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Provable security against decryption failure attacks from LWE

Authors:
Christian Majenz , Danmarks Tekniske Universitet
Fabrizio Sisinni , Danmarks Tekniske Universitet
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Conference: CRYPTO 2024
Abstract: In a recent work, Hövelmanns, Hülsing and Majenz introduced a new security proof for the Fujisaki-Okamoto transform in the quantum-accessible random oracle model (QROM) used in post-quantum key encapsulation mechanisms. While having a smaller security loss due to decryption failures present in many constructions, it requires two new security properties of the underlying public-key encryption scheme (PKE). In this work, we show that one of the properties, Find Non-Generically Failing Plaintexts (FFP-NG) security, is achievable using an efficient lattice-based PKE that does not have perfect correctness. In particular, we show that LWE reduces to breaking FFP-NG security of the PVW scheme, when all LWE errors are discrete Gaussian distributed. The reduction has an arbitrarily small constant multiplicative loss in LWE error size. For the proof, we make use of techniques by Genise, Micciancio, Peikert and Walter to analyse marginal and conditional distributions of sums of discrete Gaussians.
BibTeX
@inproceedings{crypto-2024-34165,
  title={Provable security against decryption failure attacks from LWE},
  publisher={Springer-Verlag},
  author={Christian Majenz and Fabrizio Sisinni},
  year=2024
}