Jensen, Markus V. G., H. Kjeldsen, Nielsen, Andreas S., Niklas Bille Olesen · 5 authors
End-to-end-verifiable voting systems can only meet their goals if independent auditors are capable of verifying election outcomes as easily and efficiently as possible. ElectionGuard is a prominent effort in this direction, in which simplifying the verification process guides several design decisions, from the choice of cryptographic group to the building blocks for encryption and zero-knowledge proofs. In this paper, we present the development of optimized ElectionGuard verifiers in the Go programming language, targeting versions 1.1 and 2.0 of the specification, focused on analyzability and efficiency. Our verifiers are built on an architecture emphasizing efficiency that exploits parallelism to achieve a running time up to 10 times faster than related work. We also show that version 2.0 of the specification introduces several changes that improve the verification performance by an overall factor of 2, with the decryption process being around 24 times faster. We expect that our design can be used as a reference for future ElectionGuard verifiers.
Financial institutions using blockchain smart contracts need to adhere to real-world regulations. Data on blockchain is easily accessible, so privacy protection is crucial. Our goal is to introduce an efficient protocol that satisfies both user privacy protection and hierarchical regulatory requirements, without the need for zero-knowledge proofs. To achieve this, we have developed two innovative design strategies. Firstly, we envision financial institutions serving as transaction mixers for their users. This approach offers an additional layer of privacy by obfuscating the source of each transaction. Secondly, we depend on regulatory agencies to oversee the compliance of blockchain transactions. This ensures that our protocol aligns with regulatory requirements while maintaining user privacy. The resulting protocol offers superior privacy protection for user transactions, with provable security and computational efficiency.
In MLaaS, DNN models are kept in a server operated by the service provider and inputs to the DNN models are provided by the clients. Such inputs are used to execute the DNN models and classification results are sent back to the client. In MLaaS, the DNN model owner does not reveal the DNN model parameters to the client. MLaaS there are a few trust problems: (a) The server may not be secure and an attacker may send manipulated classification results to the client. In the case of safety-critical systems using such classification in the decision-making process, an attacker may specifically manipulate the classification result to disrupt the operations of the safety-critical system, (b) The server may intentionally send wrong or random classification results without executing the DNN model to respond to a massive number of classification requests from the clients. In this paper, we investigate the problem of verifying DNN model execution by the service provider in an MLaaS paradigm. A proof of DNN model execution will prove that given an input, the DNN model is executed to generate the classification result by providing sequences of outputs of all functions used in the DNN model. As the service provider in MLaaS does not share the DNN model with the client, we need to verify DNN function outcomes without the knowledge of DNN function parameters. Hence zero-knowledge proof can be used for verifying DNN model execution. In this paper, we use Zero-Knowledge Succinct Non-interactive Arguments of Knowledge (zk-SNARKs) which reduces the size of proof and complexity of proof verification considerably. In particular, we use a quadratic arithmetic program-based zkSNARK for DNN model verification. Our main results in this paper are as follows: (a) We have developed a DNN model execution verification method using a QAP-based zkSNARK. (b) We prove that the verification protocol is correct and privacy-preserving. (c) We analyzed the cost of using such a verification protocol.
Blockchain-based solutions offer a promising avenue for privacy-preserving authentication and authorization mechanisms. Through the immutable and decentralized nature of blockchain, individuals can maintain control over their personal data while still engaging in secure transactions and interactions. These solutions leverage cryptographic techniques to ensure privacy, such as zero-knowledge proofs, which allow one party to prove possession of certain information without revealing the information itself.By storing authentication and authorization data on the blockchain, users can access services without having to repeatedly provide sensitive information. Smart contracts can automate authorization processes, ensuring that only authorized parties can access certain resources or perform specific actions. Additionally, blockchain-based identity systems offer a self-sovereign approach, where individuals have full control over their digital identities, reducing the reliance on centralized authorities. Moreover, blockchain networks provide transparency and auditability, allowing users to track how their data is being used and ensuring compliance with privacy regulations. However, challenges such as scalability, interoperability, and user adoption remain to be addressed for widespread implementation. Overall, blockchain-based solutions hold great potential in providing privacy-preserving authentication and authorization while empowering individuals with greater control over their data.Blockchain-based solutions offer a promising avenue for privacy-preserving authentication and authorization mechanisms. Through the immutable and decentralized nature of blockchain, individuals can maintain control over their personal data while still engaging in secure transactions and interactions. These solutions leverage cryptographic techniques to ensure privacy, such as zero-knowledge proofs, which allow one party to prove possession of certain information without revealing the information itself.
Ken Naganuma, Masayuki Yoshino, Noboru Kunihiro, A. Inoue · 6 authors
In recent years, the zero-knowledge succinct non-interactive argument of knowledge (zk-SNARK) have drawn significant attention as privacy-enhancing technologies in various domains. A post-quantum designated verifier type zk-SNARK for Boolean circuits was proposed by Gennaro et al. in ACM CCS '18. However, this scheme does not include arithmetic circuits and they claim that a construction of post zk-SNARKs for arithmetic circuits as open problem. In this paper we give answers to this problem. Our first proposal is based on the data structure used in Pinocchio, a previous study, and can be easily implemented using the existing Pinocchio-based systems. In our second proposal, which also employs QAPs, the zero-knowledge proof comprises three learning with errors (LWE) ciphertexts, and the size of the proof is smaller compared with that of the first proposal. Our second proposal is also more efficient than the first one or all other known post-quantum zk-SNARKs.
The secure sharing and privacy protection of medical data have become pain points for medical data management platforms. Therefore, a secure sharing electronic health record privacy protection method based on blockchain is proposed in the study, aiming to improve data security privacy and ensure absolute ownership of patients' medical data. Attribute encryption and blockchain computing are utilized to construct a data secure sharing model, and zero-knowledge proof and ElGamal encryption algorithms are introduced to further improve the construction of data privacy protection methods. Experimental verification showed that the data secure sharing method proposed in the study has more advantages in terms of production key size and time cost. Compared with other public recognition mechanisms, zero-knowledge proof reduced the average time cost of generating keys by 54.36%. The proposed data privacy protection method had an average increase of 7.73% in protection effectiveness compared to other methods. The results indicate that the data secure sharing and privacy protection methods proposed in the study can improve the overall performance and security of the system while fully ensuring the absolute ownership of patients' data. This method has positive application value in the privacy protection of medical data.
van Trijp, Remi, Beuls, Katrien; id_orcid 0000-0003-4451-4778, Van Eecke, Paul
This paper presents a case study on how to process cooking recipes (and more generally, how-to instructions) in a way that makes it possible for a robot or artificial cooking assistant to support human chefs in the kitchen. Such AI assistants would be of great benefit to society, as they can help to sustain the autonomy of aging adults or people with a physical impairment, or they may reduce the stress in a professional kitchen. We propose a novel approach to computational recipe understanding that mimics the human sense-making process, which is narrative-based. Using an English recipe for almond crescent cookies as illustration, we show how recipes can be modelled as rich narrative structures by integrating various knowledge sources such as language processing, ontologies, and mental simulation. We show how such narrative structures can be used for (a) dealing with the challenges of recipe language, such as zero anaphora, (b) optimizing a robot's planning process, (c) measuring how well an AI system understands its current tasks, and (d) allowing recipe annotations to become language-independent.
Jan 1, 2024·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
With the rise of decentralized systems and applications that run over multiple blockchains, there is a growing need for architectures and bridges that ensure the trusted transfer of data and assets between the chains. zkBridge (ACM CCS'22) is a cross-chain bridge protocol that was proposed for non-permissioned blockchain and uses a network of relays, each working (for example as a light node) on a blockchain. A relay communicates with a corresponding smart contract on another chain to transfer data from the first chain to the second, and the smart contract on the second chain is used to verify the correctness of the received data from the first chain. zkBridge designs and implements optimized zero-knowledge proofs, that minimize the work of the smart contract on the second chain to verify the correctness of the received data. In this paper, we consider applications that work across two or more permissioned blockchains. We propose sigBridge that uses the framework of zkBridge but replaces the costly zero-knowledge proof computation with a pair of algorithms based on the consensus algorithm of the first chain. The algorithms will be run by a relay node on the first chain and a smart contract on the second chain and provide verifiability of data and asset transfer from the first chain to the second. The pair of algorithms are significantly more efficient compared to generating zero-knowledge proofs, verifying them, or running the full consensus algorithm of the first blockchain. We then show how a decentralized user-centric resource-sharing application will work over this architecture. We give a proof-of-concept implementation of an attribute-based access control system for a resource-sharing application that runs over two private Ethereum blockchains, and report the computation costs of the protocol.
Haotian Deng, Tao Liu, Xiaochen Ma, Weijie Wang · 7 authors
The space-air-ground integrated networks (SAGINs) are pivotal for modern communication and surveillance, with a growing number of connected devices. The proliferation of IoT devices within these networks introduces new risks due to potential erroneous synergistic interactions that could compromise system integrity and security. This paper addresses the challenges in coordination, synchronization, and security within SAGINs by introducing a novel static program analysis (SPA) technique using zero-knowledge (ZK) proofs. This approach ensures the detection of risky interactions without compromising sensitive source code, thus safeguarding intellectual property and privacy. The proposed method overcomes the incompatibility between SPA and ZK systems by developing an imperative programming language for SAGINs and a specialized abstract domain for interaction threats. The system translates network control algorithms into arithmetic circuits suitable for ZK analysis, maintaining high accuracy in detecting risks. Evaluations of real-world scenarios demonstrate the system’s efficacy in identifying risky interactions with minimal computational overhead. This research presents the first ZK-based SPA scheme for SAGINs, enhancing security and confidentiality in network analysis while adhering to privacy regulations.
As the practical applications of fully homomorphic encryption (FHE), secure multi‐party computation (MPC) and zero‐knowledge (ZK) proof continue to increase, so does the need to design and analyze new symmetric‐key primitives that can adapt to these privacy‐preserving protocols. These designs typically have low multiplicative complexity and depth with the parameter domain adapted to their application protocols, aiming to minimize the cost associated with the number of nonlinear operations or the multiplicative depth of their representation as circuits. In this paper, we propose two differential fault attacks against a one‐way function RAIN used for Rainier (CCS 2022), a signature scheme based on the MPC‐in‐the‐head approach and an FHE‐friendly cipher HERA used for the RtF framework (Eurocrypt 2022), respectively. We show that our attacks can recover the keys for both ciphers by only injecting a fault into the internal state and requiring only one normal and one faulty ciphertext blocks. Thus, we can use only the practical complexity of 2 26.6 /2 28.8 /2 30.4 bit operations to break the full‐round RAIN with 128/192/256‐bit keys. For full‐round HERA with 80/128‐bit key, our attack is practical with complexity the complexity of 2 20 encryptions with about 2 16 memory.
Remote attestation (RA) protocols have been widely used to evaluate the integrity of software on remote devices.Currently, the state-of-the-art RA protocols lack a crucial feature: transparency.This means that the details of the final attestation verification are not openly accessible or verifiable by the public.Furthermore, the interactivity of these protocols often limits attestation to trusted parties who possess privileged access to confidential device data, such as pre-shared keys and initial measurements.These constraints impede the widespread adoption of these protocols in various applications.In this paper, we introduce zRA, a non-interactive, transparent, and publicly provable RA protocol based on zkSNARKs.zRA enables verification of device attestations without the need for pre-shared keys or access to confidential data, ensuring a trustless and open attestation process.This eliminates the reliance on online services or secure storage on the verifier side.Moreover, zRA does not impose any additional security assumptions beyond the fundamental cryptographic schemes and the essential trust anchor components on the prover side (i.e., ROM and MPU).The zero-knowledge attestation proofs generated by devices have constant size regardless of the network complexity and number of attestations.Moreover, these proofs do not reveal sensitive information regarding internal states of the device, allowing verification by anyone in a public and auditable manner.We conduct an extensive security analysis and demonstrate scalability of zRA compared to prior work.Our analysis suggests that zRA excels especially in peer-to-peer and Pub/Sub network structures.To validate the practicality, we implement an open-source prototype of zRA using the Circom language.We show that zRA can be securely deployed on public permissionless blockchains, serving as an archival platform for attestation data to achieve resilience against DoS attacks.