Paper 2020/1425

Public-Coin Zero-Knowledge Arguments with (almost) Minimal Time and Space Overheads

Alexander R. Block, Justin Holmgren, Alon Rosen, Ron D. Rothblum, and Pratik Soni

Abstract

Zero-knowledge protocols enable the truth of a mathematical statement to be certified by a verifier without revealing any other information. Such protocols are a cornerstone of modern cryptography and recently are becoming more and more practical. However, a major bottleneck in deployment is the efficiency of the prover and, in particular, the space-efficiency of the protocol. For every $\mathsf{NP}$ relation that can be verified in time $T$ and space $S$, we construct a public-coin zero-knowledge argument in which the prover runs in time $T \cdot \mathrm{polylog}(T)$ and space $S \cdot \mathrm{polylog}(T)$. Our proofs have length $\mathrm{polylog}(T)$ and the verifier runs in time $T \cdot \mathrm{polylog}(T)$ (and space $\mathrm{polylog}(T)$$. Our scheme is in the random oracle model and relies on the hardness of discrete log in prime-order groups. Our main technical contribution is a new space efficient polynomial commitment scheme for multi-linear polynomials. Recall that in such a scheme, a sender commits to a given multi-linear polynomial $P \colon \mathbb{F}^n \rightarrow \mathbb{F}$ so that later on it can prove to a receiver statements of the form "$P(x) = y$". In our scheme, which builds on the commitment schemes of Bootle et al. (Eurocrypt 2016) and Bünz et al. (S&P 2018), we assume that the sender is given multi-pass streaming access to the evaluations of $P$ on the Boolean hypercube and w show how to implement both the sender and receiver in roughly time $2^n$ and space $n$ and with communication complexity roughly $n$.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published by the IACR in TCC 2020
Keywords
zero knowledgeSNARKsspace efficiency
Contact author(s)
block9 @ purdue edu
History
2020-11-15: received
Short URL
https://ia.cr/2020/1425
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2020/1425,
      author = {Alexander R.  Block and Justin Holmgren and Alon Rosen and Ron D.  Rothblum and Pratik Soni},
      title = {Public-Coin Zero-Knowledge Arguments with (almost) Minimal Time and Space Overheads},
      howpublished = {Cryptology ePrint Archive, Paper 2020/1425},
      year = {2020},
      note = {\url{https://eprint.iacr.org/2020/1425}},
      url = {https://eprint.iacr.org/2020/1425}
}
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