Blockchain Papers

Daniel Satola, Aoife Houlihan Wiberg, Manan Singh, Sushanth Babu · 9 authors

No abstract is available for this record.

Hai‐Van Dang, Tran Viet Xuan Phuong, Thuc D. Nguyen, Thang Hoang

Zero-knowledge universal accumulator generates the succinct commitment to a set and produces the short (non) membership proof (universal) without leaking information about the set (zero-knowledge). In order to further support a generic set and zero-knowledge, existing techniques generally combine the zero-knowledge universal accumulator with other protocols, such as digital signatures and hashes to primes, which incur high overhead and may not be suitable for real-world use. It is desirable to commit a set of membership concealing the information with the optimal complexity. We devise ZAC, a new zero-knowledge Dynamic Universal Accumulator by taking the existing cryptographic primitives into account to produce a new efficient accumulator. Our underlying building blocks are Bloom Filter and vector commitment scheme in [19], utilizing the binary expression and aggregation to achieve efficiency, generic set support, zero-knowledge and universal properties. As a result, our scheme is improved in terms of proof size and proof time, also comparable to the RSA-based set accumulator in [8] in the verifying complexity. With 128 bit security, our proof size is 48 bytes while theirs is 1310 bytes and the running time of elliptic curve-based methods is faster than RSA-based counterpart. ZAC is proved to be complete, ϵ-sound and zero-knowledge. Extensively, based on ZAC as building block, we construct a new Zero-Knowledge Elementary Database (ZKEDB), which consumes 5 times less storage space, $\mathcal{O}\left( {\log N} \right)$ less bandwidth, and $\mathcal{O}\left( {\log N} \right)$ more efficient in proving and verification than the state-of-art work in [13] (where N is the domain space size). ZKEDB is proved to be complete, ϵ-sound and zero-knowledge. ZKEDB supports a new type of select top ℓ query, and can be extended to non-elementary databases.

Mengfan Wang, Guifang Huang, Hongmin Gao, Lei Hu

Zero-knowledge proof for any relation amongst committed values is crucial and widely applicable in the design of high level cryptographic schemes, especially in privacy-preserving protocols. Besides quantum resistance, efficiency is what we are most concerned about, including asymptotic efficiency and concrete efficiency. Jain et al. proposed a simple string commitment scheme based on the Learning Parity with Noise (LPN) problem (JKPT12), and then designed zero-knowledge proofs for valid opening, linear relation and multiplicative relation of committed values. As a result, they got an efficient zero-knowledge proof for any circuit C, with communication complexity $\mathcal{O}(t|C|\ell \log \ell )$, where t is a security parameter measuring soundness and ℓ is the secret length of the LPN problem. In this work, we improve the concrete communication complexity by combining some commitments in JKPT12 together. The proofs of linear relation and multiplicative relation are shortened by (6α + 4)ℓ and (42α+28)ℓ respectively, where ℓ is the size of LPN secret. As a result, the communication cost of the protocol proving arbitrary relation is reduced by a constant level.

Jingyan Yang, Shang Gao, Guyue Li, Rui Song · 5 authors

Ethereum, the largest blockchain for running smart contracts, has been widely used, especially in financial and cryptocurrency exchange applications. Among them, Tornado Cash is a typical financial application that protects the privacy of users with anonymous transactions. However, users need to pay prohibitively high gas (transaction fees for smart contract calls) for anonymous transactions, which hinders Tornado Cash from wide applications. To address this issue, we introduced a new approach that shifts the high gas-consuming operations on smart contracts to local users. Furthermore, we use zero-knowledge proofs to ensure the operations are properly executed. The smart contract only needs to verify and update the results, which significantly reduces the gas fees of Tornado Cash. To validate our approach, we implemented a prototype and showed that our proposed method could save more than 61% of gas consumption of current operations while maintaining the privacy feature of Tornado Cash. Finally, we discussed further applications and open problems of our approach.

Edward Mensah Acheampong, Shijie Zhou, Yongjian Liao, Emmanuel Antwi‐Boasiako · 5 authors

Digital technologies, such as wireless body area networks (WBANs) for mobile health (mHealth) applications, are expected to enhance the quality of the public health care system. Although mHealth can improve patients' quality of health by offering outpatient real-time health monitoring systems instead of being stuck in the hospital all the time to monitor chronic diseases. The major challenge in adopting mHealth is data security and privacy. The health data routed on the internet from the patient monitoring device to the health center for remote monitoring is vulnerable to confidentiality attacks. To handle this issue, we present an authentication scheme based on non-interactive zero-knowledge proof (NIZKP), which issues certificates and authenticates monitoring devices each time performing transactions without revealing sensitive information. Our authentication scheme provides a high level of security with a low computational cost, which is lightweight for WBANs.

Muhammad Bilal Akram Dastagir, Omer Tariq, Dongsoo Han

The adaption of the NFT to the mainstream web3 marketplace has led to the rise of challenges like authenticity and verification. On the other hand, privacy-preserving is one of the important research topics in the data-driven metaverse due to its anonymity while maintaining transparency and security. As the traditional method does not preserve privacy, there is a dire need for a novel privacy-preserving method for NFT authentication while preserving anonymity, transparency, and security. This paper proposes a smart card-based approach for privacy preservation authentication of Non-Fungible Tokens using Non-Interactive Zero Knowledge Proof (NIZKP). The paper presents a Novel NIZKP response with the integration of challenge and proof with the encapsulation of a time-based one-time password (TOTP) solution to address the most critical problem of the proof of the source of the NFT and its rightful owner. The proposed solution is a lightweight mechanism for preventing unauthorized and hostile agents from the accessibility of the system while maintaining privacy and anonymity along with the verification and authenticity of the NFT. We have implemented our approach and compared the communication overhead and functional security features with related work and its precedence over them. The results show that the proposed approach has less communication overhead than the existing work and fulfills all the functional security and privacy-preserving features. It indicates that the proposed method can be an ideal solution for NFT authentication and transaction among users.

Adesh Mukati, Satya Prakash

centralized database-based Central Bank Digital Currency (CBDC) system's vulnerability to cyberattacks and data leakage is a major concern. Any data leak can lead to large financial losses, irreversible reputational harm, and a decline in user confidence. To protect user information, the Reserve Bank of India has underlined the significance of a strong Data Leakage Prevention (DLP) system. While current incidents have demonstrated that the measures were insufficient to meet the standards, DLP may not be enough to defend CBDCs on its own. Incorporating Zero-Knowledge Proofs (ZKPs) and differential privacy tools into DLP solutions can improve their robustness and effectiveness. There is no one-size-fits-all solution for preventing data leakage, different solutions may be more effective in different scenarios. It's always a good idea to assess an organization's or system's specific needs and requirements before deciding on the best solution. It is also important to remember that there is no such thing as absolute security, and the possibility of zero-day attacks is always there. It is essential to continuously monitor and enhance security measures to stay ahead of new threats. To preserve their Central Bank Digital Currency systems and data, financial institutions and central banks must continue to be proactive and vigilant.

Haixu Zhao, Dong Ding, Feng Wang, Pengcheng Hua · 7 authors

Zk-SNARK unleashes the great potential of ZKP (zero-knowledge proof) in the blockchain, distributed storage, etc. However, the proof-generation of zk-SNARK is excessively time intensive, making it a challenge to deploy a high-performance zk-SNARK in most real applications. As a result, NTT (Number Theoretic Transform), one of the most time-consuming parts in proof-generation, needs to be accelerated significantly. To address this issue, we propose a novel and efficient “data reordering” technique to enable a highly pipelined architecture, on which an FPGA-based hardware accelerator is designed to support the large-bitwidth and large-scale NTT tasks in zk-SNARK. Our architecture achieves a two-level pipeline: 1) the top-level pipeline is achieved among smaller NTT sub-tasks, which are decomposed from a large-scale NTT task; 2) the bottom-level pipeline is achieved in each sub-task, among butterfly operations with different step sizes. This architecture can effectively reduce the data dependency and memory access requirements, meanwhile, can be flexibly scaled to different scales of FPGAs. To balance computing efficiency and flexibility, the OpenCL equipped with HLS is used to implement the heterogeneous acceleration system. We prototype the accelerator on the AMD-Xilinx Alveo U50 card (UltraScale+ XCU50 FPGA). The evaluation results show that 1) our accelerator shows high scalability for different scales of FPGAs with a stable performance improvement; 2) it performs 1.95× faster than the one in PipeZK; 3) and it achieves 27.98×, 1.74× speedup and 6.9×, 6× energy efficiency improvement than AMD Ryzen 9 5900X single core and 12 cores respectively when integrated into the well-known ZKP open-source project, Bellman.

Zhiming Song, Guiwen Wang, Yimin Yu, Taowei Chen

Due to the advantages in self-sovereignty identity management and scalability of blockchain, digital identity verification and management systems (DIVMS) of blockchain-based verifiable certificates (VC) are getting more and more attention. However, user privacy in the systems’ traditional architectures cannot be guaranteed. In this paper, the zero-knowledge succinct noninteractive arguments of knowledge (zkSNARKs) referred to as Groth16 are introduced in order to implement privacy protection of the user’s identity and behavior of DIVMS of blockchain-based VC. In the proposed architecture, the malleability attack of Groth16 is considered, and verifications of zero-knowledge proof (ZKP) and the digital signature of an identity provider (IDP) attached to VC and the status management of VC are implemented on the smart contracts of the blockchain to overcome single point failure. Furthermore, a prototype system is designed to verify the proposed architecture’s capability in privacy protection and to evaluate its performances in cost and throughput. Finally, the security of the proposed architecture is discussed, and its comparisons are conducted with those existing blockchain-based DIVMSs, especially those systems using Groth16 of zkSNARKs to improve the privacy of user. All results mentioned above have shown that the proposed system is efficient and safe, and it can improve the privacy of DIVMS of the blockchain based VC while avoiding single point failure.

Yijing Lin, Zhipeng Gao, Yaofeng Tu, Hongyang Du · 7 authors

Web 3.0 is the next-generation Internet that enables participants to read, write, and own contents in a decentralized manner. It is mainly driven by blockchain, semantic communication, edge computing, and artificial intelligence, which can construct value networks to achieve participatory economics based on participatory decision making. Web 3.0 can capture the characteristics of blockchain, semantic extraction, and communication to achieve decentralized semantic sharing and transfer information precisely. However, current Web 3.0 solutions focus on the blockchain while overlooking other new technologies' roles in Web 3.0. To further unleash the advantages of semantic extraction and communication in Web 3.0, in this article, we propose a blockchain-based semantic exchange framework to realize fair and efficient interactions. In this framework, we first attempt to tokenize semantic information into Non-Fungible Token (NFT) for semantic exchange. Then we utilize a Stackelberg game to maximize buying and pricing strategies for semantic trading. We also leverage Zero-Knowledge Proof to share authentic semantic information without publishing it before receiving payments, which can achieve a fair and privacy-preserving trading compared with current NFT marketplaces. A case study about urban planning is given to show clearly the proposed mechanisms. Finally, several challenges and opportunities are identified.

Zhuangtong Huang, Jiawei Zhu, Zhongyu Huang, Yixin Xu · 6 authors

The financial sector's adoption of technology-driven data analysis has enhanced operational efficiency and revenue generation by leveraging personal sensitive data. However, the inherent characteristics of blockchain hinder decentralized finance (DeFi) from accessing necessary sensitive user data. To address this challenge, we introduce a protocol that both safeguards user privacy and ensures data availability through the incorporation of homomorphic encryption and zero-knowledge-proof techniques in blockchain technology. This novel protocol helps mitigate privacy risks caused by sensitive data leaks while improving the capital efficiency of the DeFi market. Furthermore, we explore the applicability of these privacy-preserving methods in on-chain ecosystems and cross-border financial applications. Our solution contributes to secure, user-centric solutions for DeFi while upholding principles of decentralization and privacy protection.

Saeed Banaeian Far, Maryam Rajabzadeh Asaar, Afrooz Haghbin

Abstract Blockchain‐based data outsourcing has attracted a huge deal of attention in recent years. However, key management and reliance on pre‐defined or randomly‐selected third‐party auditors (TPAs) are still challenging owing to refusing to collaborate or break auditing policies. Additionally, it is impossible to store secrets in smart contracts (SCs) for signing or auditing. Thus, in the present study, a zero‐knowledge (ZK)‐based distributed auditing protocol (DAP) is provided. In this protocol, a user‐based key generation mechanism offers users security against curious authorities based on no TPA causing them to reveal no knowledge about under‐auditing data. Based on Pointcheval's and Sanders's signature scheme, as a ZK‐based randomizable signature applied in an SC to handle the auditing process, the proposed DAP provides confidential transactions and user accountability. Evaluation indicates that the proposed ZK‐based DAP is efficient for the user side and it is the fastest DAP in the blockchain.

Shuang Yao, Dawei Zhang

<abstract><p>With the continuous development of Internet of Things, finance, big data and many other fields, blockchain has been widely used in these areas for transactions, data sharing, product traceability and so on. Numerous assets have appeared in the blockchain, and there are some levels of conflicts among privacy protection of these assets, transaction transparency and auditability in blockchain; so how to provide privacy preserving, make public verifications and audit the encrypted assets are challenging problems. In this paper, we propose a privacy-preserving transaction scheme with public verification and reliable audit in blockchain. First, we provide privacy preserving of transaction contents based on homomorphic encryption. It is flexible, as we decouple user identity and transaction contents. Then, we propose and design a multiplicative zero-knowledge proof with formal security analysis. Furthermore, several verification rules are defined by us in the scheme, such as balance verification and multiplicative verification based on the proposed multiplicative zero-knowledge proof. Our scheme enables reliable and offline auditing for each transaction, and we aggregate the zero-knowledge proofs to save the ledger space. Finally, we make a security analysis of our proposal in terms of transaction confidentiality, public verification and audit reliability, and we give a performance analysis of the proposed scheme.</p></abstract>

Zhihu Li, Haiqing Xu, Feng Zhai, Bing Zhao · 6 authors

Consumers in electricity markets are becoming more proactive because of the rapid development of demand-response management and distributed energy resources, which boost the transformation of peer-to-peer (P2P) energy-trading mechanisms. However, in the P2P negotiation process, it is a challenging task to prevent private information from being attacked by malicious agents. In this paper, we propose a privacy-preserving, two-party, secure computation mechanism for consensus-based P2P energy trading. First, a novel P2P negotiation mechanism for energy trading is proposed based on the consensus + innovation (C + I) method and the power transfer distribution factor (PTDF), and this mechanism can simultaneously maximize social welfare and maintain physical network constraints. In addition, the C + I method only requires a minimum set of information to be exchanged. Then, we analyze the strategy of malicious neighboring agents colluding to attack in order to steal private information. To defend against this attack, we propose a two-party, secure computation mechanism in order to realize safe negotiation between each pair of prosumers based on Paillier homomorphic encryption (HE), a smart contract (SC), and zero-knowledge proof (ZKP). The energy price is updated in a safe way without leaking any private information. Finally, we simulate the functionality of the privacy-preserving mechanism in terms of convergence performance, computational efficiency, scalability, and SC operations.

Nannan Wu, Lei Xu, Liehuang Zhu

No abstract is available for this record.

Kyohei Shibano, Tohru Nakajima, Gento Mogi

The system proposed in this study uses zero-knowledge proof (ZKP) to verify the traceability of wood recorded in a public blockchain. Wood is a byproduct of several states, ranging from standing trees to logs, lumber, and wood products (hereinafter ``wood objects''). The advantage of using the blockchain for record keeping is that participants can freely record the information at their discretion, without any restrictions. However, the openness of the blockchain may allow a malicious third party to introduce disinformation. In this study, we employ ZKP and near-field communication (NFC) chips to eliminate the possibility of disinformation introduction. ZKP is used to prove/validate changes in the state of wood objects, and the unique nonce associated with that state is encrypted and recorded on an NFC chip. The nonce is concealed and id of the wood object is defined as hash value of this nonce. We developed a prototype system based on an Android application and an Ethereum smart contract. We confirm that wood traceability and verification can be performed using the prototype system.

Dharam Buddhi, Abhishek Joshi

Decentralization, autonomy, integrity, immutability, verification, fault tolerance, anonymity, auditability, and transparency are all desirable qualities in a system, and all of them are present in blockchain. In this paper, we first conduct a more in-depth survey of blockchain technology, focusing on its origins, the quantitative comparisons of consensus algorithms, the specifics of the cryptography employed in the blockchain (including public key cryptography, Zero-Knowledge Proofs, and hash functions), and the exhaustive list of use cases. Moreover, this study focuses on the blockchain's security measures. In specifically, we use a risk-based approach to evaluate blockchain security, developing a taxonomy of blockchain security risks, examining actual attacks and defects, and summarising newly created blockchain security solutions. We conclude with a discussion of the obstacles and emerging research trends that must be overcome to develop blockchain systems that are both scalable and secure enough for large-scale deployments.

Rama Rao, Prem K. Narang

Self-sovereign identity (SSID) is a digital solution intended to ameliorate the drawbacks associated with existing digital identification management approaches. This chapter begins with an overview of identity management systems. It explores the essential elements of SSID, including verifiable credentials, distributed ledger technology (DLT), and privacy engineering protocols, and highlights research initiatives, governmental projects, and regulatory frameworks that leverage evolving technologies to improve data integrity, efficiency, and security. The authors survey key challenges and advantages associated with SSID, establishing a taxonomy of the SSID model and a summary of privacy engineering techniques that work in concert with SSID, including zero knowledge proofs (ZKPs) and bring your own identity (BYOI) systems. The authors highlight several innovators in the SSID ecosystem that are contributing to the growth and maturity of this model.

Praneeth Kanagala

No abstract is available for this record.

Xin Liu, Xiaomeng Liu, Ruiling Zhang, Dan Luo · 6 authors

Manhattan distance is mainly used to calculate the total absolute wheelbase of two points in the standard coordinate system. The secure computation of Manhattan distance is a new geometric problem of secure multi-party computation. At present, the existing research secure computing protocols for Manhattan distance cannot resist the attack of malicious participants. In the real scene, the existence of malicious participants makes it necessary to study a solution that can resist malicious attacks. This paper first analyzes malicious attacks of the semi-honest model protocol of computing Manhattan distance and then designs an advanced protocol under the malicious model by using the Goldwasser–Micali encryption system and Paillier encryption algorithm, and utilizing some cryptographic tools such as the cut-choose method and zero-knowledge proof. Finally, the real/ideal model paradigm method is used to prove the security of the malicious model protocol. Compared with existing protocols, the experimental simulation shows that the proposed protocol can resist malicious participant attacks while maintaining high efficiency. It has practical value.

Ye Tao, Yuze Jiang, Pengfei Lin, Manabu Tsukada · 5 authors

Cooperative perception is an essential and widely discussed application of connected automated vehicles. However, the authenticity of perception data is not ensured, because the vehicles cannot independently verify the event they did not see. Many methods, including trust-based (i.e., statistical) approaches and plausibility-based methods, have been proposed to determine data authenticity. However, these methods cannot verify data without a priori knowledge. In this study, a novel approach of constructing a self-proving data from the number plate of target vehicles was proposed. By regarding the pseudonym and number plate as a shared secret and letting multiple vehicles prove they know it independently, the data authenticity problem can be transformed to a cryptography problem that can be solved without trust or plausibility evaluations. Our work can be adapted to the existing works including ETSI/ISO ITS standards while maintaining backward compatibility. Analyses of common attacks and attacks specific to the proposed method reveal that most attacks can be prevented, whereas preventing some other attacks, such as collusion attacks, can be mitigated. Experiments based on realistic data set show that the rate of successful verification can achieve 70\% to 80\% at rush hours.

Darko Čapko, Srđan Vukmirović, Nemanja Nedić

Blockchain technology promises a decentralized ecosystem for building apps with decentralized ownership and high security level. One of the most adopted blockchain ecosystems is based around Ethereum blockchain. Ethereum currently has a huge scaling issue, making its use very expensive. Different scaling solutions are proposed based on Optimistic rollups but they have a very long finality time. Zero-Knowledge (ZK) rollup (based on ZK Proof) is another way and offers high security with very fast final resolution. Problem with ZK rollup is that it is very computationally expensive, but some solutions have significant performance improvements. In this paper we presented different solutions that improve performance of ZK rollup.

Daniel Augot, Sarah Bordage, Jade Nardi

No abstract is available for this record.

Chin-Yao Chang, Richard Macwan, Sinnott Murphy

The control of future power grids is migrating from a centralized to a distributed/decentralized scheme to enable a massive penetration of distributed energy resources and bring extreme enhancements of autonomous operations in terms of grid resilience, security, and reliability. Most effort has been on the design of distributed/decentralized controllers; however, the guarantees of the proper execution of the controls are also essential but relatively less emphasized. A common assumption is that local controllers would fully follow the designated controller dynamics based on the data received from communication channels. Such an assumption could be risky because proper execution of the controller dynamics is then built on trust in secure communication and computation. On the other hand, it is impractical for a verifier to repeat all the computations involved in the controls to verify the computational integrity. In this work, we leverage a type of cryptography technology, known as zero-knowledge scalable transparent arguments of knowledge to verify the computational integrity of control algorithms, such that verifiers can check the computational integrity with much less computational burden. The method presented here converts the challenge of data integrity into a subset of computational integrity. In this proof-of-concept paper, our focus will be on projected linear dynamics that are commonly seen in distributed/decentralized power system controllers. In particular, we have derived polynomial conditions in the context of zk-STARKs for the projected linear dynamics.