Paper 2021/1687

Computational Irrelevancy: Bridging the Gap between Pseudo- and Real Randomness in MPC Protocols

Nariyasu Heseri and Koji Nuida

Abstract

Due to the fact that classical computers cannot efficiently obtain random numbers, it is common practice to design cryptosystems in terms of real random numbers and then replace them with (cryptographically secure) pseudorandom ones for concrete implementations. However, as pointed out by [Nuida, PKC 2021], this technique may lead to compromise of security in secure multiparty computation (MPC) protocols. Although this work suggests using information-theoretically secure protocols and pseudorandom generators (PRGs) with high min-entropy to alleviate the problem, yet it is preferable to base the security on computational assumptions rather than the stronger information-theoretic ones. By observing that the contrived constructions in the aforementioned work use MPC protocols and PRGs that are closely related to each other, we notice that it may help to alleviate the problem by using protocols and PRGs that are "unrelated" to each other. In this paper, we propose a notion called "computational irrelevancy" to formalise the term "unrelated" and under this condition provide a security guarantee under computational assumptions.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint. MINOR revision.
Keywords
secure multiparty computationpseudorandom generatorsrelativisation
Contact author(s)
nariyasu @ g ecc u-tokyo ac jp
nuida @ imi kyushu-u ac jp
History
2022-01-20: last of 5 revisions
2021-12-30: received
See all versions
Short URL
https://ia.cr/2021/1687
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2021/1687,
      author = {Nariyasu Heseri and Koji Nuida},
      title = {Computational Irrelevancy: Bridging the Gap between Pseudo- and Real Randomness in MPC Protocols},
      howpublished = {Cryptology ePrint Archive, Paper 2021/1687},
      year = {2021},
      note = {\url{https://eprint.iacr.org/2021/1687}},
      url = {https://eprint.iacr.org/2021/1687}
}
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