Practical Asynchronous Distributed Key Generation: Improved Efficiency, Weaker Assumption, and Standard Model

Haibin Zhang, Sisi Duan*, Chao Liu*, Boxin Zhao*, Xuanji Meng, Shengli Liu, Yong Yu, Fangguo Zhang, Liehuang Zhu*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Citations (Scopus)

Abstract

Distributed key generation (DKG) allows bootstrapping threshold cryptosystems without relying on a trusted party, nowadays enabling fully decentralized applications in blockchains and multiparty computation (MPC). While we have recently seen new advancements for asynchronous DKG (ADKG) protocols, their performance remains the bottleneck for many applications, with only one protocol being implemented (DYX+ ADKG, IEEE S&P 2022). DYX+ ADKG relies on the Decisional Composite Residuosity assumption (being expensive to instantiate) and the Decisional Diffie-Hellman assumption, incurring a high latency (more than 100s with a failure threshold of 16). Moreover, the security of DYX+ ADKG is based on the random oracle model (ROM) which takes hash function as an ideal function; assuming the existence of random oracle is a strong assumption, and up to now, we cannot find any theoretically-sound implementation. Furthermore, the ADKG protocol needs public key infrastructure (PKI) to support the trustworthiness of public keys. The strong models (ROM and PKI) further limit the applicability of DYX+ ADKG, as they would add extra and strong assumptions to underlying threshold cryptosystems. For instance, if the original threshold cryptosystem works in the standard model, then the system using DYX+ ADKG would need to use ROM and PKI. In this paper, we design and implement a modular ADKG protocol that offers improved efficiency and stronger security guarantees. We explore a novel and much more direct reduction from ADKG to the underlying blocks, reducing the computational overhead and communication rounds of ADKG in the normal case. Our protocol works for both the low-threshold and high-threshold scenarios, being secure under the standard assumption (the well-established discrete logarithm assumption only) in the standard model (no trusted setup, ROM, or PKI).

Original languageEnglish
Title of host publicationProceedings - 2023 53rd Annual IEEE/IFIP International Conference on Dependable Systems and Networks, DSN 2023
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages568-581
Number of pages14
ISBN (Electronic)9798350347937
DOIs
Publication statusPublished - 2023
Event53rd Annual IEEE/IFIP International Conference on Dependable Systems and Networks, DSN 2023 - Porto, Portugal
Duration: 27 Jun 202330 Jun 2023

Publication series

NameProceedings - 2023 53rd Annual IEEE/IFIP International Conference on Dependable Systems and Networks, DSN 2023

Conference

Conference53rd Annual IEEE/IFIP International Conference on Dependable Systems and Networks, DSN 2023
Country/TerritoryPortugal
CityPorto
Period27/06/2330/06/23

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