacy, usability, and scalability. Finally, you will analyze the comparative strengths and weaknesses of these systems and understand the broader implications of privacy on blockchains.
Cüneyt Gürcan Akçora, Murat Kantarcioglu, Yulia R. Gel
This chapter introduces blockchain network structures in both UTXO- and account-based systems. It begins with Bitcoin’s transaction and address graphs, showing how Satoshi Nakamoto’s design defines network topology and enables modeling through transaction graphs, address graphs, and chainlets. Privacy coins like Monero and Zcash extend this framework with ring signatures and zero-knowledge proofs that obscure data but still permit partial inference. Ethereum shifts focus to account-based networks, covering coin and token transactions, contract interactions, and trace analysis. Ripple concludes the chapter with credit networks built on trust lines and path-based settlements, showing how global credit flows can be modeled graphically.
Digital assets, a broad term encompassing crypto-currencies, tokens and digital representations of value, have transformed the financial landscape over the past decade. Ghana has transitioned from an unregulated crypto-currency environment to a structured, licensed digital assets space following the passage of the Virtual Asset Service Providers (VASP) Act 2025 Act 1154. Unlike traditional assets, digital assets exist exclusively in electronic form and are secured through cryptographic techniques, most notably blockchain technology. Bitcoin, Ethereum, and other crypto-currencies serve as prominent examples, alongside digital tokens used in decentralized finance (DeFi), security tokens, and stablecoins. They may serve a variety of functions, including use as a medium of exchange, for investment, or as a means of accessing goods, services, or applications within specific ecosystems. These assets include crypto-currencies, tokens, stablecoins, and other blockchain-based instruments. Global digital assets represent any item of value securely stored and managed via distributed ledger or blockchain technology. Encompassing cryptocurrencies, stablecoins, tokenized securities, and non-fungible tokens (NFTs), the sector has rapidly expanded into mainstream finance, revolutionizing global payments, portfolio diversification, and record-keeping. This article discusses the challenges and opportunities of digital currencies and the way forward. This research shows that digital currencies have advantages like making transactions faster, cheaper, and more accessible and also reveals a lot of disadvantages like creating major risks concerning compliance with regulations, cybersecurity, and potential impacts on monetary policy. The review emphasizes the necessity for robust regulatory frameworks for digital assets. It supports both innovation and stability for the digital currencies. It suggests that policymakers and financial institutions should adapt to changes and face the challenges by integrating digital currencies with existing systems. Overall, this review highlights the potential of digital currencies to transform finance. It also stresses the importance of focusing on the challenges they pose to ensure they can coexist successfully with traditional financial systems. As digital currencies evolve, the Ghanaian traditional financial sector faces pressure to adapt, with CBDCs, in particular, being explored as a secure, regulated alternative to volatile crypto-assets. nThe findings revealed that the central bank must adopt robust regulatory and licensing frameworks must align with Virtual Assets Service Providers (VASP) (Act 2025 Act 1154) by enforcing strict licensing for exchanges and custodians while adhering to AML/CFT (Anti-Money Laundering) directives. Also, the Bank of Ghana and the Securities and Exchange Commission must develop a comprehensive public education programme on the digital assets in the financial ecosystem. Given the novelty of the trend of criminality in the digital asset space, the establishment of specialized cybercrime courts to be presided over by judges, proficient in digital law and cybercrime would be of immense benefit. The mandate of such courts could be to expedite trials and ensure thorough adjudication of complex cyber cases. This would have the combined effect of empowering the Ghana Police Service and Cyber-Security Authority to fully invest time, money, and human resources towards the investigation of cybercrime, as well as serve as a deterrent for criminal elements, ultimately protecting our citizens and providing justice for those seeking redress.
Aircraft maintenance records are critical to airworthiness and asset valuation, yet they are often fragmented across stakeholders, creating verification bottlenecks and information asymmetry that may suppress aircraft residual value. This paper proposes a blockchain-anchored decentralized application (dApp) based on a dual-layer architecture that combines InterPlanetary File System (IPFS)-based off-chain storage with on-chain anchoring of Content Identifiers (CIDs) and selected metadata. With respect to off-chain file size, the on-chain payload per record remains $\mathcal{O}(1)$, compared with $\mathcal{O}(n)$ for direct on-chain file storage. The architecture incorporates metadata and traceability controls informed by Federal Aviation Administration (FAA) electronic recordkeeping guidance. The main contribution is an economic framework that models the relationship between tamper-evident maintenance-record provenance, audit workflow duration, aircraft residual value, and operational cost. In a 7-kB experiment conducted on the BNB Smart Chain testnet, CID anchoring reduced gas consumption by 93.9\% compared with direct on-chain storage. Under explicitly stated scenario assumptions, the audit-cost model indicates potential savings of more than 90\%. These results support the technical feasibility of the prototype and illustrate its economic potential, while the estimated financial benefits remain to be validated using operational data.
Blockchain and its killer applications, particularly decentralized finance (DeFi), are gaining widespread adoption, with over 5,200 DeFi projects deployed on mainstream blockchains as of January 2026. At the same time, security risks in DeFi are becoming increasingly serious. However, existing DeFi detection tools usually cover only specific attack types, exhibiting severely limited detection coverage. In this paper, we argue that an effective way to address this gap is to pre-screen vulnerable instances from large volumes of smart contract functions and call sequences. This is motivated by a key phenomenon we term "perilous temporal asymmetry". Inspired by this, we propose DeFiScreener, the first automated pre-screening framework for DeFi attacks that uses historical exploit cases to identify potentially vulnerable functions and call sequences. Given the full source code of a target project, DeFiScreener builds Function Call Trees (FCTs) and generates semantic embeddings for each function using a large language model (LLM), allowing both program structure and function intent to be analyzed together. It then applies a dual-level screening process. At the function level, function embeddings are matched against an Attack Pattern Library of historically exploited functions. At the sequence level, the proposed Attack Pattern Oriented Monte Carlo Tree Search (APO-MCTS) efficiently explores the FCTs and screens vulnerable call sequences. The identified candidates are ultimately passed to an LLM for further interpretive and security analysis. We empirically evaluate the DeFiScreener over datasets comprising 207 real-world DeFi attack incidents. Experimental results demonstrate that DeFiScreener achieves a remarkable 98.55% recall and 84.30% precision in attack pre-screening.
Ethereum non-fungible tokens (NFTs) implement ownership, transfer, authorization, and metadata operations through smart contracts, making contract vulnerabilities a direct risk to digital assets. Existing static analyzers provide efficient rule-based screening but can struggle with application-specific logic, whereas unconstrained large language model analysis may be distracted by irrelevant code or produce inconsistent outputs. We present a vulnerability-detection method that combines vulnerability-focused code slicing, an ERC-721-oriented knowledge base, and constrained DeepSeek analysis. Regular-expression patterns locate candidate statements for reentrancy, integer overflow or underflow, and timestamp dependence. A structure-aware context-window algorithm then extracts line-numbered code slices. DeepSeek analyzes each slice using explicit decision rules and a fixed output schema, and the resulting records support automated batch processing. On 450 NFT contract samples, the full configuration produced 437 positive labels, corresponding to a reported positive-label rate of 97.1%. Removing the external knowledge base reduced this rate to 87.11%, while analyzing complete contracts without the knowledge base reduced it to 73.78%. These results indicate that focused code context and domain constraints materially affect the detector's reported output.