### Black-Box Concurrent Zero-Knowledge Requires $\tilde\Omega(\log n)$ Rounds

Ran Canetti, Joe Kilian, Erez Petrank, and Alon Rosen

##### Abstract

We show that any concurrent zero-knowledge protocol for a non-trivial language (i.e., for a language outside $\BPP$), whose security is proven via black-box simulation, must use at least $\tilde\Omega(\log n)$ rounds of interaction. This result achieves a substantial improvement over previous lower bounds, and is the first bound to rule out the possibility of constant-round concurrent zero-knowledge when proven via black-box simulation. Furthermore, the bound is polynomially related to the number of rounds in the best known concurrent zero-knowledge protocol for languages in $\NP$.

Available format(s)
Category
Cryptographic protocols
Publication info
Published elsewhere. An extended abstract to appear in STOC01
Keywords
zero-knowledge
Contact author(s)
alon @ wisdom weizmann ac il
History
Short URL
https://ia.cr/2001/051

CC BY

BibTeX

@misc{cryptoeprint:2001/051,
author = {Ran Canetti and Joe Kilian and Erez Petrank and Alon Rosen},
title = {Black-Box Concurrent Zero-Knowledge Requires $\tilde\Omega(\log n)$ Rounds},
howpublished = {Cryptology ePrint Archive, Paper 2001/051},
year = {2001},
note = {\url{https://eprint.iacr.org/2001/051}},
url = {https://eprint.iacr.org/2001/051}
}

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