### Tight Quantum Indifferentiability of a Rate-1/3 Compression Function

Jan Czajkowski

##### Abstract

We prove classical and quantum indifferentiability of a rate-1/3 compression function introduced by Shrimpton and Stam (ICALP '08). This construction was one of the first constructions based on three random functions that achieved optimal collision-resistance. We also prove that our result is tight, we define a classical and a quantum attackers that match the indifferentiability security level. Our tight indifferentiability results provide a negative result on the optimality of security of the construction by Shrimpton and Stam, security level of the strong indifferentiability notion is below that of collision-resistance. To arrive at these results, we generalize the results of Czajkowski, Majenz, Schaffner, and Zur (arXiv '19). Our generalization allows to analyze quantum security of constructions based on multiple independent random functions, something not possible before.

Available format(s)
Category
Secret-key cryptography
Publication info
Preprint.
Keywords
quantum indifferentiabilitycompression functions
Contact author(s)
jan czajkowski @ weizmann ac il
History
Short URL
https://ia.cr/2021/1267

CC BY

BibTeX

@misc{cryptoeprint:2021/1267,
author = {Jan Czajkowski},
title = {Tight Quantum Indifferentiability of a Rate-1/3 Compression Function},
howpublished = {Cryptology ePrint Archive, Paper 2021/1267},
year = {2021},
note = {\url{https://eprint.iacr.org/2021/1267}},
url = {https://eprint.iacr.org/2021/1267}
}

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