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8,503 results · page 262 of 355
Chaya Ganesh, Yashvanth Kondi, Arpita Patra, Pratik Sarkar
No abstract is available for this record.
Eli Ben‐Sasson, Iddo Bentov, Yinon Horesh, Michael Riabzev
The family of Reed-Solomon (RS) codes plays a prominent role in the construction of quasilinear probabilistically checkable proofs (PCPs) and interactive oracle proofs (IOPs) with perfect zero knowledge and polylogarithmic verifiers. The large concrete computational complexity required to prove membership in RS codes is one of the biggest obstacles to deploying such PCP/IOP systems in practice. To advance on this problem we present a new interactive oracle proof of proximity (IOPP) for RS codes; we call it the Fast RS IOPP (FRI) because (i) it resembles the ubiquitous Fast Fourier Transform (FFT) and (ii) the arithmetic complexity of its prover is strictly linear and that of the verifier is strictly logarithmic (in comparison, FFT arithmetic complexity is quasi-linear but not strictly linear). Prior RS IOPPs and PCPs of proximity (PCPPs) required super-linear proving time even for polynomially large query complexity. For codes of block-length N, the arithmetic complexity of the (interactive) FRI prover is less than 6 * N, while the (interactive) FRI verifier has arithmetic complexity <= 21 * log N, query complexity 2 * log N and constant soundness - words that are delta-far from the code are rejected with probability min{delta * (1-o(1)),delta_0} where delta_0 is a positive constant that depends mainly on the code rate. The particular combination of query complexity and soundness obtained by FRI is better than that of the quasilinear PCPP of [Ben-Sasson and Sudan, SICOMP 2008], even with the tighter soundness analysis of [Ben-Sasson et al., STOC 2013; ECCC 2016]; consequently, FRI is likely to facilitate better concretely efficient zero knowledge proof and argument systems. Previous concretely efficient PCPPs and IOPPs suffered a constant multiplicative factor loss in soundness with each round of "proof composition" and thus used at most O(log log N) rounds. We show that when delta is smaller than the unique decoding radius of the code, FRI suffers only a negligible additive loss in soundness. This observation allows us to increase the number of "proof composition" rounds to Theta(log N) and thereby reduce prover and verifier running time for fixed soundness.
Chan Hyeok Lee, Ki‐Hyung Kim
In a block-chain IoT environment, when data or device authentication information is put on a block chain, personal information may be leaked through the proof-of-work process or address search. In this paper, we apply Zero-Knowledge proof to a smart meter system to prove that a prover without disclosing information such as public key, and we have studied how to enhance anonymity of block chain for privacy protection.
Jonathan Bootle, Jens Groth
No abstract is available for this record.
Hans-Georg Fill, Felix Haerer
Blockchains permit to store information in a tamper-resistant and irrevocable manner by reverting to distributed computing and cryptographic technologies. The primary purpose is to keep track of the ownership of tangible and intangible assets. In the paper at hand we apply these concepts and technologies to the domain of knowledge management. Based on the explication of knowledge in the form of enterprise models this permits the application of so-called knowledge proofs for a. enabling the transparent monitoring of knowledge evolution, b. tracking the provenance, ownership, and relationships of knowledge in an organization, c. establishing delegation schemes for knowledge management, and d. ensuring the existence of patterns in models via zero-knowledge proofs. To validate the technical feasibility of the approach a first technical implementation is described and applied to a fictitious use case.
Fabrice Benhamouda, Olivier Blazy, Léo Ducas, Willy Quach
No abstract is available for this record.
Benoît Libert, San Ling, Khoa Nguyen, Huaxiong Wang
No abstract is available for this record.
Carsten Baum, Jonathan Bootle, Andrea Cerulli, Rafaël del Pino · 6 authors
No abstract is available for this record.
Georg Fuchsbauer
No abstract is available for this record.
Xiaoyi Yang, Meijuan Huang
Distributed networks remarkably enhance the convenience of network connectivity. How to achieve efficient cooperative computation while preserving data privacy is a challenge in the scenario of distributed networks. Secure computation, as the key technology of information security and privacy protection in the distributed networks, attracts more and more attention. In the paper, we develop the protocols of secure two-party computation in the presence of malicious adversaries which are constructed with homomorphic probabilistic cryptosystem, and propose four honest-verifier zero-knowledge proof protocols to detect two cheating behaviours of the malicious adversary. The proposed protocols are more targeted than the existing work. The analysis shows that the proposed protocols are complete, sound and zero-knowledge. As an application, we show how to use our protocols in a secure two-party protocol to detect cheating, which can make it secure in the presence of malicious adversaries.
Bingsheng Zhang, Roman Oliynykov, Hamed Balogun
A treasury system is a community-controlled and decentralized collaborative decision-making mechanism for sustainable funding of blockchain development and maintenance. During each treasury period, project proposals are submitted, discussed, and voted for; top-ranked projects are funded from the treasury. The Dash governance system is a real-world example of such kind of systems. In this work, we, for the first time, provide a rigorous study of the treasury system. We modelled, designed, and implemented a provably secure treasury system that is compatible with most existing blockchain infrastructures, such as Bitcoin, Ethereum, etc. More specifically, the proposed treasury system supports liquid democracy/delegative voting for better collaborative intelligence. Namely, the stake holders can either vote directly on the proposed projects or delegate their votes to experts. Its core component is a distributed universally composable secure end-to-end verifiable voting protocol. The integrity of the treasury voting decisions is guaranteed even when all the voting committee members are corrupted. To further improve efficiency, we proposed the world's first honest verifier zero-knowledge proof for unit vector encryption with logarithmic size communication. This partial result may be of independent interest to other cryptographic protocols. A pilot system is implemented in Scala over the Scorex 2.0 framework, and its benchmark results indicate that the proposed system can support tens of thousands of treasury participants with high efficiency.
Jonathan Bootle, Andrea Cerulli, Jens Groth, S. Jakobsen · 5 authors
No abstract is available for this record.
Jonathan Katz, Vladimir Kolesnikov, Xiao Wang
Recent work, including ZKBoo, ZKB++, and Ligero, has developed efficient non-interactive zero-knowledge proofs of knowledge (NIZKPoKs) for Boolean circuits based on symmetric-key primitives alone, using the "MPC-in-the-head" paradigm of Ishai et al. We show how to instantiate this paradigm with MPC protocols in the preprocessing model; once optimized, this results in an NIZKPoK with shorter proofs (and comparable computation) as in prior work for circuits containing roughly 300--100,000 AND~gates. In contrast to prior work, our NIZKPoK also supports witness-independent preprocessing, which allows the prover to shift most of its work to an offline phase before the witness is known. We use our NIZKPoK to construct a signature scheme based only on symmetric-key primitives (and hence with "post-quantum" security). The resulting scheme has shorter signatures than the scheme built using ZKB++ (and comparable signing/verification time), and is even competitive with hash-based signature schemes. To further highlight the flexibility and power of our NIZKPoK, we also use it to build efficient ring and group signatures based on symmetric-key primitives alone. To our knowledge, the resulting schemes are the most efficient constructions of these primitives that offer post-quantum security.
Parthajit Roy
No abstract is available for this record.
Hafsa Assidi, Edoukou Berenger Ayebie, El Mamoun Souidi
No abstract is available for this record.
Christopher Carr, Anamaria Costache, Gareth T. Davies, Kristian Gjøsteen · 5 authors
No abstract is available for this record.
Ivan Damgård, Ji Luo, Sabine Oechsner, Peter Schöll · 5 authors
No abstract is available for this record.
Howard Wu, Wenting Zheng, Alessandro Chiesa, Raluca Ada Popa · 5 authors
No abstract is available for this record.
Nils Fleischhacker, Vipul Goyal, Abhishek Jain
We study the round complexity of zero-knowledge (ZK) proof systems. While five round ZK proofs for \({\mathsf {NP}}\) are known from standard assumptions [Goldreich-Kahan, J. Cryptology’96], Katz [TCC’08] proved that four rounds are insufficient for this task w.r.t. black-box simulation. In this work, we study the feasibility of ZK proofs using non-black-box simulation. Our main result is that three round private-coin ZK proofs for \({\mathsf {NP}}\) do not exist (even w.r.t. non-black-box simulation), under certain assumptions on program obfuscation. Our approach builds upon the recent work of Kalai et al. [Crypto’17] who ruled out constant round public-coin ZK proofs under the same assumptions as ours.
Tatsuya Sasaki, Takaaki Mizuki, Hideaki Sone
In 2009, Gradwohl, Naor, Pinkas, and Rothblum proposed physical zero-knowledge proof protocols for Sudoku. That is, for a puzzle instance of Sudoku, their excellent protocols allow a prover to convince a verifier that there is a solution to the Sudoku puzzle and that he/she knows it, without revealing any information about the solution. The possible drawback is that the existing protocols have a soundness error with a non-zero probability or need special cards (such as scratch-off cards). Thus, in this study, we propose new protocols to perform zero-knowledge proof for Sudoku that use a normal deck of playing cards and have no soundness error. Our protocols can be easily implemented by humans with a reasonable number of playing cards.
David Derler, Sebastian Ramacher, Daniel Slamanig
No abstract is available for this record.
Jonathan Bootle, Andrea Cerulli, Jens Groth, S. Jakobsen · 5 authors
No abstract is available for this record.
Rafaël del Pino, Vadim Lyubashevsky, Gregor Seiler
We present a group signature scheme, based on the hardness of lattice problems, whose outputs are more than an order of magnitude smaller than the currently most efficient schemes in the literature. Since lattice-based schemes are also usually non-trivial to efficiently implement, we additionally provide the first experimental implementation of lattice-based group signatures demonstrating that our construction is indeed practical -- all operations take less than half a second on a standard laptop. A key component of our construction is a new zero-knowledge proof system for proving that a committed value belongs to a particular set of small size. The sets for which our proofs are applicable are exactly those that contain elements that remain stable under Galois automorphisms of the underlying cyclotomic number field of our lattice-based protocol. We believe that these proofs will find applications in other settings as well. The motivation of the new zero-knowledge proof in our construction is to allow the efficient use of the selectively-secure signature scheme (i.e. a signature scheme in which the adversary declares the forgery message before seeing the public key) of Agrawal et al. (Eurocrypt 2010) in constructions of lattice-based group signatures and other privacy protocols. For selectively-secure schemes to be meaningfully converted to standard signature schemes, it is crucial that the size of the message space is not too large. Using our zero-knowledge proofs, we can strategically pick small sets for which we can provide efficient zero-knowledge proofs of membership.
Xavier Bultel, Jannik Dreier, Jean‐Guillaume Dumas, Pascal Lafourcade · 10 authors
No abstract is available for this record.