Quantum Indistinguishability of random sponges

Jan Czajkowski, Andreas Hülsing, Christian Schaffner

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

In this work we show that the sponge construction can be used to construct quantum-secure pseudorandom functions. As our main result we prove that random sponges are quantum indistinguishable from random functions. In this setting the adversary is given superposition access to the input-output behavior of the construction but not to the internal function. Our proofs hold under the assumption that the internal function is a random function or permutation. We then use this result to obtain a quantum-security version of a result by Andreeva, Daemen, Mennink, and Van Assche (FSE’15) which shows that a sponge that uses a secure PRP or PRF as internal function is a secure PRF. This result also proves that the recent attacks against CBC-MAC in the quantum-access model by Kaplan, Leurent, Leverrier, and Naya-Plasencia (Crypto’16) and Santoli, and Schaffner (QIC’16) can be prevented by introducing a state with a non-trivial inner part. The proof of our main result is derived by analyzing the joint distribution of any q input-output pairs. Our method analyzes the statistical behavior of the considered construction in great detail. The used techniques might prove useful in future analysis of different cryptographic primitives considering quantum adversaries. Using Zhandry’s PRF/PRP switching lemma we then obtain that quantum indistinguishability also holds if the internal block function is a random permutation.

Original languageEnglish
Title of host publicationAdvances in Cryptology – CRYPTO 2019 - 39th Annual International Cryptology Conference, Proceedings
EditorsAlexandra Boldyreva, Daniele Micciancio
Place of PublicationCham
PublisherSpringer
Pages296-325
Number of pages30
ISBN (Electronic)978-3-030-26951-7
ISBN (Print)978-3-030-26950-0
DOIs
Publication statusPublished - 1 Jan 2019
Event39th Annual International Cryptology Conference, CRYPTO 2019 - Santa Barbara, United States
Duration: 18 Aug 201922 Aug 2019

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume11693 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference39th Annual International Cryptology Conference, CRYPTO 2019
CountryUnited States
CitySanta Barbara
Period18/08/1922/08/19

Keywords

  • Indistinguishability
  • Keyed sponges
  • Message-authentication codes
  • Quantum security
  • Symmetric cryptography

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