Blockchain Papers

Tianyu Zhang, Yupeng Ouyang, Yupeng Zhang

No abstract is available for this record.

W. Wang, Charalampos Papamanthou, Shravan Srinivasan, Dimitrios Papadopoulos

No abstract is available for this record.

Liang ZHU, Xuetao Zhang, Xiangxue Li

The Internet of Vehicles (IoV) cloud platform enables multi-dimensional sharing of vehicle data, enhancing both its value and the quality of vehicle services. To ensure dynamic authorized access control and safeguard user privacy in the IoV cloud platform, an attribute-based encryption (ABE) scheme is employed. However, existing state-of-the-art schemes still struggle to simultaneously address the following challenges: 1) the limitation of single-application scenarios due to the difficulty of achieving cross-primitive ciphertext transformation; 2) the risk of user privacy leakage caused by the inability to fully hide access policies; 3) the potential for malicious accusations against the delegator due to a lack of verifiability. To tackle these issues, we propose PPVTAC, a Privacy-Preserving, Verifiable, and Transformable Access Control scheme for cloud-assisted IoV. Specifically, we leverage a hybrid proxy re-encryption technique to transform ABE ciphertext into identity-based encryption (IBE) ciphertext, making it more suitable for collaborative scenarios. A cuckoo filter is introduced to achieve fully hidden policies, thereby protecting user privacy. Additionally, we incorporate non-interactive zero-knowledge proofs (NIZKPs) to ensure verifiability, guaranteeing the correctness of transformed ciphertexts while preventing malicious accusations against the delegator. A further advantage of our scheme is its support for unbounded attribute spaces, eliminating the need for system reboot when adding new attributes. In addition, our scheme requires only a constant number of pairing operations during the decryption and re-encryption phases, regardless of the number of attributes. We formalize a security model and rigorously prove that our scheme achieves adaptive security. Our scheme achieves simultaneously for the first time cross-primitive ciphertext transformation, fully hidden policy, and verifiability while ensuring adaptive security. We implement our scheme in real-world environments and compare it with existing state-of-the-art schemes. Our approach offers a more comprehensive feature set without significant performance trade-offs, making it highly suitable for cloud-assisted IoV scenarios.

Mohammad Muavia

Every correction for backtest overfitting depends on N, the number of strategies a researcher tried. The deflated Sharpe ratio needs it. So do multiple-testing haircuts and the probability of backtest overfitting. And N is supplied by the researcher. Nobody has ever been able to check it. VTR-1 is an open standard that makes N a structural property of a cryptographic proof. The full set of candidate strategies is committed before evaluation, and N is the leaf count of that commitment. The winning result is forced in-circuit to be the maximum of the committed set. The anti-overfitting statistics are then recomputed inside a zero-knowledge proof, on committed price data, net of a committed cost floor. Any party can re-derive every asserted property in milliseconds against their own copy of the data. No trust is placed in the issuer at any step, and the strategy is never revealed. The standard sets out three conformance levels, a verification procedure, and an adversary model naming seven attack classes. Its normative appendices pin the estimators, the fixed-point arithmetic and the commitment constructions closely enough that an independent implementation can reproduce a credential exactly. Forty-one numbered requirements let a conformance claim be contradicted. Nine known-answer conformance vectors are published with it, so a second implementation can be tested against something. The standard is equally explicit about what it will not certify: future returns, capacity, market impact, and any strategy whose result depends on fills the committed data cannot justify. The reference implementation's first published verdict refused its own author's flagship strategy, deflated below significance and published permanently. Published under CC BY 4.0. Anyone may implement it, including competitors of its steward.

Laurane Chloé Angélina Marco

We explore the design and analysis of post-quantum cryptographic primitives with an emphasis on two angles. First, diversity of assumptions, by building and analysing cryptography that does not rely on structured lattices. Second, diversity of functionalities, focusing on various primitives that extend beyond standard encryption. Motivated by the rapid development of quantum computing and the consequent threat to classical public-key cryptography, we therefore consider two families of post-quantum assumptions: isogeny-based and code-equivalence problems from which we build and analyse various primitives. In the first part, we focus on isogeny-based cryptography. We start our study with digital signatures derived from SIDH squares and investigate their security by analysing a range of attack vectors, including higher-dimensional attack strategies (known as SIDH attacks), and consequently propose suitable parameters. Building on the powerful constructive tools that the SIDH attacks became, we design an updatable public-key encryption scheme from a variant of FESTA, a public-key encryption scheme by Basso, Maino and Pope, enabling an efficient instantiation of this primitive that allows an unbounded number of updates. Finally, we investigate isogeny-based group actions and propose a framework for general-purpose zero-knowledge proofs. The second part focuses on code-based cryptography, particularly tensor group actions and code-equivalence problems. We first analyze and break a commitment scheme based on a structured tensor isomorphism problem, and we propose a secure fix. Then, we study variants of code-equivalence problems that underlie the security of two blind signature schemes. For one variant, we provide a reduction to a standard problem, whilst for another one we show that its security has been largely over-estimated. Overall, this thesis contributes to the development of a diverse suite of post-quantum primitives by providing new constructions, security analyses, and insights into the use of alternative assumptions beyond lattice-based systems.

Lian Yang, Shujiang Xu, Pingping Song, Jian Zhu · 6 authors

Background: The inherent immutability of traditional blockchain technology fundamentally conflicts with the need for dynamic updates and secure sharing of medical data. Existing editable blockchain solutions also face limitations in update efficiency, key management security, and cross-institutional privacy protection. Objective: This paper aims to design a novel architecture that integrates chameleon hash with a permissioned blockchain to achieve secure, efficient, and auditable incremental updates and controlled sharing of medical data. Methods: We propose a hybrid architecture comprising: (1) a lightweight off-chain update protocol based on chameleon hash, enabling authorized institutions to swiftly modify off-chain data using a trapdoor key while only recording lightweight credentials on the blockchain; (2) a distributed trapdoor key management mechanism based on threshold signatures, which disperses critical authority across multiple trusted medical nodes to eliminate single points of failure; and (3) cross-institutional data sharing smart contracts with privacy protection, featuring an integrated Zero-Knowledge Proof (ZKP) verification interface that allows third parties to verify data validity without accessing the original sensitive information. Results: Compared to traditional schemes, our method improves update throughput by 3.2× and reduces on-chain storage by 76%. Authorized updates and verification complete within 5 seconds in simulated cross-hospital scenarios, while distributed key management prevents unauthorized modifications. Conclusion: The proposed scheme balances dynamic updates with trustworthy auditing in medical data management. By addressing efficiency, security, and privacy limitations of existing solutions, it supports the development of a trusted, privacy-secure medical data ecosystem.

Shiyu Wang, Xinyu Li, Qinglin Yang, Yuan Liu

No abstract is available for this record.

Zhao Zhang, Chunxiang Xu, Chuhan Ma

Communication protocol is a fundamental component of modern networking. With proliferation of networking and communication, users have become more concerned about privacy. This leads to development of end-to-end encrypted messaging systems which provides confidential communication. Besides confidentiality, there is an increasing demand for additional security properties such as unforgeability, anonymity, off-the-record (OTR), and consistency. However, efficiently achieving these properties simultaneously, especially on resource-constrained mobile devices, remains a significant challenge. In this paper, we propose MERIT, a novel multi-designated receiver authenticated broadcast encryption scheme that satisfies all the above security guarantees in a highly efficient manner. MERIT ensures the following key properties: (i) unforgeability prevents unauthorized parties from generating valid messages; (ii) privacy safeguards the messages and identities of the sender and receivers from non-designated parties; (iii) OTR ensures that receivers cannot later prove the origin of the messages even with their secret keys; and (iv) consistency ensures that all designated receivers obtain identical decrypted messages and identities. The core building block of MERIT is a practical multi-designated verifier signature (PMDVS), which might be of independent interest. We employed a novel batched cut-and-choose technology to prove that the ciphertext is well-formed. This results in an order-of-magnitude efficiency improvement in our scheme compared to its counterparts that rely on general-purpose zero-knowledge proofs. We then show how MERIT leverages PMDVS to provide unforgeability, privacy, OTR, and consistency in the scenario of group messaging. We provide security analysis to demonstrate that MERIT satisfies these security guarantees. We also conduct a thorough performance implementation, and the experimental results demonstrate that MERIT is highly efficient for deployment on mobile devices.

Mojtaba Khalili

Quasi-adaptive non-interactive zero-knowledge (QA-NIZK) arguments are fundamental cryptographic primitives widely used in privacy-preserving technologies such as anonymous credentials, group signatures, e-cash, and blockchain-based applications. We present the first tightly secure unbounded simulation sound quasi-adaptive non-interactive zero-knowledge argument system from simple assumptions. The construction has a security loss ofO(1), a compact common reference string, constant size proofs, and its security relies on the hardness of the well-known SXDH assumption. Our result improves state-of-the-art (Couteau and Hartmann, CRYPTO 2020) in terms of the proof size (about three times), a lower security loss, and also with respect to the underlying hardness assumptions. The tight security reduction enables shorter key-length recommendations, leading to improved concrete efficiency. Our main technical contribution is a novel proof technique inspired by the randomization technique of the Naor-Yung double-encryption paradigm and the adaptive partitioning due to Hofheinz (EUROCRYPT 2017).

Ali Şah Özcan, Cihangir Tezcan, Erkay Savaş

No abstract is available for this record.

Quoc Khanh Huynh, Nhat Nguyen Nguyen, Tuan-Dung Tran

No abstract is available for this record.

M. Sreelakshmi, Shaik Naseera

No abstract is available for this record.

Zhiqiang Zhang, Youwen Zhu, Xiaodong Yang, Xiaohui Ding · 7 authors

Attribute-Based Encryption (ABE) enables fine-grained access control over outsourced data, but its key generation process typically requires users to disclose their complete attribute sets, introducing significant privacy risks. Existing privacy-preserving approaches—such as those based on zero-knowledge proofs or tightly coupled interactive protocols—suffer from limited scalability, high communication costs, and insufficient support for selective attribute disclosure. To address these limitations, we propose a privacy-enhancing key generation protocol guided by the principle ofMinimal Disclosure, which ensures that users disclose only the minimally necessary subset of attributes required for authorization. Our protocol decouples attribute verification from key issuance: users first obtain cryptographically verifiable attribute tokens, and later issue blinded key requests over selectively chosen attributes. This design enables selective disclosure, supports reusable attribute credentials, and enhances user autonomy. To improve scalability, we introduce a lightweight batch verification mechanism that reduces computation and communication overhead for the attribute authority. We prove that our protocol achieves thebindingandhidingproperties under standard cryptographic assumptions, and we formally verify these guarantees in the symbolic model using the ProVerif tool. In addition, we propose two privacy metrics—AttributeInference Gain (AIG) andPrivacy Gain (PG)—alongside an entropy-based analysis to quantify resistance against attribute inference attacks. Experimental results show that our scheme effectively mitigates inference leakage while offering substantial efficiency gains compared to existing schemes.

Kaoru Aguilera Katayama

This paper presents a Blueprint theoretical-practical method for covert control over a decentralized network like Bitcoin by manipulating official distribution channels and modifying the client software. The attack, termed the "Great Tribulation Attack," transforms legitimate users into functional zombie nodes that validate blocks under hidden rules or preprogrammed transactions without their knowledge. This technique does not rely on the 51% hashing power but on client deception.

Haosu Cheng, Guanquan Shi, Kangkang Zhang, Wenyu Zhang

No abstract is available for this record.

Shuhui Zhang, Xiaochen Wang, Lianhai Wang, Shujiang Xu · 6 authors

No abstract is available for this record.

Meng-Lin Huang, Xiaodan Zhang, Wei Mi, Huimei Liao · 5 authors

No abstract is available for this record.

Zhang Dayong, Nur Haliza Abdul Wahab, Juniardi Fadila, Arafat Al-Dhaqm · 8 authors

Practical Byzantine Fault Tolerance (PBFT) serves as a cornerstone consensus protocol for distributed systems. However, its inherent limitations, including quadratic communication complexity, scalability bottlenecks, and insufficient privacy protection, hinder its applicability in large-scale and privacy-sensitive environments. This study presents a systematic and comprehensive review of cryptographic advancements aimed at addressing these challenges. By analyzing peer-reviewed literature from 2015 to 2025, we demonstrate that the integration of Verifiable Random Function (VRF) and Boneh–Lynn–Shacham (BLS) aggregate signatures effectively reduces PBFT's communication complexity from O(N²) to O(N) or even O(logN), significantly enhancing scalability and reducing consensus latency. Moreover, advanced cryptographic schemes such as zero-knowledge proofs, homomorphic encryption, group signatures, ring signatures, hash ring, threshold signatures, attribute-based Encryption and lattice-based cryptography are shown to substantially strengthen consensus efficiency, privacy preservation and node security. Despite these improvements, trade-offs arise in terms of computational overhead and system complexity. The findings provide critical insights into the synergetic application of cryptography within PBFT-based systems and offer future directions for constructing scalable, secure, and privacy-preserving distributed architectures, particularly in Internet of Things and other resource-constrained scenarios.

Xiao Wei

With the rapid increase of terminal devices in the Internet of Things (IoT), it has become a significant challenge to achieve real-time and privacy-preserving data aggregation. To address this challenge, edge computing has emerged as an effective paradigm to reduce latency, where a privacy-preserving data aggregation scheme is exploited to preserve data privacy. However, most existing privacy-preserving data aggregation schemes are limited by fixed data dimensions, low scalability, and high communication or computational overhead. To address these shortcomings, this paper proposes a multidimensional privacy-preserving data aggregation scheme that supports flexible dimension expansion and privacy protection in edge computing systems. The scheme integrates the Chinese Remainder Theorem (CRT) with an elastic modulus set to efficiently pack multidimensional data. This design enables terminal devices to add new data dimensions without interrupting current operations or modifying historical data. Furthermore, by exploiting Bulletproofs-based zero-knowledge proofs and Bellare-Neven (BN) signatures with half-aggregation, the proposed scheme enables lightweight and scalable batch verification of data integrity and authenticity. These mechanisms effectively reduce the verification workload and communication bandwidth in large-scale deployments. In addition, an optimized Paillier homomorphic encryption algorithm is used to enable efficient aggregation of encrypted multidimensional data. Experimental results and theoretical analysis show that the proposed scheme significantly reduces computational and communication costs compared with existing methods.

Steven Paul Nohr

Decentralized finance and stablecoin systems rely extensively on off-chain data oracles to supply price feeds, reserve attestations, and external state signals. While often treated as neutral data providers, oracles constitute a critical enforcement surface vulnerable to coercion, capture, and strategic manipulation. This paper defines <b><i>Off-Chain Data Oracle Coercion</i></b> as a systemic risk whereby economic, governance, or infrastructural pressures distort oracle outputs without violating cryptographic correctness. We demonstrate how oracle coercion enables silent value extraction, destabilizes stablecoin pegs, and undermines regulatory compliance. A validator-enforced, logic-layer control model is proposed to restore oracle neutrality and ensure continuous, verifiable data integrity under MiCA-aligned supervision.

Vimmi Malhotra, Sandeep Joshi, Varun Tiwari

No abstract is available for this record.

Angelo De, Kaoutar Elkhiyaoui, Sandeep Nishad, Sikhar Patranabis · 5 authors

Interoperation across distributed ledger technology (DLT) networks hinges upon the secure transmission of ledger state from one network to another.This is especially challenging for private networks whose ledger access is limited to enrolled members.Existing approaches rely on a trusted centralized proxy that receives encrypted ledger state of a network, decrypts it, and sends it to members of another network.Though effective, this approach goes against the founding principle of DLT, namely avoiding single points of failure (or single sources of trust).In this paper, we leverage fully-distributed broadcast encryption (FDBE in short) to build a fully decentralized protocol for confidential information-sharing across private networks.Compared to traditional broadcast encryption (BE), FDBE is characterized by distributed setup and key generation, where mutually distrusting parties agree on a BE's public key without a trusted setup, and securely derive their decryption keys.Given any FDBE, two private networks can securely share information as follows: a sender in one network uses the other network's FDBE public key to encrypt a message for its members.The resulting construction is secure in the simplified universal composability (UC) framework.To further demonstrate the practicality of our approach, we present the first instantiation of an FDBE that enjoys constantsized decryption keys and ciphertexts, and evaluate the resulting performances through a reference implementation that considers two private Hyperledger Fabric networks within the Hyperledger Cacti interoperation framework.

Ying Chen, Debiao He, Zijian Bao, Cong Peng · 5 authors

No abstract is available for this record.

Xiaoming Liu

This study focuses on the core needs of consumer data privacy protection in the context of the digital economy and creates a blockchain-based privacy and security architecture. Through a layered design, this architecture effectively combines data collection, blockchain core, privacy computing, smart contracts, and application integration modules. It integrates key techniques such as zero-knowledge proofs, homomorphic encryption, and decentralized identity to ensure that data is encrypted and stored throughout its creation and destruction, implements meticulous access rights management, and implements a verifiable audit process. The dataset used in this experiment is the 2024 CMS market county-level administrative district public dataset in the United States. In an environment simulating actual business pressures, the privacy protection effectiveness, system scalability, and computational and storage costs of this proposed system are tested. Comparisons are made with two typical implementations. While ensuring differential privacy and k-anonymity, the proposed system improves data transmission speed, reduces processing latency, and reduces storage consumption. This demonstrates the potential and superior performance of this system across multiple entities and industries. This study provides a practical and feasible technical implementation for blockchain-driven consumer data privacy protection and offers a verifiable engineering reference for data governance and cross-industry data sharing in the United States.