Paper 2021/1383
MHz2k: MPC from HE over $\mathbb{Z}_{2^k}$ with New Packing, Simpler Reshare, and Better ZKP
Jung Hee Cheon, Dongwoo Kim, and Keewoo Lee
Abstract
We propose a multi-party computation (MPC) protocol over $\mathbb{Z}_{2^k}$ secure against actively corrupted majority from somewhat homomorphic encryption. The main technical contributions are: (i) a new efficient packing method for $\mathbb{Z}_{2^k}$-messages in lattice-based somewhat homomorphic encryption schemes, (ii) a simpler reshare protocol for level-dependent packings, (iii) a more efficient zero-knowledge proof of plaintext knowledge on cyclotomic rings $\mathbb{Z}[X]/\Phi_M(X)$ with $M$ being a prime. Integrating them, our protocol shows from 2.2x upto 4.8x improvements in amortized communication costs compared to the previous best results. Our techniques not only improve the efficiency of MPC over $\mathbb{Z}_{2^k}$ considerably, but also provide a toolkit that can be leveraged when designing other cryptographic primitives over $\mathbb{Z}_{2^k}$.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- A major revision of an IACR publication in CRYPTO 2021
- Keywords
- Multi-party computationDishonest majorityHomomorphic encryptionPacking methodZero-knowledge proof
- Contact author(s)
-
activecondor @ snu ac kr
Dongwoo Kim @ wdc com - History
- 2021-10-15: received
- Short URL
- https://ia.cr/2021/1383
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2021/1383,
author = {Jung Hee Cheon and Dongwoo Kim and Keewoo Lee},
title = {{MHz2k}: {MPC} from {HE} over $\mathbb{Z}_{2^k}$ with New Packing, Simpler Reshare, and Better {ZKP}},
howpublished = {Cryptology {ePrint} Archive, Paper 2021/1383},
year = {2021},
url = {https://eprint.iacr.org/2021/1383}
}
