International Association for Cryptologic Research

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Strongly Secure Universal Thresholdizer

Authors:
Ehsan Ebrahimi , University of Luxembourg
Anshu Yadav , IST Austria
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Presentation: Slides
Conference: ASIACRYPT 2024
Abstract: A universal thresholdizer (UT), constructed from a threshold fully homomorphic encryption by Boneh et. al, Crypto 2018, is a general framework for universally thresholdizing many cryptographic schemes. However, their framework is insufficient to construct strongly secure threshold schemes, such as threshold signatures and threshold public-key encryption, etc. In this paper, we strengthen the security definition for a universal thresholdizer and propose a scheme which satisfies our stronger security notion. Our UT scheme is an improvement of Boneh et. al ’s construction in the level of threshold fully homomorphic encryption using a key homomorphic pseudorandom function. We apply our strongly secure UT scheme to construct strongly secure threshold signatures and threshold public-key encryption.
BibTeX
@inproceedings{asiacrypt-2024-34711,
  title={Strongly Secure Universal Thresholdizer},
  publisher={Springer-Verlag},
  author={Ehsan Ebrahimi and Anshu Yadav},
  year=2024
}