Paper 2024/658

Information-theoretic security with asymmetries

Tim Beyne, imec-COSIC, KU Leuven
Yu Long Chen, imec-COSIC, KU Leuven

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.

Available format(s)
Secret-key cryptography
Publication info
Published by the IACR in CRYPTO 2024
Information theoretic securityAsymmetrical statistical costsPower boundsMulti-user security
Contact author(s)
tim beyne @ esat kuleuven be
yulong chen @ esat kuleuven be
2024-06-07: revised
2024-04-29: received
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      author = {Tim Beyne and Yu Long Chen},
      title = {Information-theoretic security with asymmetries},
      howpublished = {Cryptology ePrint Archive, Paper 2024/658},
      year = {2024},
      note = {\url{}},
      url = {}
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