### Tight Parallel Repetition Theorems for Public-Coin Arguments using KL-divergence

Kai-Min Chung and Rafael Pass

##### Abstract

We present a new and conceptually simpler proof of a tight parallel-repetition theorem for public-coin arguments (Pass-Venkitasubramaniam, STOC'07, Hastad et al, TCC'10, Chung-Liu, TCC'10). We follow the same proof framework as the previous non-tight parallel-repetition theorem of Hastad et al---which relied on *statistical distance* to measure the distance between experiments---and show that it can be made tight (and further simplied) if instead relying on *KL-divergence* as the distance between the experiments. We then show that our proof technique directly yields tight Chernoff-type'' parallel-repetition theorems (where one considers a threshold'' verifier that accepts iff the prover manages to convince a certain fraction of the parallel verifiers, as opposed to all of them) for any public-coin interactive argument; previously, tight results were only known for either constant-round protocols, or when the gap between the threshold and the original error-probability is a constant.

Available format(s)
Category
Foundations
Publication info
Keywords
parallel repetitionpublic coininteractive argumentscomputationally sound proofsKL divergence
Contact author(s)
kmchung @ iis sinica edu tw
History
Short URL
https://ia.cr/2015/031

CC BY

BibTeX

@misc{cryptoeprint:2015/031,
author = {Kai-Min Chung and Rafael Pass},
title = {Tight Parallel Repetition Theorems for Public-Coin Arguments using KL-divergence},
howpublished = {Cryptology ePrint Archive, Paper 2015/031},
year = {2015},
note = {\url{https://eprint.iacr.org/2015/031}},
url = {https://eprint.iacr.org/2015/031}
}

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