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Information-theoretic security with asymmetries

Authors:
Tim Beyne , COSIC, KU Leuven, Leuven, Belgium
Yu Long Chen , COSIC, KU Leuven, Leuven, Belgium
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Conference: CRYPTO 2024
Abstract: In this paper, we study the problem of lower bounding any given cost function depending on the false positive and false negative probabilities of adversaries against indistinguishability security notions in symmetric-key cryptography. We take the cost model as an input, so that this becomes a purely information-theoretical question. We propose power bounds as an easy-to-use alternative for advantage bounds in the context of indistinguishability with asymmetric cost functions. We show that standard proof techniques such as hybrid arguments and the H-coefficient method can be generalized to the power model, and apply these techniques to the PRP-PRF switching lemma, the Even-Mansour (EM) construction, and the sum-of-permutations (SoP) construction. As the final and perhaps most useful contribution, we provide two methods to convert single-user power bounds into multi-user power bounds, and investigate their relation to the point-wise proximity method of Hoang and Tessaro (Crypto 2016). These method are applied to obtain tight multi-user power bounds for EM and SoP.
BibTeX
@inproceedings{crypto-2024-34361,
  title={Information-theoretic security with asymmetries},
  publisher={Springer-Verlag},
  author={Tim Beyne and Yu Long Chen},
  year=2024
}