Blockchain Papers

Yue Li, Peiting Xu, Yunfa Huang, Zengjin Liu

In recent years, the business demand of international cold chain food trade has been increasing, but the process is complex, time-consuming, and there are data trust issues. This paper proposes a blockchain-based international cold chain trade platform system, which uses the immutable and traceable

Pierre-Alain Fouque, Adela Georgescu, Chen Qian, Adeline Roux-Langlois · 5 authors

No abstract is available for this record.

Duc Anh Luong, Jong Hwan Park

Privacy plays a crucial role in the internet era, where many applications allow people to communicate and use their services through the internet. Privacy-preserving Identity Management (PPIdM) system is a scheme that helps manage users’ identities and protects users’ privacy by enabling users to authenticate themselves without disclosing their real identities. The PPIdM system also allows users to reveal some minor identity attributes while others remain secret selectively. However, anonymity also encourages malicious users to break the system’s policy and commit crimes since their real identities are anonymous. Existing PPIdM systems use the identity provider (IP) as a medium to verify users’ identity attributes, record all users’ real identities, and ensure that malicious users’ identities are traceable. Therefore, users’ identities are hidden from all entities but the IP. However, the user’s privacy is vulnerable because there is nothing to guarantee that the IP is always honest and not curious about their users’ activities and private information. This paper proposes a PPIdM system on the blockchain that helps users manage their identity attributes and keeps their real identities secret from all entities, including the IP. Still, the system’s consensus can trace malicious users’ real identities if they violate the system’s policy. The PPIdM’s security requirements are analyzed and proved informally using the game-based proof scheme. The main idea of this study is to combine zk-SNARK, a type of zero-knowledge proof (ZKP), Shamir’s secret sharing (SSS), and several other cryptographic techniques.

John Stuart

Avec la montée en puissance des ordinateurs quantiques, il est plus important que jamais de démontrer que les protocoles cryptographiques sont sécuritaires contre des adversaires quantiques. De plus, l'objectif de tout cryptographe est d’assouplir certaines hypothèses, en particulier celles qui restreignent la capacité de l’adversaire à effectuer de longs calculs. Dans cette thèse, un système multi-parties est utilisé pour créer deux preuves Zéro-Knowledge (ZK), celles-ci opèrent en temps polynomial et sont sécurisées. De plus, elles n’ont aucune restriction calculatoire pour aucune partie, même pour les adversaires qui partagent une intrication quantique. Une preuve ZK permet à une partie de prouver à une autre partie d’un fait sans révéler aucune connaissance autre que la véracité du fait. Par exemple, une telle preuve pourrait être utilisée pour permettre à un client de prouver son identité à un guichet bancaire sans donner des renseignements confidentiels tel que son numéro d'identification personnel. Un des principaux outils utilisés lors d’une preuve ZK est le schéma de mise en gage. Celui-ci est essentiellement un outil numérique permettant à un expéditeur de sceller un message dans un coffre-fort et de l’envoyer à un destinataire. Ensuite, quand l'expéditeur veut que le destinataire lise le message, la clé du coffre fort lui est envoyée. Ceci permet au message de rester inconnu du receveur jusqu'à ce qu’il reçoive la clé de l'expéditeur. De plus, l'expéditeur ne peut pas changer le message une fois le coffre-fort envoyé. Au cours de cette thèse, les propriétés homomorphiques d’un schéma multi-parties de mise en gage sont utilisées pour permettre au destinataire d’effectuer des opérations sur le gage. Ceci donne ainsi des preuves ZK pour deux problèmes NP-complets, les problèmes de la somme de sous-ensembles et 3-SAT

Megan Chen, Alessandro Chiesa, Tom Gur, Jack O’Connor · 5 authors

No abstract is available for this record.

Andrea Basso, Giulio Codogni, Deirdre Connolly, Luca De Feo · 10 authors

No abstract is available for this record.

Vitalik Buterin, Jacob Illum, Matthias Nadler, Fabian Schär · 5 authors

We study Privacy Pools, a novel smart contract-based privacy-enhancing protocol. The protocol introduces a mechanism for users to reveal certain properties of their transaction without having to reveal the transaction itself. The core concept involves allowing users to publish a zero-knowledge proof, demonstrating that their funds (do not) originate from known (un-)lawful sources, without publicly revealing their entire transaction history. This is achieved by proving membership in custom association sets, which are designed to demonstrate compliance with regulatory frameworks or social consensus. We illustrate how this mechanism can create a separating equilibrium between compliant and non-compliant withdrawals. Our work describes the technical underpinnings, incentives and broader implications of this mechanism, highlighting how Privacy Pools-like protocols can create more private yet compliant blockchain transactions.

Shahla Atapoor, Karim Baghery, Daniele Cozzo, Robi Pedersen

No abstract is available for this record.

Anton Dziatkovskii

The article is devoted to technologies of digitalization of educationzero-knowledge proof, blockchain and artificial intelligence.It analyzes the features of these technologies and lists possible uses in terms of the public good.

A.I.O. Nijsten, W. van der Schoot, J.D. de Faris Miranda Duarte

No abstract is available for this record.

Yijing Lin, Hongyang Du, Dusit Niyato, Jiangtian Nie · 7 authors

The construction of virtual transportation networks requires massive data to be transmitted from edge devices to Virtual Service Providers (VSP) to facilitate circulations between the physical and virtual domains in Metaverse. Leveraging semantic communication for reducing information redundancy, VSPs can receive semantic data from edge devices to provide varied services through advanced techniques, e.g., AI-Generated Content (AIGC), for users to explore digital worlds. But the use of semantic communication raises a security issue because attackers could send malicious semantic data with similar semantic information but different desired content to break Metaverse services and cause wrong output of AIGC. Therefore, in this paper, we first propose a blockchain-aided semantic communication framework for AIGC services in virtual transportation networks to facilitate interactions of the physical and virtual domains among VSPs and edge devices. We illustrate a training-based targeted semantic attack scheme to generate adversarial semantic data by various loss functions. We also design a semantic defense scheme that uses the blockchain and zero-knowledge proofs to tell the difference between the semantic similarities of adversarial and authentic semantic data and to check the authenticity of semantic data transformations. Simulation results show that the proposed defense method can reduce the semantic similarity of the adversarial semantic data and the authentic ones by up to 30% compared with the attack scheme.

Matthew Green, Mathias Hall-Andersen, Eric Hennenfent, Gabriel Kaptchuk · 6 authors

We consider the problem of proving in zero-knowledge the existence of vulnerabilities in executables compiled to run on real-world processors. We demonstrate that it is practical to prove knowledge of real exploits for real-world processor architectures without the need for source code and without limiting our consideration to narrow vulnerability classes. To achieve this, we devise a novel circuit compiler and a toolchain that produces highly optimized, non-interactive zero-knowledge proofs for programs executed on the MSP430, an ISA commonly used in embedded hardware. Our toolchain employs a highly optimized circuit compiler and a number of novel optimizations to construct efficient proofs for program binaries. To demonstrate the capability of our system, we test our toolchain by constructing proofs for challenges in the Microcorruption capture the flag exercises.

Carsten Baum, Lennart Braun, Cyprien Delpech de Saint Guilhem, Michael Klooß · 7 authors

We present a new method for transforming zero-knowledge protocols in the designated verifier setting into public-coin protocols, which can be made non-interactive and publicly verifiable. Our transformation applies to a large class of ZK protocols based on oblivious transfer. In particular, we show that it can be applied to recent, fast protocols based on vector oblivious linear evaluation (VOLE), with a technique we call VOLE-in-the-head, upgrading these protocols to support public verifiability. Our resulting ZK protocols have linear proof size, and are simpler, smaller and faster than related approaches based on MPC-in-the-head. To build VOLE-in-the-head while supporting both binary circuits and large finite fields, we develop several new technical tools. One of these is a new proof of security for the SoftSpokenOT protocol (Crypto 2022), which generalizes it to produce certain types of VOLE correlations over large fields. Secondly, we present a new ZK protocol that is tailored to take advantage of this form of VOLE, which leads to a publicly verifiable VOLE-in-the-head protocol with only 2x more communication than the best, designated-verifier VOLE-based protocols. We analyze the soundness of our approach when made non-interactive using the Fiat-Shamir transform, using round-by-round soundness. As an application of the resulting NIZK, we present $$\textsf{FAEST}$$ , a post-quantum signature scheme based on AES. FAEST is the first AES-based signature scheme to be smaller than SPHINCS+, with signature sizes between 5.6 and 6.6kB at the 128-bit security level. Compared with the smallest version of SPHINCS+ (7.9kB), FAEST verification is slower, but the signing times are between 8x and 40x faster.

Gongxian Zeng, Junzuo Lai, Zhengan Huang, Linru Zhang · 8 authors

No abstract is available for this record.

Muhammad Fadhil Abidin, Avinanta Tarigan, Lely Prananingrum

Blockchain merupakan sistem terdesentralisasi yang terbuka yang dapat dimanfaatkan untuk melakukan pelacakan dan verifikasi keaslian dokumen. Sifat keterbukaan tersebut menjadi masalah jika isi dari dokumen bersifat rahasia atau dilindungi oleh undang-undang perlindungan data pribadi. Dalam penelitian ini, sebuah sistem verifikasi dokumen berbasis Blockchain dirancang dengan memanfaatkan algoritma ZKP (Zero Knowledge Proof) yang diimplementasikan dalam sebuah Smart Contract pada jaringan Blockchain Polygon. Algoritma ZKP melindungi informasi yang bersifat rahasia tetapi dapat diverifikasi kebenaran dan keasliannya oleh pihak yang berkepentinga tanpa menguak informasi tersebut. Penelitian ini melibatkan perancangan smart contract yang terdiri dari fungsi-fungsi untuk mengatur proses verifikasi dokumen, serta implementasi sistem verifikasi dokumen yang terintegrasi dengan Smart Contract. Hasil penelitian menunjukkan bahwa sistem yang dibangun dapat meningkatkan keamanan proses pelacakan dokumen dengan tidak menguak isi dokumen yang bersifat rahasia dan dilindungi oleh undang-undang.

Gweonho Jeong, Nuri Lee, Jihye Kim, Hyunok Oh

With the rapid growth of the blockchain market, privacy and security issues for digital assets are becoming more important. In the most widely used public blockchains, such as Bitcoin and Ethereum, all activities on user accounts are publicly disclosed, which violates privacy regulations such as EU GDPR. Encryption of accounts and transactions may protect privacy, but it also raises issues of validity and transparency. While encrypted information can protect privacy, it cannot alone verify the validity of a transaction. Additionally, encryption makes it difficult to meet anti-money laundering regulations, such as auditability. In this paper, we propose${\sf Azeroth}$, an auditable zero-knowledge transfer framework.${\sf Azeroth}$connects a zero-knowledge proof to an encrypted transaction, enabling it to check its validation while protecting its privacy.${\sf Azeroth}$also allows authorized auditors to audit transactions.${\sf Azeroth}$is designed as a smart contract for flexible deployment on existing blockchains. We implement the${\sf Azeroth}$smart contract, and execute it on various platforms including an Ethereum testnet blockchain, and measure the time to show the practicality of our proposal. The end-to-end latency of a privacy-preserving transfer takes about$4.4s$. In particular, the client’s transaction generation time with a proof only takes about$0.9s$. The security of${\sf Azeroth}$is proven under the cryptographic assumptions.

AoXuan Li, Gabriele D’Angelo, Su-Kit Tang

No abstract is available for this record.

Ayman Nait Cherif, Youssef Achir, Mohamed Youssfi, Mohamed Youssfi · 6 authors

Abstract—This paper investigates the integration of Zero-Knowledge Proofs (ZKP) and OAuth 2.0 to enhance anonymity and security in multi-agent distributed systems. We propose an approach that allows agents to authenticate and prove possession of specific data without revealing the underlying details. Additionally, we outline a potential access control strategy using ZKP for anonymity, allowing agents to validate their access rights without identity exposure. When combined with OAuth 2.0, this mechanism provides a framework for secure data access. While the proposed methods offer promising solutions to security, privacy, and anonymity challenges in multi-agent systems, they also highlight the need for further research and validation to confirm their effectiveness.

Lingming Kong, Rui Zhao, Fan Xue

Blockchain technology emphasizes trust and collaboration through distributed networks and is deemed to contribute to building information modeling (BIM) based construction collaboration and management. However, the open nature of blockchain introduces severe cybersecurity attacks that undermine the trustworthiness of construction management. One salient point is identity authentication for security BIM data access in the blockchain environment. The traditional public-private key or password authenticate methods are vulnerable to malicious theft. Zero-Knowledge Proof (ZKP) is an emerging, password-free method for authenticating identities. It allows one party to prove the truth or falsity of a statement to another party without revealing any meaningful information to the counterpart. Therefore, this study proposes a preliminary user authentication protocol based on the non-interactive ZKP protocol, specifically the zk-SNARK protocol, for adaptive authentication of blockchain BIM. The adaptive authentication recognizes a random subset of on-chain historical BIM operation records to prove the identity according to the protocol. Without revealing any meaningful knowledge to the authentication system, this adaptive data access control prevents password attacks using the BIM records on-chain. Finally, the proposed protocol is deployed on the test blockchain and implemented in a preliminary case study to illustrate the feasibility and effectiveness of the proposed method. The main contribution of this paper is twofold. Firstly, the theoretical contribution is proposing a novel zk-SARKs-based identity authentication protocol that utilizes the on-chain BIM operation records. Secondly, the practical contribution relies on presenting a ZoKrates-based workflow of generating proofs, creating smart contracts, and deploying on the blockchain for verification

Theodoros Constantinides, John Cartlidge

We present a general purpose, privacy-preserving framework for verifying user attributes. The framework is designed for users (e.g., a job candidate) to allow a challenger (e.g., a prospective employer) to verify whether the usermeets a particular requirement (e.g., does the candidate hold a valid driving license?), without leaking any other information about the user. Importantly, the user is an active part of the challenge-verification process, which ensures that challenges cannot be made without the user’s full knowledge and participation. The framework is decentralized and requires a public blockchain. A smart contract is used to manage the challenge-verification process, and zero-knowledge proofs are used to verify challenges in a privacy-preserving manner. We implement a simplified version of the framework using smart contracts deployed on the Ethereum blockchain, and we simulate some simple use cases. All simulation code is available open-source (https://github.com/lifeisbeer/BlockVerify).

Carmit Hazay, Muthuramakrishnan Venkitasubramaniam, Mor Weiss

Abstract Distributed zero-knowledge (dZK) proofs, recently introduced by Boneh et al. (CRYPTO‘19), allow a prover $$\mathcal{P}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>P</mml:mi> </mml:math> to prove NP statements on an input x , which is distributed between k verifiers $$\mathcal{V}_1,\ldots ,\mathcal{V}_k$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>V</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mo>,</mml:mo> <mml:mo>…</mml:mo> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>k</mml:mi> </mml:msub> </mml:mrow> </mml:math> , where each $$\mathcal{V}_i$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>i</mml:mi> </mml:msub> </mml:math> holds only a piece of x . As in standard ZK proofs, dZK proofs guarantee Completeness when all parties are honest; Soundness against a malicious prover colluding with t verifiers; and Zero Knowledge against a subset of t malicious verifiers, in the sense that they learn nothing about the NP witness and the input pieces of the honest verifiers. Unfortunately, dZK proofs provide no correctness guarantee for an honest prover against a subset of maliciously corrupted verifiers. In particular, such verifiers might be able to “frame” the prover, causing honest verifiers to reject a true claim. This is a significant limitation, since such scenarios arise naturally in dZK applications, e.g., for proving honest behavior, and such attacks are indeed possible in existing dZKs (Boneh et al., CRYPTO‘19). We put forth and study the notion of strong completeness for dZKs, guaranteeing that true claims are accepted even when t verifiers are maliciously corrupted. We then design strongly-complete dZK proofs in the honest-majority setting using the “MPC-in-the-head” paradigm of Ishai et al. (STOC‘07), providing a novel analysis that exploits the unique properties of the distributed setting. To demonstrate the usefulness of strong completeness, we present several applications in which it is instrumental in obtaining security. First, we construct a certifiable version of Verifiable Secret Sharing (VSS), which is a VSS in which the dealer additionally proves that the shared secret satisfies a given NP relation. Our construction withstands a constant fraction of corruptions, whereas a previous construction of Ishai et al. (TCC‘14) required $$k={\textsf{poly}}\left( t\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>k</mml:mi> <mml:mo>=</mml:mo> <mml:mi>poly</mml:mi> <mml:mfenced> <mml:mi>t</mml:mi> </mml:mfenced> </mml:mrow> </mml:math> . We also design a reusable version of certifiable VSS that we introduce, in which the dealer can prove an unlimited number of predicates on the same shared secret. Finally, we extend a compiler of Boneh et al. (CRYPTO‘19), who used dZKs to transform a class of “natural” semi-honest protocols in the honest-majority setting into maliciously secure ones with abort. Our compiler uses strongly-complete dZKs to obtain identifiable abort.

Carmit Hazay, Muthuramakrishnan Venkitasubramaniam, Mor Weiss

No abstract is available for this record.

Jonas Groß, Johannes Sedlmeir, Simon Seiter

This paper explores the feasibility of a fiat stablecoin that provides similar privacy guarantees to cash. We show how individuals in a stablecoin privacy pool can exchange small amounts of value within pre-assigned limits outside the view of third parties, such as banks, central banks, crypto exchanges, regulators, or other parties, in a regulatorily compliant way. High privacy guarantees and compliance with limits are ensured in a trustless way via the use of cryptographic zero-knowledge proofs.

R. Fernández

This paper delves into two legal models for zero-knowledge proof protocols in the context of the eIDAS 2.0 Regulation: a trust service or a software product. The ARIES: reliAble euRopean Identity EcoSystem EU project highlighted the need for a legal framework for stakeholders to accept proof of the existence of user data with legal certainty, while Hyperledger Indy shows that ZKP solutions are currently commercialized, stressing deficiencies in the eIDAS 2.0. An overview of ZKP applied to identity, its relationship to the European Digital Identity Wallet and the electronic attestations of attributes, both introduced by the eIDAS 2.0, and Self-Sovereign Identity systems, leads to the central question of proof of the existence of user-held data as a trust service or as a software product and its data privacy implications for each approach. Finally, we outline a possible solution based on the product approach for future work. Our findings reveal that ZKP technology must have legal value and a presumption system to be effective. However, the path we take could lead us either to develop a system of surveillance and control in electronic environments or to build an environment where we share not the data itself but proof of its existence.