### Fast Actively Secure Five-Party Computation with Security Beyond Abort

Megha Byali, Carmit Hazay, Arpita Patra, and Swati Singla

##### Abstract

Secure Multi-party Computation (MPC) with small population and honest majority has drawn focus specifically due to customization in techniques and resulting efficiency that the constructions can offer. In this work, we investigate a wide range of security notions in the five-party setting, tolerating two active corruptions. Being constant-round, our protocols are best suited for real-time, high latency networks such as the Internet. In a minimal setting of pairwise-private channels, we present efficient instantiations with unanimous abort (where either all honest parties obtain the output or none of them do) and fairness (where the adversary obtains its output only if all honest parties also receive it). With the presence of an additional broadcast channel (known to be necessary), we present a construction with guaranteed output delivery (where any adversarial behaviour cannot prevent the honest parties from receiving the output). The broadcast communication is minimal and independent of circuit size. In terms of performance (communication and run time), our protocols incur minimal overhead over the best known protocol of Chandran et al. (ACM CCS 2016) that achieves the least security notion of selective abort. Further, our protocols for fairness and unanimous abort can be extended to n-parties with at most $\sqrt{n}$ corruptions, similar to Chandran et al. Going beyond the most popular honest-majority setting of three parties with one corruption, our results demonstrate feasibility of attaining stronger security notions at an expense not too far from the least desired security of selective abort.

Available format(s)
Category
Cryptographic protocols
Publication info
Published elsewhere. Major revision.ACM CCS 2019
DOI
10.1145/3319535.3345657
Keywords
Secure Multiparty ComputationGuaranteed Output DeliveryFairnessUnanimous AbortGarbled Circuits
Contact author(s)
meghabyali @ gmail com
megha @ iisc ac in
carmit hazay @ biu ac il
arpita @ iisc ac in
swatis @ iisc ac in
History
2019-10-11: last of 4 revisions
See all versions
Short URL
https://ia.cr/2019/863

CC BY

BibTeX

@misc{cryptoeprint:2019/863,
author = {Megha Byali and Carmit Hazay and Arpita Patra and Swati Singla},
title = {Fast Actively Secure Five-Party Computation with Security Beyond Abort},
howpublished = {Cryptology ePrint Archive, Paper 2019/863},
year = {2019},
doi = {10.1145/3319535.3345657},
note = {\url{https://eprint.iacr.org/2019/863}},
url = {https://eprint.iacr.org/2019/863}
}

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