CryptoDB
Single-Input Functionality against a Dishonest Majority: Practical and Round-Optimal
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| Conference: | PKC 2025 |
| Abstract: | In this work, we focus on Single-Input Functionality (SIF), a specialized case of MPC where only one designated party, called the dealer, holds a private input. SIF enables the dealer to perform computations with other parties without disclosing any additional information about the private input. SIF has a wide range of applications, such as multiple-verifier zero-knowledge and verifiable relation sharing. We propose the \emph{first} 1-round SIF protocol against a dishonest majority in the preprocessing model, achieving high efficiency. Previous works either require at least 2-round online communication (Yang and Wang, Asiacrypt 2022; Baum et al., CCS 2022; Zhou et al., Euro S\&P 2024) or are limited to feasibility results (Lepinski et al., TCC 2005; Applebaum et al., Crypto 2022). We also show the necessity of using the broadcast channels, by formally proving that 1-round SIF is \emph{impossible} to achieve in the preprocessing model, if there are no broadcast channels available. Finally, we implement our protocol and present extensive experimental results, demonstrating its practical efficiency. |
BibTeX
@inproceedings{pkc-2025-34980,
title={Single-Input Functionality against a Dishonest Majority: Practical and Round-Optimal},
publisher={Springer-Verlag},
author={Zhelei Zhou and Bingsheng Zhang and Hong-Sheng Zhou and Kui Ren},
year=2025
}