International Association for Cryptologic Research

International Association
for Cryptologic Research

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Paper: GUC-Secure Commitments via Random Oracles: New Impossibility and Feasibility

Authors:
Zhelei Zhou , Zhejiang University
Bingsheng Zhang , Zhejiang University
Hong-Sheng Zhou , Virginia Commonwealth University
Kui Ren , Zhejiang University
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Conference: ASIACRYPT 2022
Abstract: In the UC framework, protocols must be subroutine respecting; therefore, shared trusted setup might cause security issues. To address this drawback, Generalized UC (GUC) framework is introduced by Canetti {\em et al.} (TCC 2007). In this work, we investigate the impossibility and feasibility of GUC-secure commitments using global random oracles (GRO) as the trusted setup. In particular, we show that it is impossible to have a 2-round (1-round committing and 1-round opening) GUC-secure commitment in the global observable RO model by Canetti {\em et al.} (CCS 2014). We then give a new round-optimal GUC-secure commitment that uses only Minicrypt assumptions (i.e. the existence of one-way functions) in the global observable RO model. Furthermore, we also examine the complete picture on round complexity of the GUC-secure commitments in various global RO models.
BibTeX
@inproceedings{asiacrypt-2022-32632,
  title={GUC-Secure Commitments via Random Oracles: New Impossibility and Feasibility},
  publisher={Springer-Verlag},
  author={Zhelei Zhou and Bingsheng Zhang and Hong-Sheng Zhou and Kui Ren},
  year=2022
}