Paper 2008/499 Original: eprint.iacr.org/2008/499 ↗
Some Observations on HC-128
Abstract
In this paper, we use linear approximations of the addition modulo $2^n$ of three $n$-bit integers to identify linear approximations of $g_1, g_2$, the feedback functions of HC-128. This, in turn, shows that the process of keystream output generation of HC-128 can be well approximated by linear functions. In this direction, we show that the ``least significant bit" based distinguisher (presented by the designer himself) of HC-128 works for the complete 32-bit word. In a different note, in the line of Dunkelman's observation, we also study how HC-128 keystream words leak secret state information of the cipher due to the properties of the functions $h_1, h_2$ and present improved results.
Metadata
- Available format(s)
PDF- Publication info
- Preprint.
- History
- 2011-11-16: last updated
- 2008-12-02: published
- Short URL
- https://ia.cr/2008/499
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2008/499,
author = {Subhamoy Maitra and Goutam Paul and Shashwat Raizada},
title = {Some Observations on HC-128},
howpublished = {Cryptology {ePrint} Archive, Paper 2008/499},
year = {2008},
url = {https://eprint.iacr.org/2008/499}
}