### Improved Black-Box Constructions of Composable Secure Computation

Rohit Chatterjee, Xiao Liang, and Omkant Pandey

##### Abstract

We close the gap between black-box and non-black-box constructions of $\mathit{composable}$ secure multiparty computation in the plain model under the $\mathit{minimal}$ assumption of semi-honest oblivious transfer. The notion of protocol composition we target is $\mathit{angel\text{-}based}$ security, or more precisely, security with super-polynomial helpers. In this notion, both the simulator and the adversary are given access to an oracle called an $\mathit{angel}$ that can perform some predefined super-polynomial time task. Angel-based security maintains the attractive properties of the universal composition framework while providing meaningful security guarantees in complex environments without having to trust anyone. Angel-based security can be achieved using non-black-box constructions in $\max(R_{\mathsf{OT}},\widetilde{O}(\log n))$ rounds where $R_{\mathsf{OT}}$ is the round-complexity of the semi-honest oblivious transfer. However, currently, the best known $\mathit{black\text{-}box}$ constructions under the same assumption require $\max(R_{\mathsf{OT}},\widetilde{O}(\log^2 n))$ rounds. If $R_{\mathsf{OT}}$ is a constant, the gap between non-black-box and black-box constructions can be a multiplicative factor $\log n$. We close this gap by presenting a $\max(R_{\mathsf{OT}},\widetilde{O}(\log n))$-round black-box construction. We achieve this result by constructing constant-round 1-1 CCA-secure commitments assuming only black-box access to one-way functions.

Note: Full version version of the original publication.

Available format(s)
Category
Cryptographic protocols
Publication info
Published elsewhere. MAJOR revision.The 47th International Colloquium on Automata, Languages and Programming (ICALP 2020)
Keywords
Secure Multi-Party ComputationBlack-BoxComposableNon-Malleable
Contact author(s)
rochatterjee @ cs stonybrook edu
liang1 @ cs stonybrook edu
omkant @ cs stonybrook edu
History
Short URL
https://ia.cr/2020/494

CC BY

BibTeX

@misc{cryptoeprint:2020/494,
author = {Rohit Chatterjee and Xiao Liang and Omkant Pandey},
title = {Improved Black-Box Constructions of Composable Secure Computation},
howpublished = {Cryptology ePrint Archive, Paper 2020/494},
year = {2020},
note = {\url{https://eprint.iacr.org/2020/494}},
url = {https://eprint.iacr.org/2020/494}
}

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