Paper 2012/634 Original: eprint.iacr.org/2012/634 ↗
Cryptanalysis of Double-Block-Length Hash Mode MJH
Abstract
A double-block-length (DBL) hash mode of block ciphers, MJH has been proved to be collision-resistant in the ideal cipher model upto $2^{2n/3- \log n}$ queries. In this paper we provide first cryptanalytic results for MJH. We show that a collision attack on MJH has the time complexity below the birthday bound. When block ciphers with 128-bit blocks are used, it has time complexity around $2^{124}$, which is to be compared to the birthday attack having complexity $2^{128}$. We also give a preimage attack on MJH. It has the time complexity of $2^{3n/2+1}$ with $n$-bit block ciphers, which is to be compared to the brute force attack having complexity $2^{2n}$.
Metadata
- Available format(s)
PDF- Category
- Secret-key cryptography
- Publication info
- Preprint.
- History
- 2012-11-11: last updated
- 2012-11-11: published
- Short URL
- https://ia.cr/2012/634
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2012/634,
author = {Deukjo Hong and Daesung Kwon},
title = {Cryptanalysis of Double-Block-Length Hash Mode MJH},
howpublished = {Cryptology {ePrint} Archive, Paper 2012/634},
year = {2012},
url = {https://eprint.iacr.org/2012/634}
}