Paper 2017/925
ResettablySound Resettable Zero Knowledge in Constant Rounds
Wutichai Chongchitmate, Rafail Ostrovsky, and Ivan Visconti
Abstract
In FOCS 2001 Barak et al. conjectured the existence of zeroknowledge arguments that remain secure against resetting provers and resetting verifiers. The conjecture was proven true by Deng et al. in FOCS 2009 under various complexity assumptions and requiring a polynomial number of rounds. Later on in FOCS 2013 Chung et al. improved the assumptions requiring oneway functions only but still with a polynomial number of rounds. In this work we show a constantround resettablysound resettable zeroknowledge argument system, therefore improving the round complexity from polynomial to constant. We obtain this result through the following steps. 1. We show an explicit transform from any $\ell$round concurrent zeroknowledge argument system into an $O(\ell)$round resettable zeroknowledge argument system. The transform is based on techniques proposed by Barak et al. in FOCS 2001 and by Deng et al. in FOCS 2009. Then, we make use of a recent breakthrough presented by Chung et al. in CRYPTO 2015 that solved the longstanding open question of constructing a constantround concurrent zeroknowledge argument system from plausible polynomialtime hardness assumptions. Starting with their construction $\Gamma$ we obtain a constantround resettable zeroknowledge argument system $\Lambda$. 2. We then show that by carefully embedding $\Lambda$ inside $\Gamma$ (i.e., essentially by playing a modification of the construction of Chung et al. against the construction of Chung et al.) we obtain the first constantround resettablysound concurrent zeroknowledge argument system $\Delta$. 3. Finally, we apply a transformation due to Deng et al. to $\Delta$ obtaining a resettablysound resettable zeroknowledge argument system $\Pi$, the main result of this work. While our roundpreserving transform for resettable zero knowledge requires oneway functions only, both $\Lambda, \Delta$ and $\Pi$ extend the work of Chung et al. and as such they rely on the same assumptions (i.e., families of collisionresistant hash functions, oneway permutations and indistinguishability obfuscation for P/poly, with slightly superpolynomial security).
Metadata
 Available format(s)
 Category
 Cryptographic protocols
 Publication info
 Published by the IACR in TCC 2017
 Keywords
 zero knowledgeresettable ZKresettable soundnessconstantRoundindistinguishability obfuscation
 Contact author(s)
 wutichai @ cs ucla edu
 History
 20170924: received
 Short URL
 https://ia.cr/2017/925
 License

CC BY
BibTeX
@misc{cryptoeprint:2017/925, author = {Wutichai Chongchitmate and Rafail Ostrovsky and Ivan Visconti}, title = {ResettablySound Resettable Zero Knowledge in Constant Rounds}, howpublished = {Cryptology ePrint Archive, Paper 2017/925}, year = {2017}, note = {\url{https://eprint.iacr.org/2017/925}}, url = {https://eprint.iacr.org/2017/925} }