University of Oulu

Partala, J. (2021), Indifferentiable hash functions in the standard model. IET Inf. Secur, 15: 309-316.

Indifferentiable hash functions in the standard model

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Author: Partala, Juha1
Organizations: 1Center for Machine Vision and Signal Analysis, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
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Language: English
Published: Institution of Engineering and Technology, 2021
Publish Date: 2021-06-28


Indifferentiability of iterated hash functions is seen as evidence that there are no structural flaws in the iteration structure of the algorithm. However, it is often overlooked that such considerations only hold in the random oracle model and do not give any guarantee in the standard model. In this article, we show the following separation result: there is a hash function that is indifferentiable from a random oracle, but is totally insecure in the standard model. In particular, we show that it does not satisfy collision or multicollision-resistance, second preimage-resistance or preimage-resistance for any family of compression functions. Therefore, at least in theory, hash function indifferentiability does not guarantee the structural integrity of the hash algorithm in the standard model. Results in the random oracle model are not affected.

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Series: IET information security
ISSN: 1751-8709
ISSN-E: 1751-8717
ISSN-L: 1751-8709
Volume: 15
Issue: 4
Pages: 309 - 316
DOI: 10.1049/ise2.12025
Type of Publication: A1 Journal article – refereed
Field of Science: 113 Computer and information sciences
Funding: This research was conducted in a strategic research project called Personalization, Privacy and Quality Control for MaaS with Blockchain-TrustedMaaS under the focus institute Infotech Oulu, Faculty of Information Technology and Electrical Engineering (ITEE), and the University of Oulu, Finland. Furthermore, the research is supported by Academy of Finland 6Genesis Flagship [grant number: 318,927]. Declarations of interest: none.
Academy of Finland Grant Number: 318927
Detailed Information: 318927 (Academy of Finland Funding decision)
Copyright information: © 2021 The Authors. IET Information Security published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.