Blockchain Papers

Yuyu Wang, C.-J. Su, Jiaxin Pan, Yu Chen

No abstract is available for this record.

Eliana Carozza, Geoffroy Couteau, Antoine Joux

No abstract is available for this record.

Thibauld Feneuil, Matthieu Rivain

No abstract is available for this record.

Yuncong Zhang, Shi-Feng Sun, Ren Zhang, Dawu Gu

No abstract is available for this record.

Valeriia Balatska, Іvan Оpirskyy

The recent increase in security breaches and digital surveillance highlights the need to improve privacy and security, especially of users' personal data. Advances in cybersecurity and new legislation promise to improve the protection of personal data. Blockchain and distributed ledger (DTL) technologies provide new opportunities to protect user data through decentralized identification and other privacy mechanisms. These systems can give users greater sovereignty through tools that allow them to own and control their own data. The purpose of the article is to research blockchain technology and mechanisms for achieving reliability in blockchain for the protection and security of personal data. Decentralized and federated identity systems give users control over what, when and how much of their personal information can be shared and with whom. These systems can also reduce cybersecurity threats. Through various consensus algorithms, blockchain-based privacy solutions allow users to better manage their data and ensure that the data and models derived from it are more accurate, honest and reliable.

Soroush Farokhnia

Smart contracts are programs that are executed on the blockchain and can hold, manage and transfer assets in the form of cryptocurrencies. The contract's execution is then performed on-chain and is subject to consensus, i.e. every node on the blockchain network has to run the function calls and keep track of their side-effects. In most programmable blockchains, such as Ethereum, the notion of gas is introduced to prevent DoS attacks by malicious parties who might try to slow down the network by performing heavy computations. A fixed cost to each atomic operation, and the initiator of a function call pays the total gas cost as a transaction fee. This helps prevent DoS attacks, but the resulting fees are extremely high. For example, in 2022, on Ethereum alone, there has been a total gas usage of 1.77 Million ETH ~ 4.3 Billion USD. This thesis proposes "lazy contracts" as a solution to alleviate these costs. Our solution moves most of the computation off-chain, ensuring that each function call incurs only a tiny amount of gas usage, while preserving enough data on-chain to guarantee an implicit consensus about the state of the contract variables and ownership of funds. A complete on-chain execution of the functions will only be triggered in case two parties to the contract are in disagreement about the current state, which in turn can only happen if at least one party is dishonest. In such cases, our protocol can identify the dishonest party and penalize them by having them pay for the entire gas usage. Hence, no rational party has an incentive to act dishonestly. Finally, we perform extensive experiments over 160,735 real-world Solidity contracts that were involved in 9,055,492 transactions in January 2022--January 2023 on Ethereum and show that our approach reduces the overall gas usage by 55.4%, which amounts to an astounding saving of 109.9 Million USD in gas fees.

Eunsu Goh, Daeyeol Kim, Kwangkee Lee, Suyeong Oh · 6 authors

This paper presents a novel reference architecture for blockchain-enabled federated learning (BCFL), a state-of-the-art approach that amalgamates the strengths of federated learning and blockchain technology. We define smart contract functions, stakeholders and their roles, and the use of interplanetary file system (IPFS) as key components of BCFL and conduct a comprehensive analysis. In traditional centralized federated learning, the selection of local nodes and the collection of learning results for each round are merged under the control of a central server. In contrast, in BCFL, all these processes are monitored and managed via smart contracts. Additionally, we propose an extension architecture to support both cross-device and cross-silo federated learning scenarios. Furthermore, we implement and verify the architecture in a practical real-world Ethereum development environment. Our BCFL reference architecture provides significant flexibility and extensibility, accommodating the integration of various additional elements, as per specific requirements and use cases, thereby rendering it an adaptable solution for a wide range of BCFL applications. As a prominent example of extensibility, decentralized identifiers (DIDs) have been employed as an authentication method to introduce practical utilization within BCFL. This study not only bridges a crucial gap between research and practical deployment but also lays a solid foundation for future explorations in the realm of BCFL. The pivotal contribution of this study is the successful implementation and verification of a realistic BCFL reference architecture. We intend to make the source code publicly accessible shortly, fostering further advancements and adaptations within the community.

Haibao Wen, Shengmin Sun, Tao Huang, Dunhui Xiao

In the era of digital markets, the challenge for consumers is discerning quality amidst information asymmetry . While traditional markets use brand mechanisms to address this issue, transferring such systems to internet-based P2P markets – where misleading practices like fake ratings are rampant – remains challenging. Current internet platforms strive to counter this through verification algorithms, but these efforts find themselves in a continuous tug-of-war with counterfeit actions. Exploiting the transparency, immutability, and traceability of blockchain technology, this paper introduces a robust reputation voting system grounded in it. Unlike existing blockchain-based reputation systems, our model harnesses an intrinsically economically incentivized approach to bolster agent integrity. We optimize this model to mirror real-world user behavior , preserving the reputation system’s foundational sustainability . Through Monte-Carlo simulations, using both uniform and power-law distributions enabled by an innovative inverse transform method, we traverse a broad parameter landscape, replicating real-world complexity. The findings underscore the promise of a sustainable, transparent, and formidable reputation mechanism. Given its structure, our framework can potentially function as a universal, sustainable oracle for offchain-onchain bridging, aiding entities in perpetually cultivating their reputation. Future integration with technologies like Ring Signature and Zero Knowledge Proof could amplify the system’s privacy facets, rendering it particularly influential in the ever-evolving digital domain.

Mahmudun Nabi, Sepideh Avizheh, Reihaneh Safavi–Naini

No abstract is available for this record.

Authors unavailable

Blockchain has shown great potential in various fields due to its technical advantages such as peer-to-peer, timestamp, consensus algorithm and encryption. In blockchain, the protection method of transaction data or copyright is crucial and cryptographic digital signature technology has been applied as one of the copyright protection methods. The multi-signature scheme provides higher security than single-signature schemes, enhances the transparency of transactions and contracts, and is widely used in distributed systems utilizing distributed ledger technology in blockchain. Multisignature requires multiple parties to cooperate in order to produce a valid signature, reducing the risk of exposing the entire system to a single point of failure when compared to single-signature schemes. This is an important role in transactions or contracts that require consensus among multiple parties, where each party can sign to implement the agreement, increasing transparency and preventing disputes. However, the cryptographic digital signature is resource consuming and inefficient because the verification of the signature consumes lots of computational resources and excessive number of communications. Therefore, we have proposed an efficient multi-signature scheme based on Schnorr for copyright protection on Ethereum.

Xinxuan Zhang, Yi Deng

No abstract is available for this record.

Ö. M. Doğan, Hacer Karacan

Reviews and reputation scores of sellers play an important role in decision-making process of potential buyers in an e-commerce system. A trustworthy and reliable reputation system is a crucial component in the e-commerce ecosystem, as buyers rely on it to make informed decisions. In this work, we propose a privacy-preserving decentralized reputation system designed to include countermeasures against some known attacks. Our model is built on two permissioned blockchains, namely Hyperledger Indy and Hyperledger Fabric. Hyperledger Indy provides an infrastructure for implementing verifiable credentials with Zero Knowledge Proof support, which is essential for privacy preservation, while Hyperledger Fabric is a robust platform for implementing smart contracts. One of the key advantages of the proposed approach is the use of verifiable credentials for digital identities of sellers, feedback tokens issued to buyers after performing an e-commerce transaction and discount tokens issued to buyers after feedback submission. This helps to ensure that the feedback and identity information is authentic and tamper-proof, reducing the likelihood of identity-related attacks. Additionally, the collection of feedbacks and application of business rules are implemented as smart contracts on Hyperledger Fabric blockchain. This provides a secure and transparent mechanism for processing feedback, reducing the likelihood of unfair feedbacks. Overall, the proposed approach presents a robust reputation system that can help reduce identity-related attacks and unfair feedbacks. The privacy-preserving nature of the system ensures that sensitive information is protected while still enabling the verification of digital identities. The use of feedback and discount tokens incentivizes buyers to provide accurate and honest feedback, which can help reduce unfair feedbacks and identity-related attacks. Finally, the use of smart contracts ensures transparency and immutability, which enhances the overall reliability of the system.

Corentin Jeudy, Adeline Roux-Langlois, Olivier Sanders

No abstract is available for this record.

Jayana Kaneriya, Hiren Patel

Advancements in digital technologies have made the storage, sharing, and verification of educational credentials extremely important for entities such as students, universities, institutions, and companies. Digital credentials play an important role in students’ lives as a lifelong learning passport. The educational field is experiencing numerous issues such as academic record forgery, record misuse, credential data tampering, time-consuming verification procedures, and issues related to ownership and control. Modern-day technology, Blockchain, is an appropriate alternative to resolve these issues and increase trust among entities. In this research, we intend to propose a Blockchain-based educational digital credential issuance, and verification model that addresses these issues in the education system using Ethereum Blockchain and smart contracts. The method we propose offers a way to demonstrate the correctness of specific credential attributes without revealing other attributes, thereby leading to ownership, minimal disclosure, and control. We offer an interface for storing massively encrypted academic records in a decentralized file system like Interplanetary File System (IPFS). Furthermore, Ethereum provides tamper-resistant chains to maintain the integrity of digital credentials. Finally, in comparison with the time it requires to issue credentials, our model safely accelerates the verification process by about 8%.

Chuan Chen, Yuecheng Li, Zhenpeng Wu, Chengyuan Mai · 8 authors

Metaverse, the core of the next-generation Internet, is a computer-generated holographic digital environment that simultaneously combines spatio-temporal, immersive, real-time, sustainable, interoperable, and data-sensitive characteristics. It cleverly blends the virtual and real worlds, allowing users to create, communicate, and transact in virtual form. With the rapid development of emerging technologies including augmented reality, virtual reality and blockchain, the metaverse system is becoming more and more sophisticated and widely used in various fields such as social, tourism, industry and economy. However, the high level of interaction with the real world also means a huge risk of privacy leakage both for individuals and enterprises, which has hindered the wide deployment of metaverse. Then, it is inevitable to apply privacy computing techniques in the framework of metaverse, which is a current research hotspot. In this paper, we conduct comprehensive research on the necessity, taxonomy and challenges when privacy computing meets metaverse. Specifically, we first introduce the underlying technologies and various applications of metaverse, on which we analyze the challenges of data usage in metaverse, especially data privacy. Next, we review and summarize state-of-the-art solutions based on federated learning, differential privacy, homomorphic encryption, and zero-knowledge proofs for different privacy problems in metaverse. Finally, we show the current security and privacy challenges in the development of metaverse and provide open directions for building a well-established privacy-preserving metaverse system. For easy access and reference, we integrate the related publications and their codes into a GitHub repository: https://github.com/6lyc/Awesome-Privacy-Computing-in-Metaverse.git.

I. V. Martynenkov, JSC KVANT-TELECOM

The paper discusses the basic principles of construction and the main types of zeroknowledge succinct non-interactive argument of knowledge (zk-SNARK) which is used in the model of a three-way insecure computing environment and based on sets of polynomials. A number of zk-SNARK cryptographic protocols with different algorithms for generating public parameters (Trusted Setup) are given, constructing succinct proofs of reliability calculations (Prover) and public/designated verification of proofs (Verifier). The cases of satisfying the feasibility of discrete functions (arithmetic/ Boolean circuits) using different polynomial sets are presented in quadratic arithmetic programs (QAP), square arithmetic programs (SAP), quadratic span programs (QSP), square span programs (SSP), quadratic polynomial programs (QPP), etc., also the use of authenticated data are described. The cryptographic transformations needed to build zk-SNARKs based on symmetric and asymmetric hash functions, exponential knowledge problems, digital signatures, homomorphic encryption, bilinear pairings based on elliptic curves, etc. are presented. Examples of multilateral verifiable calculations based on zk-SNARK are given.

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

Octan Network, Hanoi, Vietnam., Scott K. Imig

Motivated by the need for a credibly neutral reputation mechanism on the blockchain, we study Pagerank and other properties of two Ethereum addresses, considering one address as trustworthy and the other as problematic. We show that an unmodified Pagerank algorithm does not distinguish these cases, while asserting that Pagerank is nonetheless an important starting point for such a mechanism. We give several directions for extending or modifying the mechanism to cover such cases.

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

No abstract is available for this record.

Abba Garba, David Khoury, Patrick Balian, Samir Haddad · 10 authors

These in recent days, the proliferation of the internet of things (IoT) within the emergence of five-generation (5G) networks has received a huge attention in both industrial and academic domains. A 5G network is a cornerstone of realizing the full potential of the IoT, which interconnects billions of devices wirelessly. However, wireless communication in IoT devices reveals tremendous security risks in different dimensions and precisely in the distribution of the user certificates. The existing X.509 PKI, or the proposed decentralized PKI based on blockchain solutions have lacked practicality, and continue to have security flaws, or have not yet gained widespread acceptance owing to complexity and deployment issues. We present a lightweight certificate in size (LightCert4IoTs) that is not issued by Certification Authorities (CAs) due to the cost and complexity of the assignment of a signed certificate. In LightCert4IoTs first, an end-user (i.e., mobile and IoT devices) issues a self-signed certificate and lets Local Registration Authorities (LRAs)/EDGE nodes to verify and validate the binding identity-self signed certificate of the users through the Ethereum blockchain where The Ethereum network is used as the global notary for the IoT light certificates by saving them in the blockchain immutable ledger. The LightCert4IoTs leverages the advantages of blockchain technology and smart contracts to address the existing challenges of PKI certificates in IoT devices, which neatly achieve certificate issuance, update, and revocation more securely and efficiently. Finally, the LightCert4IoTs experimental results show that LightCert, as compared to relevant solutions/baselines, achieves reasonable overheads and is suitable for use in low- constrained IoT devices where the memory and processor power are optimized.

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

No abstract is available for this record.

Shahla Atapoor, Karim Baghery, Daniele Cozzo, Robi Pedersen

No abstract is available for this record.