Paper 2022/1127

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

Zhelei Zhou, Zhejiang University
Bingsheng Zhang, Zhejiang University
Hong-Sheng Zhou, Virginia Commonwealth University
Kui Ren, Zhejiang University

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 \emph{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 \emph{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.

Available format(s)
Cryptographic protocols
Publication info
A minor revision of an IACR publication in ASIACRYPT 2022
GUC Global random oralces Commitment
Contact author(s)
zl_zhou @ zju edu cn
bingsheng @ zju edu cn
hszhou @ vcu edu
kuiren @ zju edu cn
2022-09-30: last of 2 revisions
2022-08-30: received
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Creative Commons Attribution-NonCommercial


      author = {Zhelei Zhou and Bingsheng Zhang and Hong-Sheng Zhou and Kui Ren},
      title = {GUC-Secure Commitments via Random Oracles: New Impossibility and Feasibility},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1127},
      year = {2022},
      note = {\url{}},
      url = {}
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