Paper 2019/1372
Analyzing the Linear Keystream Biases in AEGIS
Abstract
AEGIS is one of the authenticated encryption designs selected for the final portfolio of the CAESAR competition. It combines the AES round function and simple Boolean operations to update its large state and extract a keystream to achieve an excellent software performance. In 2014, Minaud discovered slight biases in the keystream based on linear characteristics. For family member AEGIS-256, these could be exploited to undermine the confidentiality faster than generic attacks, but this still requires very large amounts of data. For final portfolio member AEGIS-128, these attacks are currently less efficient than generic attacks. We propose improved keystream approximations for the AEGIS family, but also prove upper bounds below $2^{-128}$ for the squared correlation contribution of any single suitable linear characteristic.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published by the IACR in TOSC 2020
- DOI
- 10.13154/tosc.v2019.i4.348-368
- Keywords
- Authenticated encryptionCAESARAEGISLinear cryptanalysis
- Contact author(s)
-
maria eichlseder @ iaik tugraz at
marcel nageler @ student tugraz at
rprimas @ gmail com - History
- 2024-06-07: revised
- 2019-12-01: received
- See all versions
- Short URL
- https://ia.cr/2019/1372
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2019/1372,
author = {Maria Eichlseder and Marcel Nageler and Robert Primas},
title = {Analyzing the Linear Keystream Biases in {AEGIS}},
howpublished = {Cryptology {ePrint} Archive, Paper 2019/1372},
year = {2019},
doi = {10.13154/tosc.v2019.i4.348-368},
url = {https://eprint.iacr.org/2019/1372}
}