@inproceedings{c9ffc13777ca4f609b28b79d65d312d4,
title = "MHz2k: MPC from HE over Z2k with New Packing, Simpler Reshare, and Better ZKP",
abstract = "We propose a multi-party computation (MPC) protocol over Z2k secure against actively corrupted majority from somewhat homomorphic encryption. The main technical contributions are: (i) a new efficient packing method for Z2k -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 Z[ X] / ΦM(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 Z2k considerably, but also provide a toolkit that can be leveraged when designing other cryptographic primitives over Z2k.",
keywords = "Dishonest majority, Homomorphic encryption, Multi-party computation, Packing method, Z, Zero-knowledge proof",
author = "Cheon, {Jung Hee} and Dongwoo Kim and Keewoo Lee",
note = "Publisher Copyright: {\textcopyright} 2021, International Association for Cryptologic Research.; 41st Annual International Cryptology Conference, CRYPTO 2021 ; Conference date: 16-08-2021 Through 20-08-2021",
year = "2021",
doi = "10.1007/978-3-030-84245-1_15",
language = "English",
isbn = "9783030842444",
series = "Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)",
publisher = "Springer Science and Business Media Deutschland GmbH",
pages = "426--456",
editor = "Tal Malkin and Chris Peikert",
booktitle = "Advances in Cryptology – CRYPTO 2021 - 41st Annual International Cryptology Conference, CRYPTO 2021, Proceedings",
address = "Germany",
}