A consequence of our result is that, in the ROM, we obtain truly efficient non malleable NIZK proof systems essentially for free. Our definitions are sufficient for instantiating the Naor-Yung paradigm for CCA2-secure encryption, as well as a generic construction for signature schemes from hard relations and simulation-extractable NIZK proof systems. These two constructions are interesting as the former preserves both the leakage resilience and key-dependent message security of the underlying CPA-secure encryption scheme, while the latter lifts the leakage resilience of the hard relation to the leakage resilience of the resulting signature scheme.
Category / Keywords: cryptographic protocols / non-malleability, NIZK, simulation soundness, random oracle model, Fiat-Shamir Publication Info: An extended abstract of this paper is published in the proceedings of the 13th International Conference on Cryptology in India, Indocrypt 2012. This is the full version. Date: received 16 Dec 2012 Contact author: giorgia marson at cased de Available format(s): PDF | BibTeX Citation Version: 20121218:130656 (All versions of this report) Discussion forum: Show discussion | Start new discussion