Non-malleable commitments are a central cryptographic primitive that guarantee security against man-in-the-middle adversaries, and their exact round complexity has been a subject of great interest. Pass (TCC 2013, CC 2016) proved that non-malleable commitments with respect to commitment are impossible to construct in less than three rounds, via black-box reductions to polynomial hardness assumptions. Obtaining a matching positive result has remained an open problem so far. While three-round constructions of non-malleable commitments have been achieved, beginning with the work of Goyal, Pandey and Richelson (STOC 2016), current constructions require super-polynomial assumptions. In this work, we settle the question of whether three-round non-malleable commitments can be based on polynomial hardness assumptions. We give constructions based on polynomial hardness of ZAPs, as well as one out of DDH/QR/ Nth residuosity. Our protocols also satisfy concurrent non-malleability.
CITATION STYLE
Khurana, D. (2017). Round optimal concurrent non-malleability from polynomial hardness. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 10678 LNCS, pp. 139–171). Springer Verlag. https://doi.org/10.1007/978-3-319-70503-3_5
Mendeley helps you to discover research relevant for your work.