IACR News item: 20 February 2013
Yehuda Lindell
ePrint ReportIn this paper, we present a cut-and-choose protocol for secure computation based on garbled circuits, with security in the presence of malicious adversaries, that vastly improves on all previous protocols of this type. Concretely, for a cheating probability of at most $2^{-40}$, the best previous works send between 125 and 128 circuits. In contrast, in our protocol 40 circuits alone suffice (with some additional overhead). Asymptotically, we achieve a cheating probability of $2^{-s}$ where $s$ is the number of garbled circuits, in contrast to the previous best of $2^{-0.32s}$. We achieve this by introducing a new cut-and-choose methodology with the property that in order to cheat, \\emph{all} of the evaluated circuits must be incorrect, and not just the \\emph{majority} as in previous works.
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