Paper 2021/1469 Original: eprint.iacr.org/2021/1469 ↗
New Indifferentiability Security Proof of MDPH Hash Function
Abstract
MDPH is a double-block-length hash function proposed by Naito at Latincrypt 2019.This is a combination of Hirose's compression function and the domain extender called Merkle-Damg\r{a}rd with permutation (MDP). When instantiated with an $n$-bit block cipher, Naito proved that this achieves the (nearly) optimal indifferentiable security bound of $O(n-\log n)$-bit security. In this paper, we first point out that the proof of the claim contains a gap, which is related to the definition of the simulator in simulating the decryption of the block cipher. We then show that the proof can be fixed. We introduce a new simulator that addresses the issue, showing that MDPH retains its (nearly) optimal indifferentiable security bound of $O(n-\log n)$-bit security.
Metadata
- Available format(s)
PDF- Category
- Secret-key cryptography
- Publication info
- Preprint.
- History
- 2021-11-06: last updated
- 2021-11-06: published
- Short URL
- https://ia.cr/2021/1469
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2021/1469,
author = {Chun Guo and Tetsu Iwata and Kazuhiko Minematsu},
title = {New Indifferentiability Security Proof of MDPH Hash Function},
howpublished = {Cryptology {ePrint} Archive, Paper 2021/1469},
year = {2021},
url = {https://eprint.iacr.org/2021/1469}
}