### Reset Indifferentiability and its Consequences

Paul Baecher, Chris Brzuska, and Arno Mittelbach

##### Abstract

The equivalence of the random-oracle model and the ideal-cipher model has been studied in a long series of results. Holenstein, Künzler, and Tessaro (STOC, 2011) have recently completed the picture positively, assuming that, roughly speaking, equivalence is indifferentiability from each other. However, under the stronger notion of reset indifferentiability this picture changes significantly, as Demay et al. (EUROCRYPT, 2013) and Luykx et al. (ePrint, 2012) demonstrate. We complement these latter works in several ways. First, we show that any simulator satisfying the reset indifferentiability notion must be stateless and pseudo deterministic. Using this characterization we show that, with respect to reset indifferentiability, two ideal models are either equivalent or incomparable, that is, a model cannot be strictly stronger than the other model. In the case of the random-oracle model and the ideal-cipher model, this implies that the two are incomparable. Finally, we examine weaker notions of reset indifferentiability that, while not being able to allow composition in general, allow composition for a large class of multi-stage games. Here we show that the seemingly much weaker notion of 1-reset indifferentiability proposed by Luykx et al. is equivalent to reset indifferentiability. Hence, the impossibility of coming up with a reset-indifferentiable construction transfers to the setting where only one reset is permitted, thereby re-opening the quest for an achievable and meaningful notion in between the two variants.

Available format(s)
Category
Foundations
Publication info
Keywords
foundationshash functionsblock ciphers
Contact author(s)
pbaecher @ gmail com
History
2013-11-29: last of 3 revisions
See all versions
Short URL
https://ia.cr/2013/459

CC BY

BibTeX

@misc{cryptoeprint:2013/459,
author = {Paul Baecher and Chris Brzuska and Arno Mittelbach},
title = {Reset Indifferentiability and its Consequences},
howpublished = {Cryptology ePrint Archive, Paper 2013/459},
year = {2013},
note = {\url{https://eprint.iacr.org/2013/459}},
url = {https://eprint.iacr.org/2013/459}
}

Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.