CryptoDB

Paper: The role of help in Classical and Quantum Zero-Knowledge

Authors: André Chailloux Iordanis Kerenidis URL: http://eprint.iacr.org/2007/421 Search ePrint Search Google We study the role of help in Non-Interactive Zero-Knowledge protocols and its relation to the standard interactive model. In the classical case, we show that help and interaction are equivalent, answering an open question of Ben-Or and Gutfreund (\cite{BG03}). This implies a new complete problem for the class SZK, the Image Intersection Density. For this problem, we also prove a polarization lemma which is stronger than the previously known one. In the quantum setting, we define the notion of quantum help and show in a more direct way that help and interaction are again equivalent. Moreover, we define quantum Non-Interactive Zero-Knowledge with classical help and prove that it is equal to the class of languages that have classical honest-Verifier Zero Knowledge protocols secure against quantum Verifiers (\cite{Wat06, HKSZ07}). Last, we provide new complete problems for all these quantum classes. Similar results were independently discovered by Dragos Florin Ciocan and Salil Vadhan.
BibTeX
@misc{eprint-2007-13701,
title={The role of help in Classical and Quantum Zero-Knowledge},
booktitle={IACR Eprint archive},
keywords={cryptographic protocols / cryptography, zero knowledge protocols, help model, quantum},
url={http://eprint.iacr.org/2007/421},
note={ andre.chailloux@ens-lyon.fr 13826 received 9 Nov 2007},
author={André Chailloux and Iordanis Kerenidis},
year=2007
}