In FOCS 2001 Barak et al. conjectured the existence of zero-knowledge 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 one-way functions only but still with a polynomial number of rounds. In this work we show a constant-round resettably-sound resettable zero-knowledge 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 â -round concurrent zero-knowledge argument system into an O(â ) -round resettable zero-knowledge 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 constant-round concurrent zero-knowledge argument system from plausible polynomial-time hardness assumptions. Starting with their construction Î we obtain a constant-round resettable zero-knowledge argument system Î .2.We then show that by carefully embedding Î inside Î (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 constant-round resettably-sound concurrent zero-knowledge argument system Î .3.Finally, we apply a transformation due to Deng et al. to Î obtaining a resettably-sound resettable zero-knowledge argument system Î , the main result of this work. While our round-preserving transform for resettable zero knowledge requires one-way functions only, both Î , Î and Î extend the work of Chung et al. and as such they rely on the same assumptions (i.e., families of collision-resistant hash functions, one-way permutations and indistinguishability obfuscation for P/ poly, with slightly super-polynomial security).
Resettably-sound resettable zero knowledge in constant rounds / Chongchitmate, Wutichai; Ostrovsky, Rafail; Visconti, Ivan. - 10678:(2017), pp. 111-138. (Intervento presentato al convegno 15th International Conference on Theory of Cryptography, TCC 2017 tenutosi a usa) [10.1007/978-3-319-70503-3_4].
Resettably-sound resettable zero knowledge in constant rounds
Visconti, Ivan
2017
Abstract
In FOCS 2001 Barak et al. conjectured the existence of zero-knowledge 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 one-way functions only but still with a polynomial number of rounds. In this work we show a constant-round resettably-sound resettable zero-knowledge 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 â -round concurrent zero-knowledge argument system into an O(â ) -round resettable zero-knowledge 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 constant-round concurrent zero-knowledge argument system from plausible polynomial-time hardness assumptions. Starting with their construction Î we obtain a constant-round resettable zero-knowledge argument system Î .2.We then show that by carefully embedding Î inside Î (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 constant-round resettably-sound concurrent zero-knowledge argument system Î .3.Finally, we apply a transformation due to Deng et al. to Î obtaining a resettably-sound resettable zero-knowledge argument system Î , the main result of this work. While our round-preserving transform for resettable zero knowledge requires one-way functions only, both Î , Î and Î extend the work of Chung et al. and as such they rely on the same assumptions (i.e., families of collision-resistant hash functions, one-way permutations and indistinguishability obfuscation for P/ poly, with slightly super-polynomial security).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.